Re: [PATCH] vsprintf: protect kernel from panic due to non-canonical pointer dereference

[Andy Shevchenko]

On Mon, Oct 17, 2022 at 01:16:11PM -0600, Jane Chu wrote:
> While debugging a separate issue, it was found that an invalid string
> pointer could very well contain a non-canical address, such as
> 0x7665645f63616465. In that case, this line of defense isn't enough
> to protect the kernel from crashing due to general protection fault
> 
> 	if ((unsigned long)ptr < PAGE_SIZE || IS_ERR_VALUE(ptr))
>                 return "(efault)";
> 
> So instead, use kern_addr_valid() to validate the string pointer.

How did you check that value of the (invalid string) pointer?


-- 
With Best Regards,
Andy Shevchenko