Re: [PATCH v2 0/2] perf evsel: Validate cross-endian samples before byte swapping

[Ian Rogers]

On Thu, Sep 3, 2026 at 4:05 AM Mark Amirkan via B4 Relay
<devnull+markdamirkan.gmail.com@xxxxxxxxxx> wrote:
>
> Two paths in __evsel__parse_sample() use values from an
> opposite-endian perf.data record to modify the record before checking that
> the data fits within event->header.size.
>
> Patch 1 checks the complete branch stack before swapping entry flags.
> Patch 2 checks the RAW payload and the complete 64-bit words touched by
> mem_bswap_64() before swapping the data.
>
> The malformed branch-stack and RAW records reproduce as out-of-bounds
> reads and writes. Each patch adds a Sample parsing regression test that
> checks rejected records do not modify data past the declared event.
>
> Signed-off-by: Mark Amirkan <markdamirkan@xxxxxxxxx>

Reviewed-by: Ian Rogers <irogers@xxxxxxxxxx>

Thanks,
Ian

> ---
> Changes in v2:
> - Add the adjacent PERF_SAMPLE_RAW fix found during v1 review.
> - Keep the branch-stack fix unchanged.
> - Link to v1: https://patch.msgid.link/20260903-sympwn-linux-002-final-v2-v1-1-7c6e4166b814@xxxxxxxxx
>
> To: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
> To: Ingo Molnar <mingo@xxxxxxxxxx>
> To: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
> To: Namhyung Kim <namhyung@xxxxxxxxxx>
> To: Mark Rutland <mark.rutland@xxxxxxx>
> To: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
> To: Jiri Olsa <jolsa@xxxxxxxxxx>
> To: Ian Rogers <irogers@xxxxxxxxxx>
> To: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> To: James Clark <james.clark@xxxxxxxxxx>
> Cc: linux-perf-users@xxxxxxxxxxxxxxx
> Cc: linux-kernel@xxxxxxxxxxxxxxx
>
> ---
> Mark Amirkan (2):
>       perf evsel: Validate branch stack before byte swapping
>       perf evsel: Validate RAW sample before byte swapping
>
>  tools/perf/tests/sample-parsing.c | 109 ++++++++++++++++++++++++++++++++++++++
>  tools/perf/util/evsel.c           |  20 +++----
>  2 files changed, 120 insertions(+), 9 deletions(-)
> ---
> base-commit: aadea57f532882d8bab444646863c7ef8a778ff1
> change-id: 20260903-sympwn-linux-002-final-v2-e30a8df210c1
>
> Best regards,
> --
> Mark Amirkan <markdamirkan@xxxxxxxxx>
>
>