From 81278fd6c82c8a1c22c65f1ae1ea048d2473dbfe Mon Sep 17 00:00:00 2001
From: Markus Armbruster <armbru@redhat.com>
Date: Tue, 8 Sep 2015 18:06:24 +0200
Subject: [PATCH 6/7] util/uri: URI member path can be null, compare more
 carfully

Message-id: <1441735585-23432-7-git-send-email-armbru@redhat.com>
Patchwork-id: 67709
O-Subject: [RHEL-7.2 qemu-kvm PATCH 6/7] util/uri: URI member path can be null, compare more carfully
Bugzilla: 1218919
RH-Acked-by: Laszlo Ersek <lersek@redhat.com>
RH-Acked-by: Fam Zheng <famz@redhat.com>
RH-Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

uri_resolve_relative() calls strcmp(bas->path, ref->path).  However,
either argument could be null!  Evidence: the code checks for null
after the comparison.  Spotted by Coverity.

I suspect this was screwed up when we stole the code from libxml2.
There the conditional reads

    xmlStrEqual((xmlChar *)bas->path, (xmlChar *)ref->path)

with

    int
    xmlStrEqual(const xmlChar *str1, const xmlChar *str2) {
	if (str1 == str2) return(1);
	if (str1 == NULL) return(0);
	if (str2 == NULL) return(0);
	do {
	    if (*str1++ != *str2) return(0);
	} while (*str2++);
	return(1);
    }

Fix by replicating libxml2's logic faithfully.

Cc: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: Michael Tokarev <mjt@tls.msk.ru>
(cherry picked from commit afb30dde3ad71349fc65726946d58e5d3c61f8af)
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 util/uri.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/util/uri.c b/util/uri.c
index b9a7b54..1cfd78b 100644
--- a/util/uri.c
+++ b/util/uri.c
@@ -1935,7 +1935,8 @@ uri_resolve_relative (const char *uri, const char * base)
 	val = g_strdup (uri);
 	goto done;
     }
-    if (!strcmp(bas->path, ref->path)) {
+    if (bas->path == ref->path ||
+        (bas->path && ref->path && !strcmp(bas->path, ref->path))) {
 	val = g_strdup("");
 	goto done;
     }
-- 
1.8.3.1