syzbot found WARNING in squashfs_read_table [1] when length of xattr_ids exceeds KMALLOC_MAX_SIZE in squashfs_read_table() for kmalloc().
For other squashfs tables, currently such as boundary is checked with another table's boundaries. Xattr table is the last one, so there is no defined limit. But to avoid order >= MAX_ORDER warning condition, we should restrict SQUASHFS_XATTR_BLOCK_BYTES(*xattr_ids) to KMALLOC_MAX_SIZE, and it gives 1024 pages in squashfs_read_table via (length + PAGE_SIZE - 1) >> PAGE_SHIFT. [1] Call Trace: alloc_pages_current+0x18c/0x2a0 mm/mempolicy.c:2267 alloc_pages include/linux/gfp.h:547 [inline] kmalloc_order+0x2e/0xb0 mm/slab_common.c:916 kmalloc_order_trace+0x14/0x120 mm/slab_common.c:932 kmalloc include/linux/slab.h:559 [inline] squashfs_read_table+0x43/0x1e0 fs/squashfs/cache.c:413 squashfs_read_xattr_id_table+0x191/0x220 fs/squashfs/xattr_id.c:81 Reported-by: [email protected] Signed-off-by: Sabyrzhan Tasbolatov <[email protected]> --- fs/squashfs/xattr_id.c | 3 +++ 1 file changed, 3 insertions(+) diff --git a/fs/squashfs/xattr_id.c b/fs/squashfs/xattr_id.c index d99e08464554..6bb51cd3d5c1 100644 --- a/fs/squashfs/xattr_id.c +++ b/fs/squashfs/xattr_id.c @@ -78,5 +78,8 @@ __le64 *squashfs_read_xattr_id_table(struct super_block *sb, u64 start, TRACE("In read_xattr_index_table, length %d\n", len); + if (len > KMALLOC_MAX_SIZE) + return -ENOMEM; + return squashfs_read_table(sb, start + sizeof(*id_table), len); } -- 2.25.1
