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FAILED: patch "[PATCH] MIPS: KVM: Add missing gfn range check" failed to apply to 4.4-stable tree

PATCH [email protected] 1 participant 1 message Aug 18, 2016

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The patch below does not apply to the 4.4-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

Quoted 1 line

From 8985d50382359e5bf118fdbefc859d0dbf6cebc7 Mon Sep 17 00:00:00 2001

From: James Hogan <[email protected]>
Date: Thu, 11 Aug 2016 11:58:13 +0100
Subject: [PATCH] MIPS: KVM: Add missing gfn range check
MIME-Version: 1.0
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kvm_mips_handle_mapped_seg_tlb_fault() calculates the guest frame number based on the guest TLB EntryLo values, however it is not range checked to ensure it lies within the guest_pmap. If the physical memory the guest refers to is out of range then dump the guest TLB and emit an internal error.

Fixes 858dd5d45733 ("KVM/MIPS32: MMU/TLB operations for the Guest.")
Signed-off-by James Hogan <[email protected]>
Cc Paolo Bonzini <[email protected]>
Cc "Radim Krčmář" <[email protected]>
Cc Ralf Baechle <[email protected]>
Cc [email protected]
Cc [email protected]
Cc <[email protected]> # 3.10.x-
Signed-off-by Radim Krčmář <[email protected]>
arch/mips/kvm/mmu.c +15 -8
index 96e0b24cfe5c..701c1b64cef8 100644
@@ -138,6 +138,7 @@ int kvm_mips_handle_mapped_seg_tlb_fault(struct kvm_vcpu *vcpu,
 	unsigned long entryhi = 0, entrylo0 = 0, entrylo1 = 0;
 	struct kvm *kvm = vcpu->kvm;
 	kvm_pfn_t pfn0, pfn1;
+	gfn_t gfn0, gfn1;
 	long tlb_lo[2];
 	int ret;
 

@@ -152,18 +153,24 @@ int kvm_mips_handle_mapped_seg_tlb_fault(struct kvm_vcpu *vcpu,
 			VPN2_MASK & (PAGE_MASK << 1)))
 		tlb_lo[(KVM_GUEST_COMMPAGE_ADDR >> PAGE_SHIFT) & 1] = 0;
 
-	if (kvm_mips_map_page(kvm, mips3_tlbpfn_to_paddr(tlb_lo[0])
-				   >> PAGE_SHIFT) < 0)
+	gfn0 = mips3_tlbpfn_to_paddr(tlb_lo[0]) >> PAGE_SHIFT;
+	gfn1 = mips3_tlbpfn_to_paddr(tlb_lo[1]) >> PAGE_SHIFT;
+	if (gfn0 >= kvm->arch.guest_pmap_npages ||
+	    gfn1 >= kvm->arch.guest_pmap_npages) {
+		kvm_err("%s: Invalid gfn: [%#llx, %#llx], EHi: %#lx\n",
+			__func__, gfn0, gfn1, tlb->tlb_hi);
+		kvm_mips_dump_guest_tlbs(vcpu);
+		return -1;
+	}
+
+	if (kvm_mips_map_page(kvm, gfn0) < 0)
 		return -1;
 
-	if (kvm_mips_map_page(kvm, mips3_tlbpfn_to_paddr(tlb_lo[1])
-				   >> PAGE_SHIFT) < 0)
+	if (kvm_mips_map_page(kvm, gfn1) < 0)
 		return -1;
 
-	pfn0 = kvm->arch.guest_pmap[
-		mips3_tlbpfn_to_paddr(tlb_lo[0]) >> PAGE_SHIFT];
-	pfn1 = kvm->arch.guest_pmap[
-		mips3_tlbpfn_to_paddr(tlb_lo[1]) >> PAGE_SHIFT];
+	pfn0 = kvm->arch.guest_pmap[gfn0];
+	pfn1 = kvm->arch.guest_pmap[gfn1];
 
 	/* Get attributes from the Guest TLB */
 	entrylo0 = mips3_paddr_to_tlbpfn(pfn0 << PAGE_SHIFT) |