common/mlx5: fix Netlink port name padding in probing

On some kernels the string attributes within Netlink
reply messages might be not padded with zeroes (in cases
when string length is aligned with 4-byte boundary).
While device probing, the physical port name was wrongly recognized,
causing a probing failure.

Fixes: 30a86157f6d5 ("net/mlx5: support PF representor")
Cc: stable@dpdk.org
Signed-off-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
Acked-by: Matan Azrad <matan@nvidia.com>

diff --git a/drivers/common/mlx5/linux/mlx5_nl.c b/drivers/common/mlx5/linux/mlx5_nl.c
index f0d04f9..3f1912d 100644 (file)
--- a/drivers/common/mlx5/linux/mlx5_nl.c
+++ b/drivers/common/mlx5/linux/mlx5_nl.c
@@ -33,6 +33,8 @@
 #define MLX5_SEND_BUF_SIZE 32768
 /* Receive buffer size for the Netlink socket */
 #define MLX5_RECV_BUF_SIZE 32768
+/* Maximal physical port name length. */
+#define MLX5_PHYS_PORT_NAME_MAX 128
 
 /** Parameters of VLAN devices created by driver. */
 #define MLX5_VMWA_VLAN_DEVICE_PFX "evmlx"
@@ -1191,6 +1193,7 @@ mlx5_nl_switch_info_cb(struct nlmsghdr *nh, void *arg)
        size_t off = NLMSG_LENGTH(sizeof(struct ifinfomsg));
        bool switch_id_set = false;
        bool num_vf_set = false;
+       int len;
 
        if (nh->nlmsg_type != RTM_NEWLINK)
                goto error;
@@ -1206,7 +1209,24 @@ mlx5_nl_switch_info_cb(struct nlmsghdr *nh, void *arg)
                        num_vf_set = true;
                        break;
                case IFLA_PHYS_PORT_NAME:
-                       mlx5_translate_port_name((char *)payload, &info);
+                       len = RTA_PAYLOAD(ra);
+                       /* Some kernels do not pad attributes with zero. */
+                       if (len > 0 && len < MLX5_PHYS_PORT_NAME_MAX) {
+                               char name[MLX5_PHYS_PORT_NAME_MAX];
+
+                               /*
+                                * We can't just patch the message with padding
+                                * zero - it might corrupt the following items
+                                * in the message, we have to copy the string
+                                * by attribute length and pad the copied one.
+                                */
+                               memcpy(name, payload, len);
+                               name[len] = 0;
+                               mlx5_translate_port_name(name, &info);
+                       } else {
+                               info.name_type =
+                                       MLX5_PHYS_PORT_NAME_TYPE_UNKNOWN;
+                       }
                        break;
                case IFLA_PHYS_SWITCH_ID:
                        info.switch_id = 0;