touchup argc/argv handling to shrink a bit and fix a segfault when given wrong number of parameters as noted and fixed by Cristian Ionescu-Idbohrn

1 files changed, 12 insertions, 11 deletions

diff --git a/networking/ipcalc.c b/networking/ipcalc.c
index bcd272b85..c5f2ba121 100644
--- a/networking/ipcalc.c
+++ b/networking/ipcalc.c
@@ -100,18 +100,19 @@ int ipcalc_main(int argc, char **argv)
                         "mbn"
 #endif
                         );
+
+        argc -= optind;
+        argv += optind;
         if (mode & (BROADCAST | NETWORK | NETPREFIX)) {
-                if (argc - optind > 2) {
+                if (argc > 2 || argc <= 0)
                         bb_show_usage();
-                }
         } else {
-                if (argc - optind != 1) {
+                if (argc != 1)
                         bb_show_usage();
-                }
         }
 
 #ifdef CONFIG_FEATURE_IPCALC_FANCY
-        prefixstr = ipstr = argv[optind];
+        prefixstr = ipstr = argv[0];
 
         while(*prefixstr) {
                 if (*prefixstr == '/') {
@@ -142,16 +143,16 @@ int ipcalc_main(int argc, char **argv)
         }
         ipaddr = inet_aton(ipstr, &a);
 #else
-        ipaddr = inet_aton(argv[optind], &a);
+        ipaddr = inet_aton(argv[0], &a);
 #endif
 
         if (ipaddr == 0) {
-                IPCALC_MSG(bb_error_msg_and_die("bad IP address: %s", argv[optind]),
+                IPCALC_MSG(bb_error_msg_and_die("bad IP address: %s", argv[0]),
                                 exit(EXIT_FAILURE));
         }
         ipaddr = a.s_addr;
 
-        if (argc - optind == 2) {
+        if (argc == 2) {
 #ifdef CONFIG_FEATURE_IPCALC_FANCY
                 if (have_netmask) {
                         IPCALC_MSG(bb_error_msg_and_die("Both prefix and netmask were specified, use one or the other.\n"),
@@ -159,9 +160,9 @@ int ipcalc_main(int argc, char **argv)
                 }
 
 #endif
-                netmask = inet_aton(argv[optind + 1], &a);
+                netmask = inet_aton(argv[1], &a);
                 if (netmask == 0) {
-                        IPCALC_MSG(bb_error_msg_and_die("bad netmask: %s", argv[optind + 1]),
+                        IPCALC_MSG(bb_error_msg_and_die("bad netmask: %s", argv[1]),
                                         exit(EXIT_FAILURE));
                 }
                 netmask = a.s_addr;
@@ -200,7 +201,7 @@ int ipcalc_main(int argc, char **argv)
                 hostinfo = gethostbyaddr((char *) &ipaddr, sizeof(ipaddr), AF_INET);
                 if (!hostinfo) {
                         IPCALC_MSG(bb_herror_msg_and_die(
-                                                "cannot find hostname for %s", argv[optind]),);
+                                                "cannot find hostname for %s", argv[0]),);
                         exit(EXIT_FAILURE);
                 }
                 for (x = 0; hostinfo->h_name[x]; x++) {