CacheFiles: Add calls to path-based security hooks

Add calls to path-based security hooks into CacheFiles as, unlike inode-based
security, these aren't implicit in the vfs_mkdir() and similar calls.

Reported-by: Tetsuo Handa <penguin-kernel@i-love.sakura.ne.jp>
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: James Morris <jmorris@namei.org>

2 files changed, 47 insertions, 8 deletions

diff --git a/fs/cachefiles/namei.c b/fs/cachefiles/namei.c
index 42c7fafc8bfe..a0358c2189cb 100644
--- a/fs/cachefiles/namei.c
+++ b/fs/cachefiles/namei.c
@@ -275,6 +275,7 @@ static int cachefiles_bury_object(struct cachefiles_cache *cache,
                                   bool preemptive)
 {
         struct dentry *grave, *trap;
+        struct path path, path_to_graveyard;
         char nbuffer[8 + 8 + 1];
         int ret;
 
@@ -287,10 +288,18 @@ static int cachefiles_bury_object(struct cachefiles_cache *cache,
         /* non-directories can just be unlinked */
         if (!S_ISDIR(rep->d_inode->i_mode)) {
                 _debug("unlink stale object");
-                ret = vfs_unlink(dir->d_inode, rep);
 
-                if (preemptive)
-                        cachefiles_mark_object_buried(cache, rep);
+                path.mnt = cache->mnt;
+                path.dentry = dir;
+                ret = security_path_unlink(&path, rep);
+                if (ret < 0) {
+                        cachefiles_io_error(cache, "Unlink security error");
+                } else {
+                        ret = vfs_unlink(dir->d_inode, rep);
+
+                        if (preemptive)
+                                cachefiles_mark_object_buried(cache, rep);
+                }
 
                 mutex_unlock(&dir->d_inode->i_mutex);
 
@@ -379,12 +388,23 @@ try_again:
         }
 
         /* attempt the rename */
-        ret = vfs_rename(dir->d_inode, rep, cache->graveyard->d_inode, grave);
-        if (ret != 0 && ret != -ENOMEM)
-                cachefiles_io_error(cache, "Rename failed with error %d", ret);
+        path.mnt = cache->mnt;
+        path.dentry = dir;
+        path_to_graveyard.mnt = cache->mnt;
+        path_to_graveyard.dentry = cache->graveyard;
+        ret = security_path_rename(&path, rep, &path_to_graveyard, grave);
+        if (ret < 0) {
+                cachefiles_io_error(cache, "Rename security error %d", ret);
+        } else {
+                ret = vfs_rename(dir->d_inode, rep,
+                                 cache->graveyard->d_inode, grave);
+                if (ret != 0 && ret != -ENOMEM)
+                        cachefiles_io_error(cache,
+                                            "Rename failed with error %d", ret);
 
-        if (preemptive)
-                cachefiles_mark_object_buried(cache, rep);
+                if (preemptive)
+                        cachefiles_mark_object_buried(cache, rep);
+        }
 
         unlock_rename(cache->graveyard, dir);
         dput(grave);
@@ -448,6 +468,7 @@ int cachefiles_walk_to_object(struct cachefiles_object *parent,
 {
         struct cachefiles_cache *cache;
         struct dentry *dir, *next = NULL;
+        struct path path;
         unsigned long start;
         const char *name;
         int ret, nlen;
@@ -458,6 +479,7 @@ int cachefiles_walk_to_object(struct cachefiles_object *parent,
 
         cache = container_of(parent->fscache.cache,
                              struct cachefiles_cache, cache);
+        path.mnt = cache->mnt;
 
         ASSERT(parent->dentry);
         ASSERT(parent->dentry->d_inode);
@@ -511,6 +533,10 @@ lookup_again:
                         if (ret < 0)
                                 goto create_error;
 
+                        path.dentry = dir;
+                        ret = security_path_mkdir(&path, next, 0);
+                        if (ret < 0)
+                                goto create_error;
                         start = jiffies;
                         ret = vfs_mkdir(dir->d_inode, next, 0);
                         cachefiles_hist(cachefiles_mkdir_histogram, start);
@@ -536,6 +562,10 @@ lookup_again:
                         if (ret < 0)
                                 goto create_error;
 
+                        path.dentry = dir;
+                        ret = security_path_mknod(&path, next, S_IFREG, 0);
+                        if (ret < 0)
+                                goto create_error;
                         start = jiffies;
                         ret = vfs_create(dir->d_inode, next, S_IFREG, NULL);
                         cachefiles_hist(cachefiles_create_histogram, start);
@@ -692,6 +722,7 @@ struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
 {
         struct dentry *subdir;
         unsigned long start;
+        struct path path;
         int ret;
 
         _enter(",,%s", dirname);
@@ -719,6 +750,11 @@ struct dentry *cachefiles_get_directory(struct cachefiles_cache *cache,
 
                 _debug("attempt mkdir");
 
+                path.mnt = cache->mnt;
+                path.dentry = dir;
+                ret = security_path_mkdir(&path, subdir, 0700);
+                if (ret < 0)
+                        goto mkdir_error;
                 ret = vfs_mkdir(dir->d_inode, subdir, 0700);
                 if (ret < 0)
                         goto mkdir_error;
diff --git a/security/security.c b/security/security.c
index 739e40362f44..b84a89dd59c6 100644
--- a/security/security.c
+++ b/security/security.c
@@ -360,6 +360,7 @@ int security_path_mkdir(struct path *dir, struct dentry *dentry, int mode)
                 return 0;
         return security_ops->path_mkdir(dir, dentry, mode);
 }
+EXPORT_SYMBOL(security_path_mkdir);
 
 int security_path_rmdir(struct path *dir, struct dentry *dentry)
 {
@@ -374,6 +375,7 @@ int security_path_unlink(struct path *dir, struct dentry *dentry)
                 return 0;
         return security_ops->path_unlink(dir, dentry);
 }
+EXPORT_SYMBOL(security_path_unlink);
 
 int security_path_symlink(struct path *dir, struct dentry *dentry,
                           const char *old_name)
@@ -400,6 +402,7 @@ int security_path_rename(struct path *old_dir, struct dentry *old_dentry,
         return security_ops->path_rename(old_dir, old_dentry, new_dir,
                                          new_dentry);
 }
+EXPORT_SYMBOL(security_path_rename);
 
 int security_path_truncate(struct path *path)
 {