perf cs-etm: Validate num_cpu before metadata allocation

cs_etm__process_auxtrace_info_full() reads num_cpu from untrusted
perf.data and uses it to allocate the metadata pointer array:

  metadata = zalloc(sizeof(*metadata) * num_cpu);

On 32-bit, sizeof(*metadata) is 4, so num_cpu = 0x40000000 overflows
the multiplication to 0, causing zalloc(0) to return a valid zero-sized
allocation followed by out-of-bounds writes in the population loop.

Fix by computing priv_size early and using it to bound num_cpu: each
CPU needs at least one u64 metadata entry, so num_cpu cannot exceed
the total number of u64 entries in the event's private data area.

Fixes: cd8bfd8c973eaff8 ("perf tools: Add processing of coresight metadata")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: James Clark <james.clark@arm.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Tor Jeremiassen <tor@ti.com>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

0 files changed, 0 insertions, 0 deletions