From: Florin Coras <fcoras@cisco.com>
Date: Thu, 8 May 2025 04:03:59 +0000 (-0400)
Subject: tcp: fix coverity discard bytes warning
X-Git-Tag: v25.10-rc0~27
X-Git-Url: https://gerrit.fd.io/r/gitweb?a=commitdiff_plain;h=refs%2Fchanges%2F32%2F42932%2F2;p=vpp.git

tcp: fix coverity discard bytes warning

Type: fix

Change-Id: Id832d1e240e42b8ce76f243c14ca67e724a4ef34
Signed-off-by: Florin Coras <fcoras@cisco.com>
---

diff --git a/src/vnet/tcp/tcp_input.c b/src/vnet/tcp/tcp_input.c
index 404afb18764..3abfc9512a7 100644
--- a/src/vnet/tcp/tcp_input.c
+++ b/src/vnet/tcp/tcp_input.c
@@ -1179,18 +1179,21 @@ tcp_buffer_discard_bytes (vlib_buffer_t * b, u32 n_bytes_to_drop)
   /* Handle multi-buffer segments */
   if (n_bytes_to_drop > b->current_length)
     {
-      if (!(b->flags & VLIB_BUFFER_NEXT_PRESENT))
+      if (!(b->flags & VLIB_BUFFER_NEXT_PRESENT) ||
+	  (first + b->total_length_not_including_first_buffer <
+	   n_bytes_to_drop))
 	return -1;
+      b->total_length_not_including_first_buffer -= n_bytes_to_drop - first;
       do
 	{
 	  discard = clib_min (n_bytes_to_drop, b->current_length);
 	  vlib_buffer_advance (b, discard);
 	  b = vlib_get_buffer (vm, b->next_buffer);
 	  n_bytes_to_drop -= discard;
+	  if (!b && n_bytes_to_drop)
+	    return -1;
 	}
       while (n_bytes_to_drop);
-      if (n_bytes_to_drop > first)
-	b->total_length_not_including_first_buffer -= n_bytes_to_drop - first;
     }
   else
     vlib_buffer_advance (b, n_bytes_to_drop);