[PATCH v3] selinux: libselinux: Enable multiple input files to selabel_open.

[Daniel Cashman]

From: Dan Cashman <***@google.com>

The file_contexts labeling backend, specified in label_file.c, currently assumes
that only one path will be specified as an option to selabel_open(). The split
of platform and non-platform policy on device, however, will necessitate the
loading of two disparate policy files. Rather than combining the files and then
calling the existing API on a newly-formed file, just add the ability to specify
multiple files to use. Order of opt specification to selabel_open matters.

This corresponds to AOSP commit 50400d38203e4db08314168e60c281cc61a717a8, which
lead to a fork with upstream, which we'd like to correct.

Signed-off-by: Dan Cashman <***@android.com>
---
libselinux/src/label.c | 21 +++++---
libselinux/src/label_db.c | 13 ++++-
libselinux/src/label_file.c | 104 +++++++++++++++++++++++++++++-----------
libselinux/src/label_internal.h | 5 +-
libselinux/src/label_media.c | 10 +++-
libselinux/src/label_x.c | 10 +++-
6 files changed, 124 insertions(+), 39 deletions(-)

diff --git a/libselinux/src/label.c b/libselinux/src/label.c
index 48f4d2d6..0dfa054c 100644
--- a/libselinux/src/label.c
+++ b/libselinux/src/label.c
@@ -143,7 +143,11 @@ static int selabel_fini(struct selabel_handle *rec,
struct selabel_lookup_rec *lr,
int translating)
{
- if (compat_validate(rec, lr, rec->spec_file, 0))
+ char *path = NULL;
+
+ if (rec->spec_files)
+ path = rec->spec_files[0];
+ if (compat_validate(rec, lr, path, 0))
return -1;

if (translating && !lr->ctx_trans &&
@@ -226,11 +230,9 @@ struct selabel_handle *selabel_open(unsigned int backend,
rec->digest = selabel_is_digest_set(opts, nopts, rec->digest);

if ((*initfuncs[backend])(rec, opts, nopts)) {
- free(rec->spec_file);
- free(rec);
+ selabel_close(rec);
rec = NULL;
}
-
out:
return rec;
}
@@ -337,10 +339,17 @@ int selabel_digest(struct selabel_handle *rec,

void selabel_close(struct selabel_handle *rec)
{
+ size_t i;
+
+ if (rec->spec_files) {
+ for (i = 0; i < rec->spec_files_len; i++)
+ free(rec->spec_files[i]);
+ free(rec->spec_files);
+ }
if (rec->digest)
selabel_digest_fini(rec->digest);
- rec->func_close(rec);
- free(rec->spec_file);
+ if (rec->func_close)
+ rec->func_close(rec);
free(rec);
}

diff --git a/libselinux/src/label_db.c b/libselinux/src/label_db.c
index c46d0a1d..9a35abea 100644
--- a/libselinux/src/label_db.c
+++ b/libselinux/src/label_db.c
@@ -290,7 +290,18 @@ db_init(const struct selinux_opt *opts, unsigned nopts,
errno = EINVAL;
return NULL;
}
- rec->spec_file = strdup(path);
+ rec->spec_files_len = 1;
+ rec->spec_files = calloc(rec->spec_files_len, sizeof(rec->spec_files[0]));
+ if (!rec->spec_files) {
+ free(catalog);
+ return NULL;
+ }
+ rec->spec_files[0] = strdup(path);
+ if (!rec->spec_files[0]) {
+ free(catalog);
+ free(rec->spec_files);
+ return NULL;
+ }

/*
* Parse for each lines
diff --git a/libselinux/src/label_file.c b/libselinux/src/label_file.c
index 560d8c3d..b3b36bc2 100644
--- a/libselinux/src/label_file.c
+++ b/libselinux/src/label_file.c
@@ -709,28 +709,61 @@ static int init(struct selabel_handle *rec, const struct selinux_opt *opts,
unsigned n)
{
struct saved_data *data = (struct saved_data *)rec->data;
- const char *path = NULL;
+ size_t num_paths = 0;
+ char **path = NULL;
const char *prefix = NULL;
- int status = -1, baseonly = 0;
+ int status = -1;
+ size_t i;
+ bool baseonly = false;
+ bool path_provided;

/* Process arguments */
- while (n--)
- switch(opts[n].type) {
+ i = n;
+ while (i--)
+ switch(opts[i].type) {
case SELABEL_OPT_PATH:
- path = opts[n].value;
+ num_paths++;
break;
case SELABEL_OPT_SUBSET:
- prefix = opts[n].value;
+ prefix = opts[i].value;
break;
case SELABEL_OPT_BASEONLY:
- baseonly = !!opts[n].value;
+ baseonly = !!opts[i].value;
break;
}

+ if (!num_paths) {
+ num_paths = 1;
+ path_provided = false;
+ } else {
+ path_provided = true;
+ }
+
+ path = calloc(num_paths, sizeof(*path));
+ if (path == NULL) {
+ goto finish;
+ }
+ rec->spec_files = path;
+ rec->spec_files_len = num_paths;
+
+ if (path_provided) {
+ for (i = 0; i < n; i++) {
+ switch(opts[i].type) {
+ case SELABEL_OPT_PATH:
+ *path = strdup(opts[i].value);
+ if (*path == NULL)
+ goto finish;
+ path++;
+ break;
+ default:
+ break;
+ }
+ }
+ }
#if !defined(BUILD_HOST) && !defined(ANDROID)
char subs_file[PATH_MAX + 1];
/* Process local and distribution substitution files */
- if (!path) {
+ if (!path_provided) {
status = selabel_subs_init(
selinux_file_context_subs_dist_path(),
rec->digest, &data->dist_subs);
@@ -740,43 +773,52 @@ static int init(struct selabel_handle *rec, const struct selinux_opt *opts,
rec->digest, &data->subs);
if (status)
goto finish;
- path = selinux_file_context_path();
+ rec->spec_files[0] = strdup(selinux_file_context_path());
+ if (rec->spec_files[0] == NULL)
+ goto finish;
} else {
- snprintf(subs_file, sizeof(subs_file), "%s.subs_dist", path);
- status = selabel_subs_init(subs_file, rec->digest,
+ for (i = 0; i < num_paths; i++) {
+ snprintf(subs_file, sizeof(subs_file), "%s.subs_dist", rec->spec_files[i]);
+ status = selabel_subs_init(subs_file, rec->digest,
&data->dist_subs);
- if (status)
- goto finish;
- snprintf(subs_file, sizeof(subs_file), "%s.subs", path);
- status = selabel_subs_init(subs_file, rec->digest,
+ if (status)
+ goto finish;
+ snprintf(subs_file, sizeof(subs_file), "%s.subs", rec->spec_files[i]);
+ status = selabel_subs_init(subs_file, rec->digest,
&data->subs);
- if (status)
- goto finish;
+ if (status)
+ goto finish;
+ }
+ }
+#else
+ if (!path_provided) {
+ selinux_log(SELINUX_ERROR, "No path given to file labeling backend\n");
+ goto finish;
}
-
#endif
- rec->spec_file = strdup(path);

/*
- * The do detailed validation of the input and fill the spec array
+ * Do detailed validation of the input and fill the spec array
*/
- status = process_file(path, NULL, rec, prefix, rec->digest);
- if (status)
- goto finish;
-
- if (rec->validating) {
- status = nodups_specs(data, path);
+ for (i = 0; i < num_paths; i++) {
+ status = process_file(rec->spec_files[i], NULL, rec, prefix, rec->digest);
if (status)
goto finish;
+
+ if (rec->validating) {
+ status = nodups_specs(data, rec->spec_files[i]);
+ if (status)
+ goto finish;
+ }
}

if (!baseonly) {
- status = process_file(path, "homedirs", rec, prefix,
+ status = process_file(rec->spec_files[0], "homedirs", rec, prefix,
rec->digest);
if (status && errno != ENOENT)
goto finish;

- status = process_file(path, "local", rec, prefix,
+ status = process_file(rec->spec_files[0], "local", rec, prefix,
rec->digest);
if (status && errno != ENOENT)
goto finish;
@@ -804,6 +846,12 @@ static void closef(struct selabel_handle *rec)
struct stem *stem;
unsigned int i;

+ if (!data)
+ return;
+
+ /* make sure successive ->func_close() calls are harmless */
+ rec->data = NULL;
+
selabel_subs_fini(data->subs);
selabel_subs_fini(data->dist_subs);

diff --git a/libselinux/src/label_internal.h b/libselinux/src/label_internal.h
index c55efb75..43b63513 100644
--- a/libselinux/src/label_internal.h
+++ b/libselinux/src/label_internal.h
@@ -98,10 +98,11 @@ struct selabel_handle {
void *data;

/*
- * The main spec file used. Note for file contexts the local and/or
+ * The main spec file(s) used. Note for file contexts the local and/or
* homedirs could also have been used to resolve a context.
*/
- char *spec_file;
+ size_t spec_files_len;
+ char **spec_files;

/* ptr to SHA1 hash information if SELABEL_OPT_DIGEST set */
struct selabel_digest *digest;
diff --git a/libselinux/src/label_media.c b/libselinux/src/label_media.c
index d202e5d5..34260cbb 100644
--- a/libselinux/src/label_media.c
+++ b/libselinux/src/label_media.c
@@ -100,7 +100,15 @@ static int init(struct selabel_handle *rec, const struct selinux_opt *opts,
errno = EINVAL;
return -1;
}
- rec->spec_file = strdup(path);
+ rec->spec_files_len = 1;
+ rec->spec_files = calloc(rec->spec_files_len, sizeof(rec->spec_files[0]));
+ if (!rec->spec_files)
+ return -1;
+ rec->spec_files[0] = strdup(path);
+ if (!rec->spec_files[0]) {
+ free(rec->spec_files);
+ return -1;
+ }

/*
* Perform two passes over the specification file.
diff --git a/libselinux/src/label_x.c b/libselinux/src/label_x.c
index 96745299..fafe034a 100644
--- a/libselinux/src/label_x.c
+++ b/libselinux/src/label_x.c
@@ -127,7 +127,15 @@ static int init(struct selabel_handle *rec, const struct selinux_opt *opts,
errno = EINVAL;
return -1;
}
- rec->spec_file = strdup(path);
+ rec->spec_files_len = 1;
+ rec->spec_files = calloc(rec->spec_files_len, sizeof(rec->spec_files[0]));
+ if (!rec->spec_files)
+ return -1;
+ rec->spec_files[0] = strdup(path);
+ if (!rec->spec_files[0]) {
+ free(rec->spec_files);
+ return -1;
+ }

/*
* Perform two passes over the specification file.

