[PATCH resend 3/5] libata-scsi: fix overflow in mode page copy

From: tom . ty89
Date: Thu Jul 21 2016 - 14:42:46 EST

From: Tom Yan <tom.ty89@xxxxxxxxx>

ata_mselect_*() would initialize a char array for storing a copy of
the current mode page. However, if char was actually signed char,
overflow could occur.

For example, `0xff` from def_control_mpage[] would be "truncated"
to `-1`. This prevented ata_mselect_control() from working at all,
since when it did the read-only bits check, there would always be
a mismatch.

Signed-off-by: Tom Yan <tom.ty89@xxxxxxxxx>

diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
index ac90676..3c93341 100644
--- a/drivers/ata/libata-scsi.c
+++ b/drivers/ata/libata-scsi.c
@@ -3610,7 +3610,7 @@ static int ata_mselect_caching(struct ata_queued_cmd *qc,
struct ata_taskfile *tf = &qc->tf;
struct ata_device *dev = qc->dev;
- char mpage[CACHE_MPAGE_LEN];
+ u8 mpage[CACHE_MPAGE_LEN];
u8 wce;
int i;

@@ -3675,7 +3675,7 @@ static int ata_mselect_control(struct ata_queued_cmd *qc,
const u8 *buf, int len, u16 *fp)
struct ata_device *dev = qc->dev;
- char mpage[CONTROL_MPAGE_LEN];
+ u8 mpage[CONTROL_MPAGE_LEN];
u8 d_sense;
int i;