From 5f5e25f1c7933a6e1673515c0b1d5acd82fea1ed Mon Sep 17 00:00:00 2001 From: He Zhe Date: Fri, 2 Aug 2019 16:29:52 +0800 Subject: [PATCH] perf cpumap: Fix writing to illegal memory in handling cpumap mask cpu_map__snprint_mask() would write to illegal memory pointed by zalloc(0) when there is only one cpu. This patch fixes the calculation and adds sanity check against the input parameters. Signed-off-by: He Zhe Cc: Alexander Shishkin Cc: Alexey Budankov Cc: Jiri Olsa Cc: Kan Liang Cc: Namhyung Kim Cc: Peter Zijlstra Cc: Stephane Eranian Fixes: 4400ac8a9a90 ("perf cpumap: Introduce cpu_map__snprint_mask()") Link: http://lkml.kernel.org/r/1564734592-15624-2-git-send-email-zhe.he@windriver.com Signed-off-by: Arnaldo Carvalho de Melo --- tools/perf/util/cpumap.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) diff --git a/tools/perf/util/cpumap.c b/tools/perf/util/cpumap.c index 3acfbe34ebaf..39cce66b4ebc 100644 --- a/tools/perf/util/cpumap.c +++ b/tools/perf/util/cpumap.c @@ -751,7 +751,10 @@ size_t cpu_map__snprint_mask(struct cpu_map *map, char *buf, size_t size) unsigned char *bitmap; int last_cpu = cpu_map__cpu(map, map->nr - 1); - bitmap = zalloc((last_cpu + 7) / 8); + if (buf == NULL) + return 0; + + bitmap = zalloc(last_cpu / 8 + 1); if (bitmap == NULL) { buf[0] = '\0'; return 0; -- 2.30.2