From c9267aa8b794c2188d49c7d7bd2990e98b2d6b84 Mon Sep 17 00:00:00 2001
From: Alexei Starovoitov <ast@kernel.org>
Date: Mon, 13 Mar 2023 16:58:43 -0700
Subject: [PATCH] bpf: Fix bpf_strncmp proto.
bpf_strncmp() doesn't write into its first argument.
Make sure that the verifier knows about it.
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Acked-by: David Vernet <void@manifault.com>
Link: https://lore.kernel.org/r/20230313235845.61029-2-alexei.starovoitov@gmail.com
Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
---
kernel/bpf/helpers.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/bpf/helpers.c b/kernel/bpf/helpers.c
index 77d64b6951b9c..f753676ef6522 100644
--- a/kernel/bpf/helpers.c
+++ b/kernel/bpf/helpers.c
@@ -571,7 +571,7 @@ static const struct bpf_func_proto bpf_strncmp_proto = {
.func = bpf_strncmp,
.gpl_only = false,
.ret_type = RET_INTEGER,
- .arg1_type = ARG_PTR_TO_MEM,
+ .arg1_type = ARG_PTR_TO_MEM | MEM_RDONLY,
.arg2_type = ARG_CONST_SIZE,
.arg3_type = ARG_PTR_TO_CONST_STR,
};
--
2.30.2