diff options
| author | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-10-12 21:21:39 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2017-10-12 21:21:39 +0200 |
| commit | 00449628f3526aef5b682cc4c18f6c422d3be810 (patch) | |
| tree | 8a9f434000c32a01fe30a3fca9aa83fa0dc3042a | |
| parent | f82786d7a94f06a35ab273002cedc1385bae8e9f (diff) | |
Revert "socket, bpf: fix possible use after free"
This reverts commit 02f7e4101092b88e57c73171174976c8a72a3eba, which was
commit 02f7e4101092b88e57c73171174976c8a72a3eba upstream
Turns out the backport to 4.9 was broken.
Reported-by: Shuah Khan <shuahkh@osg.samsung.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | net/core/filter.c | 15 | ||||
| -rw-r--r-- | net/core/sock.c | 5 |
2 files changed, 3 insertions, 17 deletions
diff --git a/net/core/filter.c b/net/core/filter.c index bfeedbbde214..4eb4ce0aeef4 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -937,31 +937,20 @@ void sk_filter_uncharge(struct sock *sk, struct sk_filter *fp) /* try to charge the socket memory if there is space available * return true on success */ -static bool __sk_filter_charge(struct sock *sk, struct sk_filter *fp) +bool sk_filter_charge(struct sock *sk, struct sk_filter *fp) { u32 filter_size = bpf_prog_size(fp->prog->len); /* same check as in sock_kmalloc() */ if (filter_size <= sysctl_optmem_max && atomic_read(&sk->sk_omem_alloc) + filter_size < sysctl_optmem_max) { + atomic_inc(&fp->refcnt); atomic_add(filter_size, &sk->sk_omem_alloc); return true; } return false; } -bool sk_filter_charge(struct sock *sk, struct sk_filter *fp) -{ - if (!atomic_inc_not_zero(&fp->refcnt)) - return false; - - if (!__sk_filter_charge(sk, fp)) { - sk_filter_release(fp); - return false; - } - return true; -} - static struct bpf_prog *bpf_migrate_filter(struct bpf_prog *fp) { struct sock_filter *old_prog; diff --git a/net/core/sock.c b/net/core/sock.c index 2a77cc50f021..231c38d91855 100644 --- a/net/core/sock.c +++ b/net/core/sock.c @@ -1528,16 +1528,13 @@ struct sock *sk_clone_lock(const struct sock *sk, const gfp_t priority) sock_reset_flag(newsk, SOCK_DONE); skb_queue_head_init(&newsk->sk_error_queue); - rcu_read_lock(); - filter = rcu_dereference(sk->sk_filter); + filter = rcu_dereference_protected(newsk->sk_filter, 1); if (filter != NULL) /* though it's an empty new sock, the charging may fail * if sysctl_optmem_max was changed between creation of * original socket and cloning */ is_charged = sk_filter_charge(newsk, filter); - RCU_INIT_POINTER(newsk->sk_filter, filter); - rcu_read_unlock(); if (unlikely(!is_charged || xfrm_sk_clone_policy(newsk, sk))) { /* We need to make sure that we don't uncharge the new |