Please pull this fix for a double free bug in SELinux.
The following changes since commit 63f700aab4c11d46626de3cd051dae56cf7e9056:
Merge tag 'xtensa-20170612' of git://github.com/jcmvbkbc/linux-xtensa
(2017-06-13 15:09:10 +0900)
are available in the git repository at:
git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security.git
for-linus
Paul Moore (1):
selinux: fix double free in selinux_parse_opts_str()
security/selinux/hooks.c | 5 ++---
1 files changed, 2 insertions(+), 3 deletions(-)
---
commit 023f108dcc187e34ef864bf10ed966cf25e14e2a
Author: Paul Moore <p...@paul-moore.com>
Date: Wed Jun 7 16:48:19 2017 -0400
selinux: fix double free in selinux_parse_opts_str()
This patch is based on a discussion generated by an earlier patch
from Tetsuo Handa:
* https://marc.info/?t=149035659300001&r=1&w=2
The double free problem involves the mnt_opts field of the
security_mnt_opts struct, selinux_parse_opts_str() frees the memory
on error, but doesn't set the field to NULL so if the caller later
attempts to call security_free_mnt_opts() we trigger the problem.
In order to play it safe we change selinux_parse_opts_str() to call
security_free_mnt_opts() on error instead of free'ing the memory
directly. This should ensure that everything is handled correctly,
regardless of what the caller may do.
Fixes: e0007529893c1c06 ("LSM/SELinux: Interfaces to allow FS to control
mount options")
Cc: sta...@vger.kernel.org
Cc: Tetsuo Handa <penguin-ker...@i-love.sakura.ne.jp>
Reported-by: Dmitry Vyukov <dvyu...@google.com>
Signed-off-by: Paul Moore <p...@paul-moore.com>
Signed-off-by: James Morris <james.l.mor...@oracle.com>
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c
index e67a526..819fd68 100644
--- a/security/selinux/hooks.c
+++ b/security/selinux/hooks.c
@@ -1106,10 +1106,8 @@ static int selinux_parse_opts_str(char *options,
opts->mnt_opts_flags = kcalloc(NUM_SEL_MNT_OPTS, sizeof(int),
GFP_KERNEL);
- if (!opts->mnt_opts_flags) {
- kfree(opts->mnt_opts);
+ if (!opts->mnt_opts_flags)
goto out_err;
- }
if (fscontext) {
opts->mnt_opts[num_mnt_opts] = fscontext;
@@ -1132,6 +1130,7 @@ static int selinux_parse_opts_str(char *options,
return 0;
out_err:
+ security_free_mnt_opts(opts);
kfree(context);
kfree(defcontext);
kfree(fscontext);
