[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 at 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