On Mon, Mar 13, 2023 at 04:58:43PM -0700, Alexei Starovoitov wrote:
> From: Alexei Starovoitov <ast@xxxxxxxxxx>
>
> bpf_strncmp() doesn't write into its first argument.
> Make sure that the verifier knows about it.
>
> Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
Acked-by: David Vernet <void@xxxxxxxxxxxxx>
> ---
> 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
>
