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authorCong Wang <cong.wang@bytedance.com>2021-05-05 12:40:48 -0700
committerDavid S. Miller <davem@davemloft.net>2021-05-05 12:52:45 -0700
commit8621436671f3a4bba5db57482e1ee604708bf1eb (patch)
tree5a5dafac72732103c5eb548fc4a01242e40c70b3 /net/smc
parent2c16db6c92b0ee4aa61e88366df82169e83c3f7e (diff)
downloadlinux-8621436671f3a4bba5db57482e1ee604708bf1eb.tar.gz
smc: disallow TCP_ULP in smc_setsockopt()
syzbot is able to setup kTLS on an SMC socket which coincidentally
uses sk_user_data too. Later, kTLS treats it as psock so triggers a
refcnt warning. The root cause is that smc_setsockopt() simply calls
TCP setsockopt() which includes TCP_ULP. I do not think it makes
sense to setup kTLS on top of SMC sockets, so we should just disallow
this setup.

It is hard to find a commit to blame, but we can apply this patch
since the beginning of TCP_ULP.

Reported-and-tested-by: syzbot+b54a1ce86ba4a623b7f0@syzkaller.appspotmail.com
Fixes: 734942cc4ea6 ("tcp: ULP infrastructure")
Cc: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/smc')
-rw-r--r--net/smc/af_smc.c4
1 files changed, 3 insertions, 1 deletions
diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index be3e80b3e27f..5eff7cccceff 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -2161,6 +2161,9 @@ static int smc_setsockopt(struct socket *sock, int level, int optname,
 	struct smc_sock *smc;
 	int val, rc;
 
+	if (level == SOL_TCP && optname == TCP_ULP)
+		return -EOPNOTSUPP;
+
 	smc = smc_sk(sk);
 
 	/* generic setsockopts reaching us here always apply to the
@@ -2185,7 +2188,6 @@ static int smc_setsockopt(struct socket *sock, int level, int optname,
 	if (rc || smc->use_fallback)
 		goto out;
 	switch (optname) {
-	case TCP_ULP:
 	case TCP_FASTOPEN:
 	case TCP_FASTOPEN_CONNECT:
 	case TCP_FASTOPEN_KEY: