diff options
author | Dan Carpenter <dan.carpenter@oracle.com> | 2020-01-31 09:11:07 +0300 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2020-02-05 17:43:36 +0300 |
commit | 732ecd4aad51d336b49b9be431219d173ac826c8 (patch) | |
tree | 3075cef38ff75ba51f990095b43f7392dda7d7bc /mm | |
parent | cb1702c403ad392a9ae6e090702a17cca98a38ca (diff) | |
download | linux-732ecd4aad51d336b49b9be431219d173ac826c8.tar.xz |
mm/mempolicy.c: fix out of bounds write in mpol_parse_str()
commit c7a91bc7c2e17e0a9c8b9745a2cb118891218fd1 upstream.
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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
-rw-r--r-- | mm/mempolicy.c | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/mm/mempolicy.c b/mm/mempolicy.c index a4a1cab16c0f..adeb163cd661 100644 --- a/mm/mempolicy.c +++ b/mm/mempolicy.c @@ -2808,6 +2808,9 @@ int mpol_parse_str(char *str, struct mempolicy **mpol) char *flags = strchr(str, '='); int err = 1; + if (flags) + *flags++ = '\0'; /* terminate mode string */ + if (nodelist) { /* NUL-terminate mode or flags string */ *nodelist++ = '\0'; @@ -2818,9 +2821,6 @@ int mpol_parse_str(char *str, struct mempolicy **mpol) } else nodes_clear(nodes); - if (flags) - *flags++ = '\0'; /* terminate mode string */ - for (mode = 0; mode < MPOL_MAX; mode++) { if (!strcmp(str, policy_modes[mode])) { break; |