ip{6, }tunnel: Avoid copying user-supplied interface name around

In both files' parse_args() functions as well as in iptunnel's do_prl()
and do_6rd() functions, a user-supplied 'dev' parameter is uselessly
copied into a temporary buffer before passing it to ll_name_to_index()
or copying into a struct ifreq.  Avoid this by just caching the argv
pointer value until the later lookup/strcpy.

Signed-off-by: Phil Sutter <phil@nwl.cc>

diff --git a/ip/ip6tunnel.c b/ip/ip6tunnel.c
index b4a7def144226ef00065fd3a05fffb11dd97c727..c12d700e7418917a6d41a7aea6902a906b4ad285 100644 (file)
--- a/ip/ip6tunnel.c
+++ b/ip/ip6tunnel.c
@@ -136,7 +136,7 @@ static void print_tunnel(struct ip6_tnl_parm2 *p)
 static int parse_args(int argc, char **argv, int cmd, struct ip6_tnl_parm2 *p)
 {
        int count = 0;
-       char medium[IFNAMSIZ] = {};
+       const char *medium = NULL;
 
        while (argc > 0) {
                if (strcmp(*argv, "mode") == 0) {
@@ -180,7 +180,7 @@ static int parse_args(int argc, char **argv, int cmd, struct ip6_tnl_parm2 *p)
                        memcpy(&p->laddr, &laddr.data, sizeof(p->laddr));
                } else if (strcmp(*argv, "dev") == 0) {
                        NEXT_ARG();
-                       strncpy(medium, *argv, IFNAMSIZ - 1);
+                       medium = *argv;
                } else if (strcmp(*argv, "encaplimit") == 0) {
                        NEXT_ARG();
                        if (strcmp(*argv, "none") == 0) {
@@ -285,7 +285,7 @@ static int parse_args(int argc, char **argv, int cmd, struct ip6_tnl_parm2 *p)
                count++;
                argc--; argv++;
        }
-       if (medium[0]) {
+       if (medium) {
                p->link = ll_name_to_index(medium);
                if (p->link == 0) {
                        fprintf(stderr, "Cannot find device \"%s\"\n", medium);

diff --git a/ip/iptunnel.c b/ip/iptunnel.c
index 105d0f5576f1ac2ba1755114d8d196f99ce8c75f..0acfd0793d3cde09841bc66fdc5b0b82706f2248 100644 (file)
--- a/ip/iptunnel.c
+++ b/ip/iptunnel.c
@@ -60,7 +60,7 @@ static void set_tunnel_proto(struct ip_tunnel_parm *p, int proto)
 static int parse_args(int argc, char **argv, int cmd, struct ip_tunnel_parm *p)
 {
        int count = 0;
-       char medium[IFNAMSIZ] = {};
+       const char *medium = NULL;
        int isatap = 0;
 
        memset(p, 0, sizeof(*p));
@@ -139,7 +139,7 @@ static int parse_args(int argc, char **argv, int cmd, struct ip_tunnel_parm *p)
                                p->iph.saddr = htonl(INADDR_ANY);
                } else if (strcmp(*argv, "dev") == 0) {
                        NEXT_ARG();
-                       strncpy(medium, *argv, IFNAMSIZ - 1);
+                       medium = *argv;
                } else if (strcmp(*argv, "ttl") == 0 ||
                           strcmp(*argv, "hoplimit") == 0 ||
                           strcmp(*argv, "hlim") == 0) {
@@ -216,7 +216,7 @@ static int parse_args(int argc, char **argv, int cmd, struct ip_tunnel_parm *p)
                }
        }
 
-       if (medium[0]) {
+       if (medium) {
                p->link = ll_name_to_index(medium);
                if (p->link == 0) {
                        fprintf(stderr, "Cannot find device \"%s\"\n", medium);
@@ -465,9 +465,8 @@ static int do_prl(int argc, char **argv)
 {
        struct ip_tunnel_prl p = {};
        int count = 0;
-       int devname = 0;
        int cmd = 0;
-       char medium[IFNAMSIZ] = {};
+       const char *medium = NULL;
 
        while (argc > 0) {
                if (strcmp(*argv, "prl-default") == 0) {
@@ -488,8 +487,7 @@ static int do_prl(int argc, char **argv)
                        count++;
                } else if (strcmp(*argv, "dev") == 0) {
                        NEXT_ARG();
-                       strncpy(medium, *argv, IFNAMSIZ-1);
-                       devname++;
+                       medium = *argv;
                } else {
                        fprintf(stderr,
                                "Invalid PRL parameter \"%s\"\n", *argv);
@@ -502,7 +500,7 @@ static int do_prl(int argc, char **argv)
                }
                argc--; argv++;
        }
-       if (devname == 0) {
+       if (!medium) {
                fprintf(stderr, "Must specify device\n");
                exit(-1);
        }
@@ -513,9 +511,8 @@ static int do_prl(int argc, char **argv)
 static int do_6rd(int argc, char **argv)
 {
        struct ip_tunnel_6rd ip6rd = {};
-       int devname = 0;
        int cmd = 0;
-       char medium[IFNAMSIZ] = {};
+       const char *medium = NULL;
        inet_prefix prefix;
 
        while (argc > 0) {
@@ -537,8 +534,7 @@ static int do_6rd(int argc, char **argv)
                        cmd = SIOCDEL6RD;
                } else if (strcmp(*argv, "dev") == 0) {
                        NEXT_ARG();
-                       strncpy(medium, *argv, IFNAMSIZ-1);
-                       devname++;
+                       medium = *argv;
                } else {
                        fprintf(stderr,
                                "Invalid 6RD parameter \"%s\"\n", *argv);
@@ -546,7 +542,7 @@ static int do_6rd(int argc, char **argv)
                }
                argc--; argv++;
        }
-       if (devname == 0) {
+       if (!medium) {
                fprintf(stderr, "Must specify device\n");
                exit(-1);
        }