[Stephen Smalley]

Post by Daniel Cashman
The file_contexts labeling backend, specified in label_file.c,
currently assumes
that only one path will be specified as an option to
selabel_open().  The split
of platform and non-platform policy on device, however, will
necessitate the
loading of two disparate policy files.  Rather than combining the
files and then
calling the existing API on a newly-formed file, just add the ability to specify
multiple files to use.  Order of opt specification to selabel_open
matters.
This corresponds to AOSP commit
50400d38203e4db08314168e60c281cc61a717a8, which
lead to a fork with upstream, which we'd like to correct.
---
 libselinux/src/label.c          |  21 +++++---
 libselinux/src/label_db.c       |  13 ++++-
 libselinux/src/label_file.c     | 104 +++++++++++++++++++++++++++++-
----------
 libselinux/src/label_internal.h |   5 +-
 libselinux/src/label_media.c    |  10 +++-
 libselinux/src/label_x.c        |  10 +++-
 6 files changed, 124 insertions(+), 39 deletions(-)
diff --git a/libselinux/src/label.c b/libselinux/src/label.c
index 48f4d2d6..0dfa054c 100644
--- a/libselinux/src/label.c
+++ b/libselinux/src/label.c
@@ -143,7 +143,11 @@ static int selabel_fini(struct selabel_handle *rec,
      struct selabel_lookup_rec *lr,
      int translating)
 {
- if (compat_validate(rec, lr, rec->spec_file, 0))
+ char *path = NULL;
+
+ if (rec->spec_files)
+ path = rec->spec_files[0];
+ if (compat_validate(rec, lr, path, 0))
  return -1;
 
  if (translating && !lr->ctx_trans &&
@@ -226,11 +230,9 @@ struct selabel_handle *selabel_open(unsigned int backend,
  rec->digest = selabel_is_digest_set(opts, nopts, rec-

Post by Daniel Cashman
digest);

 
  if ((*initfuncs[backend])(rec, opts, nopts)) {
- free(rec->spec_file);
- free(rec);
+ selabel_close(rec);
  rec = NULL;
  }
-
  return rec;
 }
@@ -337,10 +339,17 @@ int selabel_digest(struct selabel_handle *rec,
 
 void selabel_close(struct selabel_handle *rec)
 {
+ size_t i;
+
+ if (rec->spec_files) {
+ for (i = 0; i < rec->spec_files_len; i++)
+ free(rec->spec_files[i]);
+ free(rec->spec_files);
+ }
  if (rec->digest)
  selabel_digest_fini(rec->digest);
- rec->func_close(rec);
- free(rec->spec_file);
+ if (rec->func_close)
+ rec->func_close(rec);
  free(rec);
 }
 
diff --git a/libselinux/src/label_db.c b/libselinux/src/label_db.c
index c46d0a1d..9a35abea 100644
--- a/libselinux/src/label_db.c
+++ b/libselinux/src/label_db.c
@@ -290,7 +290,18 @@ db_init(const struct selinux_opt *opts, unsigned nopts,
  errno = EINVAL;
  return NULL;
  }
- rec->spec_file = strdup(path);
+ rec->spec_files_len = 1;
+ rec->spec_files = calloc(rec->spec_files_len, sizeof(rec-

Post by Daniel Cashman
spec_files[0]));

+ if (!rec->spec_files) {
+ free(catalog);
+ return NULL;
+ }
+ rec->spec_files[0] = strdup(path);
+ if (!rec->spec_files[0]) {
+ free(catalog);
+ free(rec->spec_files);
+ return NULL;
+ }
 
  /*
   * Parse for each lines
diff --git a/libselinux/src/label_file.c
b/libselinux/src/label_file.c
index 560d8c3d..b3b36bc2 100644
--- a/libselinux/src/label_file.c
+++ b/libselinux/src/label_file.c
@@ -709,28 +709,61 @@ static int init(struct selabel_handle *rec,
const struct selinux_opt *opts,
  unsigned n)
 {
  struct saved_data *data = (struct saved_data *)rec->data;
- const char *path = NULL;
+ size_t num_paths = 0;
+ char **path = NULL;
  const char *prefix = NULL;
- int status = -1, baseonly = 0;
+ int status = -1;
+ size_t i;
+ bool baseonly = false;
+ bool path_provided;
 
  /* Process arguments */
- while (n--)
- switch(opts[n].type) {
+ i = n;
+ while (i--)
+ switch(opts[i].type) {
- path = opts[n].value;
+ num_paths++;
  break;
- prefix = opts[n].value;
+ prefix = opts[i].value;
  break;
- baseonly = !!opts[n].value;
+ baseonly = !!opts[i].value;
  break;
  }
 
+ if (!num_paths) {
+ num_paths = 1;
+ path_provided = false;
+ } else {
+ path_provided = true;
+ }
+
+ path = calloc(num_paths, sizeof(*path));
+ if (path == NULL) {
+ goto finish;
+ }
+ rec->spec_files = path;
+ rec->spec_files_len = num_paths;
+
+ if (path_provided) {
+ for (i = 0; i < n; i++) {
+ switch(opts[i].type) {
+ *path = strdup(opts[i].value);

Perhaps surprisingly, opts[i].value can be NULL here and some callers
rely on that. After applying your patch, coreutils, selabel_lookup,
and other userspace programs all seg fault as a result. The use case
is programs where the selinux_opt structure is declared with a
SELABEL_OPT_PATH entry whose value is subsequently filled in, and left
NULL if they want to use the default path for file_contexts.
Internally, libselinux also does this from the
matchpathcon_init_prefix() function.

In any event, you need to handle this case.

Post by Daniel Cashman
+ if (*path == NULL)
+ goto finish;
+ path++;
+ break;
+ break;
+ }
+ }
+ }
 #if !defined(BUILD_HOST) && !defined(ANDROID)
  char subs_file[PATH_MAX + 1];
  /* Process local and distribution substitution files */
- if (!path) {
+ if (!path_provided) {
  status = selabel_subs_init(
  selinux_file_context_subs_dist_path(),
  rec->digest, &data->dist_subs);
@@ -740,43 +773,52 @@ static int init(struct selabel_handle *rec,
const struct selinux_opt *opts,
  rec->digest, &data->subs);
  if (status)
  goto finish;
- path = selinux_file_context_path();
+ rec->spec_files[0] =
strdup(selinux_file_context_path());
+ if (rec->spec_files[0] == NULL)
+ goto finish;
  } else {
- snprintf(subs_file, sizeof(subs_file),
"%s.subs_dist", path);
- status = selabel_subs_init(subs_file, rec->digest,
+ for (i = 0; i < num_paths; i++) {
+ snprintf(subs_file, sizeof(subs_file),
"%s.subs_dist", rec->spec_files[i]);
+ status = selabel_subs_init(subs_file, rec-

Post by Daniel Cashman
digest,

     &data->dist_subs);
- if (status)
- goto finish;
- snprintf(subs_file, sizeof(subs_file), "%s.subs",
path);
- status = selabel_subs_init(subs_file, rec->digest,
+ if (status)
+ goto finish;
+ snprintf(subs_file, sizeof(subs_file),
"%s.subs", rec->spec_files[i]);
+ status = selabel_subs_init(subs_file, rec-

Post by Daniel Cashman
digest,

     &data->subs);
- if (status)
- goto finish;
+ if (status)
+ goto finish;
+ }
+ }
+#else
+ if (!path_provided) {
+ selinux_log(SELINUX_ERROR, "No path given to file
labeling backend\n");
+ goto finish;
  }
-
 #endif
- rec->spec_file = strdup(path);
 
  /*
-  * The do detailed validation of the input and fill the spec
array
+  * Do detailed validation of the input and fill the spec
array
   */
- status = process_file(path, NULL, rec, prefix, rec->digest);
- if (status)
- goto finish;
-
- if (rec->validating) {
- status = nodups_specs(data, path);
+ for (i = 0; i < num_paths; i++) {
+ status = process_file(rec->spec_files[i], NULL, rec,
prefix, rec->digest);
  if (status)
  goto finish;
+
+ if (rec->validating) {
+ status = nodups_specs(data, rec-

Post by Daniel Cashman
spec_files[i]);

+ if (status)
+ goto finish;
+ }
  }
 
  if (!baseonly) {
- status = process_file(path, "homedirs", rec, prefix,
+ status = process_file(rec->spec_files[0],
"homedirs", rec, prefix,
      rec-

Post by Daniel Cashman
digest);

  if (status && errno != ENOENT)
  goto finish;
 
- status = process_file(path, "local", rec, prefix,
+ status = process_file(rec->spec_files[0], "local",
rec, prefix,
      rec-

Post by Daniel Cashman
digest);

  if (status && errno != ENOENT)
  goto finish;
@@ -804,6 +846,12 @@ static void closef(struct selabel_handle *rec)
  struct stem *stem;
  unsigned int i;
 
+ if (!data)
+ return;
+
+ /* make sure successive ->func_close() calls are harmless */
+ rec->data = NULL;
+
  selabel_subs_fini(data->subs);
  selabel_subs_fini(data->dist_subs);
 
diff --git a/libselinux/src/label_internal.h
b/libselinux/src/label_internal.h
index c55efb75..43b63513 100644
--- a/libselinux/src/label_internal.h
+++ b/libselinux/src/label_internal.h
@@ -98,10 +98,11 @@ struct selabel_handle {
  void *data;
 
  /*
-  * The main spec file used. Note for file contexts the local
and/or
+  * The main spec file(s) used. Note for file contexts the
local and/or
   * homedirs could also have been used to resolve a context.
   */
- char *spec_file;
+ size_t spec_files_len;
+ char **spec_files;
 
  /* ptr to SHA1 hash information if SELABEL_OPT_DIGEST set */
  struct selabel_digest *digest;
diff --git a/libselinux/src/label_media.c
b/libselinux/src/label_media.c
index d202e5d5..34260cbb 100644
--- a/libselinux/src/label_media.c
+++ b/libselinux/src/label_media.c
@@ -100,7 +100,15 @@ static int init(struct selabel_handle *rec,
const struct selinux_opt *opts,
  errno = EINVAL;
  return -1;
  }
- rec->spec_file = strdup(path);
+ rec->spec_files_len = 1;
+ rec->spec_files = calloc(rec->spec_files_len, sizeof(rec-

Post by Daniel Cashman
spec_files[0]));

+ if (!rec->spec_files)
+ return -1;
+ rec->spec_files[0] = strdup(path);
+ if (!rec->spec_files[0]) {
+ free(rec->spec_files);
+ return -1;
+ }
 
  /* 
   * Perform two passes over the specification file.
diff --git a/libselinux/src/label_x.c b/libselinux/src/label_x.c
index 96745299..fafe034a 100644
--- a/libselinux/src/label_x.c
+++ b/libselinux/src/label_x.c
@@ -127,7 +127,15 @@ static int init(struct selabel_handle *rec,
const struct selinux_opt *opts,
  errno = EINVAL;
  return -1;
  }
- rec->spec_file = strdup(path);
+ rec->spec_files_len = 1;
+ rec->spec_files = calloc(rec->spec_files_len, sizeof(rec-

Post by Daniel Cashman
spec_files[0]));

+ if (!rec->spec_files)
+ return -1;
+ rec->spec_files[0] = strdup(path);
+ if (!rec->spec_files[0]) {
+ free(rec->spec_files);
+ return -1;
+ }
 
  /* 
   * Perform two passes over the specification file.

