RE: [PATCH v5] cifs: Allocate validate negotiation request through kmalloc

[Tom Talpey]

> -----Original Message-----
> From: linux-cifs-owner@xxxxxxxxxxxxxxx <linux-cifs-owner@xxxxxxxxxxxxxxx> On
> Behalf Of Long Li
> Sent: Wednesday, April 25, 2018 2:30 PM
> To: Steve French <sfrench@xxxxxxxxx>; linux-cifs@xxxxxxxxxxxxxxx; samba-
> technical@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; linux-
> rdma@xxxxxxxxxxxxxxx
> Cc: Long Li <longli@xxxxxxxxxxxxx>
> Subject: [PATCH v5] cifs: Allocate validate negotiation request through kmalloc
> 
> From: Long Li <longli@xxxxxxxxxxxxx>
> 
> The data buffer allocated on the stack can't be DMA'ed, ib_dma_map_page will
> return an invalid DMA address for a buffer on stack. Even worse, this
> incorrect address can't be detected by ib_dma_mapping_error. Sending data
> from this address to hardware will not fail, but the remote peer will get
> junk data.
> 
> Fix this by allocating the request on the heap in smb3_validate_negotiate.
> 

Looks good.

Reviewed-By: Tom Talpey <ttalpey@xxxxxxxxxxxxx>