[dpdk-dev] [PATCH 3/6] net/tap: check interface name in kvargs

[Stephen Hemminger]

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 <step...@networkplumber.org>
---
 drivers/net/tap/rte_eth_tap.c | 37 +++++++++++++++++++++++++++++++----
 1 file changed, 33 insertions(+), 4 deletions(-)

diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c
index d7f77d664502..6a388eed0dd4 100644
--- 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 +1885,23 @@ eth_dev_tap_create(struct rte_vdev_device *vdev, char 
*tap_name,
        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 +1909,17 @@ 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, tun_unit - 1);
-
+       }
        return 0;
 }
 
@@ -1907,8 +1930,14 @@ 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;
 }
-- 
2.20.1