[William Roberts]

Post by Stephen Smalley

Post by Daniel Cashman
The file_contexts labeling backend, specified in label_file.c, currently assumes
that only one path will be specified as an option to
selabel_open(). The split
of platform and non-platform policy on device, however, will
necessitate the
loading of two disparate policy files. Rather than combining the files and then
calling the existing API on a newly-formed file, just add the ability to specify
multiple files to use. Order of opt specification to selabel_open matters.
This corresponds to AOSP commit
50400d38203e4db08314168e60c281cc61a717a8, which
lead to a fork with upstream, which we'd like to correct.
---
libselinux/src/label.c | 21 +++++---
libselinux/src/label_db.c | 13 ++++-
libselinux/src/label_file.c | 104 +++++++++++++++++++++++++++++-
----------
libselinux/src/label_internal.h | 5 +-
libselinux/src/label_media.c | 10 +++-
libselinux/src/label_x.c | 10 +++-
6 files changed, 124 insertions(+), 39 deletions(-)
diff --git a/libselinux/src/label.c b/libselinux/src/label.c
index 48f4d2d6..0dfa054c 100644
--- a/libselinux/src/label.c
+++ b/libselinux/src/label.c
@@ -143,7 +143,11 @@ static int selabel_fini(struct selabel_handle *rec,
struct selabel_lookup_rec *lr,
int translating)
{
- if (compat_validate(rec, lr, rec->spec_file, 0))
+ char *path = NULL;
+
+ if (rec->spec_files)
+ path = rec->spec_files[0];
+ if (compat_validate(rec, lr, path, 0))
return -1;
if (translating && !lr->ctx_trans &&
@@ -226,11 +230,9 @@ struct selabel_handle *selabel_open(unsigned int backend,
rec->digest = selabel_is_digest_set(opts, nopts, rec-

Post by Daniel Cashman
digest);

if ((*initfuncs[backend])(rec, opts, nopts)) {
- free(rec->spec_file);
- free(rec);
+ selabel_close(rec);
rec = NULL;
}
-
return rec;
}
@@ -337,10 +339,17 @@ int selabel_digest(struct selabel_handle *rec,
void selabel_close(struct selabel_handle *rec)
{
+ size_t i;
+
+ if (rec->spec_files) {
+ for (i = 0; i < rec->spec_files_len; i++)
+ free(rec->spec_files[i]);
+ free(rec->spec_files);
+ }
if (rec->digest)
selabel_digest_fini(rec->digest);
- rec->func_close(rec);
- free(rec->spec_file);
+ if (rec->func_close)
+ rec->func_close(rec);
free(rec);
}
diff --git a/libselinux/src/label_db.c b/libselinux/src/label_db.c
index c46d0a1d..9a35abea 100644
--- a/libselinux/src/label_db.c
+++ b/libselinux/src/label_db.c
@@ -290,7 +290,18 @@ db_init(const struct selinux_opt *opts, unsigned nopts,
errno = EINVAL;
return NULL;
}
- rec->spec_file = strdup(path);
+ rec->spec_files_len = 1;
+ rec->spec_files = calloc(rec->spec_files_len, sizeof(rec-

Post by Daniel Cashman
spec_files[0]));

+ if (!rec->spec_files) {
+ free(catalog);
+ return NULL;
+ }
+ rec->spec_files[0] = strdup(path);
+ if (!rec->spec_files[0]) {
+ free(catalog);
+ free(rec->spec_files);
+ return NULL;
+ }
/*
* Parse for each lines
diff --git a/libselinux/src/label_file.c
b/libselinux/src/label_file.c
index 560d8c3d..b3b36bc2 100644
--- a/libselinux/src/label_file.c
+++ b/libselinux/src/label_file.c
@@ -709,28 +709,61 @@ static int init(struct selabel_handle *rec,
const struct selinux_opt *opts,
unsigned n)
{
struct saved_data *data = (struct saved_data *)rec->data;
- const char *path = NULL;
+ size_t num_paths = 0;
+ char **path = NULL;
const char *prefix = NULL;
- int status = -1, baseonly = 0;
+ int status = -1;
+ size_t i;
+ bool baseonly = false;
+ bool path_provided;
/* Process arguments */
- while (n--)
- switch(opts[n].type) {
+ i = n;
+ while (i--)
+ switch(opts[i].type) {
- path = opts[n].value;
+ num_paths++;
break;
- prefix = opts[n].value;
+ prefix = opts[i].value;
break;
- baseonly = !!opts[n].value;
+ baseonly = !!opts[i].value;
break;
}
+ if (!num_paths) {
+ num_paths = 1;
+ path_provided = false;
+ } else {
+ path_provided = true;
+ }
+
+ path = calloc(num_paths, sizeof(*path));
+ if (path == NULL) {
+ goto finish;
+ }
+ rec->spec_files = path;
+ rec->spec_files_len = num_paths;
+
+ if (path_provided) {
+ for (i = 0; i < n; i++) {
+ switch(opts[i].type) {
+ *path = strdup(opts[i].value);

Perhaps surprisingly, opts[i].value can be NULL here and some callers
rely on that. After applying your patch, coreutils, selabel_lookup,
and other userspace programs all seg fault as a result. The use case
is programs where the selinux_opt structure is declared with a
SELABEL_OPT_PATH entry whose value is subsequently filled in, and left
NULL if they want to use the default path for file_contexts.
Internally, libselinux also does this from the
matchpathcon_init_prefix() function.
In any event, you need to handle this case.

Poor Stephen has turned into your test bot :-)

Does any of the test suite exercise this? Maybe make a PR
on github first to get Travis to test these?

Stephen can you share with how your testing this so Dan can follow
suit?

Post by Stephen Smalley

Post by Daniel Cashman
+ if (*path == NULL)
+ goto finish;
+ path++;
+ break;
+ break;
+ }
+ }
+ }
#if !defined(BUILD_HOST) && !defined(ANDROID)
char subs_file[PATH_MAX + 1];
/* Process local and distribution substitution files */
- if (!path) {
+ if (!path_provided) {
status = selabel_subs_init(
selinux_file_context_subs_dist_path(),
rec->digest, &data->dist_subs);
@@ -740,43 +773,52 @@ static int init(struct selabel_handle *rec,
const struct selinux_opt *opts,
rec->digest, &data->subs);
if (status)
goto finish;
- path = selinux_file_context_path();
+ rec->spec_files[0] =
strdup(selinux_file_context_path());
+ if (rec->spec_files[0] == NULL)
+ goto finish;
} else {
- snprintf(subs_file, sizeof(subs_file),
"%s.subs_dist", path);
- status = selabel_subs_init(subs_file, rec->digest,
+ for (i = 0; i < num_paths; i++) {
+ snprintf(subs_file, sizeof(subs_file),
"%s.subs_dist", rec->spec_files[i]);
+ status = selabel_subs_init(subs_file, rec-

Post by Daniel Cashman
digest,

&data->dist_subs);
- if (status)
- goto finish;
- snprintf(subs_file, sizeof(subs_file), "%s.subs",
path);
- status = selabel_subs_init(subs_file, rec->digest,
+ if (status)
+ goto finish;
+ snprintf(subs_file, sizeof(subs_file),
"%s.subs", rec->spec_files[i]);
+ status = selabel_subs_init(subs_file, rec-

Post by Daniel Cashman
digest,

&data->subs);
- if (status)
- goto finish;
+ if (status)
+ goto finish;
+ }
+ }
+#else
+ if (!path_provided) {
+ selinux_log(SELINUX_ERROR, "No path given to file
labeling backend\n");
+ goto finish;
}
-
#endif
- rec->spec_file = strdup(path);
/*
- * The do detailed validation of the input and fill the spec
array
+ * Do detailed validation of the input and fill the spec
array
*/
- status = process_file(path, NULL, rec, prefix, rec->digest);
- if (status)
- goto finish;
-
- if (rec->validating) {
- status = nodups_specs(data, path);
+ for (i = 0; i < num_paths; i++) {
+ status = process_file(rec->spec_files[i], NULL, rec,
prefix, rec->digest);
if (status)
goto finish;
+
+ if (rec->validating) {
+ status = nodups_specs(data, rec-

Post by Daniel Cashman
spec_files[i]);

+ if (status)
+ goto finish;
+ }
}
if (!baseonly) {
- status = process_file(path, "homedirs", rec, prefix,
+ status = process_file(rec->spec_files[0],
"homedirs", rec, prefix,
rec-

Post by Daniel Cashman
digest);

if (status && errno != ENOENT)
goto finish;
- status = process_file(path, "local", rec, prefix,
+ status = process_file(rec->spec_files[0], "local",
rec, prefix,
rec-

Post by Daniel Cashman
digest);

if (status && errno != ENOENT)
goto finish;
@@ -804,6 +846,12 @@ static void closef(struct selabel_handle *rec)
struct stem *stem;
unsigned int i;
+ if (!data)
+ return;
+
+ /* make sure successive ->func_close() calls are harmless */
+ rec->data = NULL;
+
selabel_subs_fini(data->subs);
selabel_subs_fini(data->dist_subs);
diff --git a/libselinux/src/label_internal.h
b/libselinux/src/label_internal.h
index c55efb75..43b63513 100644
--- a/libselinux/src/label_internal.h
+++ b/libselinux/src/label_internal.h
@@ -98,10 +98,11 @@ struct selabel_handle {
void *data;
/*
- * The main spec file used. Note for file contexts the local
and/or
+ * The main spec file(s) used. Note for file contexts the
local and/or
* homedirs could also have been used to resolve a context.
*/
- char *spec_file;
+ size_t spec_files_len;
+ char **spec_files;
/* ptr to SHA1 hash information if SELABEL_OPT_DIGEST set */
struct selabel_digest *digest;
diff --git a/libselinux/src/label_media.c
b/libselinux/src/label_media.c
index d202e5d5..34260cbb 100644
--- a/libselinux/src/label_media.c
+++ b/libselinux/src/label_media.c
@@ -100,7 +100,15 @@ static int init(struct selabel_handle *rec,
const struct selinux_opt *opts,
errno = EINVAL;
return -1;
}
- rec->spec_file = strdup(path);
+ rec->spec_files_len = 1;
+ rec->spec_files = calloc(rec->spec_files_len, sizeof(rec-

Post by Daniel Cashman
spec_files[0]));

+ if (!rec->spec_files)
+ return -1;
+ rec->spec_files[0] = strdup(path);
+ if (!rec->spec_files[0]) {
+ free(rec->spec_files);
+ return -1;
+ }
/*
* Perform two passes over the specification file.
diff --git a/libselinux/src/label_x.c b/libselinux/src/label_x.c
index 96745299..fafe034a 100644
--- a/libselinux/src/label_x.c
+++ b/libselinux/src/label_x.c
@@ -127,7 +127,15 @@ static int init(struct selabel_handle *rec,
const struct selinux_opt *opts,
errno = EINVAL;
return -1;
}
- rec->spec_file = strdup(path);
+ rec->spec_files_len = 1;
+ rec->spec_files = calloc(rec->spec_files_len, sizeof(rec-

Post by Daniel Cashman
spec_files[0]));

+ if (!rec->spec_files)
+ return -1;
+ rec->spec_files[0] = strdup(path);
+ if (!rec->spec_files[0]) {
+ free(rec->spec_files);
+ return -1;
+ }
/*
* Perform two passes over the specification file.

