[Linux-kernel-mentees] [PATCH v2] block/scsi-ioctl: Prevent kernel-infoleak in scsi_put_cdrom_generic_arg()

From: Peilin Ye
Date: Mon Jul 27 2020 - 15:02:12 EST

scsi_put_cdrom_generic_arg() is copying uninitialized stack memory to
userspace due to the compiler not initializing holes in statically
allocated structures. Fix it by adding a padding field to `struct

Cc: stable@xxxxxxxxxxxxxxx
Fixes: f3ee6e63a9df ("compat_ioctl: move CDROM_SEND_PACKET handling into scsi")
Suggested-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Suggested-by: Arnd Bergmann <arnd@xxxxxxxx>
Signed-off-by: Peilin Ye <yepeilin.cs@xxxxxxxxx>
Change in v2:
- Add a padding field to `struct compat_cdrom_generic_command`,
instead of doing memset() on `cgc32`. (Suggested by Jens Axboe

block/scsi_ioctl.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/block/scsi_ioctl.c b/block/scsi_ioctl.c
index ef722f04f88a..72108404718f 100644
--- a/block/scsi_ioctl.c
+++ b/block/scsi_ioctl.c
@@ -651,6 +651,7 @@ struct compat_cdrom_generic_command {
compat_int_t stat;
compat_caddr_t sense;
unsigned char data_direction;
+ unsigned char pad[3];
compat_int_t quiet;
compat_int_t timeout;
compat_caddr_t reserved[1];