--- v9
+++ v3
@@ -9,18 +9,15 @@
Sev Secret area using a configuration table" [1]), but the secrets were
not available in the guest kernel.
-The patch series keeps the address of the EFI-provided memory for
-injected secrets, and exposes the secrets to userspace via securityfs
-using a new efi_secret kernel module. The module is autoloaded (by the
-EFI driver) if the secret area is populated.
+The patch series copies the secrets from the EFI-provided memory to
+kernel reserved memory, and optionally exposes them to userspace via
+securityfs using a new efi_secret kernel module.
-The first patch in EFI keeps the address of the secret area as passed in
-the EFI configuration table. The second patch introduces the new
-efi_secret module that exposes the content of the secret entries as
-securityfs files, and allows clearing out secrets with a file unlink
-interface. The third patch auto-loads the efi_secret module during
-startup if the injected secrets area is populated. The last patch
-documents the data flow of confidential computing secret injection.
+The first patch in efi/libstub copies the secret area from the EFI
+memory to specially allocated memory; the second patch reserves that
+memory block; and the third patch introduces the new efi_secret module
+that exposes the content of the secret entries as securityfs files, and
+allows clearing out secrets with a file unlink interface.
As a usage example, consider a guest performing computations on
encrypted files. The Guest Owner provides the decryption key (= secret)
@@ -40,24 +37,11 @@
confidential computing hardware that can publish the secret area via the
standard EFI config table entry.
-To enable this functionality, set CONFIG_EFI_SECRET=m when building the
-guest kernel.
-
Here is a simple example for usage of the efi_secret module in a guest
to which an EFI secret area with 4 secrets was injected during launch:
-...
-[ 0.000000] efi: EFI v2.70 by EDK II
-[ 0.000000] efi: CocoSecret=0x7f222680 SMBIOS=0x7f541000 ACPI=0x7f77e000 ACPI 2.0=0x7f77e014 MEMATTR=0x7ea16418
-...
-[ 1.127627] Run /init as init process
-Loading, please wait...
-Starting version 245.4-4ubuntu3.15
-...
-[ 0.763204] efi_secret efi_secret.0: Created 4 entries in securityfs secrets/coco
-...
-
-# ls -la /sys/kernel/security/secrets/coco
+# modprobe efi_secret
+# ls -la /sys/kernel/security/coco/efi_secret
total 0
drwxr-xr-x 2 root root 0 Jun 28 11:54 .
drwxr-xr-x 3 root root 0 Jun 28 11:54 ..
@@ -66,15 +50,14 @@
-r--r----- 1 root root 0 Jun 28 11:54 9553f55d-3da2-43ee-ab5d-ff17f78864d2
-r--r----- 1 root root 0 Jun 28 11:54 e6f5a162-d67f-4750-a67c-5d065f2a9910
-# hd /sys/kernel/security/secrets/coco/e6f5a162-d67f-4750-a67c-5d065f2a9910
-00000000 74 68 65 73 65 2d 61 72 65 2d 74 68 65 2d 6b 61 |these-are-the-ka|
-00000010 74 61 2d 73 65 63 72 65 74 73 00 01 02 03 04 05 |ta-secrets......|
-00000020 06 07 |..|
-00000022
+# xxd /sys/kernel/security/coco/efi_secret/e6f5a162-d67f-4750-a67c-5d065f2a9910
+00000000: 7468 6573 652d 6172 652d 7468 652d 6b61 these-are-the-ka
+00000010: 7461 2d73 6563 7265 7473 0001 0203 0405 ta-secrets......
+00000020: 0607 ..
-# rm /sys/kernel/security/secrets/coco/e6f5a162-d67f-4750-a67c-5d065f2a9910
+# rm /sys/kernel/security/coco/efi_secret/e6f5a162-d67f-4750-a67c-5d065f2a9910
-# ls -la /sys/kernel/security/secrets/coco
+# ls -la /sys/kernel/security/coco/efi_secret
total 0
drwxr-xr-x 2 root root 0 Jun 28 11:55 .
drwxr-xr-x 3 root root 0 Jun 28 11:54 ..
@@ -85,64 +68,8 @@
[1] https://github.com/tianocore/edk2/commit/01726b6d23d4
-
---
-v9 changes:
-- Change the module into a platform driver (thanks Ard)
-- Remove special auto-loading code in efi; instead register a platform
- device (udev will load the efi_secret module) (thanks Ard)
-- Change logging in the efi_secret module to dev_err() etc.
-- efi_secret: first check that the secret area header is valid; only then start
- creating securityfs dirs.
-
-v8: https://lore.kernel.org/linux-coco/20220228114254.1099945-1-dovmurik@linux.ibm.com/
-v8 changes:
- - Change path of filesystem to <securityfs>/secrets/coco and fix the
- documentation accordingly (Thanks Gerd, Matthew)
- - Remove patch 2/5 (of v7) because the latest OVMF release (edk2-stable202202)
- already contains the fix to mark the launch secret page as EFI_RESERVED_TYPE.
-
-v7: https://lore.kernel.org/linux-coco/20220201124413.1093099-1-dovmurik@linux.ibm.com/
-v7 changes:
- - Improve description of efi_secret module in Kconfig.
- - Fix sparse warnings on pointer address space mismatch
- (Reported-by: kernel test robot <lkp@intel.com>)
-
-v6: https://lore.kernel.org/linux-coco/20211129114251.3741721-1-dovmurik@linux.ibm.com/
-v6 changes:
- - Autoload the efi_secret module if the secret area is populated
- (thanks Greg KH).
