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From: Pablo Neira Ayuso <pablo@netfilter.org>
To: netdev@vger.kernel.org
Cc: netfilter-devel@vger.kernel.org, davem@davemloft.net,
	johannes.berg@intel.com
Subject: [PATCH net] netlink: Use netlink header as base to calculate bad attribute offset
Date: Wed, 26 Feb 2020 19:47:34 +0100	[thread overview]
Message-ID: <20200226184734.1866-1-pablo@netfilter.org> (raw)

Userspace might send a batch that is composed of several netlink
messages. The netlink_ack() function must use the pointer to the netlink
header as base to calculate the bad attribute offset.

Fixes: 2d4bc93368f5 ("netlink: extended ACK reporting")
Signed-off-by: Pablo Neira Ayuso <pablo@netfilter.org>
---
 net/netlink/af_netlink.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index edf3e285e242..5313f1cec170 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2434,7 +2434,7 @@ void netlink_ack(struct sk_buff *in_skb, struct nlmsghdr *nlh, int err,
 							       in_skb->len))
 				WARN_ON(nla_put_u32(skb, NLMSGERR_ATTR_OFFS,
 						    (u8 *)extack->bad_attr -
-						    in_skb->data));
+						    (u8 *)nlh));
 		} else {
 			if (extack->cookie_len)
 				WARN_ON(nla_put(skb, NLMSGERR_ATTR_COOKIE,
-- 
2.11.0


             reply	other threads:[~2020-02-26 18:47 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-02-26 18:47 Pablo Neira Ayuso [this message]
2020-03-01  5:22 ` [PATCH net] netlink: Use netlink header as base to calculate bad attribute offset David Miller

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