[PATCH net 3/3] rtnetlink: add the missing IFLA_GRO_ tb check in validate_linkmsg

[Xin Long <lucien.xin@gmail.com>]

This fixes the issue that dev gro_max_size and gso_ipv4_max_size
can be set to a huge value:

  # ip link add dummy1 type dummy
  # ip link set dummy1 gro_max_size 4294967295
  # ip -d link show dummy1 |grep gro_max_size
    dummy addrgenmode eui64 ... gro_max_size 4294967295

Fixes: 0fe79f28bfaf ("net: allow gro_max_size to exceed 65536")
Fixes: 9eefedd58ae1 ("net: add gso_ipv4_max_size and gro_ipv4_max_size per device")
Reported-by: Xiumei Mu <xmu@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
---
 net/core/rtnetlink.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/net/core/rtnetlink.c b/net/core/rtnetlink.c
index 68a58d0a7b79..4c7d84072bd4 100644
--- a/net/core/rtnetlink.c
+++ b/net/core/rtnetlink.c
@@ -2398,12 +2398,24 @@ static int validate_linkmsg(struct net_device *dev, struct nlattr *tb[],
 		return -EINVAL;
 	}
 
+	if (tb[IFLA_GRO_MAX_SIZE] &&
+	    nla_get_u32(tb[IFLA_GRO_MAX_SIZE]) > GRO_MAX_SIZE) {
+		NL_SET_ERR_MSG(extack, "too big gro_max_size");
+		return -EINVAL;
+	}
+
 	if (tb[IFLA_GSO_IPV4_MAX_SIZE] &&
 	    nla_get_u32(tb[IFLA_GSO_IPV4_MAX_SIZE]) > dev->tso_max_size) {
 		NL_SET_ERR_MSG(extack, "too big gso_ipv4_max_size");
 		return -EINVAL;
 	}
 
+	if (tb[IFLA_GRO_IPV4_MAX_SIZE] &&
+	    nla_get_u32(tb[IFLA_GRO_IPV4_MAX_SIZE]) > GRO_MAX_SIZE) {
+		NL_SET_ERR_MSG(extack, "too big gro_ipv4_max_size");
+		return -EINVAL;
+	}
+
 	if (tb[IFLA_AF_SPEC]) {
 		struct nlattr *af;
 		int rem, err;
-- 
2.39.1