From: Sabrina Dubroca <sd@queasysnail.net>
Date: Wed, 22 Apr 2020 17:29:50 +0200
Subject: vxlan: use the correct nlattr array in NL_SET_ERR_MSG_ATTR
Git-commit: cc8e7c69db4dcc565ed3020f97ddd6debab6cbe8
Patch-mainline: 5.7-rc3
References: networking-stable-20_04_27

IFLA_VXLAN_* attributes are in the data array, which is correctly
used when fetching the value, but not when setting the extended
ack. Because IFLA_VXLAN_MAX < IFLA_MAX, we avoid out of bounds
array accesses, but we don't provide a pointer to the invalid
attribute to userspace.

Fixes: 653ef6a3e4af ("vxlan: change vxlan_[config_]validate() to use netlink_ext_ack for error reporting")
Fixes: b4d3069783bc ("vxlan: Allow configuration of DF behaviour")
Signed-off-by: Sabrina Dubroca <sd@queasysnail.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
 drivers/net/vxlan.c |    6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/net/vxlan.c
+++ b/drivers/net/vxlan.c
@@ -3143,7 +3143,7 @@ static int vxlan_validate(struct nlattr
 		u32 id = nla_get_u32(data[IFLA_VXLAN_ID]);
 
 		if (id >= VXLAN_N_VID) {
-			NL_SET_ERR_MSG_ATTR(extack, tb[IFLA_VXLAN_ID],
+			NL_SET_ERR_MSG_ATTR(extack, data[IFLA_VXLAN_ID],
 					    "VXLAN ID must be lower than 16777216");
 			return -ERANGE;
 		}
@@ -3154,7 +3154,7 @@ static int vxlan_validate(struct nlattr
 			= nla_data(data[IFLA_VXLAN_PORT_RANGE]);
 
 		if (ntohs(p->high) < ntohs(p->low)) {
-			NL_SET_ERR_MSG_ATTR(extack, tb[IFLA_VXLAN_PORT_RANGE],
+			NL_SET_ERR_MSG_ATTR(extack, data[IFLA_VXLAN_PORT_RANGE],
 					    "Invalid source port range");
 			return -EINVAL;
 		}
@@ -3164,7 +3164,7 @@ static int vxlan_validate(struct nlattr
 		enum ifla_vxlan_df df = nla_get_u8(data[IFLA_VXLAN_DF]);
 
 		if (df < 0 || df > VXLAN_DF_MAX) {
-			NL_SET_ERR_MSG_ATTR(extack, tb[IFLA_VXLAN_DF],
+			NL_SET_ERR_MSG_ATTR(extack, data[IFLA_VXLAN_DF],
 					    "Invalid DF attribute");
 			return -EINVAL;
 		}