drivers/firmware/efi/Kconfig | 15 + drivers/firmware/efi/Makefile | 1 + drivers/firmware/efi/efi.c | 18 + drivers/firmware/efi/stmm/mm_communication.h | 236 +++++++ drivers/firmware/efi/stmm/tee_stmm_efi.c | 617 +++++++++++++++++++ drivers/firmware/efi/vars.c | 8 + drivers/tee/optee/supp.c | 4 + fs/efivarfs/super.c | 45 ++ include/linux/efi.h | 13 + 9 files changed, 957 insertions(+) create mode 100644 drivers/firmware/efi/stmm/mm_communication.h create mode 100644 drivers/firmware/efi/stmm/tee_stmm_efi.c
This series introduces the tee based EFI Runtime Variable Service.
The eMMC device is typically owned by the non-secure world(linux in
this case). There is an existing solution utilizing eMMC RPMB partition
for EFI Variables, it is implemented by interacting with
OP-TEE, StandaloneMM(as EFI Variable Service Pseudo TA), eMMC driver
and tee-supplicant. The last piece is the tee-based variable access
driver to interact with OP-TEE and StandaloneMM.
Changelog:
v8 -> v9
- patch #6 "tee: optee: restore efivars ops when tee-supplicant stops"
is newly added
- remove !EFI_VARS_PSTORE Kconfig dependency, we have added a non-blocking
set_variable and it just returns EFI_UNSUPPORTED.
- remove obvious comments
v7 -> v8
Only patch #3 "efi: Add tee-based EFI variable driver" is updated.
- fix typos
- refactor error handling, direct return if applicable
- use devm_add_action_or_reset() for closing of tee context/session
- remove obvious comment
v6 -> v7
Patch #1-#4 are not updated.
Patch #5 is added into this series, original patch is here:
https://lore.kernel.org/all/20230609094532.562934-1-ilias.apalodimas@linaro.org/
There are two issues in the v6 series and v7 series addresses those.
1) efivar ops is not restored when the tee-supplicant daemon terminates.
-> As the following patch says, user must remove the device before
terminating tee-supplicant daemon.
https://lore.kernel.org/all/20230728134832.326467-1-sumit.garg@linaro.org/
2) cause panic when someone remounts the efivarfs as RW even if
SetVariable is not supported
-> The fifth patch addresses this issue.
"[PATCH v7 5/5] efivarfs: force RO when remounting if SetVariable is
not supported"
v5 -> v6
- new patch #4 is added in this series, #1-#3 patches are unchanged.
automatically update super block flag when the efivarops support
SetVariable runtime service, so that user does not need to manually
remount the efivarfs as RW.
v4 -> v5
- rebase to efi-next based on v6.4-rc1
- set generic_ops.query_variable_info, it works as expected as follows.
$ df -h /sys/firmware/efi/efivars/
Filesystem Size Used Avail Use% Mounted on
efivarfs 16K 1.3K 15K 8% /sys/firmware/efi/efivars
v3 -> v4:
- replace the reference from EDK2 to PI Specification
- remove EDK2 source code reference comments
- prepare nonblocking variant of set_variable, it just returns
EFI_UNSUPPORTED
- remove redundant buffer size check
- argument name change in mm_communicate
- function interface changes in setup_mm_hdr to remove (void **) cast
v2 -> v3:
- add CONFIG_EFI dependency to TEE_STMM_EFI
- add missing return code check for tee_client_invoke_func()
- directly call efivars_register/unregister from tee_stmm_efi.c
rfc v1 -> v2:
- split patch into three patches, one for drivers/tee,
one for include/linux/efi.h, and one for the driver/firmware/efi/stmm
- context/session management into probe() and remove() same as other tee
client driver
- StMM variable driver is moved from driver/tee/optee to driver/firmware/efi
- use "tee" prefix instead of "optee" in driver/firmware/efi/stmm/tee_stmm_efi.c,
this file does not contain op-tee specific code, abstracted by tee layer and
StMM variable driver will work on other tee implementation.
