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| author | Marc Zyngier <maz@kernel.org> | 2023-03-16 17:45:46 +0000 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2023-04-06 12:12:47 +0200 |
| commit | c615e36f81923b4b149d37bff77dca4a439c81c7 (patch) | |
| tree | 21dbe195268c277ba6690d32105f7f2f0bd5e904 | |
| parent | f8ac6c88d3ebc5c55bf718e4bac45416ea4306a4 (diff) | |
| download | linux-c615e36f81923b4b149d37bff77dca4a439c81c7.tar.gz linux-c615e36f81923b4b149d37bff77dca4a439c81c7.tar.bz2 linux-c615e36f81923b4b149d37bff77dca4a439c81c7.zip | |
KVM: arm64: Check for kvm_vma_mte_allowed in the critical section
commit 8c2e8ac8ad4be68409e806ce1cc78fc7a04539f3 upstream.
On page fault, we find about the VMA that backs the page fault
early on, and quickly release the mmap_read_lock. However, using
the VMA pointer after the critical section is pretty dangerous,
as a teardown may happen in the meantime and the VMA be long gone.
Move the sampling of the MTE permission early, and NULL-ify the
VMA pointer after that, just to be on the safe side.
Signed-off-by: Marc Zyngier <maz@kernel.org>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/r/20230316174546.3777507-3-maz@kernel.org
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | arch/arm64/kvm/mmu.c | 8 |
1 files changed, 6 insertions, 2 deletions
diff --git a/arch/arm64/kvm/mmu.c b/arch/arm64/kvm/mmu.c index db6ddb8acfd1..3c24178bd493 100644 --- a/arch/arm64/kvm/mmu.c +++ b/arch/arm64/kvm/mmu.c @@ -1218,7 +1218,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, { int ret = 0; bool write_fault, writable, force_pte = false; - bool exec_fault; + bool exec_fault, mte_allowed; bool device = false; unsigned long mmu_seq; struct kvm *kvm = vcpu->kvm; @@ -1309,6 +1309,10 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, fault_ipa &= ~(vma_pagesize - 1); gfn = fault_ipa >> PAGE_SHIFT; + mte_allowed = kvm_vma_mte_allowed(vma); + + /* Don't use the VMA after the unlock -- it may have vanished */ + vma = NULL; /* * Read mmu_invalidate_seq so that KVM can detect if the results of @@ -1379,7 +1383,7 @@ static int user_mem_abort(struct kvm_vcpu *vcpu, phys_addr_t fault_ipa, if (fault_status != ESR_ELx_FSC_PERM && !device && kvm_has_mte(kvm)) { /* Check the VMM hasn't introduced a new disallowed VMA */ - if (kvm_vma_mte_allowed(vma)) { + if (mte_allowed) { sanitise_mte_tags(kvm, pfn, vma_pagesize); } else { ret = -EFAULT; |