From 26d92e951fe0a44ee4aec157cabb65a818cc8151 Mon Sep 17 00:00:00 2001 From: Cong Wang Date: Sat, 5 Jan 2019 23:45:26 -0800 Subject: smc: move unhash as early as possible in smc_release() In smc_release() we release smc->clcsock before unhash the smc sock, but a parallel smc_diag_dump() may be still reading smc->clcsock, therefore this could cause a use-after-free as reported by syzbot. Reported-and-tested-by: syzbot+fbd1e5476e4c94c7b34e@syzkaller.appspotmail.com Fixes: 51f1de79ad8e ("net/smc: replace sock_put worker by socket refcounting") Cc: Ursula Braun Signed-off-by: Cong Wang Reported-by: syzbot+0bf2e01269f1274b4b03@syzkaller.appspotmail.com Reported-by: syzbot+e3132895630f957306bc@syzkaller.appspotmail.com Signed-off-by: David S. Miller --- net/smc/af_smc.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) (limited to 'net/smc/af_smc.c') diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c index c4da4a78d369..c4e56602e0c6 100644 --- a/net/smc/af_smc.c +++ b/net/smc/af_smc.c @@ -146,6 +146,9 @@ static int smc_release(struct socket *sock) sock_set_flag(sk, SOCK_DEAD); sk->sk_shutdown |= SHUTDOWN_MASK; } + + sk->sk_prot->unhash(sk); + if (smc->clcsock) { if (smc->use_fallback && sk->sk_state == SMC_LISTEN) { /* wake up clcsock accept */ @@ -170,7 +173,6 @@ static int smc_release(struct socket *sock) smc_conn_free(&smc->conn); release_sock(sk); - sk->sk_prot->unhash(sk); sock_put(sk); /* final sock_put */ out: return rc; -- cgit v1.2.3 From 51c5aba3b672c4285fca052817f34b22dc79dda7 Mon Sep 17 00:00:00 2001 From: Karsten Graul Date: Wed, 30 Jan 2019 18:51:04 +0100 Subject: net/smc: recvmsg and splice_read should return 0 after shutdown When a socket was connected and is now shut down for read, return 0 to indicate end of data in recvmsg and splice_read (like TCP) and do not return ENOTCONN. This behavior is required by the socket api. Signed-off-by: Karsten Graul Signed-off-by: Ursula Braun Signed-off-by: David S. Miller --- net/smc/af_smc.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) (limited to 'net/smc/af_smc.c') diff --git a/net/smc/af_smc.c b/net/smc/af_smc.c index c4e56602e0c6..b04a813fc865 100644 --- a/net/smc/af_smc.c +++ b/net/smc/af_smc.c @@ -1505,6 +1505,11 @@ static int smc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len, smc = smc_sk(sk); lock_sock(sk); + if (sk->sk_state == SMC_CLOSED && (sk->sk_shutdown & RCV_SHUTDOWN)) { + /* socket was connected before, no more data to read */ + rc = 0; + goto out; + } if ((sk->sk_state == SMC_INIT) || (sk->sk_state == SMC_LISTEN) || (sk->sk_state == SMC_CLOSED)) @@ -1840,7 +1845,11 @@ static ssize_t smc_splice_read(struct socket *sock, loff_t *ppos, smc = smc_sk(sk); lock_sock(sk); - + if (sk->sk_state == SMC_CLOSED && (sk->sk_shutdown & RCV_SHUTDOWN)) { + /* socket was connected before, no more data to read */ + rc = 0; + goto out; + } if (sk->sk_state == SMC_INIT || sk->sk_state == SMC_LISTEN || sk->sk_state == SMC_CLOSED) -- cgit v1.2.3