[PATCHES v4 0/9] perf tools: Fix pre-existing bugs in machine, cs-etm, c2c, bpf, and dso

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

Hi,

Nine more pre-existing bugs found by sashiko-bot during AI-assisted
code review.  All are independent of the perf-data-validation hardening
series — they are latent bugs in surrounding code exposed during review.

The fixes are grouped by subsystem:

machine__init() error propagation (patches 1-2):
  machine__init() always returns 0 on allocation failure because the
  error code is never propagated through the return statement.  Callers
  (including machines__init() and __machine__new_host()) proceed with a
  partially initialized machine struct.  The error cleanup also uses
  zfree() on refcounted kmaps instead of maps__zput().  Additionally,
  machines__findnew() and machines__create_guest_kernel_maps() use
  sprintf() with unsanitized guestmount paths that can overflow
  PATH_MAX stack buffers.

CoreSight ETM metadata validation (patches 3-5):
  cs_etm__process_auxtrace_info_full() reads num_cpu from untrusted
  perf.data and uses it directly in a multiplication that can overflow
  to zero on 32-bit, producing a zero-sized allocation followed by OOB
  writes.  The minimum size check in cs_etm__process_auxtrace_info()
  doesn't cover the global header fields actually accessed.
  cs_etm__get_queue() indexes queue_array[] without bounds checking
  the CPU value from untrusted trace payload, and several queue
  iteration loops dereference .priv without NULL checks after array
  growth zero-initializes new entries.

c2c hist entry leaks (patches 6-7):
  When c2c_hists__init() fails, dynamically allocated format structures
  are leaked because the error path frees the container without
  unregistering them.  During resort merges, c2c_he_free() only walks
  the output-sorted tree (empty before resort), leaking all inner
  hist_entry objects from entries_in_array[] and entries_collapsed.

BPF prog info pointer validation (patch 8):
  Several functions cast bpf_prog_info u64 fields to pointers without
  checking whether bpil_offs_to_addr() actually converted the file
  offsets.  A crafted perf.data with PERF_BPIL_* bits unset but non-zero
  counts causes raw file offsets to be dereferenced as pointers.

DSO decompression errno (patch 9):
  dso__get_filename() sets errno to a negative custom DSO_LOAD_ERRNO
  value on decompression failure.  __open_dso() computes fd = -errno,
  producing a large positive value that looks like a valid fd, causing
  close_data_fd() to close an unrelated file descriptor.

Build-tested with gcc and clang.  Passes perf test on x86_64.

Changes in v4 (patch 2 only):
  - Remove incorrect get_kernel_version() reference from commit
    message — that function already uses snprintf() in the baseline
    (sashiko-bot).

Changes in v3 (patch 1 only):
  - Move perf_env__init() before machines__init() in
    __perf_session__new() so the goto out_delete error path doesn't
    call perf_env__exit() on uninitialized mutexes/rwlocks
    (sashiko-bot).

Changes in v2 (patch 1 only):
  - Move dsos__init()/threads__init() before maps__new() so that
    machine__exit() is safe to call when machine__init() fails at the
    first allocation (sashiko-bot).
  - Propagate machines__init() error in aslr_tool__init(), which was
    added by the ASLR patches after v1 was written (sashiko-bot).

Arnaldo Carvalho de Melo (9):
  perf machine: Propagate machine__init() error to callers
  perf machine: Use snprintf() for guestmount path construction
  perf cs-etm: Validate num_cpu before metadata allocation
  perf cs-etm: Require full global header in auxtrace_info size check
  perf cs-etm: Bounds-check CPU in cs_etm__get_queue()
  perf c2c: Free format list entries when c2c_hists__init() fails
  perf c2c: Fix hist entry and format list leaks in c2c_he_free()
  perf bpf: Validate array presence before casting BPF prog info pointers
  perf dso: Set standard errno on decompression failure

 tools/perf/builtin-c2c.c             |  3 ++-
 tools/perf/tests/hists_cumulate.c    |  3 ++-
 tools/perf/tests/hists_filter.c      |  3 ++-
 tools/perf/tests/hists_link.c        |  3 ++-
 tools/perf/tests/hists_output.c      |  3 ++-
 tools/perf/tests/thread-maps-share.c |  2 +-
 tools/perf/util/aslr.c               | 12 +++++++++---
 tools/perf/util/bpf-event.c          | 20 ++++++++++++++++---
 tools/perf/util/bpf-event.h          |  4 ++--
 tools/perf/util/cs-etm-base.c        |  4 +++-
 tools/perf/util/cs-etm.c             | 37 ++++++++++++++++++++++++++++++++++--
 tools/perf/util/dso.c                | 18 +++++++++++++++++-
 tools/perf/util/header.c             |  3 +--
 tools/perf/util/hist.c               |  2 +-
 tools/perf/util/hist.h               |  1 +
 tools/perf/util/machine.c            | 32 +++++++++++++++++--------------
 tools/perf/util/machine.h            |  2 +-
 tools/perf/util/session.c            |  7 ++++---
 18 files changed, 120 insertions(+), 39 deletions(-)

Developed with AI assistance (Claude/sashiko), tagged in commits.

Thanks,

- Arnaldo