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| author | Philipp Stanner <pstanner@redhat.com> | 2023-11-02 19:15:24 +0100 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2023-11-30 13:16:21 -0800 |
| commit | 573cc0e5cf142d9992d2de3502800890fc717bc0 (patch) | |
| tree | 01147a1ba8e9cc0de2a5aeb0fdaac18e4fb17b92 /arch/x86/kvm/cpuid.c | |
| parent | 63912245c19d3a4179da44beefd017eb9270f207 (diff) | |
| download | lwn-573cc0e5cf142d9992d2de3502800890fc717bc0.tar.gz lwn-573cc0e5cf142d9992d2de3502800890fc717bc0.zip | |
KVM: x86: Harden copying of userspace-array against overflow
cpuid.c utilizes vmemdup_user() and array_size() to copy two userspace
arrays. This, currently, does not check for an overflow.
Use the new wrapper vmemdup_array_user() to copy the arrays more safely,
as vmemdup_user() doesn't check for overflow.
Note, KVM explicitly checks the number of entries before duplicating the
array, i.e. adding the overflow check should be a glorified nop.
Suggested-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Philipp Stanner <pstanner@redhat.com>
Link: https://lore.kernel.org/r/20231102181526.43279-2-pstanner@redhat.com
[sean: call out that KVM pre-checks the number of entries]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'arch/x86/kvm/cpuid.c')
| -rw-r--r-- | arch/x86/kvm/cpuid.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/x86/kvm/cpuid.c b/arch/x86/kvm/cpuid.c index dda6fc4cfae8..ad441f0d2917 100644 --- a/arch/x86/kvm/cpuid.c +++ b/arch/x86/kvm/cpuid.c @@ -469,7 +469,7 @@ int kvm_vcpu_ioctl_set_cpuid(struct kvm_vcpu *vcpu, return -E2BIG; if (cpuid->nent) { - e = vmemdup_user(entries, array_size(sizeof(*e), cpuid->nent)); + e = vmemdup_array_user(entries, cpuid->nent, sizeof(*e)); if (IS_ERR(e)) return PTR_ERR(e); @@ -513,7 +513,7 @@ int kvm_vcpu_ioctl_set_cpuid2(struct kvm_vcpu *vcpu, return -E2BIG; if (cpuid->nent) { - e2 = vmemdup_user(entries, array_size(sizeof(*e2), cpuid->nent)); + e2 = vmemdup_array_user(entries, cpuid->nent, sizeof(*e2)); if (IS_ERR(e2)) return PTR_ERR(e2); } |