[William Roberts]

On Thu, Oct 19, 2017 at 9:25 AM, William Roberts

Post by William Roberts

Post by Stephen Smalley

Post by Daniel Cashman
The file_contexts labeling backend, specified in label_file.c, currently assumes
that only one path will be specified as an option to
selabel_open(). The split
of platform and non-platform policy on device, however, will
necessitate the
loading of two disparate policy files. Rather than combining the files and then
calling the existing API on a newly-formed file, just add the ability to specify
multiple files to use. Order of opt specification to selabel_open matters.
This corresponds to AOSP commit
50400d38203e4db08314168e60c281cc61a717a8, which
lead to a fork with upstream, which we'd like to correct.
---
libselinux/src/label.c | 21 +++++---
libselinux/src/label_db.c | 13 ++++-
libselinux/src/label_file.c | 104 +++++++++++++++++++++++++++++-
----------
libselinux/src/label_internal.h | 5 +-
libselinux/src/label_media.c | 10 +++-
libselinux/src/label_x.c | 10 +++-
6 files changed, 124 insertions(+), 39 deletions(-)
diff --git a/libselinux/src/label.c b/libselinux/src/label.c
index 48f4d2d6..0dfa054c 100644
--- a/libselinux/src/label.c
+++ b/libselinux/src/label.c
@@ -143,7 +143,11 @@ static int selabel_fini(struct selabel_handle *rec,
struct selabel_lookup_rec *lr,
int translating)
{
- if (compat_validate(rec, lr, rec->spec_file, 0))
+ char *path = NULL;
+
+ if (rec->spec_files)
+ path = rec->spec_files[0];
+ if (compat_validate(rec, lr, path, 0))
return -1;
if (translating && !lr->ctx_trans &&
@@ -226,11 +230,9 @@ struct selabel_handle *selabel_open(unsigned int backend,
rec->digest = selabel_is_digest_set(opts, nopts, rec-

Post by Daniel Cashman
digest);

if ((*initfuncs[backend])(rec, opts, nopts)) {
- free(rec->spec_file);
- free(rec);
+ selabel_close(rec);
rec = NULL;
}
-
return rec;
}
@@ -337,10 +339,17 @@ int selabel_digest(struct selabel_handle *rec,
void selabel_close(struct selabel_handle *rec)
{
+ size_t i;
+
+ if (rec->spec_files) {
+ for (i = 0; i < rec->spec_files_len; i++)
+ free(rec->spec_files[i]);
+ free(rec->spec_files);
+ }
if (rec->digest)
selabel_digest_fini(rec->digest);
- rec->func_close(rec);
- free(rec->spec_file);
+ if (rec->func_close)
+ rec->func_close(rec);
free(rec);
}
diff --git a/libselinux/src/label_db.c b/libselinux/src/label_db.c
index c46d0a1d..9a35abea 100644
--- a/libselinux/src/label_db.c
+++ b/libselinux/src/label_db.c
@@ -290,7 +290,18 @@ db_init(const struct selinux_opt *opts, unsigned nopts,
errno = EINVAL;
return NULL;
}
- rec->spec_file = strdup(path);
+ rec->spec_files_len = 1;
+ rec->spec_files = calloc(rec->spec_files_len, sizeof(rec-

Post by Daniel Cashman
spec_files[0]));

+ if (!rec->spec_files) {
+ free(catalog);
+ return NULL;
+ }
+ rec->spec_files[0] = strdup(path);
+ if (!rec->spec_files[0]) {
+ free(catalog);
+ free(rec->spec_files);
+ return NULL;
+ }
/*
* Parse for each lines
diff --git a/libselinux/src/label_file.c
b/libselinux/src/label_file.c
index 560d8c3d..b3b36bc2 100644
--- a/libselinux/src/label_file.c
+++ b/libselinux/src/label_file.c
@@ -709,28 +709,61 @@ static int init(struct selabel_handle *rec,
const struct selinux_opt *opts,
unsigned n)
{
struct saved_data *data = (struct saved_data *)rec->data;
- const char *path = NULL;
+ size_t num_paths = 0;
+ char **path = NULL;
const char *prefix = NULL;
- int status = -1, baseonly = 0;
+ int status = -1;
+ size_t i;
+ bool baseonly = false;
+ bool path_provided;
/* Process arguments */
- while (n--)
- switch(opts[n].type) {
+ i = n;
+ while (i--)
+ switch(opts[i].type) {
- path = opts[n].value;
+ num_paths++;
break;
- prefix = opts[n].value;
+ prefix = opts[i].value;
break;
- baseonly = !!opts[n].value;
+ baseonly = !!opts[i].value;
break;
}
+ if (!num_paths) {
+ num_paths = 1;
+ path_provided = false;
+ } else {
+ path_provided = true;
+ }
+
+ path = calloc(num_paths, sizeof(*path));
+ if (path == NULL) {
+ goto finish;
+ }
+ rec->spec_files = path;
+ rec->spec_files_len = num_paths;
+
+ if (path_provided) {
+ for (i = 0; i < n; i++) {
+ switch(opts[i].type) {
+ *path = strdup(opts[i].value);

Perhaps surprisingly, opts[i].value can be NULL here and some callers
rely on that. After applying your patch, coreutils, selabel_lookup,
and other userspace programs all seg fault as a result. The use case
is programs where the selinux_opt structure is declared with a
SELABEL_OPT_PATH entry whose value is subsequently filled in, and left
NULL if they want to use the default path for file_contexts.
Internally, libselinux also does this from the
matchpathcon_init_prefix() function.
In any event, you need to handle this case.

Poor Stephen has turned into your test bot :-)
Does any of the test suite exercise this? Maybe make a PR
on github first to get Travis to test these?

Looks like Stephen tried that to see what would happen, and it incorrectly
passed indicating we need more tests:
https://github.com/SELinuxProject/selinux/pull/67

Post by William Roberts
Stephen can you share with how your testing this so Dan can follow
suit?

Looks like we need to add whatever your doing.

Post by William Roberts

Post by Stephen Smalley

Post by Daniel Cashman
+ if (*path == NULL)
+ goto finish;
+ path++;
+ break;
+ break;
+ }
+ }
+ }
#if !defined(BUILD_HOST) && !defined(ANDROID)
char subs_file[PATH_MAX + 1];
/* Process local and distribution substitution files */
- if (!path) {
+ if (!path_provided) {
status = selabel_subs_init(
selinux_file_context_subs_dist_path(),
rec->digest, &data->dist_subs);
@@ -740,43 +773,52 @@ static int init(struct selabel_handle *rec,
const struct selinux_opt *opts,
rec->digest, &data->subs);
if (status)
goto finish;
- path = selinux_file_context_path();
+ rec->spec_files[0] =
strdup(selinux_file_context_path());
+ if (rec->spec_files[0] == NULL)
+ goto finish;
} else {
- snprintf(subs_file, sizeof(subs_file),
"%s.subs_dist", path);
- status = selabel_subs_init(subs_file, rec->digest,
+ for (i = 0; i < num_paths; i++) {
+ snprintf(subs_file, sizeof(subs_file),
"%s.subs_dist", rec->spec_files[i]);
+ status = selabel_subs_init(subs_file, rec-

Post by Daniel Cashman
digest,

&data->dist_subs);
- if (status)
- goto finish;
- snprintf(subs_file, sizeof(subs_file), "%s.subs",
path);
- status = selabel_subs_init(subs_file, rec->digest,
+ if (status)
+ goto finish;
+ snprintf(subs_file, sizeof(subs_file),
"%s.subs", rec->spec_files[i]);
+ status = selabel_subs_init(subs_file, rec-

Post by Daniel Cashman
digest,

&data->subs);
- if (status)
- goto finish;
+ if (status)
+ goto finish;
+ }
+ }
+#else
+ if (!path_provided) {
+ selinux_log(SELINUX_ERROR, "No path given to file
labeling backend\n");
+ goto finish;
}
-
#endif
- rec->spec_file = strdup(path);
/*
- * The do detailed validation of the input and fill the spec
array
+ * Do detailed validation of the input and fill the spec
array
*/
- status = process_file(path, NULL, rec, prefix, rec->digest);
- if (status)
- goto finish;
-
- if (rec->validating) {
- status = nodups_specs(data, path);
+ for (i = 0; i < num_paths; i++) {
+ status = process_file(rec->spec_files[i], NULL, rec,
prefix, rec->digest);
if (status)
goto finish;
+
+ if (rec->validating) {
+ status = nodups_specs(data, rec-

Post by Daniel Cashman
spec_files[i]);

+ if (status)
+ goto finish;
+ }
}
if (!baseonly) {
- status = process_file(path, "homedirs", rec, prefix,
+ status = process_file(rec->spec_files[0],
"homedirs", rec, prefix,
rec-

Post by Daniel Cashman
digest);

if (status && errno != ENOENT)
goto finish;
- status = process_file(path, "local", rec, prefix,
+ status = process_file(rec->spec_files[0], "local",
rec, prefix,
rec-

Post by Daniel Cashman
digest);

if (status && errno != ENOENT)
goto finish;
@@ -804,6 +846,12 @@ static void closef(struct selabel_handle *rec)
struct stem *stem;
unsigned int i;
+ if (!data)
+ return;
+
+ /* make sure successive ->func_close() calls are harmless */
+ rec->data = NULL;
+
selabel_subs_fini(data->subs);
selabel_subs_fini(data->dist_subs);
diff --git a/libselinux/src/label_internal.h
b/libselinux/src/label_internal.h
index c55efb75..43b63513 100644
--- a/libselinux/src/label_internal.h
+++ b/libselinux/src/label_internal.h
@@ -98,10 +98,11 @@ struct selabel_handle {
void *data;
/*
- * The main spec file used. Note for file contexts the local
and/or
+ * The main spec file(s) used. Note for file contexts the
local and/or
* homedirs could also have been used to resolve a context.
*/
- char *spec_file;
+ size_t spec_files_len;
+ char **spec_files;
/* ptr to SHA1 hash information if SELABEL_OPT_DIGEST set */
struct selabel_digest *digest;
diff --git a/libselinux/src/label_media.c
b/libselinux/src/label_media.c
index d202e5d5..34260cbb 100644
--- a/libselinux/src/label_media.c
+++ b/libselinux/src/label_media.c
@@ -100,7 +100,15 @@ static int init(struct selabel_handle *rec,
const struct selinux_opt *opts,
errno = EINVAL;
return -1;
}
- rec->spec_file = strdup(path);
+ rec->spec_files_len = 1;
+ rec->spec_files = calloc(rec->spec_files_len, sizeof(rec-

Post by Daniel Cashman
spec_files[0]));

+ if (!rec->spec_files)
+ return -1;
+ rec->spec_files[0] = strdup(path);
+ if (!rec->spec_files[0]) {
+ free(rec->spec_files);
+ return -1;
+ }
/*
* Perform two passes over the specification file.
diff --git a/libselinux/src/label_x.c b/libselinux/src/label_x.c
index 96745299..fafe034a 100644
--- a/libselinux/src/label_x.c
+++ b/libselinux/src/label_x.c
@@ -127,7 +127,15 @@ static int init(struct selabel_handle *rec,
const struct selinux_opt *opts,
errno = EINVAL;
return -1;
}
- rec->spec_file = strdup(path);
+ rec->spec_files_len = 1;
+ rec->spec_files = calloc(rec->spec_files_len, sizeof(rec-

Post by Daniel Cashman
spec_files[0]));

+ if (!rec->spec_files)
+ return -1;
+ rec->spec_files[0] = strdup(path);
+ if (!rec->spec_files[0]) {
+ free(rec->spec_files);
+ return -1;
+ }
/*
* Perform two passes over the specification file.

