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| author | Mathias Krause <minipli@grsecurity.net> | 2024-06-14 22:28:58 +0200 |
|---|---|---|
| committer | Sean Christopherson <seanjc@google.com> | 2024-06-18 18:03:52 +0200 |
| commit | 4b451a57809cacec00978c36c97b1c9b53cde664 (patch) | |
| tree | 1213f81f9cbd09c6446f60c5011d175746089118 /tools | |
| parent | KVM: x86: Prevent excluding the BSP on setting max_vcpu_ids (diff) | |
| download | linux-4b451a57809cacec00978c36c97b1c9b53cde664.tar.xz linux-4b451a57809cacec00978c36c97b1c9b53cde664.zip | |
KVM: selftests: Test max vCPU IDs corner cases
The KVM_CREATE_VCPU ioctl ABI had an implicit integer truncation bug,
allowing 2^32 aliases for a vCPU ID by setting the upper 32 bits of a 64
bit ioctl() argument.
It also allowed excluding a once set boot CPU ID.
Verify this no longer works and gets rejected with an error.
Signed-off-by: Mathias Krause <minipli@grsecurity.net>
Link: https://lore.kernel.org/r/20240614202859.3597745-5-minipli@grsecurity.net
[sean: tweak assert message+comment for 63:32!=0 testcase]
Signed-off-by: Sean Christopherson <seanjc@google.com>
Diffstat (limited to 'tools')
| -rw-r--r-- | tools/testing/selftests/kvm/x86_64/max_vcpuid_cap_test.c | 22 |
1 files changed, 20 insertions, 2 deletions
diff --git a/tools/testing/selftests/kvm/x86_64/max_vcpuid_cap_test.c b/tools/testing/selftests/kvm/x86_64/max_vcpuid_cap_test.c index 3cc4b86832fe..7e2bfb3c3f3b 100644 --- a/tools/testing/selftests/kvm/x86_64/max_vcpuid_cap_test.c +++ b/tools/testing/selftests/kvm/x86_64/max_vcpuid_cap_test.c @@ -26,19 +26,37 @@ int main(int argc, char *argv[]) TEST_ASSERT(ret < 0, "Setting KVM_CAP_MAX_VCPU_ID beyond KVM cap should fail"); + /* Test BOOT_CPU_ID interaction (MAX_VCPU_ID cannot be lower) */ + if (kvm_has_cap(KVM_CAP_SET_BOOT_CPU_ID)) { + vm_ioctl(vm, KVM_SET_BOOT_CPU_ID, (void *)MAX_VCPU_ID); + + /* Try setting KVM_CAP_MAX_VCPU_ID below BOOT_CPU_ID */ + ret = __vm_enable_cap(vm, KVM_CAP_MAX_VCPU_ID, MAX_VCPU_ID - 1); + TEST_ASSERT(ret < 0, + "Setting KVM_CAP_MAX_VCPU_ID below BOOT_CPU_ID should fail"); + } + /* Set KVM_CAP_MAX_VCPU_ID */ vm_enable_cap(vm, KVM_CAP_MAX_VCPU_ID, MAX_VCPU_ID); - /* Try to set KVM_CAP_MAX_VCPU_ID again */ ret = __vm_enable_cap(vm, KVM_CAP_MAX_VCPU_ID, MAX_VCPU_ID + 1); TEST_ASSERT(ret < 0, "Setting KVM_CAP_MAX_VCPU_ID multiple times should fail"); - /* Create vCPU with id beyond KVM_CAP_MAX_VCPU_ID cap*/ + /* Create vCPU with id beyond KVM_CAP_MAX_VCPU_ID cap */ ret = __vm_ioctl(vm, KVM_CREATE_VCPU, (void *)MAX_VCPU_ID); TEST_ASSERT(ret < 0, "Creating vCPU with ID > MAX_VCPU_ID should fail"); + /* Create vCPU with bits 63:32 != 0, but an otherwise valid id */ + ret = __vm_ioctl(vm, KVM_CREATE_VCPU, (void *)(1L << 32)); + TEST_ASSERT(ret < 0, "Creating vCPU with ID[63:32] != 0 should fail"); + + /* Create vCPU with id within bounds */ + ret = __vm_ioctl(vm, KVM_CREATE_VCPU, (void *)0); + TEST_ASSERT(ret >= 0, "Creating vCPU with ID 0 should succeed"); + + close(ret); kvm_vm_free(vm); return 0; } |