2010-11-06 14:42:23

by Kulikov Vasiliy

Subject: [PATCH] mtd: mtdchar: fix information leak to userland

Structure mtd_info_user is copied to userland with padding byted
between "type" and "flags" fields uninitialized. It leads to leaking
of contents of kernel stack memory.

Signed-off-by: Vasiliy Kulikov <[email protected]>
---
Compile tested.

drivers/mtd/mtdchar.c | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/drivers/mtd/mtdchar.c b/drivers/mtd/mtdchar.c
index 3eff1e5..2a0bc9e 100644
--- a/drivers/mtd/mtdchar.c
+++ b/drivers/mtd/mtdchar.c
@@ -601,6 +601,7 @@ static int mtd_ioctl(struct file *file, u_int cmd, u_long arg)
}

case MEMGETINFO:
+ memset(&info, 0, sizeof(info));
info.type = mtd->type;
info.flags = mtd->flags;
info.size = mtd->size;
@@ -609,7 +610,6 @@ static int mtd_ioctl(struct file *file, u_int cmd, u_long arg)
info.oobsize = mtd->oobsize;
/* The below fields are obsolete */
info.ecctype = -1;
- info.eccsize = 0;
if (copy_to_user(argp, &info, sizeof(struct mtd_info_user)))
return -EFAULT;
break;
--
1.7.0.4

2010-11-26 15:38:11

by Artem Bityutskiy

Subject: Re: [PATCH] mtd: mtdchar: fix information leak to userland

On Sat, 2010-11-06 at 17:41 +0300, Vasiliy Kulikov wrote:
> Structure mtd_info_user is copied to userland with padding byted
> between "type" and "flags" fields uninitialized. It leads to leaking
> of contents of kernel stack memory.
>
> Signed-off-by: Vasiliy Kulikov <[email protected]>

Pushed to l2-mtd-2.6.git, thanks.

--
Best Regards,
Artem Bityutskiy (Артём Битюцкий)