[PATCH] perf/x86/rapl: Annotate struct rapl_pmus with __counted_by

[PATCH] perf/x86/rapl: Annotate struct rapl_pmus with __counted_by

[Kees Cook]

Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
functions).

As found with Coccinelle[1], add __counted_by for struct rapl_pmus.

Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Ian Rogers <irogers@google.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: x86@kernel.org
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
Cc: linux-perf-users@vger.kernel.org
Cc: linux-hardening@vger.kernel.org
Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 arch/x86/events/rapl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/events/rapl.c b/arch/x86/events/rapl.c
index c2c37fb0a228..8d98d468b976 100644
--- a/arch/x86/events/rapl.c
+++ b/arch/x86/events/rapl.c
@@ -115,7 +115,7 @@ struct rapl_pmu {
 struct rapl_pmus {
 	struct pmu		pmu;
 	unsigned int		maxdie;
-	struct rapl_pmu		*pmus[];
+	struct rapl_pmu		*pmus[] __counted_by(maxdie);
 };
 
 enum rapl_unit_quirk {
-- 
2.34.1

Re: [PATCH] perf/x86/rapl: Annotate struct rapl_pmus with __counted_by

[Gustavo A. R. Silva]

On 10/6/23 22:17, Kees Cook wrote:
> Prepare for the coming implementation by GCC and Clang of the __counted_by
> attribute. Flexible array members annotated with __counted_by can have
> their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS (for
> array indexing) and CONFIG_FORTIFY_SOURCE (for strcpy/memcpy-family
> functions).
> 
> As found with Coccinelle[1], add __counted_by for struct rapl_pmus.
> 
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
> Cc: Mark Rutland <mark.rutland@arm.com>
> Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> Cc: Jiri Olsa <jolsa@kernel.org>
> Cc: Namhyung Kim <namhyung@kernel.org>
> Cc: Ian Rogers <irogers@google.com>
> Cc: Adrian Hunter <adrian.hunter@intel.com>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: Dave Hansen <dave.hansen@linux.intel.com>
> Cc: x86@kernel.org
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Cc: "Gustavo A. R. Silva" <gustavoars@kernel.org>
> Cc: linux-perf-users@vger.kernel.org
> Cc: linux-hardening@vger.kernel.org
> Link: https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]
> Signed-off-by: Kees Cook <keescook@chromium.org>

Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>

Thanks!
-- 
Gustavo

> ---
>   arch/x86/events/rapl.c | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/arch/x86/events/rapl.c b/arch/x86/events/rapl.c
> index c2c37fb0a228..8d98d468b976 100644
> --- a/arch/x86/events/rapl.c
> +++ b/arch/x86/events/rapl.c
> @@ -115,7 +115,7 @@ struct rapl_pmu {
>   struct rapl_pmus {
>   	struct pmu		pmu;
>   	unsigned int		maxdie;
> -	struct rapl_pmu		*pmus[];
> +	struct rapl_pmu		*pmus[] __counted_by(maxdie);
>   };
>   
>   enum rapl_unit_quirk {

[tip: perf/core] perf/x86/rapl: Annotate 'struct rapl_pmus' with __counted_by

[tip-bot2 for Kees Cook]

The following commit has been merged into the perf/core branch of tip:

Commit-ID:     a56d5551e1993ca84dd0c69df5a3d8223d13fb5f
Gitweb:        https://git.kernel.org/tip/a56d5551e1993ca84dd0c69df5a3d8223d13fb5f
Author:        Kees Cook <keescook@chromium.org>
AuthorDate:    Fri, 06 Oct 2023 13:17:54 -07:00
Committer:     Ingo Molnar <mingo@kernel.org>
CommitterDate: Sun, 08 Oct 2023 12:18:17 +02:00

perf/x86/rapl: Annotate 'struct rapl_pmus' with __counted_by

Prepare for the coming implementation by GCC and Clang of the __counted_by
attribute. Flexible array members annotated with __counted_by can have
their accesses bounds-checked at run-time via CONFIG_UBSAN_BOUNDS=y (for
array indexing) and CONFIG_FORTIFY_SOURCE=y (for strcpy/memcpy-family
functions).

Found with Coccinelle:

  https://github.com/kees/kernel-tools/blob/trunk/coccinelle/examples/counted_by.cocci [1]

Add __counted_by for 'struct rapl_pmus'.

No change in functionality intended.

Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Gustavo A. R. Silva <gustavoars@kernel.org>
Link: https://lore.kernel.org/r/20231006201754.work.473-kees@kernel.org
---
 arch/x86/events/rapl.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/arch/x86/events/rapl.c b/arch/x86/events/rapl.c
index c2c37fb..8d98d46 100644
--- a/arch/x86/events/rapl.c
+++ b/arch/x86/events/rapl.c
@@ -115,7 +115,7 @@ struct rapl_pmu {
 struct rapl_pmus {
 	struct pmu		pmu;
 	unsigned int		maxdie;
-	struct rapl_pmu		*pmus[];
+	struct rapl_pmu		*pmus[] __counted_by(maxdie);
 };
 
 enum rapl_unit_quirk {