diff options
authorDan Carpenter <dan.carpenter@oracle.com>2020-01-30 22:11:07 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2020-01-31 10:30:36 -0800
commitc7a91bc7c2e17e0a9c8b9745a2cb118891218fd1 (patch)
parentmemcg: fix a crash in wb_workfn when a device disappears (diff)
mm/mempolicy.c: fix out of bounds write in mpol_parse_str()
What we are trying to do is change the '=' character to a NUL terminator and then at the end of the function we restore it back to an '='. The problem is there are two error paths where we jump to the end of the function before we have replaced the '=' with NUL. We end up putting the '=' in the wrong place (possibly one element before the start of the buffer). Link: http://lkml.kernel.org/r/20200115055426.vdjwvry44nfug7yy@kili.mountain Reported-by: syzbot+e64a13c5369a194d67df@syzkaller.appspotmail.com Fixes: 095f1fc4ebf3 ("mempolicy: rework shmem mpol parsing and display") Signed-off-by: Dan Carpenter <dan.carpenter@oracle.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Dmitry Vyukov <dvyukov@google.com> Cc: Michal Hocko <mhocko@kernel.org> Cc: Dan Carpenter <dan.carpenter@oracle.com> Cc: Lee Schermerhorn <lee.schermerhorn@hp.com> Cc: Andrea Arcangeli <aarcange@redhat.com> Cc: Hugh Dickins <hughd@google.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to '')
1 files changed, 3 insertions, 3 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c
index b2920ae87a61..977c641f78cf 100644
--- a/mm/mempolicy.c
+++ b/mm/mempolicy.c
@@ -2821,6 +2821,9 @@ int mpol_parse_str(char *str, struct mempolicy **mpol)
char *flags = strchr(str, '=');
int err = 1, mode;
+ if (flags)
+ *flags++ = '\0'; /* terminate mode string */
if (nodelist) {
/* NUL-terminate mode or flags string */
*nodelist++ = '\0';
@@ -2831,9 +2834,6 @@ int mpol_parse_str(char *str, struct mempolicy **mpol)
} else
- if (flags)
- *flags++ = '\0'; /* terminate mode string */
mode = match_string(policy_modes, MPOL_MAX, str);
if (mode < 0)
goto out;