[PATCH net 0/2] net/smc: fixes for -net

[PATCH net 0/2] net/smc: fixes for -net

[Karsten Graul]

Fix a syzbot finding and a problem with the CLC handshake content.

Ursula Braun (2):
  net/smc: transfer fasync_list in case of fallback
  net/smc: no peer ID in CLC decline for SMCD

 net/smc/af_smc.c  | 2 ++
 net/smc/smc_clc.c | 4 +++-
 2 files changed, 5 insertions(+), 1 deletion(-)

-- 
2.17.1

[PATCH net 1/2] net/smc: transfer fasync_list in case of fallback

[Karsten Graul]

From: Ursula Braun <ubraun@linux.ibm.com>

SMC does not work together with FASTOPEN. If sendmsg() is called with
flag MSG_FASTOPEN in SMC_INIT state, the SMC-socket switches to
fallback mode. To handle the previous ioctl FIOASYNC call correctly
in this case, it is necessary to transfer the socket wait queue
fasync_list to the internal TCP socket.

Reported-by: syzbot+4b1fe8105f8044a26162@syzkaller.appspotmail.com
Fixes: ee9dfbef02d18 ("net/smc: handle sockopts forcing fallback")
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
---
 net/smc/af_smc.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c
index cee5bf4a9bb9..90988a511cd5 100644
--- a/net/smc/af_smc.c
+++ b/net/smc/af_smc.c
@@ -470,6 +470,8 @@ static void smc_switch_to_fallback(struct smc_sock *smc)
 	if (smc->sk.sk_socket && smc->sk.sk_socket->file) {
 		smc->clcsock->file = smc->sk.sk_socket->file;
 		smc->clcsock->file->private_data = smc->clcsock;
+		smc->clcsock->wq.fasync_list =
+			smc->sk.sk_socket->wq.fasync_list;
 	}
 }
 
-- 
2.17.1

[PATCH net 2/2] net/smc: no peer ID in CLC decline for SMCD

[Karsten Graul]

From: Ursula Braun <ubraun@linux.ibm.com>

Just SMCR requires a CLC Peer ID, but not SMCD. The field should be
zero for SMCD.

Fixes: c758dfddc1b5 ("net/smc: add SMC-D support in CLC messages")
Signed-off-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
---
 net/smc/smc_clc.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/net/smc/smc_clc.c b/net/smc/smc_clc.c
index 0879f7bed967..86cccc24e52e 100644
--- a/net/smc/smc_clc.c
+++ b/net/smc/smc_clc.c
@@ -372,7 +372,9 @@ int smc_clc_send_decline(struct smc_sock *smc, u32 peer_diag_info)
 	dclc.hdr.length = htons(sizeof(struct smc_clc_msg_decline));
 	dclc.hdr.version = SMC_CLC_V1;
 	dclc.hdr.flag = (peer_diag_info == SMC_CLC_DECL_SYNCERR) ? 1 : 0;
-	memcpy(dclc.id_for_peer, local_systemid, sizeof(local_systemid));
+	if (smc->conn.lgr && !smc->conn.lgr->is_smcd)
+		memcpy(dclc.id_for_peer, local_systemid,
+		       sizeof(local_systemid));
 	dclc.peer_diagnosis = htonl(peer_diag_info);
 	memcpy(dclc.trl.eyecatcher, SMC_EYECATCHER, sizeof(SMC_EYECATCHER));
 
-- 
2.17.1

Re: [PATCH net 0/2] net/smc: fixes for -net

[David Miller]

From: Karsten Graul <kgraul@linux.ibm.com>
Date: Fri, 14 Feb 2020 08:58:58 +0100

> Fix a syzbot finding and a problem with the CLC handshake content.

Series applied, thank you.