[Stephen Smalley]

Post by William Roberts

Post by Stephen Smalley

Post by Daniel Cashman
The file_contexts labeling backend, specified in label_file.c, currently assumes
that only one path will be specified as an option to
selabel_open().  The split
of platform and non-platform policy on device, however, will necessitate the
loading of two disparate policy files.  Rather than combining the
files and then
calling the existing API on a newly-formed file, just add the
ability
to specify
multiple files to use.  Order of opt specification to
selabel_open
matters.
This corresponds to AOSP commit
50400d38203e4db08314168e60c281cc61a717a8, which
lead to a fork with upstream, which we'd like to correct.
---
 libselinux/src/label.c          |  21 +++++---
 libselinux/src/label_db.c       |  13 ++++-
 libselinux/src/label_file.c     | 104
+++++++++++++++++++++++++++++-
----------
 libselinux/src/label_internal.h |   5 +-
 libselinux/src/label_media.c    |  10 +++-
 libselinux/src/label_x.c        |  10 +++-
 6 files changed, 124 insertions(+), 39 deletions(-)
diff --git a/libselinux/src/label.c b/libselinux/src/label.c
index 48f4d2d6..0dfa054c 100644
--- a/libselinux/src/label.c
+++ b/libselinux/src/label.c
@@ -143,7 +143,11 @@ static int selabel_fini(struct
selabel_handle
*rec,
                          struct selabel_lookup_rec *lr,
                          int translating)
 {
-     if (compat_validate(rec, lr, rec->spec_file, 0))
+     char *path = NULL;
+
+     if (rec->spec_files)
+             path = rec->spec_files[0];
+     if (compat_validate(rec, lr, path, 0))
              return -1;
      if (translating && !lr->ctx_trans &&
@@ -226,11 +230,9 @@ struct selabel_handle *selabel_open(unsigned
int
backend,
      rec->digest = selabel_is_digest_set(opts, nopts, rec-

Post by Daniel Cashman
digest);

      if ((*initfuncs[backend])(rec, opts, nopts)) {
-             free(rec->spec_file);
-             free(rec);
+             selabel_close(rec);
              rec = NULL;
      }
-
      return rec;
 }
@@ -337,10 +339,17 @@ int selabel_digest(struct selabel_handle *rec,
 void selabel_close(struct selabel_handle *rec)
 {
+     size_t i;
+
+     if (rec->spec_files) {
+             for (i = 0; i < rec->spec_files_len; i++)
+                     free(rec->spec_files[i]);
+             free(rec->spec_files);
+     }
      if (rec->digest)
              selabel_digest_fini(rec->digest);
-     rec->func_close(rec);
-     free(rec->spec_file);
+     if (rec->func_close)
+             rec->func_close(rec);
      free(rec);
 }
diff --git a/libselinux/src/label_db.c
b/libselinux/src/label_db.c
index c46d0a1d..9a35abea 100644
--- a/libselinux/src/label_db.c
+++ b/libselinux/src/label_db.c
@@ -290,7 +290,18 @@ db_init(const struct selinux_opt *opts,
unsigned
nopts,
              errno = EINVAL;
              return NULL;
      }
-     rec->spec_file = strdup(path);
+     rec->spec_files_len = 1;
+     rec->spec_files = calloc(rec->spec_files_len, sizeof(rec-

Post by Daniel Cashman
spec_files[0]));

+     if (!rec->spec_files) {
+             free(catalog);
+             return NULL;
+     }
+     rec->spec_files[0] = strdup(path);
+     if (!rec->spec_files[0]) {
+             free(catalog);
+             free(rec->spec_files);
+             return NULL;
+     }
      /*
       * Parse for each lines
diff --git a/libselinux/src/label_file.c
b/libselinux/src/label_file.c
index 560d8c3d..b3b36bc2 100644
--- a/libselinux/src/label_file.c
+++ b/libselinux/src/label_file.c
@@ -709,28 +709,61 @@ static int init(struct selabel_handle *rec,
const struct selinux_opt *opts,
              unsigned n)
 {
      struct saved_data *data = (struct saved_data *)rec->data;
-     const char *path = NULL;
+     size_t num_paths = 0;
+     char **path = NULL;
      const char *prefix = NULL;
-     int status = -1, baseonly = 0;
+     int status = -1;
+     size_t i;
+     bool baseonly = false;
+     bool path_provided;
      /* Process arguments */
-     while (n--)
-             switch(opts[n].type) {
+     i = n;
+     while (i--)
+             switch(opts[i].type) {
-                     path = opts[n].value;
+                     num_paths++;
                      break;
-                     prefix = opts[n].value;
+                     prefix = opts[i].value;
                      break;
-                     baseonly = !!opts[n].value;
+                     baseonly = !!opts[i].value;
                      break;
              }
+     if (!num_paths) {
+             num_paths = 1;
+             path_provided = false;
+     } else {
+             path_provided = true;
+     }
+
+     path = calloc(num_paths, sizeof(*path));
+     if (path == NULL) {
+             goto finish;
+     }
+     rec->spec_files = path;
+     rec->spec_files_len = num_paths;
+
+     if (path_provided) {
+             for (i = 0; i < n; i++) {
+                     switch(opts[i].type) {
+                             *path = strdup(opts[i].value);

Perhaps surprisingly, opts[i].value can be NULL here and some callers
rely on that.  After applying your patch, coreutils,
selabel_lookup,
and other userspace programs all seg fault as a result.  The use
case
is programs where the selinux_opt structure is declared with a
SELABEL_OPT_PATH entry whose value is subsequently filled in, and left
NULL if they want to use the default path for file_contexts.
Internally, libselinux also does this from the
matchpathcon_init_prefix() function.
In any event, you need to handle this case.

Poor Stephen has turned into your test bot :-)
Does any of the test suite exercise this? Maybe make a PR
on github first to get Travis to test these?

Unfortunately the travis-ci tests don't catch this one currently.

Post by William Roberts
Stephen can you share with how your testing this so Dan can follow
suit?

In this case, you could build and install to a private directory as per
the README, then set your LD_LIBRARY_PATH=~/obj/lib or whatever and run
selabel_lookup.

Post by William Roberts

Post by Stephen Smalley

Post by Daniel Cashman
+                             if (*path == NULL)
+                                     goto finish;
+                             path++;
+                             break;
+                             break;
+                     }
+             }
+     }
 #if !defined(BUILD_HOST) && !defined(ANDROID)
      char subs_file[PATH_MAX + 1];
      /* Process local and distribution substitution files */
-     if (!path) {
+     if (!path_provided) {
              status = selabel_subs_init(
                      selinux_file_context_subs_dist_path(),
                      rec->digest, &data->dist_subs);
@@ -740,43 +773,52 @@ static int init(struct selabel_handle *rec,
const struct selinux_opt *opts,
                      rec->digest, &data->subs);
              if (status)
                      goto finish;
-             path = selinux_file_context_path();
+             rec->spec_files[0] =
strdup(selinux_file_context_path());
+             if (rec->spec_files[0] == NULL)
+                     goto finish;
      } else {
-             snprintf(subs_file, sizeof(subs_file),
"%s.subs_dist", path);
-             status = selabel_subs_init(subs_file, rec->digest,
+             for (i = 0; i < num_paths; i++) {
+                     snprintf(subs_file, sizeof(subs_file),
"%s.subs_dist", rec->spec_files[i]);
+                     status = selabel_subs_init(subs_file, rec-

Post by Daniel Cashman
digest,

                                         &data->dist_subs);
-             if (status)
-                     goto finish;
-             snprintf(subs_file, sizeof(subs_file), "%s.subs",
path);
-             status = selabel_subs_init(subs_file, rec->digest,
+                     if (status)
+                             goto finish;
+                     snprintf(subs_file, sizeof(subs_file),
"%s.subs", rec->spec_files[i]);
+                     status = selabel_subs_init(subs_file, rec-

Post by Daniel Cashman
digest,

                                         &data->subs);
-             if (status)
-                     goto finish;
+                     if (status)
+                             goto finish;
+             }
+     }
+#else
+     if (!path_provided) {
+             selinux_log(SELINUX_ERROR, "No path given to file
labeling backend\n");
+             goto finish;
      }
-
 #endif
-     rec->spec_file = strdup(path);
      /*
-      * The do detailed validation of the input and fill the
spec
array
+      * Do detailed validation of the input and fill the spec
array
       */
-     status = process_file(path, NULL, rec, prefix, rec-

Post by Daniel Cashman
digest);

-     if (status)
-             goto finish;
-
-     if (rec->validating) {
-             status = nodups_specs(data, path);
+     for (i = 0; i < num_paths; i++) {
+             status = process_file(rec->spec_files[i], NULL,
rec,
prefix, rec->digest);
              if (status)
                      goto finish;
+
+             if (rec->validating) {
+                     status = nodups_specs(data, rec-

Post by Daniel Cashman
spec_files[i]);

+                     if (status)
+                             goto finish;
+             }
      }
      if (!baseonly) {
-             status = process_file(path, "homedirs", rec,
prefix,
+             status = process_file(rec->spec_files[0],
"homedirs", rec, prefix,
                                                          rec-

Post by Daniel Cashman
digest);

              if (status && errno != ENOENT)
                      goto finish;
-             status = process_file(path, "local", rec, prefix,
+             status = process_file(rec->spec_files[0], "local",
rec, prefix,
                                                          rec-

