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perf c2c: Bounds-check CPU IDs in setup_nodes() topology loop

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setup_nodes() iterates CPU maps from the perf.data topology header and
uses cpu.cpu directly as an array index into cpu2node[] (allocated with
c2c.cpus_cnt = env->nr_cpus_avail entries) and __set_bit(cpu.cpu, set)
(bitmap also sized to c2c.cpus_cnt).

A crafted perf.data with topology CPU IDs exceeding nr_cpus_avail causes
out-of-bounds heap writes into both the cpu2node array and the per-node
bitmap.

Add a bounds check to skip CPU IDs that fall outside the valid range.

Fixes: 1e181b92a2 ("perf c2c report: Add 'node' sort key")
Reported-by: sashiko-bot <sashiko-bot@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Assisted-by: Claude:claude-opus-4.6
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Arnaldo Carvalho de Melo 2026-06-05 11:06:30 -03:00
parent 65117c3da5
commit 5fb2e6ad8c
1 changed files with 4 additions and 0 deletions
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4
tools/perf/builtin-c2c.c
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@ -2371,6 +2371,10 @@ static int setup_nodes(struct perf_session *session)
nodes[node] = set;
perf_cpu_map__for_each_cpu_skip_any(cpu, idx, map) {
/* topology CPU IDs from perf.data may exceed nr_cpus_avail */
if (cpu.cpu < 0 || cpu.cpu >= c2c.cpus_cnt)
continue;
__set_bit(cpu.cpu, set);
if (WARN_ONCE(cpu2node[cpu.cpu] != -1, "node/cpu topology bug"))