Re: [syzbot] [jfs?] UBSAN: shift-out-of-bounds in extAlloc (2)

[Jeongjun Park]

please test shift-out-of-bounds in extAlloc

#syz test git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git master

---
 fs/jfs/jfs_extent.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/fs/jfs/jfs_extent.c b/fs/jfs/jfs_extent.c
index 63d21822d309..3d1273d35b13 100644
--- a/fs/jfs/jfs_extent.c
+++ b/fs/jfs/jfs_extent.c
@@ -316,6 +316,9 @@ extBalloc(struct inode *ip, s64 hint, s64 * nblocks, s64 * blkno)
        if (bmp->db_maxfreebud == -1)
                return -ENOSPC;
 
+       if (bmp->db_maxfreebud >= sizeof(s64) * 8 - 1)
+               return -EINVAL;
+
        max = (s64) 1 << bmp->db_maxfreebud;
        if (*nblocks >= max && *nblocks > nbperpage)
                nb = nblks = (max > nbperpage) ? max : nbperpage;
-- 
2.34.1