On Fri, Jan 26, 2018 at 06:59:06AM -0800, tip-bot for Andi Kleen wrote:
> Commit-ID: caf7501a1b4ec964190f31f9c3f163de252273b8
> Gitweb: https://git.kernel.org/tip/caf7501a1b4ec964190f31f9c3f163de252273b8
> Author: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> AuthorDate: Thu, 25 Jan 2018 15:50:28 -0800
> Committer: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> CommitDate: Fri, 26 Jan 2018 15:03:56 +0100
>
> module/retpoline: Warn about missing retpoline in module
>
> There's a risk that a kernel which has full retpoline mitigations becomes
> vulnerable when a module gets loaded that hasn't been compiled with the
> right compiler or the right option.
>
> To enable detection of that mismatch at module load time, add a module info
> string "retpoline" at build time when the module was compiled with
> retpoline support. This only covers compiled C source, but assembler source
> or prebuilt object files are not checked.
>
> If a retpoline enabled kernel detects a non retpoline protected module at
> load time, print a warning and report it in the sysfs vulnerability file.
>
> [ tglx: Massaged changelog ]
>
> Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
> Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
> Cc: David Woodhouse <dwmw2@xxxxxxxxxxxxx>
> Cc: gregkh@xxxxxxxxxxxxxxxxxxx
> Cc: torvalds@xxxxxxxxxxxxxxxxxxxx
> Cc: jeyu@xxxxxxxxxx
> Cc: arjan@xxxxxxxxxxxxxxx
> Link: https://lkml.kernel.org/r/20180125235028.31211-1-andi@xxxxxxxxxxxxxx
> ---
> arch/x86/kernel/cpu/bugs.c | 17 ++++++++++++++++-
> include/linux/module.h | 9 +++++++++
> kernel/module.c | 11 +++++++++++
> scripts/mod/modpost.c | 9 +++++++++
> 4 files changed, 45 insertions(+), 1 deletion(-)
>
> diff --git a/arch/x86/kernel/cpu/bugs.c b/arch/x86/kernel/cpu/bugs.c
> index 390b3dc..4a39d7b 100644
> --- a/arch/x86/kernel/cpu/bugs.c
> +++ b/arch/x86/kernel/cpu/bugs.c
> @@ -11,6 +11,7 @@
> #include <linux/init.h>
> #include <linux/utsname.h>
> #include <linux/cpu.h>
> +#include <linux/module.h>
>
> #include <asm/nospec-branch.h>
> #include <asm/cmdline.h>
> @@ -93,6 +94,19 @@ static const char *spectre_v2_strings[] = {
> #define pr_fmt(fmt) "Spectre V2 mitigation: " fmt
>
> static enum spectre_v2_mitigation spectre_v2_enabled = SPECTRE_V2_NONE;
> +static bool spectre_v2_bad_module;
allnoconfig says:
arch/x86/kernel/cpu/bugs.c:97:13: warning: ‘spectre_v2_bad_module’ defined but not used [-Wunused-variable]
static bool spectre_v2_bad_module;
^
--
Regards/Gruss,
Boris.
Good mailing practices for 400: avoid top-posting and trim the reply.
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