[PATCH v2] perf tools: Check for null when copying nsinfo.

From: Benno Evers <bevers@mesosphere.com>
To: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Krister Johansen <kjlx@templeofstupid.com>,
	Benno Evers <bevers@mesosphere.com>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
	Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
	linux-kernel@vger.kernel.org
Subject: [PATCH v2] perf tools: Check for null when copying nsinfo.
Date: Fri, 10 Aug 2018 15:36:13 +0200	[thread overview]
Message-ID: <20180810133614.9925-1-bevers@mesosphere.com> (raw)

The argument to nsinfo__copy() was assumed to be valid, but some code paths
exist that will lead to NULL being passed.

In particular, running 'perf script -D' on a perf.data file containing an
PERF_RECORD_MMAP event associating the '[vdso]' dso with pid 0 earlier in
the event stream will lead to a segfault.

Since all calling code is already checking for a non-null return value,
just return NULL for this case as well.

Acked-by: Namhyung Kim <namhyung@kernel.org>
Signed-off-by: Benno Evers <bevers@mesosphere.com>
---
Changes from v1:
  Added Signed-off-by line.

 tools/perf/util/namespaces.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/tools/perf/util/namespaces.c b/tools/perf/util/namespaces.c
index 5be021701f34..cf8bd123cf73 100644
--- a/tools/perf/util/namespaces.c
+++ b/tools/perf/util/namespaces.c
@@ -139,6 +139,9 @@ struct nsinfo *nsinfo__copy(struct nsinfo *nsi)
 {
 	struct nsinfo *nnsi;
 
+	if (nsi == NULL)
+		return NULL;
+
 	nnsi = calloc(1, sizeof(*nnsi));
 	if (nnsi != NULL) {
 		nnsi->pid = nsi->pid;
-- 
2.17.1

