[PATCH] libata: zpodd: Fix small read overflow in zpodd_get_mech_type()

[Kees Cook <keescook@chromium.org>]

Much like commit 18c9a99bce2a ("libata: zpodd: small read overflow in
eject_tray()"), this fixes a cdb[] buffer length, this time in
zpodd_get_mech_type():

We read from the cdb[] buffer in ata_exec_internal_sg(). It has to be
ATAPI_CDB_LEN (16) bytes long, but this buffer is only 12 bytes.

The KASAN report was:

BUG: KASAN: global-out-of-bounds in ata_exec_internal_sg+0x50f/0xc70
Read of size 16 at addr ffffffff91f41f80 by task scsi_eh_1/149
...
The buggy address belongs to the variable:
 cdb.48319+0x0/0x40

Reported-by: Jeffrin Thalakkottoor <jeffrin@rajagiritech.edu.in>
Fixes: afe759511808c ("libata: identify and init ZPODD devices")
Signed-off-by: Kees Cook <keescook@chromium.org>
---
 drivers/ata/libata-zpodd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/ata/libata-zpodd.c b/drivers/ata/libata-zpodd.c
index 173e6f2dd9af..eefda51f97d3 100644
--- a/drivers/ata/libata-zpodd.c
+++ b/drivers/ata/libata-zpodd.c
@@ -56,7 +56,7 @@ static enum odd_mech_type zpodd_get_mech_type(struct ata_device *dev)
 	unsigned int ret;
 	struct rm_feature_desc *desc;
 	struct ata_taskfile tf;
-	static const char cdb[] = {  GPCMD_GET_CONFIGURATION,
+	static const char cdb[ATAPI_CDB_LEN] = {  GPCMD_GET_CONFIGURATION,
 			2,      /* only 1 feature descriptor requested */
 			0, 3,   /* 3, removable medium feature */
 			0, 0, 0,/* reserved */
-- 
2.17.1


-- 
Kees Cook