File CVE-2015-3146-Prevent-null-pointer-dereference.patch of Package libssh.580

From 94f6955fbaee6fda9385a23e505497efe21f5b4f Mon Sep 17 00:00:00 2001
From: Aris Adamantiadis <aris@0xbadc0de.be>
Date: Wed, 15 Apr 2015 16:08:37 +0200
Subject: [PATCH 1/2] CVE-2015-3146: Fix state validation in packet handlers

The state validation in the packet handlers for SSH_MSG_NEWKEYS and
SSH_MSG_KEXDH_REPLY had a bug which did not raise an error.

The issue has been found and reported by Mariusz Ziule.

Signed-off-by: Aris Adamantiadis <aris@0xbadc0de.be>
Reviewed-by: Andreas Schneider <asn@cryptomilk.org>
(cherry picked from commit bf0c7ae0aeb0ebe661d11ea6785fff2cbf4f3dbe)
---
 src/packet_cb.c | 16 ++++++++++------
 src/server.c    |  8 +++++---
 2 files changed, 15 insertions(+), 9 deletions(-)

Index: libssh-0.6.3/src/packet_cb.c
===================================================================
--- libssh-0.6.3.orig/src/packet_cb.c
+++ libssh-0.6.3/src/packet_cb.c
@@ -88,7 +88,7 @@ SSH_PACKET_CALLBACK(ssh_packet_dh_reply)
   (void)type;
   (void)user;
   SSH_LOG(SSH_LOG_PROTOCOL,"Received SSH_KEXDH_REPLY");
-  if(session->session_state!= SSH_SESSION_STATE_DH &&
+  if (session->session_state != SSH_SESSION_STATE_DH ||
 		session->dh_handshake_state != DH_STATE_INIT_SENT){
 	ssh_set_error(session,SSH_FATAL,"ssh_packet_dh_reply called in wrong state : %d:%d",
 			session->session_state,session->dh_handshake_state);
@@ -129,12 +129,16 @@ SSH_PACKET_CALLBACK(ssh_packet_newkeys){
   (void)user;
   (void)type;
   SSH_LOG(SSH_LOG_PROTOCOL, "Received SSH_MSG_NEWKEYS");
-  if(session->session_state!= SSH_SESSION_STATE_DH &&
-		session->dh_handshake_state != DH_STATE_NEWKEYS_SENT){
-	ssh_set_error(session,SSH_FATAL,"ssh_packet_newkeys called in wrong state : %d:%d",
-			session->session_state,session->dh_handshake_state);
-	goto error;
+
+  if (session->session_state != SSH_SESSION_STATE_DH ||
+      session->dh_handshake_state != DH_STATE_NEWKEYS_SENT) {
+      ssh_set_error(session,
+                    SSH_FATAL,
+                    "ssh_packet_newkeys called in wrong state : %d:%d",
+                    session->session_state,session->dh_handshake_state);
+      goto error;
   }
+
   if(session->server){
     /* server things are done in server.c */
     session->dh_handshake_state=DH_STATE_FINISHED;
Index: libssh-0.6.3/src/server.c
===================================================================
--- libssh-0.6.3.orig/src/server.c
+++ libssh-0.6.3/src/server.c
@@ -165,7 +165,7 @@ static int ssh_server_kexdh_init(ssh_ses
 }
 
 SSH_PACKET_CALLBACK(ssh_packet_kexdh_init){
-  int rc;
+  int rc = SSH_ERROR;
   (void)type;
   (void)user;
 
@@ -193,9 +193,11 @@ SSH_PACKET_CALLBACK(ssh_packet_kexdh_ini
         ssh_set_error(session,SSH_FATAL,"Wrong kex type in ssh_packet_kexdh_init");
         rc = SSH_ERROR;
   }
-  if (rc == SSH_ERROR)
+
+error:
+  if (rc == SSH_ERROR) {
       session->session_state = SSH_SESSION_STATE_ERROR;
-  error:
+  }
 
   return SSH_PACKET_USED;
 }
Index: libssh-0.6.3/src/buffer.c
===================================================================
--- libssh-0.6.3.orig/src/buffer.c
+++ libssh-0.6.3/src/buffer.c
@@ -188,6 +188,10 @@ int buffer_reinit(struct ssh_buffer_stru
 int buffer_add_data(struct ssh_buffer_struct *buffer, const void *data, uint32_t len) {
   buffer_verify(buffer);
 
+  if (data == NULL) {
+      return -1;
+  }
+
   if (buffer->used + len < len) {
     return -1;
   }
@@ -221,6 +225,10 @@ int buffer_add_ssh_string(struct ssh_buf
     struct ssh_string_struct *string) {
   uint32_t len = 0;
 
+  if (string == NULL) {
+      return -1;
+  }
+
   len = ssh_string_len(string);
   if (buffer_add_data(buffer, string, len + sizeof(uint32_t)) < 0) {
     return -1;
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