From a3634ce7eb5fc77e22c0d3722fb30e32b0d7d9fa Mon Sep 17 00:00:00 2001
From: Vitaly Kuznetsov <vkuznets@redhat.com>
Date: Thu, 2 Jul 2015 17:21:02 +0200
Subject: [PATCH] Tools: hv: Fix for long file names from readdir

From: Tomas Hozza <thozza@redhat.com>

kvp_get_if_name and kvp_mac_to_if_name copy strings into statically
sized buffers which could be too small to store really long names.

Buffer sizes have been increased and length checks added via snprintf.

Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
---
 hv_kvp_daemon.c | 26 +++++++++-----------------
 1 file changed, 9 insertions(+), 17 deletions(-)

diff --git a/hv_kvp_daemon.c b/hv_kvp_daemon.c
index 0d9f48e..ac89056 100644
--- a/hv_kvp_daemon.c
+++ b/hv_kvp_daemon.c
@@ -42,6 +42,7 @@
 #include <fcntl.h>
 #include <dirent.h>
 #include <net/if.h>
+#include <limits.h>
 #include <getopt.h>
 
 /*
@@ -599,26 +600,22 @@ static char *kvp_get_if_name(char *guid)
 	DIR *dir;
 	struct dirent *entry;
 	FILE    *file;
-	char    *p, *q, *x;
+	char    *p, *x;
 	char    *if_name = NULL;
 	char    buf[256];
 	char *kvp_net_dir = "/sys/class/net/";
-	char dev_id[256];
+	char dev_id[PATH_MAX];
 
 	dir = opendir(kvp_net_dir);
 	if (dir == NULL)
 		return NULL;
 
-	snprintf(dev_id, sizeof(dev_id), "%s", kvp_net_dir);
-	q = dev_id + strlen(kvp_net_dir);
-
 	while ((entry = readdir(dir)) != NULL) {
 		/*
 		 * Set the state for the next pass.
 		 */
-		*q = '\0';
-		strcat(dev_id, entry->d_name);
-		strcat(dev_id, "/device/device_id");
+		snprintf(dev_id, sizeof(dev_id), "%s%s/device/device_id", kvp_net_dir,
+				entry->d_name);
 
 		file = fopen(dev_id, "r");
 		if (file == NULL)
@@ -691,28 +688,23 @@ static char *kvp_mac_to_if_name(char *mac)
 	DIR *dir;
 	struct dirent *entry;
 	FILE    *file;
-	char    *p, *q, *x;
+	char    *p, *x;
 	char    *if_name = NULL;
 	char    buf[256];
 	char *kvp_net_dir = "/sys/class/net/";
-	char dev_id[256];
+	char dev_id[PATH_MAX];
 	unsigned int i;
 
 	dir = opendir(kvp_net_dir);
 	if (dir == NULL)
 		return NULL;
 
-	snprintf(dev_id, sizeof(dev_id), kvp_net_dir);
-	q = dev_id + strlen(kvp_net_dir);
-
 	while ((entry = readdir(dir)) != NULL) {
 		/*
 		 * Set the state for the next pass.
 		 */
-		*q = '\0';
-
-		strcat(dev_id, entry->d_name);
-		strcat(dev_id, "/address");
+		snprintf(dev_id, sizeof(dev_id), "%s%s/address", kvp_net_dir,
+			 entry->d_name);
 
 		file = fopen(dev_id, "r");
 		if (file == NULL)
-- 
2.4.3