[RFC bpf-next v4 1/6] bpf: Allow PTR_TO_BTF_ID even for pointers to int.

[thinker.li@gmail.com]

From: Kui-Feng Lee <thinker.li@gmail.com>

Pointers to int are always accepted when checking accesses of a context in
btf_ctx_access(). However, we are going to support pointers to scalar types
with PTR_TO_BTF_ID.  Changing the order of checking prog->aux->ctx_arg_info
and checking is_int_ptr() enables the extension in the following patches.

Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
---
 kernel/bpf/btf.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/kernel/bpf/btf.c b/kernel/bpf/btf.c
index ef380e546952..0847035bba99 100644
--- a/kernel/bpf/btf.c
+++ b/kernel/bpf/btf.c
@@ -6252,9 +6252,6 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type,
 		 */
 		return true;
 
-	if (is_int_ptr(btf, t))
-		return true;
-
 	/* this is a pointer to another type */
 	for (i = 0; i < prog->aux->ctx_arg_info_size; i++) {
 		const struct bpf_ctx_arg_aux *ctx_arg_info = &prog->aux->ctx_arg_info[i];
@@ -6272,6 +6269,9 @@ bool btf_ctx_access(int off, int size, enum bpf_access_type type,
 		}
 	}
 
+	if (is_int_ptr(btf, t))
+		return true;
+
 	info->reg_type = PTR_TO_BTF_ID;
 	if (prog_args_trusted(prog))
 		info->reg_type |= PTR_TRUSTED;
-- 
2.34.1