- PTA_STMM_CMD_COMMUNICATE -> PTA_STMM_CMD_COMMUNICATE
- implement query_variable_store() but currently not used
- no use of TEEC_SUCCESS, it is defined in driver/tee/optee/optee_private.h.
Other tee client drivers use 0 instead of using TEEC_SUCCESS
- remove TEEC_ERROR_EXCESS_DATA status, it is referred just to output
error message
Ilias Apalodimas (1):
efivarfs: force RO when remounting if SetVariable is not supported
Masahisa Kojima (5):
efi: expose efivar generic ops register function
efi: Add EFI_ACCESS_DENIED status code
efi: Add tee-based EFI variable driver
efivarfs: automatically update super block flag
tee: optee: restore efivars ops when tee-supplicant stops
drivers/firmware/efi/Kconfig | 15 +
drivers/firmware/efi/Makefile | 1 +
drivers/firmware/efi/efi.c | 18 +
drivers/firmware/efi/stmm/mm_communication.h | 236 +++++++
drivers/firmware/efi/stmm/tee_stmm_efi.c | 617 +++++++++++++++++++
drivers/firmware/efi/vars.c | 8 +
drivers/tee/optee/supp.c | 4 +
fs/efivarfs/super.c | 45 ++
include/linux/efi.h | 13 +
9 files changed, 957 insertions(+)
create mode 100644 drivers/firmware/efi/stmm/mm_communication.h
create mode 100644 drivers/firmware/efi/stmm/tee_stmm_efi.c
base-commit: b691118f2c44d16b84fc65b8147b33620eb18cac
--
2.30.2
Kojima-san, I found some time to do some extended testing here's what I found Switching the permissions from RO->RW when the supplicant is started works correctly # mount | grep efiv efivarfs on /sys/firmware/efi/efivars type efivarfs (ro,nosuid,nodev,noexec,relatime) # tee-supplicant -d [ 77.374878] efivars: Unregistered efivars operations [ 77.381604] Use tee-based EFI runtime variable services [ 77.386862] efivars: Registered efivars operations # mount | grep efiv efivarfs on /sys/firmware/efi/efivars type efivarfs (rw,nosuid,nodev,noexec,relatime) I didn't test unbinding yet, but I assume it's going to work fine and remove the efivar ops. Reading an writing non-authenticated EFI variables seems to work fine. I verified this with U-Boot and the BootOrder changed correctly. # efibootmgr -o 0001,0002,0000 BootCurrent: 0002 BootOrder: 0001,0002,0000 Boot0000* nvme 0:1 Boot0001* nvme 0:2 Boot0002* debian # efibootmgr -o 0002,0000,0001 BootCurrent: 0002 BootOrder: 0002,0000,0001 Boot0000* nvme 0:1 Boot0001* nvme 0:2 Boot0002* debian Writing authenticated EFI variables works the first time. I also dumped those variables from both Linux and U-Boot and they matched # efi-updatevar -f PK.auth PK # efi-updatevar -f KEK.auth KEK # efi-updatevar -f db.auth db But removing the PK at runtime fails. # efi-updatevar -f noPK.auth PK # Failed to update PK: Operation not permitted My guess is that the EDK2 code prohibits that, but we need to check why this is happening. I also got similar failures trying to update KEK and db. But the most worrying thing is this. From Linux program KEK and db # efi-updatevar -f KEK.auth KEK # efi-updatevar -f db.auth db Reboot the machine and U-Boot complains when it tries to populate the runtime vars with: Loading Linux 6.6.0-rc2-00654-g82a013b37495 ... Loading initial ramdisk ... EFI stub: Booting Linux Kernel... EFI stub: Using DTB from configuration table EFI stub: Exiting boot services... Can't populate EFI variables. No runtime variables will be available <-- This If you rewrite those vars from the U-Boot shell everything seems to come back to normal => tftp $loadaddr 192.168.49.5:noKEK.auth && setenv -e -nv -bs -rt -at -i $loadaddr:$filesize KEK => tftp $loadaddr 192.168.49.5:nodb.auth && setenv -e -nv -bs -rt -at -i $loadaddr:$filesize db => tftp $loadaddr 