From 7934c98a6e04028eb34c1293bfb5a6b0ab630b66 Mon Sep 17 00:00:00 2001 From: Arnaldo Carvalho de Melo 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 Report-Link: http://lkml.kernel.org/r/20161219161821.GA294@x4 Cc: Adrian Hunter Cc: David Ahern Cc: Jiri Olsa Cc: Namhyung Kim Cc: Wang Nan Link: http://lkml.kernel.org/n/tip-ryhgs6a6jxvz207j2636w31c@git.kernel.org Signed-off-by: Arnaldo Carvalho de Melo --- 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 99400b0e8f2a..adbc6c02c3aa 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; }