Описание
In the Linux kernel, the following vulnerability has been resolved:
tpm: Disable TPM on null key name mismatch
The null key name check exists to protect against TPM reset attacks, so
a mismatch should stop the device from serving further requests.
Currently it does not disable the chip when it finds a mismatch.
The mismatch is logged:
tpm tpm0: null key integrity check failed
but the chip keeps serving commands:
/ # tpm2_getcap -c properties-fixed
TPM_PT_FAMILY_INDICATOR:
as UINT32: 0x08322e3000
as string: "2.0"
...
tpm2_load_null() where the null key name check is run sets the chip as
disabled only if the rc is non zero. When the mismatch is seen, rc is
zero at that point and it returns success. The other issue is that the
caller expects the null key handle to be populated when the function
returns 0 which it does here without writing the handle and proceeds
assuming the null key handle is valid.
During the test, I noticed that tpm2_start_auth_session() uses the
uninitialized stack value as the key handle since tpm2_load_null()
returns 0 despite the integrity failure and proceeds with
TPM2_CC_START_AUTH_SESS with this value as salt key handle.
Set rc to -ENODEV on the mismatch. The error path then disables the chip
and returns the correct code to the caller.
Tested in QEMU with swtpm and CONFIG_TCG_TPM2_HMAC=y by making
TPM2_CC_CONTEXT_LOAD fail with TPM2_RC_INTEGRITY and changing the name
of the re-created null key. The chip is now disabled on the mismatch.
A flaw was found in the Linux kernel's Trusted Platform Module (TPM) subsystem. This vulnerability allows an attacker to bypass TPM reset protections because the driver fails to disable the device when a null key integrity check fails. Consequently, the TPM continues serving requests and cryptographic authorization sessions may proceed using uninitialized key handles, compromising the integrity of secure operations.
Затронутые пакеты
| Платформа | Пакет | Состояние | Рекомендация | Релиз |
|---|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Fix deferred | ||
| Red Hat Enterprise Linux 6 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel | Not affected | ||
| Red Hat Enterprise Linux 7 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux 8 | kernel | Not affected | ||
| Red Hat Enterprise Linux 8 | kernel-rt | Not affected | ||
| Red Hat Enterprise Linux 9 | kernel | Not affected | ||
| Red Hat Enterprise Linux 9 | kernel-rt | Not affected | ||
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-8 | Not affected | ||
| Red Hat OpenShift Container Platform 4 | openshift/ose-rhel-coreos-9 | Not affected |
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Дополнительная информация
Статус:
EPSS
4.5 Medium
CVSS3
Связанные уязвимости
In the Linux kernel, the following vulnerability has been resolved: tpm: Disable TPM on null key name mismatch The null key name check exists to protect against TPM reset attacks, so a mismatch should stop the device from serving further requests. Currently it does not disable the chip when it finds a mismatch. The mismatch is logged: tpm tpm0: null key integrity check failed but the chip keeps serving commands: / # tpm2_getcap -c properties-fixed TPM_PT_FAMILY_INDICATOR: as UINT32: 0x08322e3000 as string: "2.0" ... tpm2_load_null() where the null key name check is run sets the chip as disabled only if the rc is non zero. When the mismatch is seen, rc is zero at that point and it returns success. The other issue is that the caller expects the null key handle to be populated when the function returns 0 which it does here without writing the handle and proceeds assuming the null key handle is valid. During the test, I noticed that tpm2_start_auth_session(...
In the Linux kernel, the following vulnerability has been resolved: tpm: Disable TPM on null key name mismatch The null key name check exists to protect against TPM reset attacks, so a mismatch should stop the device from serving further requests. Currently it does not disable the chip when it finds a mismatch. The mismatch is logged: tpm tpm0: null key integrity check failed but the chip keeps serving commands: / # tpm2_getcap -c properties-fixed TPM_PT_FAMILY_INDICATOR: as UINT32: 0x08322e3000 as string: "2.0" ... tpm2_load_null() where the null key name check is run sets the chip as disabled only if the rc is non zero. When the mismatch is seen, rc is zero at that point and it returns success. The other issue is that the caller expects the null key handle to be populated when the function returns 0 which it does here without writing the handle and proceeds assuming the null key handle is valid. During the test, I noti
In the Linux kernel, the following vulnerability has been resolved: t ...
In the Linux kernel, the following vulnerability has been resolved: tpm: Disable TPM on null key name mismatch The null key name check exists to protect against TPM reset attacks, so a mismatch should stop the device from serving further requests. Currently it does not disable the chip when it finds a mismatch. The mismatch is logged: tpm tpm0: null key integrity check failed but the chip keeps serving commands: / # tpm2_getcap -c properties-fixed TPM_PT_FAMILY_INDICATOR: as UINT32: 0x08322e3000 as string: "2.0" ... tpm2_load_null() where the null key name check is run sets the chip as disabled only if the rc is non zero. When the mismatch is seen, rc is zero at that point and it returns success. The other issue is that the caller expects the null key handle to be populated when the function returns 0 which it does here without writing the handle and proceeds assuming the null key handle is valid. During the test, I n...
EPSS
4.5 Medium
CVSS3