bpf, sockmap: fix sock_hash_alloc and reject zero-sized keys

Currently, it is possible to create a sock hash map with key size
of 0 and have the kernel return a fd back to user space. This is
invalid for hash maps (and kernel also hasn't been tested for zero
key size support in general at this point). Thus, reject such
configuration.

Fixes: 8111038444 ("bpf: sockmap, add hash map support")
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: John Fastabend <john.fastabend@gmail.com>
Acked-by: Song Liu <songliubraving@fb.com>
This commit is contained in:
Daniel Borkmann 2018-08-21 15:55:00 +02:00
parent 96c26e0458
commit b845c898b2

View file

@ -2140,7 +2140,9 @@ static struct bpf_map *sock_hash_alloc(union bpf_attr *attr)
return ERR_PTR(-EPERM);
/* check sanity of attributes */
if (attr->max_entries == 0 || attr->value_size != 4 ||
if (attr->max_entries == 0 ||
attr->key_size == 0 ||
attr->value_size != 4 ||
attr->map_flags & ~SOCK_CREATE_FLAG_MASK)
return ERR_PTR(-EINVAL);