From: Michal Schmidt <mschmidt@redhat.com>
Date: Fri, 2 Mar 2012 09:39:10 +0000 (+0100)
Subject: util: never follow symlinks in rm_rf_children()
X-Git-Tag: v183~501
X-Git-Url: https://www.chiark.greenend.org.uk/ucgi/~ianmdlvl/git?p=elogind.git;a=commitdiff_plain;h=5ebff5337594d690b322078c512eb222d34aaa82

util: never follow symlinks in rm_rf_children()

The function checks if the entry is a directory before recursing, but
there is a window between the check and the open, during which the
directory could be replaced with a symlink.

CVE-2012-1174
https://bugzilla.redhat.com/show_bug.cgi?id=803358
---

diff --git a/src/util.c b/src/util.c
index 20cbc2b0d..dfc1dc6b8 100644
--- a/src/util.c
+++ b/src/util.c
@@ -3593,7 +3593,8 @@ static int rm_rf_children(int fd, bool only_dirs, bool honour_sticky) {
                 if (is_dir) {
                         int subdir_fd;
 
-                        if ((subdir_fd = openat(fd, de->d_name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC)) < 0) {
+                        subdir_fd = openat(fd, de->d_name, O_RDONLY|O_NONBLOCK|O_DIRECTORY|O_CLOEXEC|O_NOFOLLOW);
+                        if (subdir_fd < 0) {
                                 if (ret == 0 && errno != ENOENT)
                                         ret = -errno;
                                 continue;