[PATCH] crypto: lib/Kconfig - fix chacha/poly1305 dependencies more more

Arnd Bergmann
2025-02-25T16:42:23Z

From: Arnd Bergmann <arnd@arndb.de>

A recent change tries to fix Kconfig dependencies, but introduced
two problems in the process:

- only arm, powerpc and x86 are changed, while mips, arm64 and s390
are now broken

- there are now configurations where the architecture enables its
own helper functions as loadable modules, but they remain silently
unused because CRYPTO_LIB_* falls back to the generic helpers

Address both by changing the logic again: the architecture functions
select CRYPTO_ARCH_MAY_HAVE_LIB_CHACHA, which may be a loadable
module or built-in, and this controls whether the library is
also built-in.

Fixes: 04f9ccc955c7 ("crypto: lib/Kconfig - Fix lib built-in failure when arch is modular")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
I did not quite understand what problem the 04f9ccc955c7 patch
actually tried to solve, so there is a chance that my version
undoes it. I tested this on randconfig builds across, arm,
arm64 and x86 and found no other dependency problems with these
libraries.
---
arch/arm64/crypto/Kconfig | 4 ++--
arch/mips/crypto/Kconfig | 4 ++--
arch/s390/crypto/Kconfig | 2 +-
lib/crypto/Kconfig | 20 +++++++++++---------
4 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/arch/arm64/crypto/Kconfig b/arch/arm64/crypto/Kconfig
index 5636ab83f22a..3d90efdcf5a5 100644
--- a/arch/arm64/crypto/Kconfig
+++ b/arch/arm64/crypto/Kconfig
@@ -29,7 +29,7 @@ config CRYPTO_POLY1305_NEON
tristate "Hash functions: Poly1305 (NEON)"
depends on KERNEL_MODE_NEON
select CRYPTO_HASH
- select CRYPTO_ARCH_HAVE_LIB_POLY1305
+ select CRYPTO_ARCH_MAY_HAVE_LIB_POLY1305
help
Poly1305 authenticator algorithm (RFC7539)

@@ -190,7 +190,7 @@ config CRYPTO_CHACHA20_NEON
depends on KERNEL_MODE_NEON
select CRYPTO_SKCIPHER
select CRYPTO_LIB_CHACHA_GENERIC
- select CRYPTO_ARCH_HAVE_LIB_CHACHA
+ select CRYPTO_ARCH_MAY_HAVE_LIB_CHACHA
help
Length-preserving ciphers: ChaCha20, XChaCha20, and XChaCha12
stream cipher algorithms
diff --git a/arch/mips/crypto/Kconfig b/arch/mips/crypto/Kconfig
index 7decd40c4e20..cbeb2f62eb79 100644
--- a/arch/mips/crypto/Kconfig
+++ b/arch/mips/crypto/Kconfig
@@ -5,7 +5,7 @@ menu "Accelerated Cryptographic Algorithms for CPU (mips)"
config CRYPTO_POLY1305_MIPS
tristate "Hash functions: Poly1305"
depends on MIPS
- select CRYPTO_ARCH_HAVE_LIB_POLY1305
+ select CRYPTO_ARCH_MAY_HAVE_LIB_POLY1305
help
Poly1305 authenticator algorithm (RFC7539)

@@ -55,7 +55,7 @@ config CRYPTO_CHACHA_MIPS
tristate "Ciphers: ChaCha20, XChaCha20, XChaCha12 (MIPS32r2)"
depends on CPU_MIPS32_R2
select CRYPTO_SKCIPHER
- select CRYPTO_ARCH_HAVE_LIB_CHACHA
+ select CRYPTO_ARCH_MAY_HAVE_LIB_CHACHA
help
Length-preserving ciphers: ChaCha20, XChaCha20, and XChaCha12
stream cipher algorithms
diff --git a/arch/s390/crypto/Kconfig b/arch/s390/crypto/Kconfig
index b760232537f1..6f7495264943 100644
--- a/arch/s390/crypto/Kconfig
+++ b/arch/s390/crypto/Kconfig
@@ -112,7 +112,7 @@ config CRYPTO_CHACHA_S390
depends on S390
select CRYPTO_SKCIPHER
select CRYPTO_LIB_CHACHA_GENERIC
- select CRYPTO_ARCH_HAVE_LIB_CHACHA
+ select CRYPTO_ARCH_MAY_HAVE_LIB_CHACHA
help
Length-preserving cipher: ChaCha20 stream cipher (RFC 7539)

diff --git a/lib/crypto/Kconfig b/lib/crypto/Kconfig
index c542ef1d64d0..6b45bd634cd9 100644
--- a/lib/crypto/Kconfig
+++ b/lib/crypto/Kconfig
@@ -50,8 +50,6 @@ config CRYPTO_ARCH_HAVE_LIB_CHACHA

