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Diffstat (limited to '')
| -rw-r--r-- | fs/verity/Kconfig | 60 |
1 files changed, 60 insertions, 0 deletions
diff --git a/fs/verity/Kconfig b/fs/verity/Kconfig new file mode 100644 index 000000000..aad1f1d99 --- /dev/null +++ b/fs/verity/Kconfig @@ -0,0 +1,60 @@ +# SPDX-License-Identifier: GPL-2.0 + +config FS_VERITY + bool "FS Verity (read-only file-based authenticity protection)" + select CRYPTO + select CRYPTO_HASH_INFO + # SHA-256 is implied as it's intended to be the default hash algorithm. + # To avoid bloat, other wanted algorithms must be selected explicitly. + # Note that CRYPTO_SHA256 denotes the generic C implementation, but + # some architectures provided optimized implementations of the same + # algorithm that may be used instead. In this case, CRYPTO_SHA256 may + # be omitted even if SHA-256 is being used. + imply 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, f2fs, and btrfs), 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. + +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. |