Ack: [lucid 1/2] floppy: ignore kernel-only members in FDRAWCMD ioctl input

[Brad Figg]

On 05/06/2014 12:10 PM, Andy Whitcroft wrote:
> From: Matthew Daley <mattd at bugfuzz.com>
> 
> Always clear out these floppy_raw_cmd struct members after copying the
> entire structure from userspace so that the in-kernel version is always
> valid and never left in an interdeterminate state.
> 
> Signed-off-by: Matthew Daley <mattd at bugfuzz.com>
> Signed-off-by: Linus Torvalds <torvalds at linux-foundation.org>
> 
> (backported from commit ef87dbe7614341c2e7bfe8d32fcb7028cc97442c upstream)
> CVE-2014-1737
> BugLink: http://bugs.launchpad.net/bugs/1316729
> Signed-off-by: Andy Whitcroft <apw at canonical.com>
> ---
>  drivers/block/floppy.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
> index 5c01f74..e0022b1 100644
> --- a/drivers/block/floppy.c
> +++ b/drivers/block/floppy.c
> @@ -3209,9 +3209,12 @@ static inline int raw_cmd_copyin(int cmd, char __user *param,
>  		if (!ptr)
>  			return -ENOMEM;
>  		*rcmd = ptr;
> -		COPYIN(*ptr);
> +		ret = _COPYIN(*ptr);
>  		ptr->next = NULL;
>  		ptr->buffer_length = 0;
> +		ptr->kernel_data = NULL;
> +		if (ret)
> +			return ret;
>  		param += sizeof(struct floppy_raw_cmd);
>  		if (ptr->cmd_count > 33)
>  			/* the command may now also take up the space
> @@ -3227,7 +3230,6 @@ static inline int raw_cmd_copyin(int cmd, char __user *param,
>  		for (i = 0; i < 16; i++)
>  			ptr->reply[i] = 0;
>  		ptr->resultcode = 0;
> -		ptr->kernel_data = NULL;
>  
>  		if (ptr->flags & (FD_RAW_READ | FD_RAW_WRITE)) {
>  			if (ptr->length <= 0)
> 


-- 
Brad Figg brad.figg at canonical.com http://www.canonical.com