net/tap: check interface name in kvargs

If interface name is passed to remote or iface then check
the length and for invalid characters. This avoids problems where
name gets truncated or rejected by kernel.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by Keith Wiles <keith.wiles@intel.com>

diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c
index 11e402e..d8e9ede 100644 (file)
--- a/drivers/net/tap/rte_eth_tap.c
+++ b/drivers/net/tap/rte_eth_tap.c
@@ -37,6 +37,7 @@
 #include <linux/if_tun.h>
 #include <linux/if_ether.h>
 #include <fcntl.h>
+#include <ctype.h>
 
 #include <tap_rss.h>
 #include <rte_eth_tap.h>
@@ -1884,6 +1885,24 @@ error_exit_nodev:
        return -EINVAL;
 }
 
+/* make sure name is a possible Linux network device name */
+static bool
+is_valid_iface(const char *name)
+{
+       if (*name == '\0')
+               return false;
+
+       if (strnlen(name, IFNAMSIZ) == IFNAMSIZ)
+               return false;
+
+       while (*name) {
+               if (*name == '/' || *name == ':' || isspace(*name))
+                       return false;
+               name++;
+       }
+       return true;
+}
+
 static int
 set_interface_name(const char *key __rte_unused,
                   const char *value,
@@ -1891,12 +1910,17 @@ set_interface_name(const char *key __rte_unused,
 {
        char *name = (char *)extra_args;
 
-       if (value)
+       if (value) {
+               if (!is_valid_iface(value)) {
+                       TAP_LOG(ERR, "TAP invalid remote interface name (%s)",
+                               value);
+                       return -1;
+               }
                strlcpy(name, value, RTE_ETH_NAME_MAX_LEN);
-       else
+       } else {
                snprintf(name, RTE_ETH_NAME_MAX_LEN, "%s%d",
                         DEFAULT_TAP_NAME, tap_unit - 1);
-
+       }
        return 0;
 }
 
@@ -1907,8 +1931,14 @@ set_remote_iface(const char *key __rte_unused,
 {
        char *name = (char *)extra_args;
 
-       if (value)
+       if (value) {
+               if (!is_valid_iface(value)) {
+                       TAP_LOG(ERR, "TAP invalid remote interface name (%s)",
+                               value);
+                       return -1;
+               }
                strlcpy(name, value, RTE_ETH_NAME_MAX_LEN);
+       }
 
        return 0;
 }