From 4bef6168c145852cebefe2f0bd78f9aaeba52843 Mon Sep 17 00:00:00 2001 From: Andi Kleen Date: Thu, 5 Sep 2024 08:07:55 -0700 Subject: [PATCH] perf script python: Avoid buffer overflow in python PEBS register interface Running a script that processes PEBS records gives buffer overflows in valgrind. The problem is that the allocation of the register string doesn't include the terminating 0 byte. Fix this. I also replaced the very magic "28" with a more reasonable larger buffer that should fit all registers. There's no need to conserve memory here. ==2106591== Memcheck, a memory error detector ==2106591== Copyright (C) 2002-2022, and GNU GPL'd, by Julian Seward et al. ==2106591== Using Valgrind-3.22.0 and LibVEX; rerun with -h for copyright info ==2106591== Command: ../perf script -i tcall.data gcov.py tcall.gcov ==2106591== ==2106591== Invalid write of size 1 ==2106591== at 0x713354: regs_map (trace-event-python.c:748) ==2106591== by 0x7134EB: set_regs_in_dict (trace-event-python.c:784) ==2106591== by 0x713E58: get_perf_sample_dict (trace-event-python.c:940) ==2106591== by 0x716327: python_process_general_event (trace-event-python.c:1499) ==2106591== by 0x7164E1: python_process_event (trace-event-python.c:1531) ==2106591== by 0x44F9AF: process_sample_event (builtin-script.c:2549) ==2106591== by 0x6294DC: evlist__deliver_sample (session.c:1534) ==2106591== by 0x6296D0: machines__deliver_event (session.c:1573) ==2106591== by 0x629C39: perf_session__deliver_event (session.c:1655) ==2106591== by 0x625830: ordered_events__deliver_event (session.c:193) ==2106591== by 0x630B23: do_flush (ordered-events.c:245) ==2106591== by 0x630E7A: __ordered_events__flush (ordered-events.c:324) ==2106591== Address 0x7186fe0 is 0 bytes after a block of size 0 alloc'd ==2106591== at 0x484280F: malloc (vg_replace_malloc.c:442) ==2106591== by 0x7134AD: set_regs_in_dict (trace-event-python.c:780) ==2106591== by 0x713E58: get_perf_sample_dict (trace-event-python.c:940) ==2106591== by 0x716327: python_process_general_event (trace-event-python.c:1499) ==2106591== by 0x7164E1: python_process_event (trace-event-python.c:1531) ==2106591== by 0x44F9AF: process_sample_event (builtin-script.c:2549) ==2106591== by 0x6294DC: evlist__deliver_sample (session.c:1534) ==2106591== by 0x6296D0: machines__deliver_event (session.c:1573) ==2106591== by 0x629C39: perf_session__deliver_event (session.c:1655) ==2106591== by 0x625830: ordered_events__deliver_event (session.c:193) ==2106591== by 0x630B23: do_flush (ordered-events.c:245) ==2106591== by 0x630E7A: __ordered_events__flush (ordered-events.c:324) ==2106591== ==2106591== Invalid read of size 1 ==2106591== at 0x484B6C6: strlen (vg_replace_strmem.c:502) ==2106591== by 0x555D494: PyUnicode_FromString (unicodeobject.c:1899) ==2106591== by 0x7134F7: set_regs_in_dict (trace-event-python.c:786) ==2106591== by 0x713E58: get_perf_sample_dict (trace-event-python.c:940) ==2106591== by 0x716327: python_process_general_event (trace-event-python.c:1499) ==2106591== by 0x7164E1: python_process_event (trace-event-python.c:1531) ==2106591== by 0x44F9AF: process_sample_event (builtin-script.c:2549) ==2106591== by 0x6294DC: evlist__deliver_sample (session.c:1534) ==2106591== by 0x6296D0: machines__deliver_event (session.c:1573) ==2106591== by 0x629C39: perf_session__deliver_event (session.c:1655) ==2106591== by 0x625830: ordered_events__deliver_event (session.c:193) ==2106591== by 0x630B23: do_flush (ordered-events.c:245) ==2106591== Address 0x7186fe0 is 0 bytes after a block of size 0 alloc'd ==2106591== at 0x484280F: malloc (vg_replace_malloc.c:442) ==2106591== by 0x7134AD: set_regs_in_dict (trace-event-python.c:780) ==2106591== by 0x713E58: get_perf_sample_dict (trace-event-python.c:940) ==2106591== by 0x716327: python_process_general_event (trace-event-python.c:1499) ==2106591== by 0x7164E1: python_process_event (trace-event-python.c:1531) ==2106591== by 0x44F9AF: process_sample_event (builtin-script.c:2549) ==2106591== by 0x6294DC: evlist__deliver_sample (session.c:1534) ==2106591== by 0x6296D0: machines__deliver_event (session.c:1573) ==2106591== by 0x629C39: perf_session__deliver_event (session.c:1655) ==2106591== by 0x625830: ordered_events__deliver_event (session.c:193) ==2106591== by 0x630B23: do_flush (ordered-events.c:245) ==2106591== by 0x630E7A: __ordered_events__flush (ordered-events.c:324) ==2106591== ==2106591== Invalid write of size 1 ==2106591== at 0x713354: regs_map (trace-event-python.c:748) ==2106591== by 0x713539: set_regs_in_dict (trace-event-python.c:789) ==2106591== by 0x713E58: get_perf_sample_dict (trace-event-python.c:940) ==2106591== by 0x716327: python_process_general_event (trace-event-python.c:1499) ==2106591== by 