Post by Daniel Cashman
digest);

              if (status && errno != ENOENT)
                      goto finish;
@@ -804,6 +846,12 @@ static void closef(struct selabel_handle *rec)
      struct stem *stem;
      unsigned int i;
+     if (!data)
+             return;
+
+     /* make sure successive ->func_close() calls are harmless
*/
+     rec->data = NULL;
+
      selabel_subs_fini(data->subs);
      selabel_subs_fini(data->dist_subs);
diff --git a/libselinux/src/label_internal.h
b/libselinux/src/label_internal.h
index c55efb75..43b63513 100644
--- a/libselinux/src/label_internal.h
+++ b/libselinux/src/label_internal.h
@@ -98,10 +98,11 @@ struct selabel_handle {
      void *data;
      /*
-      * The main spec file used. Note for file contexts the
local
and/or
+      * The main spec file(s) used. Note for file contexts the
local and/or
       * homedirs could also have been used to resolve a context.
       */
-     char *spec_file;
+     size_t spec_files_len;
+     char **spec_files;
      /* ptr to SHA1 hash information if SELABEL_OPT_DIGEST set
*/
      struct selabel_digest *digest;
diff --git a/libselinux/src/label_media.c
b/libselinux/src/label_media.c
index d202e5d5..34260cbb 100644
--- a/libselinux/src/label_media.c
+++ b/libselinux/src/label_media.c
@@ -100,7 +100,15 @@ static int init(struct selabel_handle *rec,
const struct selinux_opt *opts,
              errno = EINVAL;
              return -1;
      }
-     rec->spec_file = strdup(path);
+     rec->spec_files_len = 1;
+     rec->spec_files = calloc(rec->spec_files_len, sizeof(rec-

Post by Daniel Cashman
spec_files[0]));

+     if (!rec->spec_files)
+             return -1;
+     rec->spec_files[0] = strdup(path);
+     if (!rec->spec_files[0]) {
+             free(rec->spec_files);
+             return -1;
+     }
      /*
       * Perform two passes over the specification file.
diff --git a/libselinux/src/label_x.c b/libselinux/src/label_x.c
index 96745299..fafe034a 100644
--- a/libselinux/src/label_x.c
+++ b/libselinux/src/label_x.c
@@ -127,7 +127,15 @@ static int init(struct selabel_handle *rec,
const struct selinux_opt *opts,
              errno = EINVAL;
              return -1;
      }
-     rec->spec_file = strdup(path);
+     rec->spec_files_len = 1;
+     rec->spec_files = calloc(rec->spec_files_len, sizeof(rec-

Post by Daniel Cashman
spec_files[0]));

+     if (!rec->spec_files)
+             return -1;
+     rec->spec_files[0] = strdup(path);
+     if (!rec->spec_files[0]) {
+             free(rec->spec_files);
+             return -1;
+     }
      /*
       * Perform two passes over the specification file.

[Stephen Smalley]

Post by Stephen Smalley

Post by William Roberts

Post by Stephen Smalley

Post by Daniel Cashman
The file_contexts labeling backend, specified in label_file.c,
currently assumes
that only one path will be specified as an option to
selabel_open().  The split
of platform and non-platform policy on device, however, will necessitate the
loading of two disparate policy files.  Rather than combining the
files and then
calling the existing API on a newly-formed file, just add the
ability
to specify
multiple files to use.  Order of opt specification to
selabel_open
matters.
This corresponds to AOSP commit
50400d38203e4db08314168e60c281cc61a717a8, which
lead to a fork with upstream, which we'd like to correct.
---
 libselinux/src/label.c          |  21 +++++---
 libselinux/src/label_db.c       |  13 ++++-
 libselinux/src/label_file.c     | 104
+++++++++++++++++++++++++++++-
----------
 libselinux/src/label_internal.h |   5 +-
 libselinux/src/label_media.c    |  10 +++-
 libselinux/src/label_x.c        |  10 +++-
 6 files changed, 124 insertions(+), 39 deletions(-)
diff --git a/libselinux/src/label.c b/libselinux/src/label.c
index 48f4d2d6..0dfa054c 100644
--- a/libselinux/src/label.c
+++ b/libselinux/src/label.c
@@ -143,7 +143,11 @@ static int selabel_fini(struct
selabel_handle
*rec,
                          struct selabel_lookup_rec *lr,
                          int translating)
 {
-     if (compat_validate(rec, lr, rec->spec_file, 0))
+     char *path = NULL;
+
+     if (rec->spec_files)
+             path = rec->spec_files[0];
+     if (compat_validate(rec, lr, path, 0))
              return -1;
      if (translating && !lr->ctx_trans &&
@@ -226,11 +230,9 @@ struct selabel_handle
*selabel_open(unsigned
int
backend,
      rec->digest = selabel_is_digest_set(opts, nopts, rec-

Post by Daniel Cashman
digest);

      if ((*initfuncs[backend])(rec, opts, nopts)) {
-             free(rec->spec_file);
-             free(rec);
+             selabel_close(rec);
              rec = NULL;
      }
-
      return rec;
 }
@@ -337,10 +339,17 @@ int selabel_digest(struct selabel_handle *rec,
 void selabel_close(struct selabel_handle *rec)
 {
+     size_t i;
+
+     if (rec->spec_files) {
+             for (i = 0; i < rec->spec_files_len; i++)
+                     free(rec->spec_files[i]);
+             free(rec->spec_files);
+     }
      if (rec->digest)
              selabel_digest_fini(rec->digest);
-     rec->func_close(rec);
-     free(rec->spec_file);
+     if (rec->func_close)
+             rec->func_close(rec);
      free(rec);
 }
diff --git a/libselinux/src/label_db.c
b/libselinux/src/label_db.c
index c46d0a1d..9a35abea 100644
--- a/libselinux/src/label_db.c
+++ b/libselinux/src/label_db.c
@@ -290,7 +290,18 @@ db_init(const struct selinux_opt *opts,
unsigned
nopts,
              errno = EINVAL;
              return NULL;
      }
-     rec->spec_file = strdup(path);
+     rec->spec_files_len = 1;
+     rec->spec_files = calloc(rec->spec_files_len, sizeof(rec-

Post by Daniel Cashman
spec_files[0]));

+     if (!rec->spec_files) {
+             free(catalog);
+             return NULL;
+     }
+     rec->spec_files[0] = strdup(path);
+     if (!rec->spec_files[0]) {
+             free(catalog);
+             free(rec->spec_files);
+             return NULL;
+     }
      /*
       * Parse for each lines
diff --git a/libselinux/src/label_file.c
b/libselinux/src/label_file.c
index 560d8c3d..b3b36bc2 100644
--- a/libselinux/src/label_file.c
+++ b/libselinux/src/label_file.c
@@ -709,28 +709,61 @@ static int init(struct selabel_handle *rec,
const struct selinux_opt *opts,
              unsigned n)
 {
      struct saved_data *data = (struct saved_data *)rec->data;
-     const char *path = NULL;
+     size_t num_paths = 0;
+     char **path = NULL;
      const char *prefix = NULL;
-     int status = -1, baseonly = 0;
+     int status = -1;
+     size_t i;
+     bool baseonly = false;
+     bool path_provided;
      /* Process arguments */
-     while (n--)
-             switch(opts[n].type) {
+     i = n;
+     while (i--)
+             switch(opts[i].type) {
-                     path = opts[n].value;
+                     num_paths++;
                      break;
-                     prefix = opts[n].value;
+                     prefix = opts[i].value;
                      break;
-                     baseonly = !!opts[n].value;
+                     baseonly = !!opts[i].value;
                      break;
              }
+     if (!num_paths) {
+             num_paths = 1;
+             path_provided = false;
+     } else {
+             path_provided = true;
+     }
+
+     path = calloc(num_paths, sizeof(*path));
+     if (path == NULL) {
+             goto finish;
+     }
+     rec->spec_files = path;
+     rec->spec_files_len = num_paths;
+
+     if (path_provided) {
+             for (i = 0; i < n; i++) {
+                     switch(opts[i].type) {
+                             *path = strdup(opts[i].value);

Perhaps surprisingly, opts[i].value can be NULL here and some callers
rely on that.  After applying your patch, coreutils,
selabel_lookup,
and other userspace programs all seg fault as a result.  The use
case
is programs where the selinux_opt structure is declared with a
SELABEL_OPT_PATH entry whose value is subsequently filled in, and left
NULL if they want to use the default path for file_contexts.
Internally, libselinux also does this from the
matchpathcon_init_prefix() function.
In any event, you need to handle this case.

Poor Stephen has turned into your test bot :-)
Does any of the test suite exercise this? Maybe make a PR
on github first to get Travis to test these?

Unfortunately the travis-ci tests don't catch this one currently.

Post by William Roberts
Stephen can you share with how your testing this so Dan can follow
suit?

In this case, you could build and install to a private directory as per
the README, then set your LD_LIBRARY_PATH=~/obj/lib or whatever and run
selabel_lookup.

Ala:
$ make DESTDIR=~/obj install
$ LD_LIBRARY_PATH=~/obj/lib selabel_lookup -b file -k /etc
Segmentation fault (core dumped)

BTW, I guess this exposes another issue with the patch; there is no
support for exercising the new code included with it, e.g. an extension
to utils/selabel_lookup.c to permit specifying multiple input files via
multiple -f options. Otherwise, we have no upstream way of testing it.

Post by Stephen Smalley

Post by William Roberts

Post by Stephen Smalley

Post by Daniel Cashman
+                             if (*path == NULL)
+                                     goto finish;
+                             path++;
+                             break;
+                             break;
+                     }
+             }
+     }
 #if !defined(BUILD_HOST) && !defined(ANDROID)
      char subs_file[PATH_MAX + 1];
      /* Process local and distribution substitution files */
-     if (!path) {
+     if (!path_provided) {
              status = selabel_subs_init(
                      selinux_file_context_subs_dist_path(),
                      rec->digest, &data->dist_subs);
@@ -740,43 +773,52 @@ static int init(struct selabel_handle *rec,
const struct selinux_opt *opts,
                      rec->digest, &data->subs);
              if (status)
                      goto finish;
-             path = selinux_file_context_path();
+             rec->spec_files[0] =
strdup(selinux_file_context_path());
+             if (rec->spec_files[0] == NULL)
+                     goto finish;
      } else {
-             snprintf(subs_file, sizeof(subs_file),
"%s.subs_dist", path);
-             status = selabel_subs_init(subs_file, rec-

Post by Daniel Cashman
digest,

+             for (i = 0; i < num_paths; i++) {
+                     snprintf(subs_file, sizeof(subs_file),
"%s.subs_dist", rec->spec_files[i]);
+                     status = selabel_subs_init(subs_file,
rec-

Post by Daniel Cashman
digest,

                                         &data->dist_subs);
-             if (status)
-                     goto finish;
-             snprintf(subs_file, sizeof(subs_file), "%s.subs",
path);
-             status = selabel_subs_init(subs_file, rec-

Post by Daniel Cashman
digest,

+                     if (status)
+                             goto finish;
+                     snprintf(subs_file, sizeof(subs_file),
"%s.subs", rec->spec_files[i]);
+                     status = selabel_subs_init(subs_file,
rec-

