From 340b09010e2c329608af82c2fbd8cb73209eb58c Mon Sep 17 00:00:00 2001
Message-Id: <340b09010e2c329608af82c2fbd8cb73209eb58c@dist-git>
From: Michal Privoznik <mprivozn@redhat.com>
Date: Fri, 13 Jul 2018 15:44:42 +0200
Subject: [PATCH] virnetdevtap: Don't crash on !ifname in
 virNetDevTapInterfaceStats
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https://bugzilla.redhat.com/show_bug.cgi?id=1595184

Some domain <interfaces/> do not have a name (because they are
not TAP devices). Therefore, if
virNetDevTapInterfaceStats(net->ifname, ...) is called an instant
crash occurs. In Linux version of the function strlen() is called
over the name and in BSD version STREQ() is called.

Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Andrea Bolognani <abologna@redhat.com>
(cherry picked from commit 318d54e5201295239869655c2c60fb44d9d9466e)
Signed-off-by: Michal Privoznik <mprivozn@redhat.com>
Reviewed-by: Ján Tomko <jtomko@redhat.com>
---
 src/util/virnetdevtap.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/src/util/virnetdevtap.c b/src/util/virnetdevtap.c
index bd0710ad2e..3118ca18e8 100644
--- a/src/util/virnetdevtap.c
+++ b/src/util/virnetdevtap.c
@@ -691,6 +691,12 @@ virNetDevTapInterfaceStats(const char *ifname,
     FILE *fp;
     char line[256], *colon;
 
+    if (!ifname) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("Interface name not provided"));
+        return -1;
+    }
+
     fp = fopen("/proc/net/dev", "r");
     if (!fp) {
         virReportSystemError(errno, "%s",
@@ -768,6 +774,12 @@ virNetDevTapInterfaceStats(const char *ifname,
     struct if_data *ifd;
     int ret = -1;
 
+    if (!ifname) {
+        virReportError(VIR_ERR_INTERNAL_ERROR, "%s",
+                       _("Interface name not provided"));
+        return -1;
+    }
+
     if (getifaddrs(&ifap) < 0) {
         virReportSystemError(errno, "%s",
                              _("Could not get interface list"));
-- 
2.18.0