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perf evsel: Tidy up sample parsing overflow checking 

The size of data retrieved from a sample event must be validated to
ensure it does not go past the end of the event.  That was being done
sporadically and without considering integer overflows.

Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Jiri Olsa <jolsa@redhat.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Namhyung Kim <namhyung@gmail.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1377591794-30553-3-git-send-email-adrian.hunter@intel.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Adrian Hunter 2013-08-27 11:23:04 +03:00 committed by Arnaldo Carvalho de Melo
parent 314add6b1f
commit 03b6ea9b91
1 changed files with 73 additions and 43 deletions
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116
tools/perf/util/evsel.c
View File

@ -1131,24 +1131,30 @@ static int perf_evsel__parse_id_sample(const struct perf_evsel *evsel,
return 0;
}
static bool sample_overlap(const union perf_event *event,
const void *offset, u64 size)
static inline bool overflow(const void *endp, u16 max_size, const void *offset,
u64 size)
{
const void *base = event;
if (offset + size > base + event->header.size)
return true;
return false;
return size > max_size || offset + size > endp;
}
#define OVERFLOW_CHECK(offset, size, max_size) \
do { \
if (overflow(endp, (max_size), (offset), (size))) \
return -EFAULT; \
} while (0)
#define OVERFLOW_CHECK_u64(offset) \
OVERFLOW_CHECK(offset, sizeof(u64), sizeof(u64))
int perf_evsel__parse_sample(struct perf_evsel *evsel, union perf_event *event,
struct perf_sample *data)
{
u64 type = evsel->attr.sample_type;
u64 regs_user = evsel->attr.sample_regs_user;
bool swapped = evsel->needs_swap;
const u64 *array;
u16 max_size = event->header.size;
const void *endp = (void *)event + max_size;
u64 sz;
/*
* used for cross-endian analysis. See git commit 65014ab3
@ -1170,6 +1176,11 @@ int perf_evsel__parse_sample(struct perf_evsel *evsel, union perf_event *event,
array = event->sample.array;
/*
* The evsel's sample_size is based on PERF_SAMPLE_MASK which includes
* up to PERF_SAMPLE_PERIOD. After that overflow() must be used to
* check the format does not go past the end of the event.
*/
if (evsel->sample_size + sizeof(event->header) > event->header.size)
return -EFAULT;
@ -1235,6 +1246,7 @@ int perf_evsel__parse_sample(struct perf_evsel *evsel, union perf_event *event,
if (type & PERF_SAMPLE_READ) {
u64 read_format = evsel->attr.read_format;
OVERFLOW_CHECK_u64(array);
if (read_format & PERF_FORMAT_GROUP)
data->read.group.nr = *array;
else
@ -1243,41 +1255,51 @@ int perf_evsel__parse_sample(struct perf_evsel *evsel, union perf_event *event,
array++;
if (read_format & PERF_FORMAT_TOTAL_TIME_ENABLED) {
OVERFLOW_CHECK_u64(array);
data->read.time_enabled = *array;
array++;
}
if (read_format & PERF_FORMAT_TOTAL_TIME_RUNNING) {
OVERFLOW_CHECK_u64(array);
data->read.time_running = *array;
array++;
}
/* PERF_FORMAT_ID is forced for PERF_SAMPLE_READ */
if (read_format & PERF_FORMAT_GROUP) {
data->read.group.values = (struct sample_read_value *) array;
array = (void *) array + data->read.group.nr *
sizeof(struct sample_read_value);
const u64 max_group_nr = UINT64_MAX /
