File xsa140-qemut-1.patch of Package xen.6738

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File xsa140-qemut-1.patch of Package xen.6738

References: bsc#939712 XSA-140

From 5e0c290415b9d57077a86e70c8e6a058868334d3 Mon Sep 17 00:00:00 2001
From: Stefan Hajnoczi <stefanha@redhat.com>
Date: Wed, 15 Jul 2015 18:16:58 +0100
Subject: [PATCH 1/7] rtl8139: avoid nested ifs in IP header parsing

Transmit offload needs to parse packet headers.  If header fields have
unexpected values the offload processing is skipped.

The code currently uses nested ifs because there is relatively little
input validation.  The next patches will add missing input validation
and a goto label is more appropriate to avoid deep if statement nesting.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/rtl8139.c | 41 ++++++++++++++++++++++-------------------
 1 file changed, 22 insertions(+), 19 deletions(-)

Index: xen-4.4.2-testing/tools/qemu-xen-traditional-dir-remote/hw/rtl8139.c
===================================================================
--- xen-4.4.2-testing.orig/tools/qemu-xen-traditional-dir-remote/hw/rtl8139.c
+++ xen-4.4.2-testing/tools/qemu-xen-traditional-dir-remote/hw/rtl8139.c
@@ -2113,26 +2113,30 @@ static int rtl8139_cplus_transmit_one(RT
             size_t   eth_payload_len  = 0;
 
             int proto = be16_to_cpu(*(uint16_t *)(saved_buffer + 12));
-            if (proto == ETH_P_IP)
+            if (proto != ETH_P_IP)
             {
-                DEBUG_PRINT(("RTL8139: +++ C+ mode has IP packet\n"));
+                goto skip_offload;
+            }
 
-                /* not aligned */
-                eth_payload_data = saved_buffer + ETH_HLEN;
-                eth_payload_len  = saved_size   - ETH_HLEN;
-
-                ip = (ip_header*)eth_payload_data;
-
-                if (IP_HEADER_VERSION(ip) != IP_HEADER_VERSION_4) {
-                    DEBUG_PRINT(("RTL8139: +++ C+ mode packet has bad IP version %d expected %d\n", IP_HEADER_VERSION(ip), IP_HEADER_VERSION_4));
-                    ip = NULL;
-                } else {
-                    hlen = IP_HEADER_LENGTH(ip);
-                    ip_protocol = ip->ip_p;
-                    ip_data_len = be16_to_cpu(ip->ip_len) - hlen;
-                }
+            DEBUG_PRINT(("RTL8139: +++ C+ mode has IP packet\n"));
+
+            /* not aligned */
+            eth_payload_data = saved_buffer + ETH_HLEN;
+            eth_payload_len  = saved_size   - ETH_HLEN;
+
+            ip = (ip_header*)eth_payload_data;
+
+            if (IP_HEADER_VERSION(ip) != IP_HEADER_VERSION_4) {
+                DEBUG_PRINT(("RTL8139: +++ C+ mode packet has bad IP version %d "
+                    "expected %d\n", IP_HEADER_VERSION(ip),
+                    IP_HEADER_VERSION_4));
+                goto skip_offload;
             }
 
+            hlen = IP_HEADER_LENGTH(ip);
+            ip_protocol = ip->ip_p;
+            ip_data_len = be16_to_cpu(ip->ip_len) - hlen;
+
             if (ip)
             {
                 if (txdw0 & CP_TX_IPCS)
@@ -2315,6 +2319,7 @@ static int rtl8139_cplus_transmit_one(RT
             }
         }
 
+skip_offload:
         /* update tally counter */
         ++s->tally_counters.TxOk;

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File xsa140-qemut-1.patch of Package xen.6738

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