[PATCH -next] 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>
---
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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