Eric Lee / smarc-fsl-linux-kernel

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671e67b47   Eric Biggers   fs-verity: add Kc... 
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  # SPDX-License-Identifier: GPL-2.0
  
  config FS_VERITY
  	bool "FS Verity (read-only file-based authenticity protection)"
  	select CRYPTO
  	# SHA-256 is selected as it's intended to be the default hash algorithm.
  	# To avoid bloat, other wanted algorithms must be selected explicitly.
  	select CRYPTO_SHA256
  	help
  	  This option enables fs-verity.  fs-verity is the dm-verity
  	  mechanism implemented at the file level.  On supported
  	  filesystems (currently EXT4 and F2FS), userspace can use an
  	  ioctl to enable verity for a file, which causes the filesystem
  	  to build a Merkle tree for the file.  The filesystem will then
  	  transparently verify any data read from the file against the
  	  Merkle tree.  The file is also made read-only.
  
  	  This serves as an integrity check, but the availability of the
  	  Merkle tree root hash also allows efficiently supporting
  	  various use cases where normally the whole file would need to
  	  be hashed at once, such as: (a) auditing (logging the file's
  	  hash), or (b) authenticity verification (comparing the hash
  	  against a known good value, e.g. from a digital signature).
  
  	  fs-verity is especially useful on large files where not all
  	  the contents may actually be needed.  Also, fs-verity verifies
  	  data each time it is paged back in, which provides better
  	  protection against malicious disks vs. an ahead-of-time hash.
  
  	  If unsure, say N.
  
  config FS_VERITY_DEBUG
  	bool "FS Verity debugging"
  	depends on FS_VERITY
  	help
  	  Enable debugging messages related to fs-verity by default.
  
  	  Say N unless you are an fs-verity developer.
432434c9f   Eric Biggers   fs-verity: suppor... 
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  config FS_VERITY_BUILTIN_SIGNATURES
  	bool "FS Verity builtin signature support"
  	depends on FS_VERITY
  	select SYSTEM_DATA_VERIFICATION
  	help
  	  Support verifying signatures of verity files against the X.509
  	  certificates that have been loaded into the ".fs-verity"
  	  kernel keyring.
  
  	  This is meant as a relatively simple mechanism that can be
  	  used to provide an authenticity guarantee for verity files, as
  	  an alternative to IMA appraisal.  Userspace programs still
  	  need to check that the verity bit is set in order to get an
  	  authenticity guarantee.
  
  	  If unsure, say N.