The aa_policy_cache_new() and aa_policy_cache_remove() functions are
changed to accept a dirfd parameter.

The cache dirfd (by default, /etc/apparmor.d/cache) is opened earlier in
aa_policy_cache_new(). Previously, the directory wasn't accessed until
later in the following call chain:

  aa_policy_cache_new() -> init_cache_features() -> create_cache()

Because of this change, the logic to create the cache dir must be moved
from create_cache() to aa_policy_cache_new().

Signed-off-by: Tyler Hicks <[email protected]>
---
 libraries/libapparmor/include/sys/apparmor.h |  6 +-
 libraries/libapparmor/src/policy_cache.c     | 91 +++++++++++-----------------
 parser/parser_main.c                         |  6 +-
 tests/regression/apparmor/aa_policy_cache.c  |  8 ++-
 4 files changed, 48 insertions(+), 63 deletions(-)

diff --git a/libraries/libapparmor/include/sys/apparmor.h 
b/libraries/libapparmor/include/sys/apparmor.h
index 8fc3bda..ca75e5a 100644
--- a/libraries/libapparmor/include/sys/apparmor.h
+++ b/libraries/libapparmor/include/sys/apparmor.h
@@ -142,12 +142,12 @@ int aa_kernel_interface_write_policy(int fd, const char 
*buffer, size_t size);
 
 typedef struct aa_policy_cache aa_policy_cache;
 int aa_policy_cache_new(aa_policy_cache **policy_cache,
-                       aa_features *kernel_features, const char *path,
-                       uint16_t max_caches);
+                       aa_features *kernel_features,
+                       int dirfd, const char *path, uint16_t max_caches);
 aa_policy_cache *aa_policy_cache_ref(aa_policy_cache *policy_cache);
 void aa_policy_cache_unref(aa_policy_cache *policy_cache);
 
-int aa_policy_cache_remove(const char *path);
+int aa_policy_cache_remove(int dirfd, const char *path);
 int aa_policy_cache_replace_all(aa_policy_cache *policy_cache,
                                aa_kernel_interface *kernel_interface);
 
diff --git a/libraries/libapparmor/src/policy_cache.c 
b/libraries/libapparmor/src/policy_cache.c
index f59198a..04086e7 100644
--- a/libraries/libapparmor/src/policy_cache.c
+++ b/libraries/libapparmor/src/policy_cache.c
@@ -28,12 +28,13 @@
 
 #include "private.h"
 
+#define CACHE_FEATURES_FILE    ".features"
+
 struct aa_policy_cache {
        unsigned int ref_count;
        aa_features *features;
        aa_features *kernel_features;
-       char *path;
-       char *features_path;
+       int dirfd;
 };
 
 static int clear_cache_cb(int dirfd, const char *path, struct stat *st,
@@ -49,37 +50,16 @@ static int clear_cache_cb(int dirfd, const char *path, 
struct stat *st,
 
 static int create_cache(aa_policy_cache *policy_cache, aa_features *features)
 {
-       struct stat stat_file;
-       autofclose FILE * f = NULL;
-
-       if (aa_policy_cache_remove(policy_cache->path))
-               goto error;
+       if (aa_policy_cache_remove(policy_cache->dirfd, "."))
+               return -1;
 
-create_file:
-       if (aa_features_write_to_file(features, -1,
-                                     policy_cache->features_path) == -1)
-               goto error;
+       if (aa_features_write_to_file(features, policy_cache->dirfd,
+                                     CACHE_FEATURES_FILE) == -1)
+               return -1;
 
        aa_features_unref(policy_cache->features);
        policy_cache->features = aa_features_ref(features);
        return 0;
-
-error:
-       /* does the dir exist? */
-       if (stat(policy_cache->path, &stat_file) == -1) {
-               if (mkdir(policy_cache->path, 0700) == 0)
-                       goto create_file;
-               PERROR("Can't create cache directory: %s\n",
-                      policy_cache->path);
-       } else if (!S_ISDIR(stat_file.st_mode)) {
-               PERROR("File in cache directory location: %s\n",
-                      policy_cache->path);
-       } else {
-               PERROR("Can't update cache directory: %s\n",
-                      policy_cache->path);
-       }
-
-       return -1;
 }
 
 static int init_cache_features(aa_policy_cache *policy_cache,
@@ -87,8 +67,8 @@ static int init_cache_features(aa_policy_cache *policy_cache,
 {
        bool call_create_cache = false;
 
