Messages in this thread Patch in this message | | | From | Wang Nan <> | Subject | [PATCH] perf tools: Fix a problem when opening old perf.data with different byte order | Date | Wed, 17 Jun 2015 03:40:42 +0000 |
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Following error occurs when trying to use 'perf report' on x86_64 to cross analysis a perf.data generated by an old perf on a big-endian machine:
# perf report *** Error in `/home/w00229757/perf': free(): invalid next size (fast): 0x00000000032c99f0 *** ======= Backtrace: ========= /lib64/libc.so.6(+0x6eeef)[0x7ff6ff7e2eef] /lib64/libc.so.6(+0x78cae)[0x7ff6ff7eccae] /lib64/libc.so.6(+0x79987)[0x7ff6ff7ed987] /path/to/perf[0x4ac734] /path/to/perf[0x4ac829] /path/to/perf(perf_header__process_sections+0x129)[0x4ad2c9] /path/to/perf(perf_session__read_header+0x2e1)[0x4ad9e1] /path/to/perf(perf_session__new+0x168)[0x4bd458] /path/to/perf(cmd_report+0xfa0)[0x43eb70] /path/to/perf[0x47adc3] /path/to/perf(main+0x5f6)[0x42fd06] /lib64/libc.so.6(__libc_start_main+0xf5)[0x7ff6ff795bd5] /path/to/perf[0x42fe35] ======= Memory map: ======== [SNIP]
The bug is in perf_event__attr_swap(). It swaps all fields in 'struct perf_event_attr' without checking whether the swapped field exist or not. In addition, in read_event_desc() allocs memory for attr according to size read from perf.data. Therefore, if the perf.data is collected by an old perf (without aux_watermark, for example), when perf_event__attr_swap() swaping attr->aux_watermark it destroy malloc's metadata.
This patch introduces boundary checking in perf_event__attr_swap(). It adds macros bswap_field_64 and bswap_field_32 into perf_event__attr_swap() to make it only swap exist fields.
Signed-off-by: Wang Nan <wangnan0@huawei.com> --- tools/perf/util/session.c | 40 ++++++++++++++++++++++++++-------------- 1 file changed, 26 insertions(+), 14 deletions(-)
diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c index 88d87bf..d51ba31 100644 --- a/tools/perf/util/session.c +++ b/tools/perf/util/session.c @@ -517,20 +517,32 @@ void perf_event__attr_swap(struct perf_event_attr *attr) { attr->type = bswap_32(attr->type); attr->size = bswap_32(attr->size); - attr->config = bswap_64(attr->config); - attr->sample_period = bswap_64(attr->sample_period); - attr->sample_type = bswap_64(attr->sample_type); - attr->read_format = bswap_64(attr->read_format); - attr->wakeup_events = bswap_32(attr->wakeup_events); - attr->bp_type = bswap_32(attr->bp_type); - attr->bp_addr = bswap_64(attr->bp_addr); - attr->bp_len = bswap_64(attr->bp_len); - attr->branch_sample_type = bswap_64(attr->branch_sample_type); - attr->sample_regs_user = bswap_64(attr->sample_regs_user); - attr->sample_stack_user = bswap_32(attr->sample_stack_user); - attr->aux_watermark = bswap_32(attr->aux_watermark); - - swap_bitfield((u8 *) (&attr->read_format + 1), sizeof(u64)); +#define bswap_safe(f) \ + (attr->size > offsetof(struct perf_event_attr, f)) +#define bswap_field(f, sz) \ +do { \ + if (bswap_safe(f)) \ + attr->f = bswap_##sz(attr->f); \ +} while(0) +#define bswap_field_32(f) bswap_field(f, 32) +#define bswap_field_64(f) bswap_field(f, 64) + + bswap_field_64(config); + bswap_field_64(sample_period); + bswap_field_64(sample_type); + bswap_field_64(read_format); + bswap_field_32(wakeup_events); + bswap_field_32(bp_type); + bswap_field_64(bp_addr); + bswap_field_64(bp_len); + bswap_field_64(branch_sample_type); + bswap_field_64(sample_regs_user); + bswap_field_32(sample_stack_user); + bswap_field_32(aux_watermark); + + if (bswap_safe(read_format)) + swap_bitfield((u8 *) (&attr->read_format + 1), + sizeof(u64)); } static void perf_event__hdr_attr_swap(union perf_event *event, -- 1.8.3.4
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