On Tue, Jun 04, 2019 at 09:38:27AM +0200, Ard Biesheuvel wrote:
On Tue, 4 Jun 2019 at 00:38, Zubin Mithra zsm@chromium.org wrote:
Hello,
CVE-2019-12380 was fixed in the upstream linux kernel with the commit :-
- 4e78921ba4dd ("efi/x86/Add missing error handling to old_memmap 1:1 mapping code")
Could the patch be applied in order to v4.19.y?
Tests run:
- Chrome OS tryjob
Unless I am missing something, it seems to me that there is some inflation going on when it comes to CVE number assignments.
The code in question only affects systems that are explicitly booted with efi=old_map, and the memory allocation occurs so early during the boot sequence that even if we fail and handle it gracefully, it is highly unlikely that we can get to a point where the system is usable at all.
Does Chrome OS boot in EFI mode? Does it use efi=old_map? Is the kernel built with 5 level paging enabled? Did you run it on 5 level paging hardware?
Or is this just a tick the box exercise?
Also, I am annoyed (does it show? :-)) that nobody mentioned the CVE at any point when the patch was under review (not even privately)
CVEs are almost always asked for _after_ the patch is merged, as the average fix-to-CVE request timeframe is -100 days.
Also, for the kernel, CVEs almost mean nothing, so if this really isn't an issue, I'll not backport this.
And I really doubt that any chromeos device has 5 level page tables just yet :)
thanks,
greg k-h