From b845c898b2f1ea458d5453f0fa1da6e2dfce3bb4 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Tue, 21 Aug 2018 15:55:00 +0200 Subject: [PATCH] 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: 81110384441a ("bpf: sockmap, add hash map support") Signed-off-by: Daniel Borkmann Acked-by: John Fastabend Acked-by: Song Liu --- kernel/bpf/sockmap.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/kernel/bpf/sockmap.c b/kernel/bpf/sockmap.c index 98e621a29e8e..60ceb0e1fa56 100644 --- a/kernel/bpf/sockmap.c +++ b/kernel/bpf/sockmap.c @@ -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);