sizeof(struct sample_read_value);
if (data->read.group.nr > max_group_nr)
return -EFAULT;
sz = data->read.group.nr *
sizeof(struct sample_read_value);
OVERFLOW_CHECK(array, sz, max_size);
data->read.group.values =
(struct sample_read_value *)array;
array = (void *)array + sz;
} else {
OVERFLOW_CHECK_u64(array);
data->read.one.id = *array;
array++;
}
}
if (type & PERF_SAMPLE_CALLCHAIN) {
if (sample_overlap(event, array, sizeof(data->callchain->nr)))
const u64 max_callchain_nr = UINT64_MAX / sizeof(u64);
OVERFLOW_CHECK_u64(array);
data->callchain = (struct ip_callchain *)array++;
if (data->callchain->nr > max_callchain_nr)
return -EFAULT;
data->callchain = (struct ip_callchain *)array;
if (sample_overlap(event, array, data->callchain->nr))
return -EFAULT;
array += 1 + data->callchain->nr;
sz = data->callchain->nr * sizeof(u64);
OVERFLOW_CHECK(array, sz, max_size);
array = (void *)array + sz;
}
if (type & PERF_SAMPLE_RAW) {
const u64 *pdata;
OVERFLOW_CHECK_u64(array);
u.val64 = *array;
if (WARN_ONCE(swapped,
"Endianness of raw data not corrected!\n")) {
@ -1286,65 +1308,73 @@ int perf_evsel__parse_sample(struct perf_evsel *evsel, union perf_event *event,
u.val32[0] = bswap_32(u.val32[0]);
u.val32[1] = bswap_32(u.val32[1]);
}
if (sample_overlap(event, array, sizeof(u32)))
return -EFAULT;
data->raw_size = u.val32[0];
pdata = (void *) array + sizeof(u32);
array = (void *)array + sizeof(u32);
if (sample_overlap(event, pdata, data->raw_size))
return -EFAULT;
data->raw_data = (void *) pdata;
array = (void *)array + data->raw_size + sizeof(u32);
OVERFLOW_CHECK(array, data->raw_size, max_size);
data->raw_data = (void *)array;
array = (void *)array + data->raw_size;
}
if (type & PERF_SAMPLE_BRANCH_STACK) {
u64 sz;
const u64 max_branch_nr = UINT64_MAX /
sizeof(struct branch_entry);
data->branch_stack = (struct branch_stack *)array;
array++; /* nr */
OVERFLOW_CHECK_u64(array);
data->branch_stack = (struct branch_stack *)array++;
if (data->branch_stack->nr > max_branch_nr)
return -EFAULT;
sz = data->branch_stack->nr * sizeof(struct branch_entry);
sz /= sizeof(u64);
array += sz;
OVERFLOW_CHECK(array, sz, max_size);
array = (void *)array + sz;
}
if (type & PERF_SAMPLE_REGS_USER) {
u64 avail;
/* First u64 tells us if we have any regs in sample. */
u64 avail = *array++;
OVERFLOW_CHECK_u64(array);
avail = *array++;
if (avail) {
u64 regs_user = evsel->attr.sample_regs_user;
sz = hweight_long(regs_user) * sizeof(u64);
OVERFLOW_CHECK(array, sz, max_size);
data->user_regs.regs = (u64 *)array;
array += hweight_long(regs_user);
array = (void *)array + sz;
}
}
if (type & PERF_SAMPLE_STACK_USER) {
u64 size = *array++;
OVERFLOW_CHECK_u64(array);
sz = *array++;
data->user_stack.offset = ((char *)(array - 1)
- (char *) event);
if (!size) {
if (!sz) {
data->user_stack.size = 0;
} else {
OVERFLOW_CHECK(array, sz, max_size);
data->user_stack.data = (char *)array;
array += size / sizeof(*array);
array = (void *)array + sz;
OVERFLOW_CHECK_u64(array);
data->user_stack.size = *array++;
}
}
data->weight = 0;
if (type & PERF_SAMPLE_WEIGHT) {
OVERFLOW_CHECK_u64(array);
data->weight = *array;
array++;
}
data->data_src = PERF_MEM_DATA_SRC_NONE;
if (type & PERF_SAMPLE_DATA_SRC) {
OVERFLOW_CHECK_u64(array);
data->data_src = *array;
array++;
}