aboutsummaryrefslogtreecommitdiff
diff options
context:
space:
mode:
authorEric Dumazet <edumazet@google.com>2018-02-02 10:27:27 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-02-12 07:07:21 +0100
commit4c92abe86a20e74e76ac47938275e12a7ffad0c5 (patch)
tree8844238f0e62be4c38a8fb9d565b28daf56c0989
parent07055dd6c806e714d50680940a9cdb1ae393722a (diff)
download96b-common-4c92abe86a20e74e76ac47938275e12a7ffad0c5.tar.gz
soreuseport: fix mem leak in reuseport_add_sock()
[ 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>
-rw-r--r--net/core/sock_reuseport.c35
1 files changed, 20 insertions, 15 deletions
diff --git a/net/core/sock_reuseport.c b/net/core/sock_reuseport.c
index 5eeb1d20cc38..676092d7bd81 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;