[PATCH 4.8 20/37] perf/core: Fix address filter parser

[Greg Kroah-Hartman]

4.8-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>

commit e96271f3ed7e702fa36dd0605c0c5b5f065af816 upstream.

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.

Reported-by: Vince Weaver <vincent.weaver@xxxxxxxxx>
Tested-by: Vince Weaver <vincent.weaver@xxxxxxxxx>
Signed-off-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
Acked-by: Peter Zijlstra (Intel) <peterz@xxxxxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: dvyukov@xxxxxxxxxx
Fixes: 375637bc524 ("perf/core: Introduce address range filtering")
Link: http://lkml.kernel.org/r/877f81f264.fsf@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 kernel/events/core.c |    2 ++
 1 file changed, 2 insertions(+)

--- a/kernel/events/core.c
+++ b/kernel/events/core.c
@@ -7908,6 +7908,7 @@ restart:
  * 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,
@@ -7931,6 +7932,7 @@ 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 },
 };
 
 /*