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authorArd Biesheuvel <ardb@kernel.org>2021-04-21 09:55:11 +0200
committerHerbert Xu <herbert@gondor.apana.org.au>2021-04-22 17:31:32 +1000
commite3a606f2c544b231f6079c8c5fea451e772e1139 (patch)
tree521f09bddea0897314857693e1b4c381613b4c74 /fs/verity
parenta0fc20333ee4bac1147c4cf75dea098c26671a2f (diff)
fsverity: relax build time dependency on CRYPTO_SHA256
CONFIG_CRYPTO_SHA256 denotes the generic C implementation of the SHA-256 shash algorithm, which is selected as the default crypto shash provider for fsverity. However, fsverity has no strict link time dependency, and the same shash could be exposed by an optimized implementation, and arm64 has a number of those (scalar, NEON-based and one based on special crypto instructions). In such cases, it makes little sense to require that the generic C implementation is incorporated as well, given that it will never be called. To address this, relax the 'select' clause to 'imply' so that the generic driver can be omitted from the build if desired. Acked-by: Eric Biggers <ebiggers@google.com> Signed-off-by: Ard Biesheuvel <ardb@kernel.org> Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Diffstat (limited to 'fs/verity')
-rw-r--r--fs/verity/Kconfig8
1 files changed, 6 insertions, 2 deletions
diff --git a/fs/verity/Kconfig b/fs/verity/Kconfig
index 88fb25119899..24d1b54de807 100644
--- a/fs/verity/Kconfig
+++ b/fs/verity/Kconfig
@@ -3,9 +3,13 @@
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.
+ # SHA-256 is implied as it's intended to be the default hash algorithm.
# To avoid bloat, other wanted algorithms must be selected explicitly.
- select CRYPTO_SHA256
+ # 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