This is a note to let you know that I've just added the patch titled
soreuseport: fix mem leak in reuseport_add_sock()
to the 4.9-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...
The filename of the patch is: soreuseport-fix-mem-leak-in-reuseport_add_sock.patch and it can be found in the queue-4.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.
From foo@baz Tue Feb 6 12:42:23 PST 2018
From: Eric Dumazet edumazet@google.com Date: Fri, 2 Feb 2018 10:27:27 -0800 Subject: soreuseport: fix mem leak in reuseport_add_sock()
From: Eric Dumazet edumazet@google.com
[ Upstream commit 4db428a7c9ab07e08783e0fcdc4ca0f555da0567 ]
reuseport_add_sock() needs to deal with attaching a socket having its own sk_reuseport_cb, after a prior setsockopt(SO_ATTACH_REUSEPORT_?BPF)
Without this fix, not only a WARN_ONCE() was issued, but we were also leaking memory.
Thanks to sysbot and Eric Biggers for providing us nice C repros.
------------[ cut here ]------------ socket already in reuseport group WARNING: CPU: 0 PID: 3496 at net/core/sock_reuseport.c:119 reuseport_add_sock+0x742/0x9b0 net/core/sock_reuseport.c:117 Kernel panic - not syncing: panic_on_warn set ...
CPU: 0 PID: 3496 Comm: syzkaller869503 Not tainted 4.15.0-rc6+ #245 Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011 Call Trace: __dump_stack lib/dump_stack.c:17 [inline] dump_stack+0x194/0x257 lib/dump_stack.c:53 panic+0x1e4/0x41c kernel/panic.c:183 __warn+0x1dc/0x200 kernel/panic.c:547 report_bug+0x211/0x2d0 lib/bug.c:184 fixup_bug.part.11+0x37/0x80 arch/x86/kernel/traps.c:178 fixup_bug arch/x86/kernel/traps.c:247 [inline] do_error_trap+0x2d7/0x3e0 arch/x86/kernel/traps.c:296 do_invalid_op+0x1b/0x20 arch/x86/kernel/traps.c:315 invalid_op+0x22/0x40 arch/x86/entry/entry_64.S:1079
Fixes: ef456144da8e ("soreuseport: define reuseport groups") Signed-off-by: Eric Dumazet edumazet@google.com Reported-by: syzbot+c0ea2226f77a42936bf7@syzkaller.appspotmail.com Acked-by: Craig Gallek kraig@google.com
Signed-off-by: David S. Miller davem@davemloft.net Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- net/core/sock_reuseport.c | 35 ++++++++++++++++++++--------------- 1 file changed, 20 insertions(+), 15 deletions(-)
--- a/net/core/sock_reuseport.c +++ b/net/core/sock_reuseport.c @@ -93,6 +93,16 @@ static struct sock_reuseport *reuseport_ return more_reuse; }
+static void reuseport_free_rcu(struct rcu_head *head) +{ + struct sock_reuseport *reuse; + + reuse = container_of(head, struct sock_reuseport, rcu); + if (reuse->prog) + bpf_prog_destroy(reuse->prog); + kfree(reuse); +} + /** * reuseport_add_sock - Add a socket to the reuseport group of another. * @sk: New socket to add to the group. @@ -101,7 +111,7 @@ static struct sock_reuseport *reuseport_ */ int reuseport_add_sock(struct sock *sk, struct sock *sk2) { - struct sock_reuseport *reuse; + struct sock_reuseport *old_reuse, *reuse;
if (!rcu_access_pointer(sk2->sk_reuseport_cb)) { int err = reuseport_alloc(sk2); @@ -112,10 +122,13 @@ int reuseport_add_sock(struct sock *sk,
spin_lock_bh(&reuseport_lock); reuse = rcu_dereference_protected(sk2->sk_reuseport_cb, - lockdep_is_held(&reuseport_lock)), - WARN_ONCE(rcu_dereference_protected(sk->sk_reuseport_cb, - lockdep_is_held(&reuseport_lock)), - "socket already in reuseport group"); + lockdep_is_held(&reuseport_lock)); + old_reuse = rcu_dereference_protected(sk->sk_reuseport_cb, + lockdep_is_held(&reuseport_lock)); + if (old_reuse && old_reuse->num_socks != 1) { + spin_unlock_bh(&reuseport_lock); + return -EBUSY; + }
if (reuse->num_socks == reuse->max_socks) { reuse = reuseport_grow(reuse); @@ -133,19 +146,11 @@ int reuseport_add_sock(struct sock *sk,
spin_unlock_bh(&reuseport_lock);
+ if (old_reuse) + call_rcu(&old_reuse->rcu, reuseport_free_rcu); return 0; }
-static void reuseport_free_rcu(struct rcu_head *head) -{ - struct sock_reuseport *reuse; - - reuse = container_of(head, struct sock_reuseport, rcu); - if (reuse->prog) - bpf_prog_destroy(reuse->prog); - kfree(reuse); -} - void reuseport_detach_sock(struct sock *sk) { struct sock_reuseport *reuse;
Patches currently in stable-queue which might be from edumazet@google.com are
queue-4.9/tcp-release-sk_frag.page-in-tcp_disconnect.patch queue-4.9/net-igmp-add-a-missing-rcu-locking-section.patch queue-4.9/soreuseport-fix-mem-leak-in-reuseport_add_sock.patch