192.168.49.5:KEK.auth && setenv -e -nv -bs -rt -at -i $loadaddr:$filesize KEK => tftp $loadaddr 192.168.49.5:db.auth && setenv -e -nv -bs -rt -at -i $loadaddr:$filesize db Loading Linux 6.6.0-rc2-00654-g82a013b37495 ... Loading initial ramdisk ... EFI stub: Booting Linux Kernel... EFI stub: Using DTB from configuration table EFI stub: Exiting boot services... Let me know if you need any more information Regards /Ilias On Fri, Oct 13, 2023 at 04:45:33PM +0900, Masahisa Kojima wrote: > This series introduces the tee based EFI Runtime Variable Service. > > The eMMC device is typically owned by the non-secure world(linux in > this case). There is an existing solution utilizing eMMC RPMB partition > for EFI Variables, it is implemented by interacting with > OP-TEE, StandaloneMM(as EFI Variable Service Pseudo TA), eMMC driver > and tee-supplicant. The last piece is the tee-based variable access > driver to interact with OP-TEE and StandaloneMM. > > Changelog: > v8 -> v9 > - patch #6 "tee: optee: restore efivars ops when tee-supplicant stops" > is newly added > - remove !EFI_VARS_PSTORE Kconfig dependency, we have added a non-blocking > set_variable and it just returns EFI_UNSUPPORTED. > - remove obvious comments > > v7 -> v8 > Only patch #3 "efi: Add tee-based EFI variable driver" is updated. > - fix typos > - refactor error handling, direct return if applicable > - use devm_add_action_or_reset() for closing of tee context/session > - remove obvious comment > > v6 -> v7 > Patch #1-#4 are not updated. > Patch #5 is added into this series, original patch is here: > https://lore.kernel.org/all/20230609094532.562934-1-ilias.apalodimas@linaro.org/ > > There are two issues in the v6 series and v7 series addresses those. > > 1) efivar ops is not restored when the tee-supplicant daemon terminates. > -> As the following patch says, user must remove the device before > terminating tee-supplicant daemon. > https://lore.kernel.org/all/20230728134832.326467-1-sumit.garg@linaro.org/ > > 2) cause panic when someone remounts the efivarfs as RW even if > SetVariable is not supported > -> The fifth patch addresses this issue. > "[PATCH v7 5/5] efivarfs: force RO when remounting if SetVariable is > not supported" > > v5 -> v6 > - new patch #4 is added in this series, #1-#3 patches are unchanged. > automatically update super block flag when the efivarops support > SetVariable runtime service, so that user does not need to manually > remount the efivarfs as RW. > > v4 -> v5 > - rebase to efi-next based on v6.4-rc1 > - set generic_ops.query_variable_info, it works as expected as follows. > $ df -h /sys/firmware/efi/efivars/ > Filesystem Size Used Avail Use% Mounted on > efivarfs 16K 1.3K 15K 8% /sys/firmware/efi/efivars > > v3 -> v4: > - replace the reference from EDK2 to PI Specification > - remove EDK2 source code reference comments > - prepare nonblocking variant of set_variable, it just returns > EFI_UNSUPPORTED > - remove redundant buffer size check > - argument name change in mm_communicate > - function interface changes in setup_mm_hdr to remove (void **) cast > > v2 -> v3: > - add CONFIG_EFI dependency to TEE_STMM_EFI > - add missing return code check for tee_client_invoke_func() > - directly call efivars_register/unregister from tee_stmm_efi.c > > rfc v1 -> v2: > - split patch into three patches, one for drivers/tee, > one for include/linux/efi.h, and one for the driver/firmware/efi/stmm > - context/session management into probe() and remove() same as other tee > client driver > - StMM variable driver is moved from driver/tee/optee