[dpdk-dev] [PATCH] vhost: fix unchecked return value of fstat

[dpdk-dev] [PATCH] vhost: fix unchecked return value of fstat

[Huawei Xie]

Value returned from fstat is not checked for errors before being used.
Fixes the coverity issue:

static uint64_t
get_blk_size(int fd)
{
	struct stat stat;

	fstat(fd, &stat);
	return (uint64_t)stat.st_blksize;
>>>  CID 107103 (#1 of 1): Unchecked return value from library (CHECKED_RETURN)
>>>  check_return: Calling fstat(fd, &stat) without checking return value.
>>>  This library function may fail and return an error code.

Fixes: 8f972312b8f4 ("vhost: support vhost-user")

Signed-off-by: Huawei Xie <huawei.xie@intel.com>
---
 lib/librte_vhost/vhost_user/virtio-net-user.c | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/lib/librte_vhost/vhost_user/virtio-net-user.c b/lib/librte_vhost/vhost_user/virtio-net-user.c
index f5248bc..5803182 100644
--- a/lib/librte_vhost/vhost_user/virtio-net-user.c
+++ b/lib/librte_vhost/vhost_user/virtio-net-user.c
@@ -64,9 +64,10 @@ static uint64_t
 get_blk_size(int fd)
 {
 	struct stat stat;
+	int ret;
 
-	fstat(fd, &stat);
-	return (uint64_t)stat.st_blksize;
+	ret = fstat(fd, &stat);
+	return ret == -1 ? (uint64_t)-1 : (uint64_t)stat.st_blksize;
 }
 
 static void
@@ -162,6 +163,11 @@ user_set_mem_table(struct vhost_device_ctx ctx, struct VhostUserMsg *pmsg)
 		 * aligned.
 		 */
 		alignment = get_blk_size(pmsg->fds[idx]);
+		if (alignment == (uint64_t)-1) {
+			RTE_LOG(ERR, VHOST_CONFIG,
+				"couldn't get hugepage size through fstat\n");
+			goto err_mmap;
+		}
 		mapped_size = RTE_ALIGN_CEIL(mapped_size, alignment);
 
 		mapped_address = (uint64_t)(uintptr_t)mmap(NULL,
-- 
1.8.1.4

Re: [dpdk-dev] [PATCH] vhost: fix unchecked return value of fstat

[Yuanhan Liu]

On Wed, Jun 15, 2016 at 01:45:23AM +0800, Huawei Xie wrote:
> Value returned from fstat is not checked for errors before being used.
> Fixes the coverity issue:
> 
> static uint64_t
> get_blk_size(int fd)
> {
> 	struct stat stat;
> 
> 	fstat(fd, &stat);
> 	return (uint64_t)stat.st_blksize;
> >>>  CID 107103 (#1 of 1): Unchecked return value from library (CHECKED_RETURN)
> >>>  check_return: Calling fstat(fd, &stat) without checking return value.
> >>>  This library function may fail and return an error code.
> 
> Fixes: 8f972312b8f4 ("vhost: support vhost-user")
> 
> Signed-off-by: Huawei Xie <huawei.xie@intel.com>

Acked-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>

Applied to dpdk-next-virtio. Thanks.

	--yliu