Post by Daniel Cashman
digest,

                                         &data->subs);
-             if (status)
-                     goto finish;
+                     if (status)
+                             goto finish;
+             }
+     }
+#else
+     if (!path_provided) {
+             selinux_log(SELINUX_ERROR, "No path given to file
labeling backend\n");
+             goto finish;
      }
-
 #endif
-     rec->spec_file = strdup(path);
      /*
-      * The do detailed validation of the input and fill the
spec
array
+      * Do detailed validation of the input and fill the spec
array
       */
-     status = process_file(path, NULL, rec, prefix, rec-

Post by Daniel Cashman
digest);

-     if (status)
-             goto finish;
-
-     if (rec->validating) {
-             status = nodups_specs(data, path);
+     for (i = 0; i < num_paths; i++) {
+             status = process_file(rec->spec_files[i], NULL,
rec,
prefix, rec->digest);
              if (status)
                      goto finish;
+
+             if (rec->validating) {
+                     status = nodups_specs(data, rec-

Post by Daniel Cashman
spec_files[i]);

+                     if (status)
+                             goto finish;
+             }
      }
      if (!baseonly) {
-             status = process_file(path, "homedirs", rec,
prefix,
+             status = process_file(rec->spec_files[0],
"homedirs", rec, prefix,
                                                          rec-

Post by Daniel Cashman
digest);

              if (status && errno != ENOENT)
                      goto finish;
-             status = process_file(path, "local", rec, prefix,
+             status = process_file(rec->spec_files[0], "local",
rec, prefix,
                                                          rec-

Post by Daniel Cashman
digest);

              if (status && errno != ENOENT)
                      goto finish;
@@ -804,6 +846,12 @@ static void closef(struct selabel_handle *rec)
      struct stem *stem;
      unsigned int i;
+     if (!data)
+             return;
+
+     /* make sure successive ->func_close() calls are harmless
*/
+     rec->data = NULL;
+
      selabel_subs_fini(data->subs);
      selabel_subs_fini(data->dist_subs);
diff --git a/libselinux/src/label_internal.h
b/libselinux/src/label_internal.h
index c55efb75..43b63513 100644
--- a/libselinux/src/label_internal.h
+++ b/libselinux/src/label_internal.h
@@ -98,10 +98,11 @@ struct selabel_handle {
      void *data;
      /*
-      * The main spec file used. Note for file contexts the
local
and/or
+      * The main spec file(s) used. Note for file contexts the
local and/or
       * homedirs could also have been used to resolve a context.
       */
-     char *spec_file;
+     size_t spec_files_len;
+     char **spec_files;
      /* ptr to SHA1 hash information if SELABEL_OPT_DIGEST set
*/
      struct selabel_digest *digest;
diff --git a/libselinux/src/label_media.c
b/libselinux/src/label_media.c
index d202e5d5..34260cbb 100644
--- a/libselinux/src/label_media.c
+++ b/libselinux/src/label_media.c
@@ -100,7 +100,15 @@ static int init(struct selabel_handle *rec,
const struct selinux_opt *opts,
              errno = EINVAL;
              return -1;
      }
-     rec->spec_file = strdup(path);
+     rec->spec_files_len = 1;
+     rec->spec_files = calloc(rec->spec_files_len, sizeof(rec-

Post by Daniel Cashman
spec_files[0]));

+     if (!rec->spec_files)
+             return -1;
+     rec->spec_files[0] = strdup(path);
+     if (!rec->spec_files[0]) {
+             free(rec->spec_files);
+             return -1;
+     }
      /*
       * Perform two passes over the specification file.
diff --git a/libselinux/src/label_x.c
b/libselinux/src/label_x.c
index 96745299..fafe034a 100644
--- a/libselinux/src/label_x.c
+++ b/libselinux/src/label_x.c
@@ -127,7 +127,15 @@ static int init(struct selabel_handle *rec,
const struct selinux_opt *opts,
              errno = EINVAL;
              return -1;
      }
-     rec->spec_file = strdup(path);
+     rec->spec_files_len = 1;
+     rec->spec_files = calloc(rec->spec_files_len, sizeof(rec-

Post by Daniel Cashman
spec_files[0]));

+     if (!rec->spec_files)
+             return -1;
+     rec->spec_files[0] = strdup(path);
+     if (!rec->spec_files[0]) {
+             free(rec->spec_files);
+             return -1;
+     }
      /*
       * Perform two passes over the specification file.

[Nicolas Iooss]

Post by Stephen Smalley

Post by Stephen Smalley

Post by William Roberts

Post by Stephen Smalley

Post by Daniel Cashman
[...]
diff --git a/libselinux/src/label_file.c
b/libselinux/src/label_file.c
index 560d8c3d..b3b36bc2 100644
--- a/libselinux/src/label_file.c
+++ b/libselinux/src/label_file.c
@@ -709,28 +709,61 @@ static int init(struct selabel_handle *rec,
const struct selinux_opt *opts,
unsigned n)
{
struct saved_data *data = (struct saved_data *)rec->data;
- const char *path = NULL;
+ size_t num_paths = 0;
+ char **path = NULL;
const char *prefix = NULL;
- int status = -1, baseonly = 0;
+ int status = -1;
+ size_t i;
+ bool baseonly = false;
+ bool path_provided;
/* Process arguments */
- while (n--)
- switch(opts[n].type) {
+ i = n;
+ while (i--)
+ switch(opts[i].type) {
- path = opts[n].value;
+ num_paths++;
break;
- prefix = opts[n].value;
+ prefix = opts[i].value;
break;
- baseonly = !!opts[n].value;
+ baseonly = !!opts[i].value;
break;
}
+ if (!num_paths) {
+ num_paths = 1;
+ path_provided = false;
+ } else {
+ path_provided = true;
+ }
+
+ path = calloc(num_paths, sizeof(*path));
+ if (path == NULL) {
+ goto finish;
+ }
+ rec->spec_files = path;
+ rec->spec_files_len = num_paths;
+
+ if (path_provided) {
+ for (i = 0; i < n; i++) {
+ switch(opts[i].type) {
+ *path = strdup(opts[i].value);

Perhaps surprisingly, opts[i].value can be NULL here and some callers
rely on that. After applying your patch, coreutils,
selabel_lookup,
and other userspace programs all seg fault as a result. The use case
is programs where the selinux_opt structure is declared with a
SELABEL_OPT_PATH entry whose value is subsequently filled in, and left
NULL if they want to use the default path for file_contexts.
Internally, libselinux also does this from the
matchpathcon_init_prefix() function.
In any event, you need to handle this case.

Poor Stephen has turned into your test bot :-)
Does any of the test suite exercise this? Maybe make a PR
on github first to get Travis to test these?

Unfortunately the travis-ci tests don't catch this one currently.

Post by William Roberts
Stephen can you share with how your testing this so Dan can follow
suit?

In this case, you could build and install to a private directory as per
the README, then set your LD_LIBRARY_PATH=~/obj/lib or whatever and run
selabel_lookup.

$ make DESTDIR=~/obj install
$ LD_LIBRARY_PATH=~/obj/lib selabel_lookup -b file -k /etc
Segmentation fault (core dumped)
BTW, I guess this exposes another issue with the patch; there is no
support for exercising the new code included with it, e.g. an extension
to utils/selabel_lookup.c to permit specifying multiple input files via
multiple -f options. Otherwise, we have no upstream way of testing it.

For selabel_lookup, it would be possible to write a test script (or a
CUnit-based test program like libsepol and libsemanage have) which
does not need an SELinux policy to be installed on the system, thanks
to option -f.
Nevertheless other parts of libselinux (and programs) can not
currently be tested on a system without SELinux, as /etc/selinux and
/sys/fs/selinux are needed. If we want to automatize the testing of
such parts in a CI like Travis-CI, I suppose we would need to run a
virtual machine with its own filesystem, a kernel with SELinux
enabled, and some programs like coreutils compiled with the tested
version of libselinux/libsepol/... As implementing such an idea may
take quite a long time, would there be simpler ways to perform
automatic testing of libselinux? Perhaps using another continuous
integration system?

Cheers,
Nicolas

[William Roberts]

Post by Nicolas Iooss

Post by Stephen Smalley

Post by Stephen Smalley

Post by William Roberts

Post by Stephen Smalley

Post by Daniel Cashman
[...]
diff --git a/libselinux/src/label_file.c
b/libselinux/src/label_file.c
index 560d8c3d..b3b36bc2 100644
--- a/libselinux/src/label_file.c
+++ b/libselinux/src/label_file.c
@@ -709,28 +709,61 @@ static int init(struct selabel_handle *rec,
const struct selinux_opt *opts,
unsigned n)
{
struct saved_data *data = (struct saved_data *)rec->data;
- const char *path = NULL;
+ size_t num_paths = 0;
+ char **path = NULL;
const char *prefix = NULL;
- int status = -1, baseonly = 0;
+ int status = -1;
+ size_t i;
+ bool baseonly = false;
+ bool path_provided;
/* Process arguments */
- while (n--)
- switch(opts[n].type) {
+ i = n;
+ while (i--)
+ switch(opts[i].type) {
- path = opts[n].value;
+ num_paths++;
break;
- prefix = opts[n].value;
+ prefix = opts[i].value;
break;
- baseonly = !!opts[n].value;
+ baseonly = !!opts[i].value;
break;
}
+ if (!num_paths) {
+ num_paths = 1;
+ path_provided = false;
+ } else {
+ path_provided = true;
+ }
+
+ path = calloc(num_paths, sizeof(*path));
+ if (path == NULL) {
+ goto finish;
+ }
+ rec->spec_files = path;
+ rec->spec_files_len = num_paths;
+
+ if (path_provided) {
+ for (i = 0; i < n; i++) {
+ switch(opts[i].type) {
+ *path = strdup(opts[i].value);

Perhaps surprisingly, opts[i].value can be NULL here and some callers
rely on that. After applying your patch, coreutils,
selabel_lookup,
and other userspace programs all seg fault as a result. The use case
is programs where the selinux_opt structure is declared with a
SELABEL_OPT_PATH entry whose value is subsequently filled in, and left
NULL if they want to use the default path for file_contexts.
Internally, libselinux also does this from the
matchpathcon_init_prefix() function.
In any event, you need to handle this case.

Poor Stephen has turned into your test bot :-)
Does any of the test suite exercise this? Maybe make a PR
on github first to get Travis to test these?

Unfortunately the travis-ci tests don't catch this one currently.

Post by William Roberts
Stephen can you share with how your testing this so Dan can follow
suit?

In this case, you could build and install to a private directory as per
the README, then set your LD_LIBRARY_PATH=~/obj/lib or whatever and run
selabel_lookup.

$ make DESTDIR=~/obj install
$ LD_LIBRARY_PATH=~/obj/lib selabel_lookup -b file -k /etc
Segmentation fault (core dumped)
BTW, I guess this exposes another issue with the patch; there is no
support for exercising the new code included with it, e.g. an extension
to utils/selabel_lookup.c to permit specifying multiple input files via
multiple -f options. Otherwise, we have no upstream way of testing it.

