[PATCH][next] block/rnbd: fix a null pointer dereference on dev->blk_symlink_name

From: Colin King
Date: Mon Dec 07 2020 - 09:55:31 EST


From: Colin Ian King <colin.king@xxxxxxxxxxxxx>

Currently in the case where dev->blk_symlink_name fails to be allocates
the error return path attempts to set an end-of-string character to
the unallocated dev->blk_symlink_name causing a null pointer dereference
error. Fix this by returning with an explicity ENOMEM error (which also
is missing in the original code as was not initialized).

Addresses-Coverity: ("Dereference after null check")
Fixes: 1eb54f8f5dd8 ("block/rnbd: client: sysfs interface functions")
Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
---
drivers/block/rnbd/rnbd-clt-sysfs.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/block/rnbd/rnbd-clt-sysfs.c b/drivers/block/rnbd/rnbd-clt-sysfs.c
index c3c96a567568..a7caeedeb198 100644
--- a/drivers/block/rnbd/rnbd-clt-sysfs.c
+++ b/drivers/block/rnbd/rnbd-clt-sysfs.c
@@ -499,7 +499,7 @@ static int rnbd_clt_add_dev_symlink(struct rnbd_clt_dev *dev)
dev->blk_symlink_name = kzalloc(len, GFP_KERNEL);
if (!dev->blk_symlink_name) {
rnbd_clt_err(dev, "Failed to allocate memory for blk_symlink_name\n");
- goto out_err;
+ return -ENOMEM;
}

ret = rnbd_clt_get_path_name(dev, dev->blk_symlink_name,
--
2.29.2