-       if (aa_features_new(&policy_cache->features, -1,
-                           policy_cache->features_path)) {
+       if (aa_features_new(&policy_cache->features, policy_cache->dirfd,
+                           CACHE_FEATURES_FILE)) {
                policy_cache->features = NULL;
                if (!create || errno != ENOENT)
                        return -1;
@@ -122,17 +102,11 @@ static int replace_all_cb(int dirfd unused, const char 
*name, struct stat *st,
 
        if (!S_ISDIR(st->st_mode) && !_aa_is_blacklisted(name, NULL)) {
                struct replace_all_cb_data *data;
-               autofree char *path = NULL;
 
                data = (struct replace_all_cb_data *) cb_data;
-               if (asprintf(&path, "%s/%s",
-                            data->policy_cache->path, name) < 0) {
-                       path = NULL;
-                       errno = ENOMEM;
-                       return -1;
-               }
                retval = 
aa_kernel_interface_replace_policy_from_file(data->kernel_interface,
-                                                                     -1, path);
+                                                                     
data->policy_cache->dirfd,
+                                                                     name);
        }
 
        return retval;
@@ -144,6 +118,7 @@ static int replace_all_cb(int dirfd unused, const char 
*name, struct stat *st,
  *                aa_policy_cache_new object upon success
  * @kernel_features: features representing a kernel (may be NULL if you want to
  *                   use the features of the currently running kernel)
+ * @dirfd: directory file descriptor or AT_FDCWD (see openat(2))
  * @path: path to the policy cache
  * @max_caches: The maximum number of policy caches, one for each unique set of
  *              kernel features, before older caches are auto-reaped. 0 means
@@ -155,8 +130,8 @@ static int replace_all_cb(int dirfd unused, const char 
*name, struct stat *st,
  *          pointing to NULL
  */
 int aa_policy_cache_new(aa_policy_cache **policy_cache,
-                       aa_features *kernel_features, const char *path,
-                       uint16_t max_caches)
+                       aa_features *kernel_features,
+                       int dirfd, const char *path, uint16_t max_caches)
 {
        aa_policy_cache *pc;
        bool create = max_caches > 0;
@@ -178,19 +153,26 @@ int aa_policy_cache_new(aa_policy_cache **policy_cache,
                errno = ENOMEM;
                return -1;
        }
+       pc->dirfd = -1;
        aa_policy_cache_ref(pc);
 
-       pc->path = strdup(path);
-       if (!pc->path) {
-               aa_policy_cache_unref(pc);
-               errno = ENOMEM;
-               return -1;
-       }
+open:
+       pc->dirfd = openat(dirfd, path, O_RDONLY | O_CLOEXEC | O_DIRECTORY);
+       if (pc->dirfd < 0) {
+               int save;
+
+               /* does the dir exist? */
+               if (create && errno == ENOENT) {
+                       if (mkdirat(dirfd, path, 0700) == 0)
+                               goto open;
+                       PERROR("Can't create cache directory '%s': %m\n", path);
+               } else {
+                       PERROR("Can't update cache directory '%s': %m\n", path);
+               }
 
-       if (asprintf(&pc->features_path, "%s/.features", pc->path) == -1) {
-               pc->features_path = NULL;
+               save = errno;
                aa_policy_cache_unref(pc);
-               errno = ENOMEM;
+               errno = save;
                return -1;
        }
 
@@ -239,21 +221,22 @@ void aa_policy_cache_unref(aa_policy_cache *policy_cache)
        if (policy_cache && atomic_dec_and_test(&policy_cache->ref_count)) {
                aa_features_unref(policy_cache->features);
                aa_features_unref(policy_cache->kernel_features);
-               free(policy_cache->features_path);
-               free(policy_cache->path);
+               if (policy_cache->dirfd != -1)
+                       close(policy_cache->dirfd);
                free(policy_cache);
        }
 }
 
