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author | Linus Torvalds <torvalds@linux-foundation.org> | 2023-04-03 19:34:08 +0300 |
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committer | Linus Torvalds <torvalds@linux-foundation.org> | 2023-04-03 19:34:08 +0300 |
commit | 2d72ab2449fa9fce8f6898fd5adda10497f7c111 (patch) | |
tree | d74f5711ab2a14dacc4646002784ab94f2f17ac9 /arch/x86/kernel/cpu | |
parent | 7e364e56293bb98cae1b55fd835f5991c4e96e7d (diff) | |
parent | f8acb24aaf89fc46cd953229462ea8abe31b395f (diff) | |
download | linux-2d72ab2449fa9fce8f6898fd5adda10497f7c111.tar.xz |
Merge tag 'hyperv-fixes-signed-20230402' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux
Pull hyperv fixes from Wei Liu:
- Fix a bug in channel allocation for VMbus (Mohammed Gamal)
- Do not allow root partition functionality in CVM (Michael Kelley)
* tag 'hyperv-fixes-signed-20230402' of git://git.kernel.org/pub/scm/linux/kernel/git/hyperv/linux:
x86/hyperv: Block root partition functionality in a Confidential VM
Drivers: vmbus: Check for channel allocation before looking up relids
Diffstat (limited to 'arch/x86/kernel/cpu')
-rw-r--r-- | arch/x86/kernel/cpu/mshyperv.c | 12 |
1 files changed, 8 insertions, 4 deletions
diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c index f36dc2f796c5..f1197366a97d 100644 --- a/arch/x86/kernel/cpu/mshyperv.c +++ b/arch/x86/kernel/cpu/mshyperv.c @@ -358,12 +358,16 @@ static void __init ms_hyperv_init_platform(void) * To mirror what Windows does we should extract CPU management * features and use the ReservedIdentityBit to detect if Linux is the * root partition. But that requires negotiating CPU management - * interface (a process to be finalized). + * interface (a process to be finalized). For now, use the privilege + * flag as the indicator for running as root. * - * For now, use the privilege flag as the indicator for running as - * root. + * Hyper-V should never specify running as root and as a Confidential + * VM. But to protect against a compromised/malicious Hyper-V trying + * to exploit root behavior to expose Confidential VM memory, ignore + * the root partition setting if also a Confidential VM. */ - if (cpuid_ebx(HYPERV_CPUID_FEATURES) & HV_CPU_MANAGEMENT) { + if ((ms_hyperv.priv_high & HV_CPU_MANAGEMENT) && + !(ms_hyperv.priv_high & HV_ISOLATION)) { hv_root_partition = true; pr_info("Hyper-V: running as root partition\n"); } |