linux-kernel - [PATCH net] sctp: get sctphdr by offset in sctp_compute

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [thread-next>] [day] [month] [year] [list]

Message-Id: <2aee76766861ac9e46b7acf123d5d6e8f2adf8e0.1551093937.git.lucien.xin@gmail.com>
Date:   Mon, 25 Feb 2019 19:25:37 +0800
From:   Xin Long <lucien.xin@...il.com>
To:     linux-kernel@...r.kernel.org, network dev <netdev@...r.kernel.org>,
        linux-sctp@...r.kernel.org
Cc:     davem@...emloft.net,
        Marcelo Ricardo Leitner <marcelo.leitner@...il.com>,
        Neil Horman <nhorman@...driver.com>
Subject: [PATCH net] sctp: get sctphdr by offset in sctp_compute_cksum

sctp_hdr(skb) only works when skb->transport_header is set properly.

But in the path of nf_conntrack_in: sctp_packet() -> sctp_error()

skb->transport_header is not guaranteed to be right value for sctp.
It will cause to fail to check the checksum for sctp packets.

So fix it by using offset, which is always right in all places.

Fixes: e6d8b64b34aa ("net: sctp: fix and consolidate SCTP checksumming code")
Reported-by: Li Shuang <shuali@...hat.com>
Signed-off-by: Xin Long <lucien.xin@...il.com>
---
 include/net/sctp/checksum.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/net/sctp/checksum.h b/include/net/sctp/checksum.h
index 32ee65a..1c6e6c0 100644
--- a/include/net/sctp/checksum.h
+++ b/include/net/sctp/checksum.h
@@ -61,7 +61,7 @@ static inline __wsum sctp_csum_combine(__wsum csum, __wsum csum2,
 static inline __le32 sctp_compute_cksum(const struct sk_buff *skb,
 					unsigned int offset)
 {
-	struct sctphdr *sh = sctp_hdr(skb);
+	struct sctphdr *sh = (struct sctphdr *)(skb->data + offset);
 	const struct skb_checksum_ops ops = {
 		.update  = sctp_csum_update,
 		.combine = sctp_csum_combine,
-- 
2.1.0