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Diffstat (limited to 'results/classifier/deepseek-2/output/hypervisor/1142')
| -rw-r--r-- | results/classifier/deepseek-2/output/hypervisor/1142 | 47 |
1 files changed, 47 insertions, 0 deletions
diff --git a/results/classifier/deepseek-2/output/hypervisor/1142 b/results/classifier/deepseek-2/output/hypervisor/1142 new file mode 100644 index 000000000..116875789 --- /dev/null +++ b/results/classifier/deepseek-2/output/hypervisor/1142 @@ -0,0 +1,47 @@ + +Measurements fail with direct kernel boot for AMD SEV confidential virtualization with 7.1 machine type +Description of problem: +When booting the QEMU with the 'kernel-hashes:true' property set for 'sev-guest' confidential virtualization, the contents of the `-kernel` file are measured by the firmware. + +A remote tenant can then validate the measurement against its expected contents to see if the boot was trustworthy. + +With the pc-q35-7.1 machine type the measurement always fails to validate against expected state. + +Making the following code change + +``` +diff --git a/hw/i386/pc.c b/hw/i386/pc.c +index 7280c02ce3..3a4bf5cba3 100644 +--- a/hw/i386/pc.c ++++ b/hw/i386/pc.c +@@ -1899,6 +1899,8 @@ static void pc_machine_class_init(ObjectClass *oc, void *data) + pcmc->rsdp_in_ram = true; + pcmc->smbios_defaults = true; + pcmc->smbios_uuid_encoded = true; ++ pcmc->legacy_no_rng_seed = true; ++ + pcmc->gigabyte_align = true; + pcmc->has_reserved_memory = true; + pcmc->kvmclock_enabled = true; +``` + +results in successfully validating the measurement. + +THis is not surprising, the RNG seed patch introduced in + +``` +commit 67f7e426e53833a5db75b0d813e8d537b8a75bd2 +Author: Jason A. Donenfeld <Jason@zx2c4.com> +Date: Thu Jul 21 14:56:36 2022 +0200 + + hw/i386: pass RNG seed via setup_data entry +``` + +intentionally modifies the contents of the kernel image before passing it to the firmware, to inject a random seed. This will ensure the boot measuremnts are different every time. + +This RNG seed functionality must NOT be used when AMD SEV is active. +Steps to reproduce: +1. Create an AMD SEV guest with kernel-hashes=true and pc-q35-7.1 machine type +2. Attempt to validate the boot measurement +Additional information: + |