Always check context access if the register we're operating on is
PTR_TO_CTX, rather than relying on ARG_PTR_TO_CTX.
Signed-off-by: Lorenz Bauer <lmb@xxxxxxxxxxxxxx>
---
kernel/bpf/verifier.c | 9 ++++++---
1 file changed, 6 insertions(+), 3 deletions(-)
diff --git a/kernel/bpf/verifier.c b/kernel/bpf/verifier.c
index c7df4ccad8e2..ba710a702cae 100644
--- a/kernel/bpf/verifier.c
+++ b/kernel/bpf/verifier.c
@@ -3979,9 +3979,6 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
arg_type == ARG_PTR_TO_CTX_OR_NULL)) {
if (type != expected_type)
goto err_type;
- err = check_ctx_reg(env, reg, regno);
- if (err < 0)
- return err;
}
} else if (arg_type == ARG_PTR_TO_SOCK_COMMON) {
expected_type = PTR_TO_SOCK_COMMON;
@@ -4081,6 +4078,12 @@ static int check_func_arg(struct bpf_verifier_env *env, u32 arg,
meta->ref_obj_id = reg->ref_obj_id;
}
+ if (type == PTR_TO_CTX) {
+ err = check_ctx_reg(env, reg, regno);
+ if (err < 0)
+ return err;
+ }
+
if (arg_type == ARG_CONST_MAP_PTR) {
/* bpf_map_xxx(map_ptr) call: remember that map_ptr */
meta->map_ptr = reg->map_ptr;
--
2.25.1
