Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 08b9a967 authored by Liran Alon's avatar Liran Alon Committed by Greg Kroah-Hartman
Browse files

KVM: x86: Fix kernel info-leak in KVM_HC_CLOCK_PAIRING hypercall 



commit bcbfbd8ec21096027f1ee13ce6c185e8175166f6 upstream.

kvm_pv_clock_pairing() allocates local var
"struct kvm_clock_pairing clock_pairing" on stack and initializes
all it's fields besides padding (clock_pairing.pad[]).

Because clock_pairing var is written completely (including padding)
to guest memory, failure to init struct padding results in kernel
info-leak.

Fix the issue by making sure to also init the padding with zeroes.

Fixes: 55dd00a7 ("KVM: x86: add KVM_HC_CLOCK_PAIRING hypercall")
Reported-by: default avatar <syzbot+a8ef68d71211ba264f56@syzkaller.appspotmail.com>
Reviewed-by: default avatarMark Kanda <mark.kanda@oracle.com>
Signed-off-by: default avatarLiran Alon <liran.alon@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 57e972ec

arch/x86/kvm/x86.c

+1 −0
Original line number Diff line number Diff line
@@ -6378,6 +6378,7 @@ static int kvm_pv_clock_pairing(struct kvm_vcpu *vcpu, gpa_t paddr, 
	clock_pairing.nsec = ts.tv_nsec;

	clock_pairing.tsc = kvm_read_l1_tsc(vcpu, cycle);

	clock_pairing.flags = 0;

	memset(&clock_pairing.pad, 0, sizeof(clock_pairing.pad));



	ret = 0;

	if (kvm_write_guest(vcpu->kvm, paddr, &clock_pairing,