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authorLinus Torvalds <torvalds@linux-foundation.org>2026-08-19 10:09:22 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2026-08-19 10:09:22 -0700
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tree60a31895b2446cd7fa27514e8c2843534a0de0da /Documentation/ABI/testing/securityfs-secrets-coco
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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 ...
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+What: security/secrets/coco
+Date: February 2022
+Contact: Dov Murik <dovmurik@linux.ibm.com>
+Description:
+ Exposes confidential computing (coco) EFI secrets to
+ userspace via securityfs.
+
+ EFI can declare memory area used by confidential computing
+ platforms (such as AMD SEV and SEV-ES) for secret injection by
+ the Guest Owner during VM's launch. The secrets are encrypted
+ by the Guest Owner and decrypted inside the trusted enclave,
+ and therefore are not readable by the untrusted host.
+
+ The efi_secret module exposes the secrets to userspace. Each
+ secret appears as a file under <securityfs>/secrets/coco,
+ where the filename is the GUID of the entry in the secrets
+ table. This module is loaded automatically by the EFI driver
+ if the EFI secret area is populated.
+
+ Two operations are supported for the files: read and unlink.
+ Reading the file returns the content of secret entry.
+ Unlinking the file overwrites the secret data with zeroes and
+ removes the entry from the filesystem. A secret cannot be read
+ after it has been unlinked.
+
+ For example, listing the available secrets::
+
+ # modprobe efi_secret
+ # ls -l /sys/kernel/security/secrets/coco
+ -r--r----- 1 root root 0 Jun 28 11:54 736870e5-84f0-4973-92ec-06879ce3da0b
+ -r--r----- 1 root root 0 Jun 28 11:54 83c83f7f-1356-4975-8b7e-d3a0b54312c6
+ -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
+
+ Reading the secret data by reading a file::
+
+ # cat /sys/kernel/security/secrets/coco/e6f5a162-d67f-4750-a67c-5d065f2a9910
+ the-content-of-the-secret-data
+
+ Wiping a secret by unlinking a file::
+
+ # rm /sys/kernel/security/secrets/coco/e6f5a162-d67f-4750-a67c-5d065f2a9910
+ # ls -l /sys/kernel/security/secrets/coco
+ -r--r----- 1 root root 0 Jun 28 11:54 736870e5-84f0-4973-92ec-06879ce3da0b
+ -r--r----- 1 root root 0 Jun 28 11:54 83c83f7f-1356-4975-8b7e-d3a0b54312c6
+ -r--r----- 1 root root 0 Jun 28 11:54 9553f55d-3da2-43ee-ab5d-ff17f78864d2
+
+ Note: The binary format of the secrets table injected by the
+ Guest Owner is described in
+ drivers/virt/coco/efi_secret/efi_secret.c under "Structure of
+ the EFI secret area".