soreuseport: fix mem leak in reuseport_add_sock() (4db428a7) · Commits · 戴 / test

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: ("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>

net/core/sock_reuseport.c

+20 −15

Original line number	Diff line number	Diff line
		@@ -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;

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