diff options
| author | Reshetova, Elena <elena.reshetova@intel.com> | 2017-03-21 13:59:19 +0200 |
|---|---|---|
| committer | David S. Miller <davem@davemloft.net> | 2017-03-22 12:06:08 -0700 |
| commit | 4c355cdfbba537971b5c3849680b1b6453a7a383 (patch) | |
| tree | 0992566cf726ff06986c271a2f7aff0c911d9441 /net/core | |
| parent | 726bceca81ba09956226ea03c9fb58e037c3db7d (diff) | |
net: convert sk_filter.refcnt from atomic_t to refcount_t
refcount_t type and corresponding API should be
used instead of atomic_t when the variable is used as
a reference counter. This allows to avoid accidental
refcounter overflows that might lead to use-after-free
situations.
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
Acked-by: Daniel Borkmann <daniel@iogearbox.net>
Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/core')
| -rw-r--r-- | net/core/filter.c | 17 |
1 files changed, 12 insertions, 5 deletions
diff --git a/net/core/filter.c b/net/core/filter.c index ebaeaf2e46e8..c7f0ccd1c0d3 100644 --- a/net/core/filter.c +++ b/net/core/filter.c @@ -928,7 +928,7 @@ static void sk_filter_release_rcu(struct rcu_head *rcu) */ static void sk_filter_release(struct sk_filter *fp) { - if (atomic_dec_and_test(&fp->refcnt)) + if (refcount_dec_and_test(&fp->refcnt)) call_rcu(&fp->rcu, sk_filter_release_rcu); } @@ -943,20 +943,27 @@ 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 */ -bool sk_filter_charge(struct sock *sk, struct sk_filter *fp) +static 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) +{ + bool ret = __sk_filter_charge(sk, fp); + if (ret) + refcount_inc(&fp->refcnt); + return ret; +} + static struct bpf_prog *bpf_migrate_filter(struct bpf_prog *fp) { struct sock_filter *old_prog; @@ -1179,12 +1186,12 @@ static int __sk_attach_prog(struct bpf_prog *prog, struct sock *sk) return -ENOMEM; fp->prog = prog; - atomic_set(&fp->refcnt, 0); - if (!sk_filter_charge(sk, fp)) { + if (!__sk_filter_charge(sk, fp)) { kfree(fp); return -ENOMEM; } + refcount_set(&fp->refcnt, 1); old_fp = rcu_dereference_protected(sk->sk_filter, lockdep_sock_is_held(sk)); |