Messages in this thread Patch in this message | | | From | Baokun Li <> | Subject | [PATCH -next] nbd: add the check to prevent overflow in __nbd_ioctl() | Date | Sat, 31 Jul 2021 09:48:54 +0800 |
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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> --- drivers/block/nbd.c | 2 ++ 1 file changed, 2 insertions(+)
diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c index c38317979f74..7c838bf8cc31 100644 --- a/drivers/block/nbd.c +++ b/drivers/block/nbd.c @@ -1398,6 +1398,8 @@ static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd, case NBD_SET_SIZE: return nbd_set_size(nbd, arg, config->blksize); case NBD_SET_SIZE_BLOCKS: + if (arg && (LLONG_MAX / arg <= config->blksize)) + return -EINVAL; return nbd_set_size(nbd, arg * config->blksize, config->blksize); case NBD_SET_TIMEOUT: -- 2.31.1
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