config CRYPTO_ARCH_MAY_HAVE_LIB_CHACHA
tristate
- select CRYPTO_ARCH_HAVE_LIB_CHACHA if CRYPTO_LIB_CHACHA=m
- select CRYPTO_ARCH_HAVE_LIB_CHACHA if CRYPTO_ARCH_MAY_HAVE_LIB_CHACHA=y

config CRYPTO_LIB_CHACHA_GENERIC
tristate
@@ -65,7 +63,9 @@ config CRYPTO_LIB_CHACHA_GENERIC

config CRYPTO_LIB_CHACHA
tristate "ChaCha library interface"
- select CRYPTO_LIB_CHACHA_GENERIC if CRYPTO_ARCH_HAVE_LIB_CHACHA=n
+ select CRYPTO_LIB_CHACHA_GENERIC if CRYPTO_ARCH_MAY_HAVE_LIB_CHACHA=n
+ select CRYPTO_ARCH_HAVE_LIB_CHACHA if CRYPTO_ARCH_MAY_HAVE_LIB_CHACHA!=n
+ depends on CRYPTO_ARCH_MAY_HAVE_LIB_CHACHA || !CRYPTO_ARCH_MAY_HAVE_LIB_CHACHA
help
Enable the ChaCha library interface. This interface may be fulfilled
by either the generic implementation or an arch-specific one, if one
@@ -80,8 +80,6 @@ config CRYPTO_ARCH_HAVE_LIB_CURVE25519

config CRYPTO_ARCH_MAY_HAVE_LIB_CURVE25519
tristate
- select CRYPTO_ARCH_HAVE_LIB_CURVE25519 if CRYPTO_LIB_CURVE25519=m
- select CRYPTO_ARCH_HAVE_LIB_CURVE25519 if CRYPTO_ARCH_MAY_HAVE_LIB_CURVE25519=y

config CRYPTO_LIB_CURVE25519_GENERIC
tristate
@@ -94,7 +92,9 @@ config CRYPTO_LIB_CURVE25519_GENERIC

config CRYPTO_LIB_CURVE25519
tristate "Curve25519 scalar multiplication library"
- select CRYPTO_LIB_CURVE25519_GENERIC if CRYPTO_ARCH_HAVE_LIB_CURVE25519=n
+ select CRYPTO_LIB_CURVE25519_GENERIC if CRYPTO_ARCH_MAY_HAVE_LIB_CURVE25519=n
+ select CRYPTO_ARCH_HAVE_LIB_CURVE25519 if CRYPTO_ARCH_MAY_HAVE_LIB_CURVE25519!=n
+ depends on CRYPTO_ARCH_MAY_HAVE_LIB_CURVE25519 || !CRYPTO_ARCH_MAY_HAVE_LIB_CURVE25519
select CRYPTO_LIB_UTILS
help
Enable the Curve25519 library interface. This interface may be
@@ -120,8 +120,6 @@ config CRYPTO_ARCH_HAVE_LIB_POLY1305

config CRYPTO_ARCH_MAY_HAVE_LIB_POLY1305
tristate
- select CRYPTO_ARCH_HAVE_LIB_POLY1305 if CRYPTO_LIB_POLY1305=m
- select CRYPTO_ARCH_HAVE_LIB_POLY1305 if CRYPTO_ARCH_MAY_HAVE_LIB_POLY1305=y

config CRYPTO_LIB_POLY1305_GENERIC
tristate
@@ -134,7 +132,9 @@ config CRYPTO_LIB_POLY1305_GENERIC

config CRYPTO_LIB_POLY1305
tristate "Poly1305 library interface"
- select CRYPTO_LIB_POLY1305_GENERIC if CRYPTO_ARCH_HAVE_LIB_POLY1305=n
+ select CRYPTO_LIB_POLY1305_GENERIC if CRYPTO_ARCH_MAY_HAVE_LIB_POLY1305=n
+ select CRYPTO_ARCH_HAVE_LIB_POLY1305 if CRYPTO_ARCH_MAY_HAVE_LIB_POLY1305!=n
+ depends on CRYPTO_ARCH_MAY_HAVE_LIB_POLY1305 || !CRYPTO_ARCH_MAY_HAVE_LIB_POLY1305
help
Enable the Poly1305 library interface. This interface may be fulfilled
by either the generic implementation or an arch-specific one, if one
@@ -143,6 +143,8 @@ config CRYPTO_LIB_POLY1305
config CRYPTO_LIB_CHACHA20POLY1305
tristate "ChaCha20-Poly1305 AEAD support (8-byte nonce library version)"
depends on CRYPTO
+ depends on CRYPTO_ARCH_MAY_HAVE_LIB_POLY1305 || !CRYPTO_ARCH_MAY_HAVE_LIB_POLY1305
+ depends on CRYPTO_ARCH_MAY_HAVE_LIB_CHACHA || !CRYPTO_ARCH_MAY_HAVE_LIB_CHACHA
select CRYPTO_LIB_CHACHA
select CRYPTO_LIB_POLY1305
select CRYPTO_ALGAPI
--
2.39.5