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| author | Paul Moore <paul@paul-moore.com> | 2017-06-07 23:48:19 +0300 |
|---|---|---|
| committer | Ben Hutchings <ben@decadent.org.uk> | 2017-09-15 20:30:53 +0300 |
| commit | 96769d9b5c25e842da75f720f7dc7c619a64b29b (patch) | |
| tree | f97d07d98610c18bc88718f69a279b633bde099c | |
| parent | 466621f4858c27d263a3f5ce6c9f15d1c5bd4cfc (diff) | |
| download | linux-96769d9b5c25e842da75f720f7dc7c619a64b29b.tar.xz | |
selinux: fix double free in selinux_parse_opts_str()
commit 023f108dcc187e34ef864bf10ed966cf25e14e2a upstream.
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: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp>
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Paul Moore <paul@paul-moore.com>
Signed-off-by: James Morris <james.l.morris@oracle.com>
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
| -rw-r--r-- | security/selinux/hooks.c | 5 |
1 files changed, 2 insertions, 3 deletions
diff --git a/security/selinux/hooks.c b/security/selinux/hooks.c index c279f2f3372d..4c6a34700d49 100644 --- a/security/selinux/hooks.c +++ b/security/selinux/hooks.c @@ -911,10 +911,8 @@ static int selinux_parse_opts_str(char *options, goto out_err; opts->mnt_opts_flags = kcalloc(NUM_SEL_MNT_OPTS, sizeof(int), GFP_ATOMIC); - 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; @@ -937,6 +935,7 @@ static int selinux_parse_opts_str(char *options, return 0; out_err: + security_free_mnt_opts(opts); kfree(context); kfree(defcontext); kfree(fscontext); |