NIST FIPS 186-5 states that it is recommended that the security
strength associated with the bit length of n and the security strength
of the hash function be the same, or higher upon agreement. Given NIST
P384 curve is used, force using either SHA384 or SHA512.
Signed-off-by: Dimitri John Ledkov <dimitri.led...@canonical.com>
---
certs/Kconfig | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/certs/Kconfig b/certs/Kconfig
index 1f109b0708..84582de66b 100644
--- a/certs/Kconfig
+++ b/certs/Kconfig
@@ -30,9 +30,11 @@ config MODULE_SIG_KEY_TYPE_RSA
config MODULE_SIG_KEY_TYPE_ECDSA
bool "ECDSA"
select CRYPTO_ECDSA
+ depends on MODULE_SIG_SHA384 || MODULE_SIG_SHA512
help
- Use an elliptic curve key (NIST P384) for module signing. Consider
- using a strong hash like sha256 or sha384 for hashing modules.
+ Use an elliptic curve key (NIST P384) for module signing. Use
+ a strong hash of same or higher bit length, i.e. sha384 or
+ sha512 for hashing modules.
Note: Remove all ECDSA signing keys, e.g. certs/signing_key.pem,
when falling back to building Linux 5.14 and older kernels.
--
2.34.1
