[PATCH v1 01/15] perf, tools, stat: Fix buffer overflow while freeing events

[Andi Kleen]

From: Andi Kleen <ak@xxxxxxxxxxxxxxx>

Fix buffer overflow for

% perf stat -e msr/tsc/,cstate_core/c7-residency/ true

that causes glibc free list corruption. For some reason
it doesn't trigger in valgrind, but it is visible in AS:

=================================================================
==32681==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x603000003f5c at pc 0x0000005671ef bp 0x7ffdaaac9ac0 sp 0x7ffdaaac9ab0
READ of size 4 at 0x603000003f5c thread T0
    #0 0x5671ee in perf_evsel__close_fd util/evsel.c:1196
    #1 0x56c57a in perf_evsel__close util/evsel.c:1717
    #2 0x55ed5f in perf_evlist__close util/evlist.c:1631
    #3 0x4647e1 in __run_perf_stat /home/ak/hle/linux-hle-2.6/tools/perf/builtin-stat.c:749
    #4 0x4648e3 in run_perf_stat /home/ak/hle/linux-hle-2.6/tools/perf/builtin-stat.c:767
    #5 0x46e1bc in cmd_stat /home/ak/hle/linux-hle-2.6/tools/perf/builtin-stat.c:2785
    #6 0x52f83d in run_builtin /home/ak/hle/linux-hle-2.6/tools/perf/perf.c:296
    #7 0x52fd49 in handle_internal_command /home/ak/hle/linux-hle-2.6/tools/perf/perf.c:348
    #8 0x5300de in run_argv /home/ak/hle/linux-hle-2.6/tools/perf/perf.c:392
    #9 0x5308f3 in main /home/ak/hle/linux-hle-2.6/tools/perf/perf.c:530
    #10 0x7f0672d13400 in __libc_start_main (/lib64/libc.so.6+0x20400)
    #11 0x428419 in _start (/home/ak/hle/obj-perf/perf+0x428419)

0x603000003f5c is located 0 bytes to the right of 28-byte region [0x603000003f40,0x603000003f5c)
allocated by thread T0 here:
    #0 0x7f0675139020 in calloc (/lib64/libasan.so.3+0xc7020)
    #1 0x648a2d in zalloc util/util.h:23
    #2 0x648a88 in xyarray__new util/xyarray.c:9
    #3 0x566419 in perf_evsel__alloc_fd util/evsel.c:1039
    #4 0x56b427 in perf_evsel__open util/evsel.c:1529
    #5 0x56c620 in perf_evsel__open_per_thread util/evsel.c:1730
    #6 0x461dea in create_perf_stat_counter /home/ak/hle/linux-hle-2.6/tools/perf/builtin-stat.c:263
    #7 0x4637d7 in __run_perf_stat /home/ak/hle/linux-hle-2.6/tools/perf/builtin-stat.c:600
    #8 0x4648e3 in run_perf_stat /home/ak/hle/linux-hle-2.6/tools/perf/builtin-stat.c:767
    #9 0x46e1bc in cmd_stat /home/ak/hle/linux-hle-2.6/tools/perf/builtin-stat.c:2785
    #10 0x52f83d in run_builtin /home/ak/hle/linux-hle-2.6/tools/perf/perf.c:296
    #11 0x52fd49 in handle_internal_command /home/ak/hle/linux-hle-2.6/tools/perf/perf.c:348
    #12 0x5300de in run_argv /home/ak/hle/linux-hle-2.6/tools/perf/perf.c:392
    #13 0x5308f3 in main /home/ak/hle/linux-hle-2.6/tools/perf/perf.c:530
    #14 0x7f0672d13400 in __libc_start_main (/lib64/libc.so.6+0x20400)

The event is allocated with cpus == 1, but freed with cpus == real number
When the evsel close function walks the file descriptors it exceeds the
fd xyarray boundaries and reads random memory.

Just make sure to always use the same dummy cpu map following
the same logic as the open call.

Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
---
 tools/perf/builtin-stat.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/tools/perf/builtin-stat.c b/tools/perf/builtin-stat.c
index 48ac53b199fc..97d6b6c42014 100644
--- a/tools/perf/builtin-stat.c
+++ b/tools/perf/builtin-stat.c
@@ -715,6 +715,8 @@ static int __run_perf_stat(int argc, const char **argv)
 	 * group leaders.
 	 */
 	read_counters();
+	if (!target__has_cpu(&target))
+		evsel_list->cpus = cpu_map__dummy_new();
 	perf_evlist__close(evsel_list);
 
 	return WEXITSTATUS(status);
-- 
2.9.4