]> git.proxmox.com Git - mirror_ubuntu-kernels.git/commit
nbd: add the check to prevent overflow in __nbd_ioctl()
authorBaokun Li <libaokun1@huawei.com>
Wed, 4 Aug 2021 02:12:12 +0000 (10:12 +0800)
committerJens Axboe <axboe@kernel.dk>
Fri, 13 Aug 2021 16:09:26 +0000 (10:09 -0600)
commitfad7cd3310db3099f95dd34312c77740fbc455e5
tree35e8edc8f8c4696ad38ab9ffeb07be76e4cfaf1a
parentda20b58d5bbbb0d23ae9530992a37d0f0d1787a4
nbd: add the check to prevent overflow in __nbd_ioctl()

If user specify a large enough value of NBD blocks option, it may trigger
signed integer overflow which may lead to nbd->config->bytesize becomes a
large or small value, zero in particular.

UBSAN: Undefined behaviour in drivers/block/nbd.c:325:31
signed integer overflow:
1024 * 4611686155866341414 cannot be represented in type 'long long int'
[...]
Call trace:
[...]
 handle_overflow+0x188/0x1dc lib/ubsan.c:192
 __ubsan_handle_mul_overflow+0x34/0x44 lib/ubsan.c:213
 nbd_size_set drivers/block/nbd.c:325 [inline]
 __nbd_ioctl drivers/block/nbd.c:1342 [inline]
 nbd_ioctl+0x998/0xa10 drivers/block/nbd.c:1395
 __blkdev_driver_ioctl block/ioctl.c:311 [inline]
[...]

Although it is not a big deal, still silence the UBSAN by limit
the input value.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Link: https://lore.kernel.org/r/20210804021212.990223-1-libaokun1@huawei.com
[axboe: dropped unlikely()]
Signed-off-by: Jens Axboe <axboe@kernel.dk>
drivers/block/nbd.c