- - efi_secret: Depend on X86_64 because we use ioremap_encrypted() which
- is only defined for this arch.
- - efi_secret.c: Remove unneeded tableheader_guid local variable.
- - Documentation fixes.
-
-v5: https://lore.kernel.org/linux-coco/20211118113359.642571-1-dovmurik@linux.ibm.com/
-v5 changes:
- - Simplify EFI code: instead of copying the secret area, the firmware
- marks the secret area as EFI_RESERVED_TYPE, and then the uefi_init()
- code just keeps the pointer as it appears in the EFI configuration
- table. The use of reserved pages is similar to the AMD SEV-SNP
- patches for handling SNP-Secrets and SNP-CPUID pages.
- - In order to handle OVMF releases out there which mark the
- confidential computing secrets page as EFI_BOOT_SERVICES_DATA, add
- efi/libstub code that detects this and fixes the E820 map to reserve
- this page.
- - In the efi_secret module code, map the secrets page using
- ioremap_encrypted (again, similar to the AMD SEV-SNP guest patches
- for accessing SNP-Secrets and SNP-CPUID pages).
- - Add documentation in Documentation/security/coco/efi_secret.
-
-v4: https://lore.kernel.org/linux-coco/20211020061408.3447533-1-dovmurik@linux.ibm.com/
-v4 changes:
- - Guard all the new EFI and efi-stub code (patches 1+2) with #ifdef
- CONFIG_EFI_COCO_SECRET (thanks Greg KH). Selecting
- CONFIG_EFI_SECRET=m (patch 3) will enable the EFI parts as well.
- - Guard call to clflush_cache_range() with #ifdef CONFIG_X86
- (Reported-by: kernel test robot <lkp@intel.com>)
-
-v3: https://lore.kernel.org/linux-coco/20211014130848.592611-1-dovmurik@linux.ibm.com/
v3 changes:
- Rename the module to efi_secret
- Remove the exporting of clean_cache_range
@@ -162,37 +89,37 @@
RFC: https://lore.kernel.org/linux-coco/20210628183431.953934-1-dovmurik@linux.ibm.com/
+Dov Murik (3):
+ efi/libstub: Copy confidential computing secret area
+ efi: Reserve confidential computing secret area
+ virt: Add efi_secret module to expose confidential computing secrets
-Dov Murik (4):
- efi: Save location of EFI confidential computing area
- virt: Add efi_secret module to expose confidential computing secrets
- efi: Register efi_secret platform device if EFI secret area is
- declared
- docs: security: Add secrets/coco documentation
-
- Documentation/ABI/testing/securityfs-secrets-coco | 51 +++
- Documentation/security/index.rst | 1 +
- Documentation/security/secrets/coco.rst | 103 ++++++
- Documentation/security/secrets/index.rst | 9 +
- arch/x86/platform/efi/efi.c | 3 +
- drivers/firmware/efi/Kconfig | 16 +
- drivers/firmware/efi/efi.c | 9 +
- drivers/virt/Kconfig | 3 +
- drivers/virt/Makefile | 1 +
- drivers/virt/coco/efi_secret/Kconfig | 16 +
- drivers/virt/coco/efi_secret/Makefile | 2 +
- drivers/virt/coco/efi_secret/efi_secret.c | 349 ++++++++++++++++++++
- include/linux/efi.h | 10 +
- 13 files changed, 573 insertions(+)
- create mode 100644 Documentation/ABI/testing/securityfs-secrets-coco
- create mode 100644 Documentation/security/secrets/coco.rst
- create mode 100644 Documentation/security/secrets/index.rst
+ .../ABI/testing/securityfs-coco-efi_secret | 50 +++
+ arch/x86/platform/efi/efi.c | 1 +
+ drivers/firmware/efi/Makefile | 2 +-
+ drivers/firmware/efi/coco.c | 41 +++
+ drivers/firmware/efi/efi.c | 4 +
+ drivers/firmware/efi/libstub/Makefile | 2 +-
+ drivers/firmware/efi/libstub/coco.c | 68 ++++
+ drivers/firmware/efi/libstub/efi-stub.c | 2 +
+ drivers/firmware/efi/libstub/efistub.h | 2 +
+ drivers/firmware/efi/libstub/x86-stub.c | 2 +
+ drivers/virt/Kconfig | 3 +
+ drivers/virt/Makefile | 1 +
+ drivers/virt/coco/efi_secret/Kconfig | 10 +
+ drivers/virt/coco/efi_secret/Makefile | 2 +
+ drivers/virt/coco/efi_secret/efi_secret.c | 324 ++++++++++++++++++
+ include/linux/efi.h | 9 +
+ 16 files changed, 521 insertions(+), 2 deletions(-)
+ create mode 100644 Documentation/ABI/testing/securityfs-coco-efi_secret
+ create mode 100644 drivers/firmware/efi/coco.c
+ create mode 100644 drivers/firmware/efi/libstub/coco.c
create mode 100644 drivers/virt/coco/efi_secret/Kconfig
create mode 100644 drivers/virt/coco/efi_secret/Makefile
create mode 100644 drivers/virt/coco/efi_secret/efi_secret.c
-base-commit: 7e57714cd0ad2d5bb90e50b5096a0e671dec1ef3
+base-commit: 60a9483534ed0d99090a2ee1d4bb0b8179195f51
--
2.25.1