crypto: des - split off DES library from generic DES cipher driver

Another one for the cipher museum: split off DES core processing into
a separate module so other drivers (mostly for crypto accelerators)
can reuse the code without pulling in the generic DES cipher itself.
This will also permit the cipher interface to be made private to the
crypto API itself once we move the only user in the kernel (CIFS) to
this library interface.
Signed-off-by: NArd Biesheuvel <ard.biesheuvel@linaro.org>
Signed-off-by: NHerbert Xu <herbert@gondor.apana.org.au>

arch/x86/crypto/des3_ede_glue.c

@@ -11,7 +11,7 @@
  */
 
 #include <crypto/algapi.h>
-#include <crypto/des.h>
+#include <crypto/internal/des.h>
 #include <crypto/internal/skcipher.h>
 #include <linux/crypto.h>
 #include <linux/init.h>

crypto/Kconfig

@@ -1306,9 +1306,13 @@ config CRYPTO_CAST6_AVX_X86_64
 	  This module provides the Cast6 cipher algorithm that processes
 	  eight blocks parallel using the AVX instruction set.
 
+config CRYPTO_LIB_DES
+	tristate
+
 config CRYPTO_DES
 	tristate "DES and Triple DES EDE cipher algorithms"
 	select CRYPTO_ALGAPI
+	select CRYPTO_LIB_DES
 	help
 	  DES cipher algorithm (FIPS 46-2), and Triple DES EDE (FIPS 46-3).
 
@@ -1316,7 +1320,7 @@ config CRYPTO_DES_SPARC64
 	tristate "DES and Triple DES EDE cipher algorithms (SPARC64)"
 	depends on SPARC64
 	select CRYPTO_ALGAPI
-	select CRYPTO_DES
+	select CRYPTO_LIB_DES
 	help
 	  DES cipher algorithm (FIPS 46-2), and Triple DES EDE (FIPS 46-3),
 	  optimized using SPARC64 crypto opcodes.
@@ -1325,7 +1329,7 @@ config CRYPTO_DES3_EDE_X86_64
 	tristate "Triple DES EDE cipher algorithm (x86-64)"
 	depends on X86 && 64BIT
 	select CRYPTO_BLKCIPHER
-	select CRYPTO_DES
+	select CRYPTO_LIB_DES
 	help
 	  Triple DES EDE (FIPS 46-3) algorithm.
 

drivers/crypto/Kconfig

@@ -150,7 +150,7 @@ config CRYPTO_DES_S390
 	depends on S390
 	select CRYPTO_ALGAPI
 	select CRYPTO_BLKCIPHER
-	select CRYPTO_DES
+	select CRYPTO_LIB_DES
 	help
 	  This is the s390 hardware accelerated implementation of the
 	  DES cipher algorithm (FIPS 46-2), and Triple DES EDE (FIPS 46-3).
@@ -215,7 +215,7 @@ config CRYPTO_DEV_MARVELL_CESA
 	tristate "Marvell's Cryptographic Engine driver"
 	depends on PLAT_ORION || ARCH_MVEBU
 	select CRYPTO_LIB_AES
-	select CRYPTO_DES
+	select CRYPTO_LIB_DES
 	select CRYPTO_BLKCIPHER
 	select CRYPTO_HASH
 	select SRAM
@@ -227,7 +227,7 @@ config CRYPTO_DEV_MARVELL_CESA
 
 config CRYPTO_DEV_NIAGARA2
        tristate "Niagara2 Stream Processing Unit driver"
-       select CRYPTO_DES
+       select CRYPTO_LIB_DES
        select CRYPTO_BLKCIPHER
        select CRYPTO_HASH
        select CRYPTO_MD5
@@ -244,7 +244,7 @@ config CRYPTO_DEV_NIAGARA2
 
