[PATCH v2 2/3] Revert "perf session: Avoid infinite loop when seeing invalid header.size"

From: Petr Malat <oss@malat.biz>
To: linux-kernel@vger.kernel.org
Cc: Petr Malat <oss@malat.biz>, Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Kan Liang <kan.liang@linux.intel.com>,
	Alexey Budankov <alexey.budankov@linux.intel.com>
Subject: [PATCH v2 2/3] Revert "perf session: Avoid infinite loop when seeing invalid header.size"
Date: Tue, 24 Nov 2020 11:29:17 +0100	[thread overview]
Message-ID: <20201124102919.15312-2-oss@malat.biz> (raw)
In-Reply-To: <20201124102919.15312-1-oss@malat.biz>

An event may be split by a buffer boundary, we should not abort processing
if that happens.

Fixes: bb1835a3b86c ("perf session: Fix decompression of PERF_RECORD_COMPRESSED records")
Fixes: 57fc032ad643 ("perf session: Avoid infinite loop when seeing invalid header.size")
Signed-off-by: Petr Malat <oss@malat.biz>
---
 tools/perf/util/session.c | 11 +----------
 1 file changed, 1 insertion(+), 10 deletions(-)

diff --git a/tools/perf/util/session.c b/tools/perf/util/session.c
index 0d7a59c1aeb6..5f7bc5ad620f 100644
--- a/tools/perf/util/session.c
+++ b/tools/perf/util/session.c
@@ -1,7 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <errno.h>
 #include <inttypes.h>
-#include <linux/err.h>
 #include <linux/kernel.h>
 #include <linux/zalloc.h>
 #include <api/fs/fs.h>
@@ -2059,9 +2058,7 @@ fetch_mmaped_event(struct perf_session *session,
 		/* We're not fetching the event so swap back again */
 		if (session->header.needs_swap)
 			perf_event_header__bswap(&event->header);
-		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 NULL;
 	}
 
 	return event;
@@ -2079,9 +2076,6 @@ static int __perf_session__process_decomp_events(struct perf_session *session)
 	while (decomp->head < decomp->size && !session_done()) {
 		union perf_event *event = fetch_mmaped_event(session, decomp->head, decomp->size, decomp->data);
 
-		if (IS_ERR(event))
-			return PTR_ERR(event);
-
 		if (!event)
 			break;
 
@@ -2181,9 +2175,6 @@ reader__process_events(struct reader *rd, struct perf_session *session,
 
 more:
 	event = fetch_mmaped_event(session, head, mmap_size, buf);
-	if (IS_ERR(event))
-		return PTR_ERR(event);
-
 	if (!event) {
 		if (mmaps[map_idx]) {
 			munmap(mmaps[map_idx], mmap_size);
-- 
2.20.1

