tools/hv: Fix fortify format warning

With fortify enabled, gcc warns:

tools/hv/hv_kvp_daemon.c:705:2: error: format not a string literal and no format arguments [-Werror=format-security]
  snprintf(dev_id, sizeof(dev_id), kvp_net_dir);
  ^

kvp_net_dir is a pointer to a string literal, but lacks const
qualification.  As it is never modified, it should be a const
array rather than a pointer.

Also, while snprintf() has a bounds check, the following strcat()s
do not.  Combine them into a single snprintf().

Signed-off-by: Ben Hutchings <ben@decadent.org.uk>
Gbp-Pq: Topic bugfix/x86
Gbp-Pq: Name tools-hv-fix-fortify-format-warning.patch

diff --git a/tools/hv/hv_kvp_daemon.c b/tools/hv/hv_kvp_daemon.c
index 60a94b3e532e4d5ec07cd96c179911c378b9ca51..112b3001520942f6663520cabecb846720f840cc 100644 (file)
--- a/tools/hv/hv_kvp_daemon.c
+++ b/tools/hv/hv_kvp_daemon.c
@@ -649,10 +649,10 @@ 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/";
+       const char kvp_net_dir[] = "/sys/class/net/";
        char dev_id[256];
        unsigned int i;
 
@@ -660,17 +660,9 @@ static char *kvp_mac_to_if_name(char *mac)
        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)