Mat Martineau <mathew.j.martin...@linux.intel.com> wrote:
> +struct keyctl_kdf_params {
> + char *name;
> + __u8 reserved[32]; /* Reserved for future use, must be 0 */
> +};
> +
> #endif /* _LINUX_KEYCTL_H */
> diff --git a/security/keys/compat.c b/security/keys/compat.c
> index c8783b3..36c80bf 100644
> --- a/security/keys/compat.c
> +++ b/security/keys/compat.c
> @@ -134,7 +134,7 @@ COMPAT_SYSCALL_DEFINE5(keyctl, u32, option,
>
> case KEYCTL_DH_COMPUTE:
> return keyctl_dh_compute(compat_ptr(arg2), compat_ptr(arg3),
> - arg4);
> + arg4, compat_ptr(arg5));
Given the new structure above, this won't work. The problem is that on a
64-bit system the kernel expects 'name' to be a 64-bit pointer, but if we're
in the compat handler, we have a 32-bit userspace's idea of the struct - in
which 'name' is a 31-bit (s390x) or a 32-bit pointer without any padding.
So in compat code you can't just pass the user pointer direct through to
keyctl_dh_compute(). You need to supply a compat_keyctl_kdf_params struct and
translator code.
What I would recommend you do at the moment is to mark the syscall argument as
"reserved, must be 0" and deal with the implementation in the next merge
window.
David
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