 /**
  * aa_policy_cache_remove - removes all policy cache files under a path
+ * @dirfd: directory file descriptor or AT_FDCWD (see openat(2))
  * @path: the path to a policy cache directory
  *
  * Returns: 0 on success, -1 on error with errno set
  */
-int aa_policy_cache_remove(const char *path)
+int aa_policy_cache_remove(int dirfd, const char *path)
 {
-       return _aa_dirat_for_each(AT_FDCWD, path, NULL, clear_cache_cb);
+       return _aa_dirat_for_each(dirfd, path, NULL, clear_cache_cb);
 }
 
 /**
@@ -283,7 +266,7 @@ int aa_policy_cache_replace_all(aa_policy_cache 
*policy_cache,
 
        cb_data.policy_cache = policy_cache;
        cb_data.kernel_interface = kernel_interface;
-       retval = _aa_dirat_for_each(AT_FDCWD, policy_cache->path, &cb_data,
+       retval = _aa_dirat_for_each(policy_cache->dirfd, ".", &cb_data,
                                    replace_all_cb);
 
        aa_kernel_interface_unref(kernel_interface);
diff --git a/parser/parser_main.c b/parser/parser_main.c
index dda594c..cff0813 100644
--- a/parser/parser_main.c
+++ b/parser/parser_main.c
@@ -905,7 +905,7 @@ int main(int argc, char *argv[])
                }
 
                if (force_clear_cache) {
-                       if (aa_policy_cache_remove(cacheloc)) {
+                       if (aa_policy_cache_remove(AT_FDCWD, cacheloc)) {
                                PERROR(_("Failed to clear cache files (%s): 
%s\n"),
                                       cacheloc, strerror(errno));
                                return 1;
@@ -917,8 +917,8 @@ int main(int argc, char *argv[])
                if (create_cache_dir)
                        pwarn(_("The --create-cache-dir option is deprecated. 
Please use --write-cache.\n"));
 
-               retval = aa_policy_cache_new(&policy_cache, features, cacheloc,
-                                            max_caches);
+               retval = aa_policy_cache_new(&policy_cache, features,
+                                            AT_FDCWD, cacheloc, max_caches);
                if (retval) {
                        if (errno != ENOENT) {
                                PERROR(_("Failed setting up policy cache (%s): 
%s\n"),
diff --git a/tests/regression/apparmor/aa_policy_cache.c 
b/tests/regression/apparmor/aa_policy_cache.c
index ad3670d..d243f06 100644
--- a/tests/regression/apparmor/aa_policy_cache.c
+++ b/tests/regression/apparmor/aa_policy_cache.c
@@ -47,7 +47,8 @@ static int test_new(const char *path, uint16_t max_caches)
        aa_policy_cache *policy_cache = NULL;
        int rc = 1;
 
-       if (aa_policy_cache_new(&policy_cache, NULL, path, max_caches)) {
+       if (aa_policy_cache_new(&policy_cache, NULL,
+                               AT_FDCWD, path, max_caches)) {
                perror("FAIL - aa_policy_cache_new");
                goto out;
        }
@@ -62,7 +63,7 @@ static int test_remove(const char *path)
 {
        int rc = 1;
 
-       if (aa_policy_cache_remove(path)) {
+       if (aa_policy_cache_remove(AT_FDCWD, path)) {
                perror("FAIL - aa_policy_cache_remove");
                goto out;
        }
@@ -98,7 +99,8 @@ static int test_replace_all(const char *path, uint16_t 
max_caches)
        aa_policy_cache *policy_cache = NULL;
        int rc = 1;
 
-       if (aa_policy_cache_new(&policy_cache, NULL, path, max_caches)) {
+       if (aa_policy_cache_new(&policy_cache, NULL,
+                               AT_FDCWD, path, max_caches)) {
                perror("FAIL - aa_policy_cache_new");
                goto out;
        }
-- 
2.1.4


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