 config CRYPTO_DEV_HIFN_795X
 	tristate "Driver HIFN 795x crypto accelerator chips"
-	select CRYPTO_DES
+	select CRYPTO_LIB_DES
 	select CRYPTO_BLKCIPHER
 	select HW_RANDOM if CRYPTO_DEV_HIFN_795X_RNG
 	depends on PCI
@@ -300,7 +300,7 @@ config CRYPTO_DEV_TALITOS2
 config CRYPTO_DEV_IXP4XX
 	tristate "Driver for IXP4xx crypto hardware acceleration"
 	depends on ARCH_IXP4XX && IXP4XX_QMGR && IXP4XX_NPE
-	select CRYPTO_DES
+	select CRYPTO_LIB_DES
 	select CRYPTO_AEAD
 	select CRYPTO_AUTHENC
 	select CRYPTO_BLKCIPHER
@@ -366,7 +366,7 @@ config CRYPTO_DEV_OMAP_AES
 config CRYPTO_DEV_OMAP_DES
 	tristate "Support for OMAP DES/3DES hw engine"
 	depends on ARCH_OMAP2PLUS
-	select CRYPTO_DES
+	select CRYPTO_LIB_DES
 	select CRYPTO_BLKCIPHER
 	select CRYPTO_ENGINE
 	help
@@ -384,7 +384,7 @@ config CRYPTO_DEV_PICOXCELL
 	select CRYPTO_AES
 	select CRYPTO_AUTHENC
 	select CRYPTO_BLKCIPHER
-	select CRYPTO_DES
+	select CRYPTO_LIB_DES
 	select CRYPTO_CBC
 	select CRYPTO_ECB
 	select CRYPTO_SEQIV
@@ -497,7 +497,7 @@ config CRYPTO_DEV_ATMEL_AES
 config CRYPTO_DEV_ATMEL_TDES
 	tristate "Support for Atmel DES/TDES hw accelerator"
 	depends on ARCH_AT91 || COMPILE_TEST
-	select CRYPTO_DES
+	select CRYPTO_LIB_DES
 	select CRYPTO_BLKCIPHER
 	help
 	  Some Atmel processors have DES/TDES hw accelerator.
@@ -595,7 +595,7 @@ config CRYPTO_DEV_QCE
 	depends on ARCH_QCOM || COMPILE_TEST
 	depends on HAS_IOMEM
 	select CRYPTO_AES
-	select CRYPTO_DES
+	select CRYPTO_LIB_DES
 	select CRYPTO_ECB
 	select CRYPTO_CBC
 	select CRYPTO_XTS
@@ -643,7 +643,7 @@ config CRYPTO_DEV_SUN4I_SS
 	select CRYPTO_MD5
 	select CRYPTO_SHA1
 	select CRYPTO_AES
-	select CRYPTO_DES
+	select CRYPTO_LIB_DES
 	select CRYPTO_BLKCIPHER
 	help
 	  Some Allwinner SoC have a crypto accelerator named
@@ -666,7 +666,7 @@ config CRYPTO_DEV_ROCKCHIP
 	tristate "Rockchip's Cryptographic Engine driver"
 	depends on OF && ARCH_ROCKCHIP
 	select CRYPTO_AES
-	select CRYPTO_DES
+	select CRYPTO_LIB_DES
 	select CRYPTO_MD5
 	select CRYPTO_SHA1
 	select CRYPTO_SHA256
@@ -703,7 +703,7 @@ config CRYPTO_DEV_BCM_SPU
 	depends on MAILBOX
 	default m
 	select CRYPTO_AUTHENC
-	select CRYPTO_DES
+	select CRYPTO_LIB_DES
 	select CRYPTO_MD5
 	select CRYPTO_SHA1
 	select CRYPTO_SHA256
@@ -722,7 +722,7 @@ config CRYPTO_DEV_SAFEXCEL
 	select CRYPTO_LIB_AES
 	select CRYPTO_AUTHENC
 	select CRYPTO_BLKCIPHER
-	select CRYPTO_DES
+	select CRYPTO_LIB_DES
 	select CRYPTO_HASH
 	select CRYPTO_HMAC
 	select CRYPTO_MD5
@@ -760,7 +760,7 @@ config CRYPTO_DEV_CCREE
 	default n
 	select CRYPTO_HASH
 	select CRYPTO_BLKCIPHER
-	select CRYPTO_DES
+	select CRYPTO_LIB_DES
 	select CRYPTO_AEAD
 	select CRYPTO_AUTHENC
 	select CRYPTO_SHA1

drivers/crypto/caam/Kconfig

@@ -98,7 +98,7 @@ config CRYPTO_DEV_FSL_CAAM_CRYPTO_API
 	select CRYPTO_AEAD
 	select CRYPTO_AUTHENC
 	select CRYPTO_BLKCIPHER
-	select CRYPTO_DES
+	select CRYPTO_LIB_DES
 	help
 	  Selecting this will offload crypto for users of the
 	  scatterlist crypto API (such as the linux native IPSec

