[PATCH 1/3] tools/hv: Fix for long file names from readdir

From: Tomas Hozza
Date: Tue Nov 27 2012 - 02:56:55 EST


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 changed to PATH_MAX, include "limits.h" where
PATH_MAX is defined was added and length checks ware added via snprintf.

Signed-off-by: Tomas Hozza <thozza@xxxxxxxxxx>
---
tools/hv/hv_kvp_daemon.c | 26 +++++++++-----------------
1 file changed, 9 insertions(+), 17 deletions(-)

diff --git a/tools/hv/hv_kvp_daemon.c b/tools/hv/hv_kvp_daemon.c
index d25a469..90f1f07 100644
--- a/tools/hv/hv_kvp_daemon.c
+++ b/tools/hv/hv_kvp_daemon.c
@@ -44,6 +44,7 @@
#include <fcntl.h>
#include <dirent.h>
#include <net/if.h>
+#include <limits.h>

/*
* KVP protocol: The user mode component first registers with the
@@ -592,26 +593,22 @@ 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)
@@ -684,28 +681,23 @@ 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];
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)
--
1.7.11.7

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