On Tue, May 24, 2022 at 05:27:56PM +0200, Vegard Nossum wrote: > > On 5/24/22 17:22, Greg KH wrote: > > On Tue, May 24, 2022 at 05:11:18PM +0200, Vegard Nossum wrote: > >> From: Paolo Bonzini <pbonzini@xxxxxxxxxx> > >> > >> commit 9f46c187e2e680ecd9de7983e4d081c3391acc76 upstream. > >> > >> With shadow paging enabled, the INVPCID instruction results in a call > >> to kvm_mmu_invpcid_gva. If INVPCID is executed with CR0.PG=0, the > >> invlpg callback is not set and the result is a NULL pointer dereference. > >> Fix it trivially by checking for mmu->invlpg before every call. > >> > >> There are other possibilities: > >> > >> - check for CR0.PG, because KVM (like all Intel processors after P5) > >> flushes guest TLB on CR0.PG changes so that INVPCID/INVLPG are a > >> nop with paging disabled > >> > >> - check for EFER.LMA, because KVM syncs and flushes when switching > >> MMU contexts outside of 64-bit mode > >> > >> All of these are tricky, go for the simple solution. This is CVE-2022-1789. > >> > >> Reported-by: Yongkang Jia <kangel@xxxxxxxxxx> > >> Cc: stable@xxxxxxxxxxxxxxx > >> Signed-off-by: Paolo Bonzini <pbonzini@xxxxxxxxxx> > >> [fix conflict due to missing b9e5603c2a3accbadfec570ac501a54431a6bdba] > >> Signed-off-by: Vegard Nossum <vegard.nossum@xxxxxxxxxx> > >> --- > >> arch/x86/kvm/mmu/mmu.c | 6 ++++-- > >> 1 file changed, 4 insertions(+), 2 deletions(-) > > > > What kernel tree(s) are you wanting this to be applied to? > > I replied to the v5.17 email > (https://lore.kernel.org/stable/165314153515625@xxxxxxxxx/T/#u) and I've > only tested this on top of 5.17.9. > > Is that generally enough to trigger attempts to automatically > cherry-pick it onto the older branches or should I test and submit for > the older ones as well? You should test and submit for the older ones as well please. > How would you prefer to indicate the kernel tree(s) in the future? Just say so in the [PATCH 5.17.y] subject line, or in the signed-off-by area or below the --- line. Responding to the email and relying on the thread alone doesn't usually work as the original message is long gone from my mailboxes, I can't keep that old stuff cluttering up the place :) thanks, greg k-h
