From 7934c98a6e04028eb34c1293bfb5a6b0ab630b66 Mon Sep 17 00:00:00 2001
From: Arnaldo Carvalho de Melo <acme@redhat.com>
Date: Tue, 3 Jan 2017 15:19:21 -0300
Subject: [PATCH] perf symbols: Robustify reading of build-id from sysfs
Markus reported that perf segfaults when reading /sys/kernel/notes from
a kernel linked with GNU gold, due to what looks like a gold bug, so do
some bounds checking to avoid crashing in that case.
Reported-by: Markus Trippelsdorf <markus@trippelsdorf.de>
Report-Link: http://lkml.kernel.org/r/20161219161821.GA294@x4
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/n/tip-ryhgs6a6jxvz207j2636w31c@git.kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
tools/perf/util/symbol-elf.c | 6 ++++++
1 file changed, 6 insertions(+)
diff --git a/tools/perf/util/symbol-elf.c b/tools/perf/util/symbol-elf.c
index 99400b0e8f2a8..adbc6c02c3aaa 100644
--- a/tools/perf/util/symbol-elf.c
+++ b/tools/perf/util/symbol-elf.c
@@ -537,6 +537,12 @@ int sysfs__read_build_id(const char *filename, void *build_id, size_t size)
break;
} else {
int n = namesz + descsz;
+
+ if (n > (int)sizeof(bf)) {
+ n = sizeof(bf);
+ pr_debug("%s: truncating reading of build id in sysfs file %s: n_namesz=%u, n_descsz=%u.\n",
+ __func__, filename, nhdr.n_namesz, nhdr.n_descsz);
+ }
if (read(fd, bf, n) != n)
break;
}
--
2.30.2