to driver/firmware/efi > - use "tee" prefix instead of "optee" in driver/firmware/efi/stmm/tee_stmm_efi.c, > this file does not contain op-tee specific code, abstracted by tee layer and > StMM variable driver will work on other tee implementation. > - PTA_STMM_CMD_COMMUNICATE -> PTA_STMM_CMD_COMMUNICATE > - implement query_variable_store() but currently not used > - no use of TEEC_SUCCESS, it is defined in driver/tee/optee/optee_private.h. > Other tee client drivers use 0 instead of using TEEC_SUCCESS > - remove TEEC_ERROR_EXCESS_DATA status, it is referred just to output > error message > > Ilias Apalodimas (1): > efivarfs: force RO when remounting if SetVariable is not supported > > Masahisa Kojima (5): > efi: expose efivar generic ops register function > efi: Add EFI_ACCESS_DENIED status code > efi: Add tee-based EFI variable driver > efivarfs: automatically update super block flag > tee: optee: restore efivars ops when tee-supplicant stops > > drivers/firmware/efi/Kconfig | 15 + > drivers/firmware/efi/Makefile | 1 + > drivers/firmware/efi/efi.c | 18 + > drivers/firmware/efi/stmm/mm_communication.h | 236 +++++++ > drivers/firmware/efi/stmm/tee_stmm_efi.c | 617 +++++++++++++++++++ > drivers/firmware/efi/vars.c | 8 + > drivers/tee/optee/supp.c | 4 + > fs/efivarfs/super.c | 45 ++ > include/linux/efi.h | 13 + > 9 files changed, 957 insertions(+) > create mode 100644 drivers/firmware/efi/stmm/mm_communication.h > create mode 100644 drivers/firmware/efi/stmm/tee_stmm_efi.c > > > base-commit: b691118f2c44d16b84fc65b8147b33620eb18cac > -- > 2.30.2 >
Hi Ilias, On Wed, 18 Oct 2023 at 20:35, Ilias Apalodimas <ilias.apalodimas@linaro.org> wrote: > > Kojima-san, > > I found some time to do some extended testing here's what I found > > Switching the permissions from RO->RW when the supplicant is started works > correctly > # mount | grep efiv > efivarfs on /sys/firmware/efi/efivars type efivarfs (ro,nosuid,nodev,noexec,relatime) > # tee-supplicant -d > [ 77.374878] efivars: Unregistered efivars operations > [ 77.381604] Use tee-based EFI runtime variable services > [ 77.386862] efivars: Registered efivars operations > # mount | grep efiv > efivarfs on /sys/firmware/efi/efivars type efivarfs (rw,nosuid,nodev,noexec,relatime) > I didn't test unbinding yet, but I assume it's going to work fine and > remove the efivar ops. > > Reading an writing non-authenticated EFI variables seems to work fine. > I verified this with U-Boot and the BootOrder changed correctly. > # efibootmgr -o 0001,0002,0000 > BootCurrent: 0002 > BootOrder: 0001,0002,0000 > Boot0000* nvme 0:1 > Boot0001* nvme 0:2 > Boot0002* debian > # efibootmgr -o 0002,0000,0001 > BootCurrent: 0002 > BootOrder: 0002,0000,0001 > Boot0000* nvme 0:1 > Boot0001* nvme 0:2 > Boot0002* debian > > Writing authenticated EFI variables works the first time. > I also dumped those variables from both Linux and U-Boot and they matched > # efi-updatevar -f PK.auth PK > # efi-updatevar -f KEK.auth KEK > # efi-updatevar -f db.auth db > > But removing the PK at runtime fails. > # efi-updatevar -f noPK.auth PK > # Failed to update PK: Operation not permitted > My guess is that the EDK2 code prohibits that, but we need to check why > this is happening. I also got similar failures trying to update KEK and db. "# efi-updatevar -f noPK.auth PK" does not reach the kernel efivarfs code. With strace, error occurs when efi-updatevar tries to open /sys/firmware/efi/efivars/KEK-*** file. I guess O_TRUNC option in open() is not required? openat(AT_FDCWD, "/sys/firmware/efi/efivars/KEK-8be4df61-93ca-11d2-aa0d-00e098032b8c", O_RDWR|O_CREAT|O_TRUNC, 