0x7164E1: python_process_event (trace-event-python.c:1531) ==2106591== by 0x44F9AF: process_sample_event (builtin-script.c:2549) ==2106591== by 0x6294DC: evlist__deliver_sample (session.c:1534) ==2106591== by 0x6296D0: machines__deliver_event (session.c:1573) ==2106591== by 0x629C39: perf_session__deliver_event (session.c:1655) ==2106591== by 0x625830: ordered_events__deliver_event (session.c:193) ==2106591== by 0x630B23: do_flush (ordered-events.c:245) ==2106591== by 0x630E7A: __ordered_events__flush (ordered-events.c:324) ==2106591== Address 0x7186fe0 is 0 bytes after a block of size 0 alloc'd ==2106591== at 0x484280F: malloc (vg_replace_malloc.c:442) ==2106591== by 0x7134AD: set_regs_in_dict (trace-event-python.c:780) ==2106591== by 0x713E58: get_perf_sample_dict (trace-event-python.c:940) ==2106591== by 0x716327: python_process_general_event (trace-event-python.c:1499) ==2106591== by 0x7164E1: python_process_event (trace-event-python.c:1531) ==2106591== by 0x44F9AF: process_sample_event (builtin-script.c:2549) ==2106591== by 0x6294DC: evlist__deliver_sample (session.c:1534) ==2106591== by 0x6296D0: machines__deliver_event (session.c:1573) ==2106591== by 0x629C39: perf_session__deliver_event (session.c:1655) ==2106591== by 0x625830: ordered_events__deliver_event (session.c:193) ==2106591== by 0x630B23: do_flush (ordered-events.c:245) ==2106591== by 0x630E7A: __ordered_events__flush (ordered-events.c:324) ==2106591== ==2106591== Invalid read of size 1 ==2106591== at 0x484B6C6: strlen (vg_replace_strmem.c:502) ==2106591== by 0x555D494: PyUnicode_FromString (unicodeobject.c:1899) ==2106591== by 0x713545: set_regs_in_dict (trace-event-python.c:791) ==2106591== by 0x713E58: get_perf_sample_dict (trace-event-python.c:940) ==2106591== by 0x716327: python_process_general_event (trace-event-python.c:1499) ==2106591== by 0x7164E1: python_process_event (trace-event-python.c:1531) ==2106591== by 0x44F9AF: process_sample_event (builtin-script.c:2549) ==2106591== by 0x6294DC: evlist__deliver_sample (session.c:1534) ==2106591== by 0x6296D0: machines__deliver_event (session.c:1573) ==2106591== by 0x629C39: perf_session__deliver_event (session.c:1655) ==2106591== by 0x625830: ordered_events__deliver_event (session.c:193) ==2106591== by 0x630B23: do_flush (ordered-events.c:245) ==2106591== Address 0x7186fe0 is 0 bytes after a block of size 0 alloc'd ==2106591== at 0x484280F: malloc (vg_replace_malloc.c:442) ==2106591== by 0x7134AD: set_regs_in_dict (trace-event-python.c:780) ==2106591== by 0x713E58: get_perf_sample_dict (trace-event-python.c:940) ==2106591== by 0x716327: python_process_general_event (trace-event-python.c:1499) ==2106591== by 0x7164E1: python_process_event (trace-event-python.c:1531) ==2106591== by 0x44F9AF: process_sample_event (builtin-script.c:2549) ==2106591== by 0x6294DC: evlist__deliver_sample (session.c:1534) ==2106591== by 0x6296D0: machines__deliver_event (session.c:1573) ==2106591== by 0x629C39: perf_session__deliver_event (session.c:1655) ==2106591== by 0x625830: ordered_events__deliver_event (session.c:193) ==2106591== by 0x630B23: do_flush (ordered-events.c:245) ==2106591== by 0x630E7A: __ordered_events__flush (ordered-events.c:324) ==2106591== 73056 total, 29 ignored Signed-off-by: Andi Kleen Cc: Adrian Hunter Cc: Namhyung Kim Link: https://lore.kernel.org/r/20240905151058.2127122-2-ak@linux.intel.com Signed-off-by: Arnaldo Carvalho de Melo --- .../perf/util/scripting-engines/trace-event-python.c | 11 +++-------- 1 file changed, 3 insertions(+), 8 deletions(-) diff --git a/tools/perf/util/scripting-engines/trace-event-python.c b/tools/perf/util/scripting-engines/trace-event-python.c index 6971dd6c231f8..d7183134b6699 100644 --- a/tools/perf/util/scripting-engines/trace-event-python.c +++ b/tools/perf/util/scripting-engines/trace-event-python.c @@ -762,6 +762,8 @@ static void regs_map(struct regs_dump *regs, uint64_t mask, const char *arch, ch } } +#define MAX_REG_SIZE 128 + static int set_regs_in_dict(PyObject *dict, struct perf_sample *sample, struct evsel *evsel) @@ -769,14 +771,7 @@ static int set_regs_in_dict(PyObject *dict, struct perf_event_attr *attr = &evsel->core.attr; const char *arch = perf_env__arch(evsel__env(evsel)); - /* - * Here value 28 is a constant size which can be used to print - * one register value and its corresponds to: - * 16 chars is to specify 64 bit register in hexadecimal. - * 2 chars is for appending "0x" to the hexadecimal value and - * 10 chars is for register name. - */ - int size = __sw_hweight64(attr->sample_regs_intr) * 28; + int size = (__sw_hweight64(attr->sample_regs_intr) * MAX_REG_SIZE) + 1; char *bf = malloc(size); if (!bf) return -1; -- 2.50.1