[PATCH] perf: Fix address filter parser

[Alexander Shishkin]

The token table passed into match_token() must be null-terminated, which
it currently is not in the perf's address filter string parser, as caught
by Vince's perf_fuzzer and KASAN. It doesn't blow up otherwise because of
the alignment padding of the table to the next element in the .rodata,
which is luck.

Fixing by adding a null-terminator to the token table.

Signed-off-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Fixes: 375637bc524 ("perf/core: Introduce address range filtering")
Reported-by: Vince Weaver <vincent.weaver@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx # v4.7+
---
 kernel/events/core.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/kernel/events/core.c b/kernel/events/core.c
index c6e47e97b3..63c72dee71 100644
--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -8012,6 +8012,7 @@ static void perf_event_addr_filters_apply(struct perf_event *event)
  * if <size> is not specified, the range is treated as a single address.
  */
 enum {
+	IF_ACT_NONE = -1,
 	IF_ACT_FILTER,
 	IF_ACT_START,
 	IF_ACT_STOP,
@@ -8035,6 +8036,7 @@ static const match_table_t if_tokens = {
 	{ IF_SRC_KERNEL,	"%u/%u" },
 	{ IF_SRC_FILEADDR,	"%u@%s" },
 	{ IF_SRC_KERNELADDR,	"%u" },
+	{ IF_ACT_NONE,		NULL },
 };
 
 /*
-- 
2.10.2