From 5fb2e6ad8c5d6b3b380f94c7456595511f3731be Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo Date: Fri, 5 Jun 2026 11:06:30 -0300 Subject: [PATCH] perf c2c: Bounds-check CPU IDs in setup_nodes() topology loop 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: 1e181b92a2da ("perf c2c report: Add 'node' sort key") Reported-by: sashiko-bot Cc: Jiri Olsa Cc: Namhyung Kim Assisted-by: Claude:claude-opus-4.6 Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/builtin-c2c.c | 4 ++++ 1 file changed, 4 insertions(+) diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c index f060dfbe11c2..cfc1ebe8c0af 100644 --- a/tools/perf/builtin-c2c.c +++ b/tools/perf/builtin-c2c.c @@ -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"))