From: Jonathan McDowell noodles@meta.com
[ Upstream commit 1dbf74e00a5f882b04b398399b6def65cd51ef21 ]
Lazy flushing of TPM auth sessions can interact badly with IMA + kexec, resulting in loaded session handles being leaked across the kexec and not cleaned up. Fix by ensuring any active auth session is ended before the TPM is told about the shutdown, matching what is done when suspending.
Before:
root@debian-qemu-efi:~# tpm2_getcap handles-loaded-session root@debian-qemu-efi:~# tpm2_getcap handles-saved-session root@debian-qemu-efi:~# kexec --load --kexec-file-syscall … root@debian-qemu-efi:~# systemctl kexec … root@debian-qemu-efi:~# tpm2_getcap handles-loaded-session - 0x2000000 root@debian-qemu-efi:~# tpm2_getcap handles-saved-session root@debian-qemu-efi:~# (repeat kexec steps) root@debian-qemu-efi:~# tpm2_getcap handles-loaded-session - 0x2000000 - 0x2000001 root@debian-qemu-efi:~# tpm2_getcap handles-saved-session root@debian-qemu-efi:~#
After:
root@debian-qemu-efi:~# tpm2_getcap handles-loaded-session root@debian-qemu-efi:~# tpm2_getcap handles-saved-session root@debian-qemu-efi:~# kexec --load --kexec-file-syscall … root@debian-qemu-efi:~# systemctl kexec … root@debian-qemu-efi:~# tpm2_getcap handles-loaded-session root@debian-qemu-efi:~# tpm2_getcap handles-saved-session root@debian-qemu-efi:~#
Signed-off-by: Jonathan McDowell noodles@meta.com Signed-off-by: Jarkko Sakkinen jarkko@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/char/tpm/tpm-chip.c | 1 + 1 file changed, 1 insertion(+)
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c index 7df7abaf3e526..87f01269b9b53 100644 --- a/drivers/char/tpm/tpm-chip.c +++ b/drivers/char/tpm/tpm-chip.c @@ -300,6 +300,7 @@ int tpm_class_shutdown(struct device *dev) down_write(&chip->ops_sem); if (chip->flags & TPM_CHIP_FLAG_TPM2) { if (!tpm_chip_start(chip)) { + tpm2_end_auth_session(chip); tpm2_shutdown(chip, TPM2_SU_CLEAR); tpm_chip_stop(chip); }