drivers/crypto/cavium/nitrox/Kconfig

@@ -6,7 +6,7 @@ config CRYPTO_DEV_NITROX
 	tristate
 	select CRYPTO_BLKCIPHER
 	select CRYPTO_AES
-	select CRYPTO_DES
+	select CRYPTO_LIB_DES
 	select FW_LOADER
 
 config CRYPTO_DEV_NITROX_CNN55XX

drivers/crypto/inside-secure/safexcel_cipher.c

@@ -13,7 +13,7 @@
 #include <crypto/aes.h>
 #include <crypto/authenc.h>
 #include <crypto/ctr.h>
-#include <crypto/des.h>
+#include <crypto/internal/des.h>
 #include <crypto/sha.h>
 #include <crypto/skcipher.h>
 #include <crypto/internal/aead.h>

drivers/crypto/stm32/Kconfig

@@ -25,7 +25,7 @@ config CRYPTO_DEV_STM32_CRYP
 	depends on ARCH_STM32
 	select CRYPTO_HASH
 	select CRYPTO_ENGINE
-	select CRYPTO_DES
+	select CRYPTO_LIB_DES
 	help
           This enables support for the CRYP (AES/DES/TDES) hw accelerator which
 	  can be found on STMicroelectronics STM32 SOC.

drivers/crypto/ux500/Kconfig

@@ -9,7 +9,7 @@ config CRYPTO_DEV_UX500_CRYP
 	depends on CRYPTO_DEV_UX500
 	select CRYPTO_ALGAPI
 	select CRYPTO_BLKCIPHER
-	select CRYPTO_DES
+	select CRYPTO_LIB_DES
 	help
         This selects the crypto driver for the UX500_CRYP hardware. It supports
         AES-ECB, CBC and CTR with keys sizes of 128, 192 and 256 bit sizes.

include/crypto/des.h

@@ -6,10 +6,7 @@
 #ifndef __CRYPTO_DES_H
 #define __CRYPTO_DES_H
 
-#include <crypto/skcipher.h>
-#include <linux/compiler.h>
-#include <linux/fips.h>
-#include <linux/string.h>
+#include <linux/types.h>
 
 #define DES_KEY_SIZE		8
 #define DES_EXPKEY_WORDS	32
@@ -19,6 +16,44 @@
 #define DES3_EDE_EXPKEY_WORDS	(3 * DES_EXPKEY_WORDS)
 #define DES3_EDE_BLOCK_SIZE	DES_BLOCK_SIZE
 
+struct des_ctx {
+	u32 expkey[DES_EXPKEY_WORDS];
+};
+
+struct des3_ede_ctx {
+	u32 expkey[DES3_EDE_EXPKEY_WORDS];
+};
+
+void des_encrypt(const struct des_ctx *ctx, u8 *dst, const u8 *src);
+void des_decrypt(const struct des_ctx *ctx, u8 *dst, const u8 *src);
+
+void des3_ede_encrypt(const struct des3_ede_ctx *dctx, u8 *dst, const u8 *src);
+void des3_ede_decrypt(const struct des3_ede_ctx *dctx, u8 *dst, const u8 *src);
+
+/**
+ * des_expand_key - Expand a DES input key into a key schedule
+ * @ctx: the key schedule
+ * @key: buffer containing the input key
+ * @len: size of the buffer contents
+ *
+ * Returns 0 on success, -EINVAL if the input key is rejected and -ENOKEY if
+ * the key is accepted but has been found to be weak.
+ */
+int des_expand_key(struct des_ctx *ctx, const u8 *key, unsigned int keylen);
+
+/**
+ * des3_ede_expand_key - Expand a triple DES input key into a key schedule
+ * @ctx: the key schedule
+ * @key: buffer containing the input key
+ * @len: size of the buffer contents
+ *
+ * Returns 0 on success, -EINVAL if the input key is rejected and -ENOKEY if
+ * the key is accepted but has been found to be weak. Note that weak keys will
+ * be rejected (and -EINVAL will be returned) when running in FIPS mode.
+ */
+int des3_ede_expand_key(struct des3_ede_ctx *ctx, const u8 *key,
+			unsigned int keylen);
+
 extern int __des3_ede_setkey(u32 *expkey, u32 *flags, const u8 *key,
 			     unsigned int keylen);
 

