nbd: validate the block size in nbd_set_size

mainline inclusion
from mainline-v5.1-rc1
commit dcbddf54
category: bugfix
bugzilla: 188268
CVE: NA

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=dcbddf541f18e367ac9cdad8e223d382cd303161

----------------------------------------

Move the validation of the block from the callers into nbd_set_size.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Reviewed-by: NJosef Bacik <josef@toxicpanda.com>
Signed-off-by: NJens Axboe <axboe@kernel.dk>
Signed-off-by: NZhong Jinghua <zhongjinghua@huawei.com>
Reviewed-by: NYu Kuai <yukuai3@huawei.com>
Reviewed-by: NHou Tao <houtao1@huawei.com>

drivers/block/nbd.c

@@ -301,16 +301,21 @@ static void nbd_size_clear(struct nbd_device *nbd)
 	}
 }
 
-static void nbd_set_size(struct nbd_device *nbd, loff_t bytesize,
+static int nbd_set_size(struct nbd_device *nbd, loff_t bytesize,
 		loff_t blksize)
 {
 	struct block_device *bdev;
 
+	if (!blksize)
+		blksize = NBD_DEF_BLKSIZE;
+	if (blksize < 512 || blksize > PAGE_SIZE || !is_power_of_2(blksize))
+		return -EINVAL;
+
 	nbd->config->bytesize = bytesize;
 	nbd->config->blksize = blksize;
 
 	if (!nbd->pid)
-		return;
+		return 0;
 
 	if (nbd->config->flags & NBD_FLAG_SEND_TRIM) {
 		nbd->disk->queue->limits.discard_granularity = blksize;
@@ -330,6 +335,7 @@ static void nbd_set_size(struct nbd_device *nbd, loff_t bytesize,
 		bdput(bdev);
 	}
 	kobject_uevent(&nbd_to_dev(nbd)->kobj, KOBJ_CHANGE);
+	return 0;
 }
 
 static void nbd_complete_rq(struct request *req)
@@ -1388,8 +1394,7 @@ static int nbd_start_device(struct nbd_device *nbd)
 		args->index = i;
 		queue_work(nbd->recv_workq, &args->work);
 	}
-	nbd_set_size(nbd, config->bytesize, config->blksize);
-	return error;
+	return nbd_set_size(nbd, config->bytesize, config->blksize);
 }
 
 static int nbd_start_device_ioctl(struct nbd_device *nbd, struct block_device *bdev)
@@ -1438,14 +1443,6 @@ static void nbd_clear_sock_ioctl(struct nbd_device *nbd,
 		nbd_config_put(nbd);
 }
 
-static bool nbd_is_valid_blksize(unsigned long blksize)
-{
-	if (!blksize || !is_power_of_2(blksize) || blksize < 512 ||
-	    blksize > PAGE_SIZE)
-		return false;
-	return true;
-}
-
 static void nbd_set_cmd_timeout(struct nbd_device *nbd, u64 timeout)
 {
 	nbd->tag_set.timeout = timeout * HZ;
@@ -1471,20 +1468,13 @@ static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
 	case NBD_SET_SOCK:
 		return nbd_add_socket(nbd, arg, false);
 	case NBD_SET_BLKSIZE:
-		if (!arg)
-			arg = NBD_DEF_BLKSIZE;
-		if (!nbd_is_valid_blksize(arg))
-			return -EINVAL;
-		nbd_set_size(nbd, config->bytesize, arg);
-		return 0;
+		return nbd_set_size(nbd, config->bytesize, arg);
 	case NBD_SET_SIZE:
-		nbd_set_size(nbd, arg, config->blksize);
-		return 0;
+		return nbd_set_size(nbd, arg, config->blksize);
 	case NBD_SET_SIZE_BLOCKS:
 		if (check_mul_overflow((loff_t)arg, config->blksize, &bytesize))
 			return -EINVAL;
-		nbd_set_size(nbd, bytesize, config->blksize);
-		return 0;
+		return nbd_set_size(nbd, bytesize, config->blksize);
 	case NBD_SET_TIMEOUT:
 		nbd_set_cmd_timeout(nbd, arg);
 		return 0;
@@ -1908,18 +1898,11 @@ static int nbd_genl_size_set(struct genl_info *info, struct nbd_device *nbd)
 	if (info->attrs[NBD_ATTR_SIZE_BYTES])
 		bytes = nla_get_u64(info->attrs[NBD_ATTR_SIZE_BYTES]);
 
-	if (info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]) {
+	if (info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES])
 		bsize = nla_get_u64(info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]);
-		if (!bsize)
-			bsize = NBD_DEF_BLKSIZE;
-		if (!nbd_is_valid_blksize(bsize)) {
-			printk(KERN_ERR "Invalid block size %llu\n", bsize);
-			return -EINVAL;
-		}
-	}
 
 	if (bytes != config->bytesize || bsize != config->blksize)
-		nbd_set_size(nbd, bytes, bsize);
+		return nbd_set_size(nbd, bytes, bsize);
 	return 0;
 }