| Message ID | 1517596047.3715.135.camel@gmail.com |
|---|---|
| State | Accepted, archived |
| Delegated to: | David Miller |
| Headers | show |
| Series | [net] soreuseport: fix mem leak in reuseport_add_sock() | expand |
On Fri, Feb 2, 2018 at 1:27 PM, Eric Dumazet <eric.dumazet@gmail.com> wrote: > From: Eric Dumazet <edumazet@google.com> > > 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 Clever fix, thanks Eric(s)! Acked-by: Craig Gallek <kraig@google.com>
From: Eric Dumazet <eric.dumazet@gmail.com> Date: Fri, 02 Feb 2018 10:27:27 -0800 > From: Eric Dumazet <edumazet@google.com> > > 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. ... > Fixes: ef456144da8e ("soreuseport: define reuseport groups") > Signed-off-by: Eric Dumazet <edumazet@google.com> > Reported-by: syzbot+c0ea2226f77a42936bf7@syzkaller.appspotmail.com Applied, thanks.
diff --git a/net/core/sock_reuseport.c b/net/core/sock_reuseport.c index c5bb52bc73a18689c358389b5f1c89cf6a2402a2..064acb04be0f73ff48cf1b4f340476793eceb5cd 100644 --- a/net/core/sock_reuseport.c +++ b/net/core/sock_reuseport.c @@ -94,6 +94,16 @@ static struct sock_reuseport *reuseport_grow(struct sock_reuseport *reuse) 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. @@ -102,7 +112,7 @@ static struct sock_reuseport *reuseport_grow(struct sock_reuseport *reuse) */ 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); @@ -113,10 +123,13 @@ int reuseport_add_sock(struct sock *sk, struct sock *sk2) 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); @@ -134,19 +147,11 @@ int reuseport_add_sock(struct sock *sk, struct sock *sk2) 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;