[PATCHES 00/27] perf.data validation and hardening

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Hi,

A crafted or corrupted perf.data file can cause out-of-bounds
reads/writes, infinite loops, heap overflows, and segfaults in perf
report, perf script, perf inject, perf timechart, and perf kwork.
This series adds defense-in-depth validation for file parsing:

- Per-event-type minimum size table, enforced before swap and
  processing on both native and cross-endian paths.
- Swap handler return values (void -> int) so handlers can propagate
  errors instead of silently corrupting adjacent memory.
- Bounds checking for string fields (null-termination), array counts
  (nr vs payload size), feature section sizes (vs file size), and
  CPU indices (vs nr_cpus_avail / array allocation).
- ABI0 handling for perf_event_attr.size == 0 across all code paths
  (swap, native, synthesize, read_event_desc), with consistent
  behavior regardless of file endianness.
- Sanitizer-aware shell test: the truncated perf.data test captures
  stderr and checks for ASAN/MSAN/TSAN/UBSAN markers, since sanitizer
  exits use code 1 which otherwise looks like a clean error exit.

Pre-existing bugs fixed along the way:

- event_contains() macro off-by-one (checked start, not full extent)
- zstd_decompress_stream multi-iteration output.pos bug
- zstd_compress_stream_to_records: broken memcpy fallback -> return -1
  + ZSTD context reset + dst_size underflow guard
- PERF_RECORD_SWITCH sample_id_all offset wrong for non-CPU_WIDE
- cpu_map__from_range any_cpu used as count instead of boolean
- cpu_map__from_mask double-fetch heap overflow (j >= weight guard)
- kwork cpus_runtime BUG_ON with signed comparison
- perf_header__getbuffer64 EOF without errno (silent success)
- read_event_desc ABI0 sentinel (attr.size=0 -> free_event_desc early stop)
- EVENT_UPDATE MASK: missing offsetof underflow guard + pr_warning on
  mask32/mask64 validation paths

Additional pre-existing issues were noticed during review and will be
addressed in follow-up series.

Testing
-------

- perf test at baseline and at patches 1, 7, 10, 16, 20, 25, 27
  with 300s timeout -- no regressions detected.
- Build with both gcc and clang at every patch.
- checkpatch.pl on all 27 patches.

Developed with AI assistance in a local loop involving Claude Code and
Sashiko/Gemini, tagged in commits.

Best regards,

- Arnaldo