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 <dan...@iogearbox.net>
Cc: Björn Töpel <bjorn.to...@intel.com>
---
kernel/bpf/xskmap.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/kernel/bpf/xskmap.c b/kernel/bpf/xskmap.c
index 869dbb1..cb3a121 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;
--
2.9.5