include/crypto/internal/des.h

@@ -25,18 +25,21 @@
  */
 static inline int crypto_des_verify_key(struct crypto_tfm *tfm, const u8 *key)
 {
-	u32 tmp[DES_EXPKEY_WORDS];
-	int err = 0;
-
-	if (!(crypto_tfm_get_flags(tfm) & CRYPTO_TFM_REQ_FORBID_WEAK_KEYS))
-		return 0;
+	struct des_ctx tmp;
+	int err;
+
+	err = des_expand_key(&tmp, key, DES_KEY_SIZE);
+	if (err == -ENOKEY) {
+		if (crypto_tfm_get_flags(tfm) & CRYPTO_TFM_REQ_FORBID_WEAK_KEYS)
+			err = -EINVAL;
+		else
+			err = 0;
+	}
 
-	if (!des_ekey(tmp, key)) {
+	if (err)
 		crypto_tfm_set_flags(tfm, CRYPTO_TFM_RES_WEAK_KEY);
-		err = -EINVAL;
-	}
 
-	memzero_explicit(tmp, sizeof(tmp));
+	memzero_explicit(&tmp, sizeof(tmp));
 	return err;
 }
 
@@ -53,6 +56,28 @@ static inline int crypto_des_verify_key(struct crypto_tfm *tfm, const u8 *key)
  *   property.
  *
  */
+static inline int des3_ede_verify_key(const u8 *key, unsigned int key_len,
+				      bool check_weak)
+{
+	int ret = fips_enabled ? -EINVAL : -ENOKEY;
+	u32 K[6];
+
+	memcpy(K, key, DES3_EDE_KEY_SIZE);
+
+	if ((!((K[0] ^ K[2]) | (K[1] ^ K[3])) ||
+	     !((K[2] ^ K[4]) | (K[3] ^ K[5]))) &&
+	    (fips_enabled || check_weak))
+		goto bad;
+
+	if ((!((K[0] ^ K[4]) | (K[1] ^ K[5]))) && fips_enabled)
+		goto bad;
+
+	ret = 0;
+bad:
+	memzero_explicit(K, DES3_EDE_KEY_SIZE);
+
+	return ret;
+}
 
 /**
  * crypto_des3_ede_verify_key - Check whether a DES3-EDE key is weak
@@ -70,28 +95,14 @@ static inline int crypto_des_verify_key(struct crypto_tfm *tfm, const u8 *key)
 static inline int crypto_des3_ede_verify_key(struct crypto_tfm *tfm,
 					     const u8 *key)
 {
-	int err = -EINVAL;
-	u32 K[6];
-
-	memcpy(K, key, DES3_EDE_KEY_SIZE);
-
-	if ((!((K[0] ^ K[2]) | (K[1] ^ K[3])) ||
-	     !((K[2] ^ K[4]) | (K[3] ^ K[5]))) &&
-	    (fips_enabled || (crypto_tfm_get_flags(tfm) &
-		              CRYPTO_TFM_REQ_FORBID_WEAK_KEYS)))
-		goto bad;
-
-	if ((!((K[0] ^ K[4]) | (K[1] ^ K[5]))) && fips_enabled)
-		goto bad;
+	int err;
 
-	err = 0;
-out:
-	memzero_explicit(K, DES3_EDE_KEY_SIZE);
+	err = des3_ede_verify_key(key, DES3_EDE_KEY_SIZE,
+				  crypto_tfm_get_flags(tfm) &
+				  CRYPTO_TFM_REQ_FORBID_WEAK_KEYS);
+	if (err)
+		crypto_tfm_set_flags(tfm, CRYPTO_TFM_RES_WEAK_KEY);
 	return err;
-
-bad:
-	crypto_tfm_set_flags(tfm, CRYPTO_TFM_RES_WEAK_KEY);
-	goto out;
 }
 
 static inline int verify_skcipher_des_key(struct crypto_skcipher *tfm,

lib/crypto/Makefile

@@ -5,3 +5,6 @@ libaes-y := aes.o
 
 obj-$(CONFIG_CRYPTO_LIB_ARC4) += libarc4.o
 libarc4-y := arc4.o
+
+obj-$(CONFIG_CRYPTO_LIB_DES) += libdes.o
+libdes-y := des.o