From: Manas Ghandat ghandatmanas@gmail.com
[ Upstream commit cca974daeb6c43ea971f8ceff5a7080d7d49ee30 ]
Currently while joining the leaf in a buddy system there is shift out of bound error in calculation of BUDSIZE. Added the required check to the BUDSIZE and fixed the documentation as well.
Reported-by: syzbot+411debe54d318eaed386@syzkaller.appspotmail.com Closes: https://syzkaller.appspot.com/bug?extid=411debe54d318eaed386 Signed-off-by: Manas Ghandat ghandatmanas@gmail.com Signed-off-by: Dave Kleikamp dave.kleikamp@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- fs/jfs/jfs_dmap.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/fs/jfs/jfs_dmap.c b/fs/jfs/jfs_dmap.c index cb3cda1390ad..8eec84c651bf 100644 --- a/fs/jfs/jfs_dmap.c +++ b/fs/jfs/jfs_dmap.c @@ -2763,7 +2763,9 @@ static int dbBackSplit(dmtree_t *tp, int leafno, bool is_ctl) * leafno - the number of the leaf to be updated. * newval - the new value for the leaf. * - * RETURN VALUES: none + * RETURN VALUES: + * 0 - success + * -EIO - i/o error */ static int dbJoin(dmtree_t *tp, int leafno, int newval, bool is_ctl) { @@ -2790,6 +2792,10 @@ static int dbJoin(dmtree_t *tp, int leafno, int newval, bool is_ctl) * get the buddy size (number of words covered) of * the new value. */ + + if ((newval - tp->dmt_budmin) > BUDMIN) + return -EIO; + budsz = BUDSIZE(newval, tp->dmt_budmin);
/* try to join.