For selabel_lookup, it would be possible to write a test script (or a
CUnit-based test program like libsepol and libsemanage have) which
does not need an SELinux policy to be installed on the system, thanks
to option -f.
Nevertheless other parts of libselinux (and programs) can not
currently be tested on a system without SELinux, as /etc/selinux and
/sys/fs/selinux are needed. If we want to automatize the testing of
such parts in a CI like Travis-CI, I suppose we would need to run a
virtual machine with its own filesystem, a kernel with SELinux
enabled, and some programs like coreutils compiled with the tested
version of libselinux/libsepol/... As implementing such an idea may
take quite a long time, would there be simpler ways to perform
automatic testing of libselinux? Perhaps using another continuous
integration system?

The free travis just provides an Ubuntu image.... if you use sudo: true
you get a full VM if you don't, you get a docker container.

With that said, we could try to hack up the VM image to support what we need,
or perhaps we can use CMockaand mock out the filesystem calls to proc/selinuxfs
with something that replicates it.(not sure if that's how mock objects work)

Post by Nicolas Iooss
Cheers,
Nicolas

[Dan Cashman]

Post by William Roberts

Post by Nicolas Iooss

Post by Stephen Smalley

Post by Stephen Smalley

Post by William Roberts

Post by Stephen Smalley

Post by Daniel Cashman
[...]
diff --git a/libselinux/src/label_file.c
b/libselinux/src/label_file.c
index 560d8c3d..b3b36bc2 100644
--- a/libselinux/src/label_file.c
+++ b/libselinux/src/label_file.c
@@ -709,28 +709,61 @@ static int init(struct selabel_handle *rec,
const struct selinux_opt *opts,
unsigned n)
{
struct saved_data *data = (struct saved_data *)rec->data;
- const char *path = NULL;
+ size_t num_paths = 0;
+ char **path = NULL;
const char *prefix = NULL;
- int status = -1, baseonly = 0;
+ int status = -1;
+ size_t i;
+ bool baseonly = false;
+ bool path_provided;
/* Process arguments */
- while (n--)
- switch(opts[n].type) {
+ i = n;
+ while (i--)
+ switch(opts[i].type) {
- path = opts[n].value;
+ num_paths++;
break;
- prefix = opts[n].value;
+ prefix = opts[i].value;
break;
- baseonly = !!opts[n].value;
+ baseonly = !!opts[i].value;
break;
}
+ if (!num_paths) {
+ num_paths = 1;
+ path_provided = false;
+ } else {
+ path_provided = true;
+ }
+
+ path = calloc(num_paths, sizeof(*path));
+ if (path == NULL) {
+ goto finish;
+ }
+ rec->spec_files = path;
+ rec->spec_files_len = num_paths;
+
+ if (path_provided) {
+ for (i = 0; i < n; i++) {
+ switch(opts[i].type) {
+ *path = strdup(opts[i].value);

Perhaps surprisingly, opts[i].value can be NULL here and some callers
rely on that. After applying your patch, coreutils,
selabel_lookup,
and other userspace programs all seg fault as a result. The use case
is programs where the selinux_opt structure is declared with a
SELABEL_OPT_PATH entry whose value is subsequently filled in, and left
NULL if they want to use the default path for file_contexts.
Internally, libselinux also does this from the
matchpathcon_init_prefix() function.
In any event, you need to handle this case.

Poor Stephen has turned into your test bot :-)
Does any of the test suite exercise this? Maybe make a PR
on github first to get Travis to test these?

Unfortunately the travis-ci tests don't catch this one currently.

Post by William Roberts
Stephen can you share with how your testing this so Dan can follow
suit?

In this case, you could build and install to a private directory as per
the README, then set your LD_LIBRARY_PATH=~/obj/lib or whatever and run
selabel_lookup.

$ make DESTDIR=~/obj install
$ LD_LIBRARY_PATH=~/obj/lib selabel_lookup -b file -k /etc
Segmentation fault (core dumped)
BTW, I guess this exposes another issue with the patch; there is no
support for exercising the new code included with it, e.g. an extension
to utils/selabel_lookup.c to permit specifying multiple input files via
multiple -f options. Otherwise, we have no upstream way of testing it.

For selabel_lookup, it would be possible to write a test script (or a
CUnit-based test program like libsepol and libsemanage have) which
does not need an SELinux policy to be installed on the system, thanks
to option -f.
Nevertheless other parts of libselinux (and programs) can not
currently be tested on a system without SELinux, as /etc/selinux and
/sys/fs/selinux are needed. If we want to automatize the testing of
such parts in a CI like Travis-CI, I suppose we would need to run a
virtual machine with its own filesystem, a kernel with SELinux
enabled, and some programs like coreutils compiled with the tested
version of libselinux/libsepol/... As implementing such an idea may
take quite a long time, would there be simpler ways to perform
automatic testing of libselinux? Perhaps using another continuous
integration system?

The free travis just provides an Ubuntu image.... if you use sudo: true
you get a full VM if you don't, you get a docker container.
With that said, we could try to hack up the VM image to support what we need,
or perhaps we can use CMockaand mock out the filesystem calls to proc/selinuxfs
with something that replicates it.(not sure if that's how mock objects work)

Post by Nicolas Iooss
Cheers,
Nicolas

Is there selinux-specific travis documentation, or a pointer to
appropriate travis documetnation in general? I'd obviously like to cut
down on bad patch submissions, so having a test suite batter a patch
before wasting reveiwer time would be great. We could/should probably
add this to the README as well if a proper standard workflow is developed.

Thanks,
Dan

[Dan Cashman]

On Mon, Oct 23, 2017 at 9:12 AM, William Roberts

Post by William Roberts

Post by Nicolas Iooss

Post by Stephen Smalley

Post by Stephen Smalley

Post by William Roberts

Post by Stephen Smalley

Post by Daniel Cashman
[...]
diff --git a/libselinux/src/label_file.c
b/libselinux/src/label_file.c
index 560d8c3d..b3b36bc2 100644
--- a/libselinux/src/label_file.c
+++ b/libselinux/src/label_file.c
@@ -709,28 +709,61 @@ static int init(struct selabel_handle *rec,
const struct selinux_opt *opts,
unsigned n)
{
struct saved_data *data = (struct saved_data *)rec->data;
- const char *path = NULL;
+ size_t num_paths = 0;
+ char **path = NULL;
const char *prefix = NULL;
- int status = -1, baseonly = 0;
+ int status = -1;
+ size_t i;
+ bool baseonly = false;
+ bool path_provided;
/* Process arguments */
- while (n--)
- switch(opts[n].type) {
+ i = n;
+ while (i--)
+ switch(opts[i].type) {
- path = opts[n].value;
+ num_paths++;
break;
- prefix = opts[n].value;
+ prefix = opts[i].value;
break;
- baseonly = !!opts[n].value;
+ baseonly = !!opts[i].value;
break;
}
+ if (!num_paths) {
+ num_paths = 1;
+ path_provided = false;
+ } else {
+ path_provided = true;
+ }
+
+ path = calloc(num_paths, sizeof(*path));
+ if (path == NULL) {
+ goto finish;
+ }
+ rec->spec_files = path;
+ rec->spec_files_len = num_paths;
+
+ if (path_provided) {
+ for (i = 0; i < n; i++) {
+ switch(opts[i].type) {
+ *path = strdup(opts[i].value);

Perhaps surprisingly, opts[i].value can be NULL here and some callers
rely on that. After applying your patch, coreutils,
selabel_lookup,
and other userspace programs all seg fault as a result. The use case
is programs where the selinux_opt structure is declared with a
SELABEL_OPT_PATH entry whose value is subsequently filled in, and left
NULL if they want to use the default path for file_contexts.
Internally, libselinux also does this from the
matchpathcon_init_prefix() function.
In any event, you need to handle this case.

Poor Stephen has turned into your test bot :-)
Does any of the test suite exercise this? Maybe make a PR
on github first to get Travis to test these?

Unfortunately the travis-ci tests don't catch this one currently.

Post by William Roberts
Stephen can you share with how your testing this so Dan can follow
suit?

In this case, you could build and install to a private directory as per
the README, then set your LD_LIBRARY_PATH=~/obj/lib or whatever and run
selabel_lookup.

$ make DESTDIR=~/obj install
$ LD_LIBRARY_PATH=~/obj/lib selabel_lookup -b file -k /etc
Segmentation fault (core dumped)
BTW, I guess this exposes another issue with the patch; there is no
support for exercising the new code included with it, e.g. an extension
to utils/selabel_lookup.c to permit specifying multiple input files via
multiple -f options. Otherwise, we have no upstream way of testing it.

For selabel_lookup, it would be possible to write a test script (or a
CUnit-based test program like libsepol and libsemanage have) which
does not need an SELinux policy to be installed on the system, thanks
to option -f.
Nevertheless other parts of libselinux (and programs) can not
currently be tested on a system without SELinux, as /etc/selinux and
/sys/fs/selinux are needed. If we want to automatize the testing of
such parts in a CI like Travis-CI, I suppose we would need to run a
virtual machine with its own filesystem, a kernel with SELinux
enabled, and some programs like coreutils compiled with the tested
version of libselinux/libsepol/... As implementing such an idea may
take quite a long time, would there be simpler ways to perform
automatic testing of libselinux? Perhaps using another continuous
integration system?

We have travis up and running, but it's not excising this code path. Any PR
submitted to the selinux project on githib has travis "test" it via
the .travis.yml
file in the root of the tree.
If you have a fork of selinux on github you could set up travis to run it. It's
https://docs.travis-ci.com/user/getting-started/
You could also just submit a PR for testing and publish a patch to the list
when you're ready for review...

1. Add a test as outlined previously in this thread
1. Setting it up on your fork of selinux project on github (hardest)
2. Submitting a PR to the selinux github project (easiest)
If its part of the test suite, you can run that by hand....
3. Submit patch to mailing list for review.

Ok, I'll look into that a bit when I get around to attempting v4.
Option 2 should suffice.

I know you tested all these on Android, but I think we need it as part of the
test framework.,,

Yes, this patch has clearly illustrated that android testing is
insufficient for upstream use-cases. That's why I'd like to eventually
have the upstream tests running as part of android builds and also why
I'm hoping to establish some sort of upstreaming workflow beyond "fire
away and let sds@ catch issues."

Thanks!
Dan

Post by William Roberts
The free travis just provides an Ubuntu image.... if you use sudo: true
you get a full VM if you don't, you get a docker container.
With that said, we could try to hack up the VM image to support what we need,
or perhaps we can use CMockaand mock out the filesystem calls to proc/selinuxfs
with something that replicates it.(not sure if that's how mock objects work)

Post by Nicolas Iooss
Cheers,
Nicolas

Is there selinux-specific travis documentation, or a pointer to appropriate
travis documetnation in general? I'd obviously like to cut down on bad
patch submissions, so having a test suite batter a patch before wasting
reveiwer time would be great. We could/should probably add this to the
README as well if a proper standard workflow is developed.
Thanks,
Dan