[PATCH] net/tap: drop too small packets

[Vladimir Sementsov-Ogievskiy]

Theoretically tap_read_packet() may return size less than
s->host_vnet_hdr_len, and next, we'll work with negative size
(in case of !s->using_vnet_hdr). Let's avoid it.

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsement...@yandex-team.ru>
---
 net/tap.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/net/tap.c b/net/tap.c
index ae1c7e39832..20d0dc2eb35 100644
--- a/net/tap.c
+++ b/net/tap.c
@@ -172,6 +172,11 @@ static void tap_send(void *opaque)
             break;
         }
 
+        if (s->host_vnet_hdr_len && size < s->host_vnet_hdr_len) {
+            /* Invalid packet */
+            break;
+        }
+
         if (s->host_vnet_hdr_len && !s->using_vnet_hdr) {
             buf  += s->host_vnet_hdr_len;
             size -= s->host_vnet_hdr_len;
-- 
2.48.1