From e7947ea770d0de434d38a0f823e660d3fd4bebb5 Mon Sep 17 00:00:00 2001 From: Isaac Boukris Date: Tue, 1 Nov 2016 02:41:35 +0200 Subject: unix: escape all null bytes in abstract unix domain socket Abstract unix domain socket may embed null characters, these should be translated to '@' when printed out to proc the same way the null prefix is currently being translated. This helps for tools such as netstat, lsof and the proc based implementation in ss to show all the significant bytes of the name (instead of getting cut at the first null occurrence). Signed-off-by: Isaac Boukris Signed-off-by: David S. Miller --- net/unix/af_unix.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'net/unix/af_unix.c') diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 145082e2ba36..5d1c14a2f268 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -2812,7 +2812,8 @@ static int unix_seq_show(struct seq_file *seq, void *v) i++; } for ( ; i < len; i++) - seq_putc(seq, u->addr->name->sun_path[i]); + seq_putc(seq, u->addr->name->sun_path[i] ?: + '@'); } unix_state_unlock(s); seq_putc(seq, '\n'); -- cgit v1.2.3 From 06a77b07e3b44aea2b3c0e64de420ea2cfdcbaa9 Mon Sep 17 00:00:00 2001 From: WANG Cong Date: Thu, 17 Nov 2016 15:55:26 -0800 Subject: af_unix: conditionally use freezable blocking calls in read Commit 2b15af6f95 ("af_unix: use freezable blocking calls in read") converts schedule_timeout() to its freezable version, it was probably correct at that time, but later, commit 2b514574f7e8 ("net: af_unix: implement splice for stream af_unix sockets") breaks the strong requirement for a freezable sleep, according to commit 0f9548ca1091: We shouldn't try_to_freeze if locks are held. Holding a lock can cause a deadlock if the lock is later acquired in the suspend or hibernate path (e.g. by dpm). Holding a lock can also cause a deadlock in the case of cgroup_freezer if a lock is held inside a frozen cgroup that is later acquired by a process outside that group. The pipe_lock is still held at that point. So use freezable version only for the recvmsg call path, avoid impact for Android. Fixes: 2b514574f7e8 ("net: af_unix: implement splice for stream af_unix sockets") Reported-by: Dmitry Vyukov Cc: Tejun Heo Cc: Colin Cross Cc: Rafael J. Wysocki Cc: Hannes Frederic Sowa Signed-off-by: Cong Wang Signed-off-by: David S. Miller --- net/unix/af_unix.c | 17 +++++++++++------ 1 file changed, 11 insertions(+), 6 deletions(-) (limited to 'net/unix/af_unix.c') diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c index 5d1c14a2f268..2358f2690ec5 100644 --- a/net/unix/af_unix.c +++ b/net/unix/af_unix.c @@ -2199,7 +2199,8 @@ out: * Sleep until more data has arrived. But check for races.. */ static long unix_stream_data_wait(struct sock *sk, long timeo, - struct sk_buff *last, unsigned int last_len) + struct sk_buff *last, unsigned int last_len, + bool freezable) { struct sk_buff *tail; DEFINE_WAIT(wait); @@ -2220,7 +2221,10 @@ static long unix_stream_data_wait(struct sock *sk, long timeo, sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); unix_state_unlock(sk); - timeo = freezable_schedule_timeout(timeo); + if (freezable) + timeo = freezable_schedule_timeout(timeo); + else + timeo = schedule_timeout(timeo); unix_state_lock(sk); if (sock_flag(sk, SOCK_DEAD)) @@ -2250,7 +2254,8 @@ struct unix_stream_read_state { unsigned int splice_flags; }; -static int unix_stream_read_generic(struct unix_stream_read_state *state) +static int unix_stream_read_generic(struct unix_stream_read_state *state, + bool freezable) { struct scm_cookie scm; struct socket *sock = state->socket; @@ -2330,7 +2335,7 @@ again: mutex_unlock(&u->iolock); timeo = unix_stream_data_wait(sk, timeo, last, - last_len); + last_len, freezable); if (signal_pending(current)) { err = sock_intr_errno(timeo); @@ -2472,7 +2477,7 @@ static int unix_stream_recvmsg(struct socket *sock, struct msghdr *msg, .flags = flags }; - return unix_stream_read_generic(&state); + return unix_stream_read_generic(&state, true); } static int unix_stream_splice_actor(struct sk_buff *skb, @@ -2503,7 +2508,7 @@ static ssize_t unix_stream_splice_read(struct socket *sock, loff_t *ppos, flags & SPLICE_F_NONBLOCK) state.flags = MSG_DONTWAIT; - return unix_stream_read_generic(&state); + return unix_stream_read_generic(&state, false); } static int unix_shutdown(struct socket *sock, int mode) -- cgit v1.2.3