Re: [PATCH bpf-next] bpf: btf: Fix arg verification in btf_ctx_access()

[Alexei Starovoitov]

On Mon, Mar 30, 2020 at 7:43 AM KP Singh <kpsingh@xxxxxxxxxxxx> wrote:
>
> From: KP Singh <kpsingh@xxxxxxxxxx>
>
> The bounds checking for the arguments accessed in the BPF program breaks
> when the expected_attach_type is not BPF_TRACE_FEXIT, BPF_LSM_MAC or
> BPF_MODIFY_RETURN resulting in no check being done for the default case
> (the programs which do not receive the return value of the attached
> function in its arguments) when the index of the argument being accessed
> is equal to the number of arguments (nr_args).
>
> This was a result of a misplaced "else if" block  introduced by the
> Commit 6ba43b761c41 ("bpf: Attachment verification for
> BPF_MODIFY_RETURN")
>
> Signed-off-by: KP Singh <kpsingh@xxxxxxxxxx>
> Fixes: 6ba43b761c41 ("bpf: Attachment verification for BPF_MODIFY_RETURN")
> Reported-by: Jann Horn <jannh@xxxxxxxxxx>

Applied. Thanks