Re: [PATCH] bsg: Fix sense buffer bug in SG_IO

[Boaz Harrosh <bharrosh@panasas.com>]

Jens Axboe wrote:
> On Tue, Jan 20 2009, Boaz Harrosh wrote:
>> When submitting requests via SG_IO, which does a sync io, a
>> bsg_command is not allocated, so an in-Kernel sense_buffer was not
>> set. However when calling blk_execute_rq() with no sense buffer
>> one is provided from the stack. Now bsg at blk_complete_sgv4_hdr_rq()
>> would check if rq->sense_len and a sense was requested by sg_io_v4
>> the rq->sense was copy_user() back, but by now it is already mangled
>> stack memory.
>>
>> I have fixed that by forcing a sense_buffer when calling bsg_map_hdr().
>> The bsg_command->sense is provided in the write/read path like before,
>> and on-the-stack buffer is provided when doing SG_IO.
>>
>> I have also fixed a dprintk message to print rq->errors in hex because
>> of the scsi bit-field use of this member. For other block devices it
>> does not matter anyway.
>>
>> Signed-off-by: Boaz Harrosh <bharrosh@panasas.com>
> 
> Acked-by: Jens Axboe <jens.axboe@oracle.com>
> 

Jens hi.

Do we need to push this for 2.6.29-rcx. As this is a theoretical
security problem, copying and returning to user-mode a mangled
Kernel stack? Also we might need to push this to stable?

Thanks
Boaz