Re: [Bug] UBSAN: shift-out-of-bounds in sg_build_indirect

[Bart Van Assche]

On 4/9/24 05:51, Sam Sun wrote:
> We further analyzed the root cause of this bug. In function
> sg_build_indirect of drivers/scsi/sg.c, variable order of line 1900 is
> calculated out using get_order(num), and num comes from
> scatter_elem_sz. If scatter_elem_sz is equal or below zero, the order
> returned will be 52, so that PAGE_SHIFT + order is 64, which is larger
> than 32 bits int range, causing shift-out-of bound. This bug is tested
> and still remains in the latest upstream linux (6.9-rc3).
> If you have any questions, please contact us.

Thank you for having root-caused this issue and also for having shared
your root-cause analysis. Do you perhaps plan to post a patch that fixes
this issue?

Thanks,

Bart.