Ack: [precise, quantal, precise/lts-backport-raring, saucy, trusty 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>
> 
> (cherry picked from commit ef87dbe7614341c2e7bfe8d32fcb7028cc97442c)
> 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, 3 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/block/floppy.c b/drivers/block/floppy.c
> index 000abe2..10fbd3f 100644
> --- a/drivers/block/floppy.c
> +++ b/drivers/block/floppy.c
> @@ -3107,10 +3107,11 @@ loop:
>  		return -ENOMEM;
>  	*rcmd = ptr;
>  	ret = copy_from_user(ptr, param, sizeof(*ptr));
> -	if (ret)
> -		return -EFAULT;
>  	ptr->next = NULL;
>  	ptr->buffer_length = 0;
> +	ptr->kernel_data = NULL;
> +	if (ret)
> +		return -EFAULT;
>  	param += sizeof(struct floppy_raw_cmd);
>  	if (ptr->cmd_count > 33)
>  			/* the command may now also take up the space
> @@ -3126,7 +3127,6 @@ loop:
>  	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