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x86 fixes for overflows and other nastiness.

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Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

Pull kvm fixes from Paolo Bonzini:
 "x86 fixes for overflows and other nastiness"

* tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm:
  KVM: x86: nVMX: fix x2APIC VTPR read intercept
  KVM: x86: nVMX: close leak of L0's x2APIC MSRs (CVE-2019-3887)
  KVM: SVM: prevent DBG_DECRYPT and DBG_ENCRYPT overflow
  kvm: svm: fix potential get_num_contig_pages overflow
This commit is contained in:
Linus Torvalds 2019-04-05 13:43:07 -10:00
commit bc5725f974
2 changed files with 59 additions and 37 deletions
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22
arch/x86/kvm/svm.c
View File

@ -6422,11 +6422,11 @@ e_free:
return ret;
}
static int get_num_contig_pages(int idx, struct page **inpages,
unsigned long npages)
static unsigned long get_num_contig_pages(unsigned long idx,
struct page **inpages, unsigned long npages)
{
unsigned long paddr, next_paddr;
int i = idx + 1, pages = 1;
unsigned long i = idx + 1, pages = 1;
/* find the number of contiguous pages starting from idx */
paddr = __sme_page_pa(inpages[idx]);
@ -6445,12 +6445,12 @@ static int get_num_contig_pages(int idx, struct page **inpages,
static int sev_launch_update_data(struct kvm *kvm, struct kvm_sev_cmd *argp)
{
unsigned long vaddr, vaddr_end, next_vaddr, npages, size;
unsigned long vaddr, vaddr_end, next_vaddr, npages, pages, size, i;
struct kvm_sev_info *sev = &to_kvm_svm(kvm)->sev_info;
struct kvm_sev_launch_update_data params;
struct sev_data_launch_update_data *data;
struct page **inpages;
int i, ret, pages;
int ret;
if (!sev_guest(kvm))
return -ENOTTY;
@ -6799,7 +6799,8 @@ static int sev_dbg_crypt(struct kvm *kvm, struct kvm_sev_cmd *argp, bool dec)
struct page **src_p, **dst_p;
struct kvm_sev_dbg debug;
unsigned long n;
int ret, size;
unsigned int size;
int ret;
if (!sev_guest(kvm))
return -ENOTTY;
@ -6807,6 +6808,11 @@ static int sev_dbg_crypt(struct kvm *kvm, struct kvm_sev_cmd *argp, bool dec)
if (copy_from_user(&debug, (void __user *)(uintptr_t)argp->data, sizeof(debug)))
return -EFAULT;
if (!debug.len || debug.src_uaddr + debug.len < debug.src_uaddr)
return -EINVAL;
if (!debug.dst_uaddr)
return -EINVAL;
vaddr = debug.src_uaddr;
size = debug.len;
vaddr_end = vaddr + size;
@ -6857,8 +6863,8 @@ static int sev_dbg_crypt(struct kvm *kvm, struct kvm_sev_cmd *argp, bool dec)
dst_vaddr,
len, &argp->error);
sev_unpin_memory(kvm, src_p, 1);
sev_unpin_memory(kvm, dst_p, 1);
sev_unpin_memory(kvm, src_p, n);
sev_unpin_memory(kvm, dst_p, n);
if (ret)
goto err;

74
arch/x86/kvm/vmx/nested.c
View File

@ -500,6 +500,17 @@ static void nested_vmx_disable_intercept_for_msr(unsigned long *msr_bitmap_l1,
}
}
static inline void enable_x2apic_msr_intercepts(unsigned long *msr_bitmap) {
int msr;
for (msr = 0x800; msr <= 0x8ff; msr += BITS_PER_LONG) {
unsigned word = msr / BITS_PER_LONG;
msr_bitmap[word] = ~0;
msr_bitmap[word + (0x800 / sizeof(long))] = ~0;
}
}
/*
* Merge L0's and L1's MSR bitmap, return false to indicate that
* we do not use the hardware.
@ -541,39 +552,44 @@ static inline bool nested_vmx_prepare_msr_bitmap(struct kvm_vcpu *vcpu,
return false;
msr_bitmap_l1 = (unsigned long *)kmap(page);
if (nested_cpu_has_apic_reg_virt(vmcs12)) {
/*
* L0 need not intercept reads for MSRs between 0x800 and 0x8ff, it
* just lets the processor take the value from the virtual-APIC page;
* take those 256 bits directly from the L1 bitmap.
*/
for (msr = 0x800; msr <= 0x8ff; msr += BITS_PER_LONG) {
unsigned word = msr / BITS_PER_LONG;
msr_bitmap_l0[word] = msr_bitmap_l1[word];
msr_bitmap_l0[word + (0x800 / sizeof(long))] = ~0;
}
} else {
for (msr = 0x800; msr <= 0x8ff; msr += BITS_PER_LONG) {
unsigned word = msr / BITS_PER_LONG;
msr_bitmap_l0[word] = ~0;
msr_bitmap_l0[word + (0x800 / sizeof(long))] = ~0;
}
}
nested_vmx_disable_intercept_for_msr(
msr_bitmap_l1, msr_bitmap_l0,
X2APIC_MSR(APIC_TASKPRI),
MSR_TYPE_W);
/*
* To keep the control flow simple, pay eight 8-byte writes (sixteen
* 4-byte writes on 32-bit systems) up front to enable intercepts for
* the x2APIC MSR range and selectively disable them below.
*/
enable_x2apic_msr_intercepts(msr_bitmap_l0);
if (nested_cpu_has_virt_x2apic_mode(vmcs12)) {
if (nested_cpu_has_apic_reg_virt(vmcs12)) {
/*
* L0 need not intercept reads for MSRs between 0x800
* and 0x8ff, it just lets the processor take the value
* from the virtual-APIC page; take those 256 bits
* directly from the L1 bitmap.
*/
for (msr = 0x800; msr <= 0x8ff; msr += BITS_PER_LONG) {
unsigned word = msr / BITS_PER_LONG;
msr_bitmap_l0[word] = msr_bitmap_l1[word];
}
}
if (nested_cpu_has_vid(vmcs12)) {
nested_vmx_disable_intercept_for_msr(
msr_bitmap_l1, msr_bitmap_l0,
X2APIC_MSR(APIC_EOI),
MSR_TYPE_W);
nested_vmx_disable_intercept_for_msr(
msr_bitmap_l1, msr_bitmap_l0,
X2APIC_MSR(APIC_SELF_IPI),
MSR_TYPE_W);
X2APIC_MSR(APIC_TASKPRI),
MSR_TYPE_R | MSR_TYPE_W);
if (nested_cpu_has_vid(vmcs12)) {
nested_vmx_disable_intercept_for_msr(
msr_bitmap_l1, msr_bitmap_l0,
X2APIC_MSR(APIC_EOI),
MSR_TYPE_W);
nested_vmx_disable_intercept_for_msr(
msr_bitmap_l1, msr_bitmap_l0,
X2APIC_MSR(APIC_SELF_IPI),
MSR_TYPE_W);
}
}
if (spec_ctrl)