2015-12-08 18:26:27

by Scott Bauer

[permalink] [raw]
Subject: Re: [PATCH] dm ioctl: Access user-land memory through safe functions.


On 12/01/2015 11:11 AM, Scotty wrote:
>
> 0001-dm-ioctl-Access-user-land-memory-through-safe-functi.patch
>
>
> From b26adf880eba03ac6f2b1dd87426bb96fd2a0282 Mon Sep 17 00:00:00 2001
> From: Scotty Bauer <[email protected]>
> Date: Tue, 1 Dec 2015 10:52:46 -0700
> Subject: [PATCH] dm ioctl: Access user-land memory through safe functions.
>
> This patch fixes a user-land dereference. Now we use
> the safe copy_from_user to access the memory.
>
> Signed-off-by: Scotty Bauer <[email protected]>
> ---
> drivers/md/dm-ioctl.c | 8 ++++++--
> 1 file changed, 6 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/md/dm-ioctl.c b/drivers/md/dm-ioctl.c
> index 80a4395..39a9d1a 100644
> --- a/drivers/md/dm-ioctl.c
> +++ b/drivers/md/dm-ioctl.c
> @@ -1642,9 +1642,13 @@ static ioctl_fn lookup_ioctl(unsigned int cmd, int *ioctl_flags)
> static int check_version(unsigned int cmd, struct dm_ioctl __user *user)
> {
> uint32_t version[3];
> + uint32_t __user *version_ptr;
> int r = 0;
>
> - if (copy_from_user(version, user->version, sizeof(version)))
> + if (copy_from_user(&version_ptr, &user->version, sizeof(version_ptr)))
> + return -EFAULT;
> +
> + if (copy_from_user(version, version_ptr, sizeof(version)))
> return -EFAULT;
>
> if ((DM_VERSION_MAJOR != version[0]) ||
> @@ -1663,7 +1667,7 @@ static int check_version(unsigned int cmd, struct dm_ioctl __user *user)
> version[0] = DM_VERSION_MAJOR;
> version[1] = DM_VERSION_MINOR;
> version[2] = DM_VERSION_PATCHLEVEL;
> - if (copy_to_user(user->version, version, sizeof(version)))
> + if (copy_to_user(version_ptr, version, sizeof(version)))
> return -EFAULT;
>
> return r;
> --


Friendly ping, is anyone interested in this?