Re: [PATCH bpf-next 1/3] bpf: Fix bpf_strncmp proto.

[David Vernet <void@manifault.com>]

On Mon, Mar 13, 2023 at 04:58:43PM -0700, Alexei Starovoitov wrote:
> From: Alexei Starovoitov <ast@kernel.org>
> 
> 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>

> ---
>  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 77d64b6951b9..f753676ef652 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,
>  };
> -- 
> 2.34.1
>