From 0e3bb8cbf99bd1eaab01744280fb07fcad07171d Mon Sep 17 00:00:00 2001
From: Norbert Pocs <npocs@redhat.com>
Date: Tue, 2 May 2023 16:47:57 +0200
Subject: [PATCH] buffer.c: Fix null pointer dereference error

This issue was discovered by covscan tool.

Signed-off-by: Norbert Pocs <npocs@redhat.com>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
---
 src/buffer.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/src/buffer.c b/src/buffer.c
index 5d5512e7..299eac54 100644
--- a/src/buffer.c
+++ b/src/buffer.c
@@ -748,7 +748,8 @@ uint32_t ssh_buffer_get_u64(struct ssh_buffer_struct *buffer, uint64_t *data){
  */
 int ssh_buffer_validate_length(struct ssh_buffer_struct *buffer, size_t len)
 {
-    if (buffer->pos + len < len || buffer->pos + len > buffer->used) {
+    if (buffer == NULL || buffer->pos + len < len ||
+        buffer->pos + len > buffer->used) {
         return SSH_ERROR;
     }