0644) = -1 EPERM (Operation not permitted) write(2, "Failed to update KEK: ", 22Failed to update KEK: ) = 22 write(2, "Operation not permitted\n", 24Operation not permitted ) = 24 exit_group(1) = ? +++ exited with 1 +++ We can use "efivar" instead to remove the keys. It also works for KEK and db. # efi-updatevar -f PK.auth PK # efi-updatevar -f noPK.auth PK <--- it does not work # efivar -w -n 8be4df61-93ca-11d2-aa0d-00e098032b8c-PK -f noPK.auth <--- it works > > But the most worrying thing is this. From Linux program KEK and db > # efi-updatevar -f KEK.auth KEK > # efi-updatevar -f db.auth db > > Reboot the machine and U-Boot complains when it tries to populate the > runtime vars with: > Loading Linux 6.6.0-rc2-00654-g82a013b37495 ... > Loading initial ramdisk ... > EFI stub: Booting Linux Kernel... > EFI stub: Using DTB from configuration table > EFI stub: Exiting boot services... > Can't populate EFI variables. No runtime variables will be available <-- This I could not reproduce this issue. I tried the following command then reboot the board. Linux boots fine. # efi-updatevar -f KEK.auth KEK # efi-updatevar -f db.auth db I also enroll the PK, then UEFI secure boot works. Signed grub and signed kernel boot in UEFI secure boot enabled. Are there any additional steps to reproduce? Thanks, Masahisa Kojima > > If you rewrite those vars from the U-Boot shell everything seems to come > back to normal > => tftp $loadaddr 192.168.49.5:noKEK.auth && setenv -e -nv -bs -rt -at -i $loadaddr:$filesize KEK > => tftp $loadaddr 192.168.49.5:nodb.auth && setenv -e -nv -bs -rt -at -i $loadaddr:$filesize db > => tftp $loadaddr 192.168.49.5:KEK.auth && setenv -e -nv -bs -rt -at -i $loadaddr:$filesize KEK > => tftp $loadaddr 192.168.49.5:db.auth && setenv -e -nv -bs -rt -at -i $loadaddr:$filesize db > > Loading Linux 6.6.0-rc2-00654-g82a013b37495 ... > Loading initial ramdisk ... > EFI stub: Booting Linux Kernel... > EFI stub: Using DTB from configuration table > EFI stub: Exiting boot services... > > Let me know if you need any more information > > Regards > /Ilias > On Fri, Oct 13, 2023 at 04:45:33PM +0900, Masahisa Kojima wrote: > > This series introduces the tee based EFI Runtime Variable Service. > > > > The eMMC device is typically owned by the non-secure world(linux in > > this case). There is an existing solution utilizing eMMC RPMB partition > > for EFI Variables, it is implemented by interacting with > > OP-TEE, StandaloneMM(as EFI Variable Service Pseudo TA), eMMC driver > > and tee-supplicant. The last piece is the tee-based variable access > > driver to interact with OP-TEE and StandaloneMM. > > > > Changelog: > > v8 -> v9 > > - patch #6 "tee: optee: restore efivars ops when tee-supplicant stops" > > is newly added > > - remove !EFI_VARS_PSTORE Kconfig dependency, we have added a non-blocking > > set_variable and it just returns EFI_UNSUPPORTED. > > - remove obvious comments > > > > v7 -> v8 > > Only patch #3 "efi: Add tee-based EFI variable driver" is updated. > > - fix typos > > - refactor error handling, direct return if applicable > > - use devm_add_action_or_reset() for closing of tee context/session > > - remove obvious comment > > > > v6 -> v7 > > Patch #1-#4 are not updated. > > Patch #5 is added into this series, original patch is here: > > https://lore.kernel.org/all/20230609094532.562934-1-ilias.apalodimas@linaro.org/ > > > > There are two issues in the v6 series and v7 series addresses those. > > > > 1) efivar ops is not restored when the tee-supplicant