In PATCH v2 fixed return -ENOMEM as error pointer. >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: syzbot+2ccea6339d3683608...@syzkaller.appspotmail.com Reported-by: kernel test robot <l...@intel.com> Signed-off-by: Sabyrzhan Tasbolatov <snovit...@gmail.com> --- 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..2462876c66c4 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 ERR_PTR(-ENOMEM); + return squashfs_read_table(sb, start + sizeof(*id_table), len); } -- 2.25.1