summaryrefslogtreecommitdiffstats
diff options
context:
space:
mode:
authorJakub Hrozek <jhrozek@redhat.com>2012-12-12 18:02:33 (GMT)
committerJakub Hrozek <jhrozek@redhat.com>2013-01-23 13:27:58 (GMT)
commit020bf88fd1c5bdac8fc671b37c7118f5378c7047 (patch)
tree73b677832a498b2ee4b843ea59c21c57c0909bd8
parent2bd514cfde1938b1e245af11c9b548d58d49b325 (diff)
downloadsssd-020bf88fd1c5bdac8fc671b37c7118f5378c7047.zip
sssd-020bf88fd1c5bdac8fc671b37c7118f5378c7047.tar.gz
sssd-020bf88fd1c5bdac8fc671b37c7118f5378c7047.tar.xz
TOOLS: Use openat/unlinkat when removing the homedir
The removal of a home directory is sensitive to concurrent modification of the directory tree being removed and can unlink files outside the directory tree. This security issue was assigned CVE-2013-0219 https://fedorahosted.org/sssd/ticket/1782
-rw-r--r--src/tools/files.c83
1 files changed, 41 insertions, 42 deletions
diff --git a/src/tools/files.c b/src/tools/files.c
index d80e3bd..3d7b8d4 100644
--- a/src/tools/files.c
+++ b/src/tools/files.c
@@ -78,8 +78,9 @@ struct copy_ctx {
/* wrapper in order not to create a temporary context in
* every iteration */
static int remove_tree_with_ctx(TALLOC_CTX *mem_ctx,
- dev_t parent_dev,
- const char *root);
+ int parent_fd,
+ const char *dir_name,
+ dev_t parent_dev);
int remove_tree(const char *root)
{
@@ -91,7 +92,7 @@ int remove_tree(const char *root)
return ENOMEM;
}
- ret = remove_tree_with_ctx(tmp_ctx, 0, root);
+ ret = remove_tree_with_ctx(tmp_ctx, AT_FDCWD, root, 0);
talloc_free(tmp_ctx);
return ret;
}
@@ -102,75 +103,75 @@ int remove_tree(const char *root)
* reach the top level remove_tree() again
*/
static int remove_tree_with_ctx(TALLOC_CTX *mem_ctx,
- dev_t parent_dev,
- const char *root)
+ int parent_fd,
+ const char *dir_name,
+ dev_t parent_dev)
{
- char *fullpath = NULL;
struct dirent *result;
- struct dirent direntp;
struct stat statres;
DIR *rootdir = NULL;
int ret, err;
+ int dir_fd;
+
+ dir_fd = openat(parent_fd, dir_name,
+ O_RDONLY | O_CLOEXEC | O_DIRECTORY | O_NOFOLLOW);
+ if (dir_fd == -1) {
+ ret = errno;
+ DEBUG(SSSDBG_CRIT_FAILURE, ("Cannot open %s: [%d]: %s\n",
+ dir_name, ret, strerror(ret)));
+ return ret;
+ }
- rootdir = opendir(root);
+ rootdir = fdopendir(dir_fd);
if (rootdir == NULL) {
ret = errno;
- DEBUG(1, ("Cannot open directory %s [%d][%s]\n",
- root, ret, strerror(ret)));
+ DEBUG(SSSDBG_CRIT_FAILURE,
+ ("Cannot open directory: [%d][%s]\n", ret, strerror(ret)));
+ close(dir_fd);
goto fail;
}
- while (readdir_r(rootdir, &direntp, &result) == 0) {
- if (result == NULL) {
- /* End of directory */
- break;
- }
-
- if (strcmp (direntp.d_name, ".") == 0 ||
- strcmp (direntp.d_name, "..") == 0) {
+ while ((result = readdir(rootdir)) != NULL) {
+ if (strcmp(result->d_name, ".") == 0 ||
+ strcmp(result->d_name, "..") == 0) {
continue;
}
- fullpath = talloc_asprintf(mem_ctx, "%s/%s", root, direntp.d_name);
- if (fullpath == NULL) {
- ret = ENOMEM;
- goto fail;
- }
-
- ret = lstat(fullpath, &statres);
+ ret = fstatat(dir_fd, result->d_name,
+ &statres, AT_SYMLINK_NOFOLLOW);
if (ret != 0) {
ret = errno;
- DEBUG(1, ("Cannot stat %s: [%d][%s]\n",
- fullpath, ret, strerror(ret)));
+ DEBUG(SSSDBG_CRIT_FAILURE,
+ ("stat failed: [%d][%s]\n", ret, strerror(ret)));
goto fail;
}
if (S_ISDIR(statres.st_mode)) {
/* if directory, recursively descend, but check if on the same FS */
if (parent_dev && parent_dev != statres.st_dev) {
- DEBUG(1, ("Directory %s is on different filesystem, "
- "will not follow\n", fullpath));
+ DEBUG(SSSDBG_CRIT_FAILURE,
+ ("Directory %s is on different filesystem, "
+ "will not follow\n"));
ret = EFAULT;
goto fail;
}
- ret = remove_tree_with_ctx(mem_ctx, statres.st_dev, fullpath);
+ ret = remove_tree_with_ctx(mem_ctx, dir_fd, result->d_name, statres.st_dev);
if (ret != EOK) {
- DEBUG(1, ("Removing subdirectory %s failed: [%d][%s]\n",
- fullpath, ret, strerror(ret)));
+ DEBUG(SSSDBG_CRIT_FAILURE,
+ ("Removing subdirectory failed: [%d][%s]\n",
+ ret, strerror(ret)));
goto fail;
}
} else {
- ret = unlink(fullpath);
+ ret = unlinkat(dir_fd, result->d_name, 0);
if (ret != 0) {
ret = errno;
- DEBUG(1, ("Removing file %s failed: [%d][%s]\n",
- fullpath, ret, strerror(ret)));
+ DEBUG(SSSDBG_CRIT_FAILURE,
+ ("Removing file failed: [%d][%s]\n", ret, strerror(ret)));
goto fail;
}
}
-
- talloc_free(fullpath);
}
ret = closedir(rootdir);
@@ -180,19 +181,17 @@ static int remove_tree_with_ctx(TALLOC_CTX *mem_ctx,
goto fail;
}
- ret = rmdir(root);
- if (ret != 0) {
+ ret = unlinkat(parent_fd, dir_name, AT_REMOVEDIR);
+ if (ret == -1) {
ret = errno;
- goto fail;
}
ret = EOK;
-
fail:
if (rootdir) { /* clean up on abnormal exit but retain return code */
err = closedir(rootdir);
if (err) {
- DEBUG(1, ("closedir failed, bad dirp?\n"));
+ DEBUG(SSSDBG_CRIT_FAILURE, ("closedir failed, bad dirp?\n"));
}
}
return ret;