daemon terminates. > > -> As the following patch says, user must remove the device before > > terminating tee-supplicant daemon. > > https://lore.kernel.org/all/20230728134832.326467-1-sumit.garg@linaro.org/ > > > > 2) cause panic when someone remounts the efivarfs as RW even if > > SetVariable is not supported > > -> The fifth patch addresses this issue. > > "[PATCH v7 5/5] efivarfs: force RO when remounting if SetVariable is > > not supported" > > > > v5 -> v6 > > - new patch #4 is added in this series, #1-#3 patches are unchanged. > > automatically update super block flag when the efivarops support > > SetVariable runtime service, so that user does not need to manually > > remount the efivarfs as RW. > > > > v4 -> v5 > > - rebase to efi-next based on v6.4-rc1 > > - set generic_ops.query_variable_info, it works as expected as follows. > > $ df -h /sys/firmware/efi/efivars/ > > Filesystem Size Used Avail Use% Mounted on > > efivarfs 16K 1.3K 15K 8% /sys/firmware/efi/efivars > > > > v3 -> v4: > > - replace the reference from EDK2 to PI Specification > > - remove EDK2 source code reference comments > > - prepare nonblocking variant of set_variable, it just returns > > EFI_UNSUPPORTED > > - remove redundant buffer size check > > - argument name change in mm_communicate > > - function interface changes in setup_mm_hdr to remove (void **) cast > > > > v2 -> v3: > > - add CONFIG_EFI dependency to TEE_STMM_EFI > > - add missing return code check for tee_client_invoke_func() > > - directly call efivars_register/unregister from tee_stmm_efi.c > > > > rfc v1 -> v2: > > - split patch into three patches, one for drivers/tee, > > one for include/linux/efi.h, and one for the driver/firmware/efi/stmm > > - context/session management into probe() and remove() same as other tee > > client driver > > - StMM variable driver is moved from driver/tee/optee to driver/firmware/efi > > - use "tee" prefix instead of "optee" in driver/firmware/efi/stmm/tee_stmm_efi.c, > > this file does not contain op-tee specific code, abstracted by tee layer and > > StMM variable driver will work on other tee implementation. > > - PTA_STMM_CMD_COMMUNICATE -> PTA_STMM_CMD_COMMUNICATE > > - implement query_variable_store() but currently not used > > - no use of TEEC_SUCCESS, it is defined in driver/tee/optee/optee_private.h. > > Other tee client drivers use 0 instead of using TEEC_SUCCESS > > - remove TEEC_ERROR_EXCESS_DATA status, it is referred just to output > > error message > > > > Ilias Apalodimas (1): > > efivarfs: force RO when remounting if SetVariable is not supported > > > > Masahisa Kojima (5): > > efi: expose efivar generic ops register function > > efi: Add EFI_ACCESS_DENIED status code > > efi: Add tee-based EFI variable driver > > efivarfs: automatically update super block flag > > tee: optee: restore efivars ops when tee-supplicant stops > > > > drivers/firmware/efi/Kconfig | 15 + > > drivers/firmware/efi/Makefile | 1 + > > drivers/firmware/efi/efi.c | 18 + > > drivers/firmware/efi/stmm/mm_communication.h | 236 +++++++ > > drivers/firmware/efi/stmm/tee_stmm_efi.c | 617 +++++++++++++++++++ > > drivers/firmware/efi/vars.c | 8 + > > drivers/tee/optee/supp.c | 4 + > > fs/efivarfs/super.c | 45 ++ > > include/linux/efi.h | 13 + > > 9 files changed, 957 insertions(+) > > create mode 100644 drivers/firmware/efi/stmm/mm_communication.h > > create mode 100644 drivers/firmware/efi/stmm/tee_stmm_efi.c > > > > > > base-commit: b691118f2c44d16b84fc65b8147b33620eb18cac > > -- > > 2.30.2 > >
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