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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-19 10:09:22 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-19 10:09:22 -0700 |
| commit | f4cdf7ca9a1fdcca413157df19753f388a5a224e (patch) | |
| tree | 60a31895b2446cd7fa27514e8c2843534a0de0da /Documentation/ABI/testing/evm | |
| download | linux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.tar.gz linux-stable-f4cdf7ca9a1fdcca413157df19753f388a5a224e.zip | |
Merge tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-mediagrafted
Pull media updates from Mauro Carvalho Chehab:
- v4l2-core: added ISP statistics support and per-block validation
- v4l2-core: Allow unknown HDR10 white point and luminance
- New camera sensors: Sony IMX678 and IMX471m, Himax HM1092 IR sensor
- New codec: Milos: VPU v2.0 codec support
- isp driver: gained support for Dreamchip RPPX1 ISP framework
- vsp1 driver: gained support for RZ/T2H and RZ/N2H
- Novalake driver: gained CVS support for new NVL hardware
- dvb-core: fix feed leak on failed DMX_ADD_PID
- several driver fixes, cleanups and minor improvements
* tag 'media/v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (308 commits)
media: ipu-bridge: check all DMI entries when overriding sensor rotation
media: v4l2-async: avoid deleting unlinked ASC entry on link error
media: rzg2l-cru: Align bytesperline to hardware DMA stride requirement
media: intel/ipu6: fix async notifier cleanup leak on parse error
media: staging/ipu7: fix async notifier UAF on probe error path
media: amd: isp4: fix self-deadlock in isp4sd_pwron_and_init() error path
media: amd: isp4: release partial allocations in isp4if_alloc_fw_gpumem()
media: rcar-isp: Fix VSPX reference leaks
media: rcar-isp: Release ISPCORE resources
media: i2c: imx415: Release runtime PM reference on VBLANK error
media: i2c: imx415: Return test pattern write errors
media: renesas: vsp1: Declare index variables in for loop statement
media: renesas: vsp1: Make reset control optional to support platforms without a reset line
media: dt-bindings: media: renesas,vsp1: Document RZ/T2H and RZ/N2H SoCs
media: dt-bindings: media: renesas,fcp: Document RZ/T2H and RZ/N2H SoCs
media: nxp: imx8-isi: Add additional 32-bit RGB format support
media: nxp: imx8-isi: Add 16-bit raw Bayer format support
media: nxp: imx8-isi: Implement per-stream reference counting for multiplexed streams
media: nxp: imx8-isi: Use BIT_ULL() for 64-bit stream masks
media: nxp: imx8-isi: Correct color map between V4L2 and ISI
...
Diffstat (limited to 'Documentation/ABI/testing/evm')
| -rw-r--r-- | Documentation/ABI/testing/evm | 109 |
1 files changed, 109 insertions, 0 deletions
diff --git a/Documentation/ABI/testing/evm b/Documentation/ABI/testing/evm new file mode 100644 index 000000000..db3007bab --- /dev/null +++ b/Documentation/ABI/testing/evm @@ -0,0 +1,109 @@ +What: /sys/kernel/security/evm +What: /sys/kernel/security/*/evm +Date: March 2011 +Contact: Mimi Zohar <zohar@us.ibm.com> +Description: + EVM protects a file's security extended attributes(xattrs) + against integrity attacks. The initial method maintains an + HMAC-sha1 value across the extended attributes, storing the + value as the extended attribute 'security.evm'. + + EVM supports two classes of security.evm. The first is + an HMAC-sha1 generated locally with a + trusted/encrypted key stored in the Kernel Key + Retention System. The second is a digital signature + generated either locally or remotely using an + asymmetric key. These keys are loaded onto root's + keyring using keyctl, and EVM is then enabled by + echoing a value to <securityfs>/evm made up of the + following bits: + + === ================================================== + Bit Effect + === ================================================== + 0 Enable HMAC validation and creation + 1 Enable digital signature validation + 2 Permit modification of EVM-protected metadata at + runtime. Not supported if HMAC validation and + creation is enabled (deprecated). + 3 Require asymmetric signatures to be version 3 + 31 Disable further runtime modification of EVM policy + === ================================================== + + For example:: + + echo 1 ><securityfs>/evm + + will enable HMAC validation and creation + + :: + + echo 0x80000003 ><securityfs>/evm + + will enable HMAC and digital signature validation and + HMAC creation and disable all further modification of policy. + + :: + + echo 0x80000006 ><securityfs>/evm + + will enable digital signature validation, permit + modification of EVM-protected metadata and + disable all further modification of policy. This option is now + deprecated in favor of:: + + echo 0x80000002 ><securityfs>/evm + + as the outstanding issues that prevent the usage of EVM portable + signatures have been solved. + + Echoing a value is additive, the new value is added to the + existing initialization flags. + + For example, after:: + + echo 2 ><securityfs>/evm + + another echo can be performed:: + + echo 1 ><securityfs>/evm + + and the resulting value will be 3. + + Note that once an HMAC key has been loaded, it will no longer + be possible to enable metadata modification. Signaling that an + HMAC key has been loaded will clear the corresponding flag. + For example, if the current value is 6 (2 and 4 set):: + + echo 1 ><securityfs>/evm + + will set the new value to 3 (4 cleared). + + Loading an HMAC key is the only way to disable metadata + modification. + + Until key loading has been signaled EVM can not create + or validate the 'security.evm' xattr, but returns + INTEGRITY_UNKNOWN. Loading keys and signaling EVM + should be done as early as possible. Normally this is + done in the initramfs, which has already been measured + as part of the trusted boot. For more information on + creating and loading existing trusted/encrypted keys, + refer to: + Documentation/security/keys/trusted-encrypted.rst. Both + dracut (via 97masterkey and 98integrity) and systemd (via + core/ima-setup) have support for loading keys at boot + time. + +What: /sys/kernel/security/*/evm/evm_xattrs +Date: April 2018 +Contact: Matthew Garrett <mjg59@google.com> +Description: + Shows the set of extended attributes used to calculate or + validate the EVM signature, and allows additional attributes + to be added at runtime. Any signatures generated after + additional attributes are added (and on files possessing those + additional attributes) will only be valid if the same + additional attributes are configured on system boot. Writing + a single period (.) will lock the xattr list from any further + modification. |
