Re: [PATCH net] e1000e: Fix out-of-bounds MMIO access by validating BAR0 size

[Breno Leitao]

On Mon, Jul 20, 2026 at 07:56:20PM +0800, Pu Lehui wrote:
> 
> On 2026/7/20 17:47, Breno Leitao wrote:
> > On Wed, Jul 15, 2026 at 03:58:50AM +0000, Pu Lehui wrote:
> > > +/* Minimum MMIO (BAR0) len, the largest offset is lower than 64K */
> > 
> > Why "the largest" in this case?
> 
> Hi Breno,
> 
> Thanks for pointing that out. I meant the maximum register offset accessed
> by the driver.
> 
> IIUC, common e1000e NIC usually have a 128K BAR0. But since I'm not 100%
> sure if older NIC might be smaller, I picked 64K as a safe lower limit
> because it covers the largest register offset used in the driver's codebase.
> If my assumption here is off, I'd really appreciate any corrections!
> 
> And for this comment, how about the follow?
> /* Minimum MMIO (BAR0) length to safely cover the maximum register offset
> accessed by the driver */

Thanks, Would something like this be a bit better?

     /* 
      * Smallest BAR0 that covers every register the driver accesses
      */