[PATCH v2 perf-tools-next 0/6] perf trace: Validate payload bounds across augmented argument beautifiers

[Aaron Tomlin <atomlin@atomlin.com>]

When pretty-printing augmented syscall arguments in perf trace, raw payload
data captured from BPF programs is passed to various argument formatters
via struct syscall_arg.

However, when processing malformed, truncated, or untrusted perf.data
records (e.g., truncated reads in BPF ringbuffers, cross-architecture
replays, or crafted sample records), the payload can be shorter than
expected or contain invalid size fields:
    1.  Dereferencing augmented_arg fields before validating that
        arg->augmented.size is at least sizeof(struct augmented_arg) can read
        past the available buffer.

    2.  Passing augmented_arg->size to formatters or loop counters without
        bounding it against the remaining buffer can cause out-of-bounds memory
        reads.

    3.  In multi-argument syscalls, calculating consumed bytes as:

            consumed = sizeof(*augmented_arg) + augmented_arg->size;

        without bounds checking can overflow signed integer bounds or cause
        arg->augmented.size to underflow. This advances arg->augmented.args
        out of bounds, corrupting parsing state for all subsequent
        arguments in the same syscall.

    4.  Type/family-specific beautifiers (i.e., BTF struct dump, sockaddr,
        timespec, perf_event_attr) can dereference structure fields without
        verifying that the payload contains sufficient bytes for the target
        type.

This series adds comprehensive upper-bound and payload-size checks across
all augmented argument beautifiers in perf trace. If validation fails in
any beautifier, it cleanly falls back to printing the raw pointer/hex
value.

To facilitate clean, conflict-free backports across active LTS kernels,
each formatter fix is isolated to its own commit.

Changes since v1:

 - Expanded the original single patch into a 6-patch series in response to
   reviewer feedback from sashiko-bot regarding similar bounds check
   omissions across other augmented formatters in perf trace

 - Added new patch validating payload bounds and consumed offset
   calculations in syscall_arg__scnprintf_augmented_string()

 - Added new patch validating payload bounds before byte traversal in
   syscall_arg__scnprintf_buf(), isolated to ensure an independent Fixes:
   tag for stable backports

 - Added new patch validating payload size against sizeof(struct timespec)
   in syscall_arg__scnprintf_augmented_timespec()

 - Added new patch validating payload bounds and family-specific lengths in
   syscall_arg__scnprintf_augmented_sockaddr()

 - Added new patch validating payload size against at least
   PERF_ATTR_SIZE_VER0 in
   syscall_arg__scnprintf_augmented_perf_event_attr()

 - Link to v1: https://lore.kernel.org/all/20260906011132.279321-1-atomlin@atomlin.com/

Aaron Tomlin (6):
  perf trace: Add upper bound checks for augmented BTF struct printing
  perf trace: Validate payload bounds in augmented string beautifier
  perf trace: Validate payload bounds in augmented buffer beautifier
  perf trace beauty: Validate payload size in augmented timespec
    beautifier
  perf trace beauty: Validate payload size in augmented sockaddr
    beautifier
  perf trace beauty: Validate payload size in augmented perf_event_open
    beautifier

 tools/perf/builtin-trace.c                | 36 +++++++++++++++++------
 tools/perf/trace/beauty/perf_event_open.c | 19 ++++++++++--
 tools/perf/trace/beauty/sockaddr.c        | 35 ++++++++++++++++++----
 tools/perf/trace/beauty/timespec.c        | 19 ++++++++++--
 4 files changed, 89 insertions(+), 20 deletions(-)


base-commit: 02f6847e1822714a4201b87e42f92b0d43e8549d
-- 
2.55.0