On Thu, Sep 22, 2022 at 3:38 PM Nathan Lynch <nath...@linux.ibm.com> wrote:
>
> The error injection facility on pseries VMs allows corruption of
> arbitrary guest memory, potentially enabling a sufficiently privileged
> user to disable lockdown or perform other modifications of the running
> kernel via the rtas syscall.
>
> Block the PAPR error injection facility from being opened or called
> when locked down.
>
> Signed-off-by: Nathan Lynch <nath...@linux.ibm.com>
> ---
> arch/powerpc/kernel/rtas.c | 25 ++++++++++++++++++++++++-
> include/linux/security.h | 1 +
> security/security.c | 1 +
> 3 files changed, 26 insertions(+), 1 deletion(-)
...
> diff --git a/include/linux/security.h b/include/linux/security.h
> index 1ca8dbacd3cc..b5d5138ae66a 100644
> --- a/include/linux/security.h
> +++ b/include/linux/security.h
> @@ -123,6 +123,7 @@ enum lockdown_reason {
> LOCKDOWN_BPF_WRITE_USER,
> LOCKDOWN_DBG_WRITE_KERNEL,
> LOCKDOWN_DEVICE_TREE,
> + LOCKDOWN_RTAS_ERROR_INJECTION,
With the understanding that I've never heard of RTAS until now, are
there any other RTAS events that would require a lockdown reason? As
a follow up, is it important to distinguish between different RTAS
lockdown reasons?
I'm trying to determine if we can just call it LOCKDOWN_RTAS.
> LOCKDOWN_INTEGRITY_MAX,
> LOCKDOWN_KCORE,
> LOCKDOWN_KPROBES,
> diff --git a/security/security.c b/security/security.c
> index 2863fc31eec6..6518b239ada2 100644
> --- a/security/security.c
> +++ b/security/security.c
> @@ -61,6 +61,7 @@ const char *const
> lockdown_reasons[LOCKDOWN_CONFIDENTIALITY_MAX+1] = {
> [LOCKDOWN_BPF_WRITE_USER] = "use of bpf to write user RAM",
> [LOCKDOWN_DBG_WRITE_KERNEL] = "use of kgdb/kdb to write kernel RAM",
> [LOCKDOWN_DEVICE_TREE] = "modifying device tree contents",
> + [LOCKDOWN_RTAS_ERROR_INJECTION] = "RTAS error injection",
See above.
> [LOCKDOWN_INTEGRITY_MAX] = "integrity",
> [LOCKDOWN_KCORE] = "/proc/kcore access",
> [LOCKDOWN_KPROBES] = "use of kprobes",
> --
> 2.37.3
--
paul-moore.com
