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perf session: Avoid infinite loop when seeing invalid header.size 

Vince reported that when fuzzing the userland perf tool with a bogus
perf.data file he got into a infinite loop in 'perf report'.

Changing the return of fetch_mmaped_event() to ERR_PTR(-EINVAL) for that
case gets us out of that infinite loop.

Reported-by: Vince Weaver <vincent.weaver@maine.edu>
Tested-by: Vince Weaver <vincent.weaver@maine.edu>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20190726211415.GE24867@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
This commit is contained in:
Arnaldo Carvalho de Melo 2019-07-30 10:58:41 -03:00
parent 272172bd41
commit 57fc032ad6
1 changed files with 10 additions and 1 deletions
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11
tools/perf/util/session.c
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@ -1,6 +1,7 @@
// SPDX-License-Identifier: GPL-2.0 // SPDX-License-Identifier: GPL-2.0
#include <errno.h> #include <errno.h>
#include <inttypes.h> #include <inttypes.h>
#include <linux/err.h>
#include <linux/kernel.h> #include <linux/kernel.h>
#include <linux/zalloc.h> #include <linux/zalloc.h>
#include <traceevent/event-parse.h> #include <traceevent/event-parse.h>
@ -1955,7 +1956,9 @@ fetch_mmaped_event(struct perf_session *session,
/* We're not fetching the event so swap back again */ /* We're not fetching the event so swap back again */
if (session->header.needs_swap) if (session->header.needs_swap)
perf_event_header__bswap(&event->header); perf_event_header__bswap(&event->header);
return NULL; pr_debug("%s: head=%#" PRIx64 " event->header_size=%#x, mmap_size=%#zx: fuzzed perf.data?\n",
__func__, head, event->header.size, mmap_size);
return ERR_PTR(-EINVAL);
} }
return event; return event;
@ -1973,6 +1976,9 @@ static int __perf_session__process_decomp_events(struct perf_session *session)
while (decomp->head < decomp->size && !session_done()) { while (decomp->head < decomp->size && !session_done()) {
union perf_event *event = fetch_mmaped_event(session, decomp->head, decomp->size, decomp->data); union perf_event *event = fetch_mmaped_event(session, decomp->head, decomp->size, decomp->data);
if (IS_ERR(event))
return PTR_ERR(event);
if (!event) if (!event)
break; break;
@ -2072,6 +2078,9 @@ remap:
more: more:
event = fetch_mmaped_event(session, head, mmap_size, buf); event = fetch_mmaped_event(session, head, mmap_size, buf);
if (IS_ERR(event))
return PTR_ERR(event);
if (!event) { if (!event) {
if (mmaps[map_idx]) { if (mmaps[map_idx]) {
munmap(mmaps[map_idx], mmap_size); munmap(mmaps[map_idx], mmap_size);