[PATCH bpf 5/7] bpf: fix direct packet write into pop/peek helpers

[Daniel Borkmann]

Commit f1a2e44a3aec ("bpf: add queue and stack maps") probably just
copy-pasted .pkt_access for bpf_map_{pop,peek}_elem() helpers, but
this is buggy in this context since it would allow writes into cloned
skbs which is invalid. Therefore, disable .pkt_access for the two.

Fixes: f1a2e44a3aec ("bpf: add queue and stack maps")
Signed-off-by: Daniel Borkmann <dan...@iogearbox.net>
Acked-by: Alexei Starovoitov <a...@kernel.org>
Cc: Mauricio Vasquez B <mauricio.vasq...@polito.it>
---
 kernel/bpf/helpers.c | 2 --
 1 file changed, 2 deletions(-)

diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index ab0d5e3..a74972b 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -99,7 +99,6 @@ BPF_CALL_2(bpf_map_pop_elem, struct bpf_map *, map, void *, 
value)
 const struct bpf_func_proto bpf_map_pop_elem_proto = {
        .func           = bpf_map_pop_elem,
        .gpl_only       = false,
-       .pkt_access     = true,
        .ret_type       = RET_INTEGER,
        .arg1_type      = ARG_CONST_MAP_PTR,
        .arg2_type      = ARG_PTR_TO_UNINIT_MAP_VALUE,
@@ -113,7 +112,6 @@ BPF_CALL_2(bpf_map_peek_elem, struct bpf_map *, map, void 
*, value)
 const struct bpf_func_proto bpf_map_peek_elem_proto = {
        .func           = bpf_map_pop_elem,
        .gpl_only       = false,
-       .pkt_access     = true,
        .ret_type       = RET_INTEGER,
        .arg1_type      = ARG_CONST_MAP_PTR,
        .arg2_type      = ARG_PTR_TO_UNINIT_MAP_VALUE,
-- 
2.9.5