From: Zelin Deng zelin.deng@linux.alibaba.com
commit 773e89ab0056aaa2baa1ffd9f044551654410104 upstream.
hv_clock is preallocated to have only HVC_BOOT_ARRAY_SIZE (64) elements; if the PTP_SYS_OFFSET_PRECISE ioctl is executed on vCPUs whose index is 64 of higher, retrieving the struct pvclock_vcpu_time_info pointer with "src = &hv_clock[cpu].pvti" will result in an out-of-bounds access and a wild pointer. Change it to "this_cpu_pvti()" which is guaranteed to be valid.
Fixes: 95a3d4454bb1 ("Switch kvmclock data to a PER_CPU variable") Signed-off-by: Zelin Deng zelin.deng@linux.alibaba.com Cc: stable@vger.kernel.org Message-Id: 1632892429-101194-3-git-send-email-zelin.deng@linux.alibaba.com Signed-off-by: Paolo Bonzini pbonzini@redhat.com Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/ptp/ptp_kvm_x86.c | 9 ++------- 1 file changed, 2 insertions(+), 7 deletions(-)
--- a/drivers/ptp/ptp_kvm_x86.c +++ b/drivers/ptp/ptp_kvm_x86.c @@ -15,8 +15,6 @@ #include <linux/ptp_clock_kernel.h> #include <linux/ptp_kvm.h>
-struct pvclock_vsyscall_time_info *hv_clock; - static phys_addr_t clock_pair_gpa; static struct kvm_clock_pairing clock_pair;
@@ -28,8 +26,7 @@ int kvm_arch_ptp_init(void) return -ENODEV;
clock_pair_gpa = slow_virt_to_phys(&clock_pair); - hv_clock = pvclock_get_pvti_cpu0_va(); - if (!hv_clock) + if (!pvclock_get_pvti_cpu0_va()) return -ENODEV;
ret = kvm_hypercall2(KVM_HC_CLOCK_PAIRING, clock_pair_gpa, @@ -64,10 +61,8 @@ int kvm_arch_ptp_get_crosststamp(u64 *cy struct pvclock_vcpu_time_info *src; unsigned int version; long ret; - int cpu;
- cpu = smp_processor_id(); - src = &hv_clock[cpu].pvti; + src = this_cpu_pvti();
do { /*