From e94fa1d93117e7f1eb783dc9cae6c70650944449 Mon Sep 17 00:00:00 2001 From: Daniel Borkmann Date: Fri, 4 May 2018 16:27:53 +0200 Subject: [PATCH] bpf, xskmap: fix crash in xsk_map_alloc error path handling MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit If bpf_map_precharge_memlock() did not fail, then we set err to zero. However, any subsequent failure from either alloc_percpu() or the bpf_map_area_alloc() will return ERR_PTR(0) which in find_and_alloc_map() will cause NULL pointer deref. In devmap we have the convention that we return -EINVAL on page count overflow, so keep the same logic here and just set err to -ENOMEM after successful bpf_map_precharge_memlock(). Fixes: fbfc504a24f5 ("bpf: introduce new bpf AF_XDP map type BPF_MAP_TYPE_XSKMAP") Signed-off-by: Daniel Borkmann Cc: Björn Töpel Acked-by: David S. Miller Signed-off-by: Alexei Starovoitov --- kernel/bpf/xskmap.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/kernel/bpf/xskmap.c b/kernel/bpf/xskmap.c index 869dbb11b612..cb3a12137404 100644 --- a/kernel/bpf/xskmap.c +++ b/kernel/bpf/xskmap.c @@ -56,6 +56,8 @@ static struct bpf_map *xsk_map_alloc(union bpf_attr *attr) if (err) goto free_m; + err = -ENOMEM; + m->flush_list = alloc_percpu(struct list_head); if (!m->flush_list) goto free_m; -- 2.45.2