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Subject[PATCH 4.19 080/114] nbd: fix crash when the blksize is zero
Date
From: Xiubo Li <xiubli@redhat.com>

[ Upstream commit 553768d1169a48c0cd87c4eb4ab57534ee663415 ]

This will allow the blksize to be set zero and then use 1024 as
default.

Reviewed-by: Josef Bacik <josef@toxicpanda.com>
Signed-off-by: Xiubo Li <xiubli@redhat.com>
[fix to use goto out instead of return in genl_connect]
Signed-off-by: Mike Christie <mchristi@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/block/nbd.c | 23 ++++++++++++++++++++---
1 file changed, 20 insertions(+), 3 deletions(-)

diff --git a/drivers/block/nbd.c b/drivers/block/nbd.c
index 21f54c7946a0e..bc2fa4e85f0ca 100644
--- a/drivers/block/nbd.c
+++ b/drivers/block/nbd.c
@@ -133,6 +133,8 @@ static struct dentry *nbd_dbg_dir;

#define NBD_MAGIC 0x68797548

+#define NBD_DEF_BLKSIZE 1024
+
static unsigned int nbds_max = 16;
static int max_part = 16;
static int part_shift;
@@ -1241,6 +1243,14 @@ 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;
+}
+
/* Must be called with config_lock held */
static int __nbd_ioctl(struct block_device *bdev, struct nbd_device *nbd,
unsigned int cmd, unsigned long arg)
@@ -1256,8 +1266,9 @@ 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 || !is_power_of_2(arg) || arg < 512 ||
- arg > PAGE_SIZE)
+ if (!arg)
+ arg = NBD_DEF_BLKSIZE;
+ if (!nbd_is_valid_blksize(arg))
return -EINVAL;
nbd_size_set(nbd, arg,
div_s64(config->bytesize, arg));
@@ -1337,7 +1348,7 @@ static struct nbd_config *nbd_alloc_config(void)
atomic_set(&config->recv_threads, 0);
init_waitqueue_head(&config->recv_wq);
init_waitqueue_head(&config->conn_wait);
- config->blksize = 1024;
+ config->blksize = NBD_DEF_BLKSIZE;
atomic_set(&config->live_connections, 0);
try_module_get(THIS_MODULE);
return config;
@@ -1773,6 +1784,12 @@ static int nbd_genl_connect(struct sk_buff *skb, struct genl_info *info)
if (info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]) {
u64 bsize =
nla_get_u64(info->attrs[NBD_ATTR_BLOCK_SIZE_BYTES]);
+ if (!bsize)
+ bsize = NBD_DEF_BLKSIZE;
+ if (!nbd_is_valid_blksize(bsize)) {
+ ret = -EINVAL;
+ goto out;
+ }
nbd_size_set(nbd, bsize, div64_u64(config->bytesize, bsize));
}
if (info->attrs[NBD_ATTR_TIMEOUT]) {
--
2.20.1


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