ipaddress: strengthen check on 'label' input

As mentioned in the ip-address man page, an address label must
be equal to the device name or prefixed by the device name
followed by a colon. Currently the only check on this input is
to see if the device name appears at the beginning of the label
string.

This commit adds an additional check to ensure label == dev or
continues with a colon.

Signed-off-by: Patrick Talbert <ptalbert@redhat.com>
Suggested-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>

diff --git a/ip/ipaddress.c b/ip/ipaddress.c
index bbd35e797e3b305d3c33294f43f5091f834efc38..5009bfe6d2e3a20753e045a0bb0974728542bed8 100644 (file)
--- a/ip/ipaddress.c
+++ b/ip/ipaddress.c
@@ -2065,6 +2065,16 @@ static bool ipaddr_is_multicast(inet_prefix *a)
                return false;
 }
 
+static bool is_valid_label(const char *dev, const char *label)
+{
+       size_t len = strlen(dev);
+
+       if (strncmp(label, dev, len) != 0)
+               return false;
+
+       return label[len] == '\0' || label[len] == ':';
+}
+
 static int ipaddr_modify(int cmd, int flags, int argc, char **argv)
 {
        struct {
@@ -2208,8 +2218,10 @@ static int ipaddr_modify(int cmd, int flags, int argc, char **argv)
                fprintf(stderr, "Not enough information: \"dev\" argument is required.\n");
                return -1;
        }
-       if (l && matches(d, l) != 0) {
-               fprintf(stderr, "\"dev\" (%s) must match \"label\" (%s).\n", d, l);
+       if (l && !is_valid_label(d, l)) {
+               fprintf(stderr,
+                       "\"label\" (%s) must match \"dev\" (%s) or be prefixed by \"dev\" with a colon.\n",
+                       l, d);
                return -1;
        }