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| author | Liran Alon <liran.alon@oracle.com> | 2018-11-08 00:43:06 +0200 |
|---|---|---|
| committer | Paolo Bonzini <pbonzini@redhat.com> | 2018-11-27 12:49:57 +0100 |
| commit | bcbfbd8ec21096027f1ee13ce6c185e8175166f6 (patch) | |
| tree | 37f93e550fe07cf619662e165db685793e9ae347 /arch/x86/kvm/x86.c | |
| parent | 7f9ad1dfa3c768d1116c2dbacd7a09f9a871534e (diff) | |
| download | lwn-bcbfbd8ec21096027f1ee13ce6c185e8175166f6.tar.gz lwn-bcbfbd8ec21096027f1ee13ce6c185e8175166f6.zip | |
KVM: x86: Fix kernel info-leak in KVM_HC_CLOCK_PAIRING hypercall
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: 55dd00a73a51 ("KVM: x86: add KVM_HC_CLOCK_PAIRING hypercall")
Reported-by: syzbot+a8ef68d71211ba264f56@syzkaller.appspotmail.com
Reviewed-by: Mark Kanda <mark.kanda@oracle.com>
Signed-off-by: Liran Alon <liran.alon@oracle.com>
Cc: stable@vger.kernel.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Diffstat (limited to 'arch/x86/kvm/x86.c')
| -rw-r--r-- | arch/x86/kvm/x86.c | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/kvm/x86.c b/arch/x86/kvm/x86.c index 64cae03b2c20..7e4be1f2f253 100644 --- a/arch/x86/kvm/x86.c +++ b/arch/x86/kvm/x86.c @@ -6918,6 +6918,7 @@ 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, |