bpf: fix sock_map_alloc() error path

In case user program provides silly parameters, we want
a map_alloc() handler to return an error, not a NULL pointer,
otherwise we crash later in find_and_alloc_map()

Fixes: 1aa12bdf1b ("bpf: sockmap, add sock close() hook to remove socks")
Signed-off-by: Eric Dumazet <edumazet@google.com>
Reported-by: syzbot <syzkaller@googlegroups.com>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
This commit is contained in:
Eric Dumazet 2018-02-13 15:33:52 -08:00 committed by Alexei Starovoitov
parent 9a3efb6b66
commit 952fad8e32

View File

@ -521,8 +521,8 @@ static struct smap_psock *smap_init_psock(struct sock *sock,
static struct bpf_map *sock_map_alloc(union bpf_attr *attr)
{
struct bpf_stab *stab;
int err = -EINVAL;
u64 cost;
int err;
if (!capable(CAP_NET_ADMIN))
return ERR_PTR(-EPERM);
@ -547,6 +547,7 @@ static struct bpf_map *sock_map_alloc(union bpf_attr *attr)
/* make sure page count doesn't overflow */
cost = (u64) stab->map.max_entries * sizeof(struct sock *);
err = -EINVAL;
if (cost >= U32_MAX - PAGE_SIZE)
goto free_stab;