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[3/9] crypto: serpent - use unaligned accessors instead of alignmask

Message ID 20210201180237.3171-4-ardb@kernel.org
State Accepted
Commit 81d091a293a24912a61c22e073824d29496301d5
Headers show
Series crypto: fix alignmask handling | expand

Commit Message

Ard Biesheuvel Feb. 1, 2021, 6:02 p.m. UTC 
Instead of using an alignmask of 0x3 to ensure 32-bit alignment of the
Serpent input and output blocks, which propagates to mode drivers, and
results in pointless copying on architectures that don't care about
alignment, use the unaligned accessors, which will do the right thing on
each respective architecture, avoiding the need for double buffering.

Signed-off-by: Ard Biesheuvel <ardb@kernel.org>
---
 crypto/serpent_generic.c | 44 ++++++++------------
 1 file changed, 17 insertions(+), 27 deletions(-)
diff mbox series

Patch

diff --git a/crypto/serpent_generic.c b/crypto/serpent_generic.c
index a932e0b2964f..236c87547a17 100644
--- a/crypto/serpent_generic.c
+++ b/crypto/serpent_generic.c
@@ -10,7 +10,7 @@ 
 #include <linux/init.h>
 #include <linux/module.h>
 #include <linux/errno.h>
-#include <asm/byteorder.h>
+#include <asm/unaligned.h>
 #include <linux/crypto.h>
 #include <linux/types.h>
 #include <crypto/serpent.h>
@@ -448,19 +448,12 @@  void __serpent_encrypt(const void *c, u8 *dst, const u8 *src)
 {
 	const struct serpent_ctx *ctx = c;
 	const u32 *k = ctx->expkey;
-	const __le32 *s = (const __le32 *)src;
-	__le32	*d = (__le32 *)dst;
 	u32	r0, r1, r2, r3, r4;
 
-/*
- * Note: The conversions between u8* and u32* might cause trouble
- * on architectures with stricter alignment rules than x86
- */
-
-	r0 = le32_to_cpu(s[0]);
-	r1 = le32_to_cpu(s[1]);
-	r2 = le32_to_cpu(s[2]);
-	r3 = le32_to_cpu(s[3]);
+	r0 = get_unaligned_le32(src);
+	r1 = get_unaligned_le32(src + 4);
+	r2 = get_unaligned_le32(src + 8);
+	r3 = get_unaligned_le32(src + 12);
 
 					K(r0, r1, r2, r3, 0);
 	S0(r0, r1, r2, r3, r4);		LK(r2, r1, r3, r0, r4, 1);
@@ -496,10 +489,10 @@  void __serpent_encrypt(const void *c, u8 *dst, const u8 *src)
 	S6(r0, r1, r3, r2, r4);		LK(r3, r4, r1, r2, r0, 31);
 	S7(r3, r4, r1, r2, r0);		K(r0, r1, r2, r3, 32);
 
-	d[0] = cpu_to_le32(r0);
-	d[1] = cpu_to_le32(r1);
-	d[2] = cpu_to_le32(r2);
-	d[3] = cpu_to_le32(r3);
+	put_unaligned_le32(r0, dst);
+	put_unaligned_le32(r1, dst + 4);
+	put_unaligned_le32(r2, dst + 8);
+	put_unaligned_le32(r3, dst + 12);
 }
 EXPORT_SYMBOL_GPL(__serpent_encrypt);
 
@@ -514,14 +507,12 @@  void __serpent_decrypt(const void *c, u8 *dst, const u8 *src)
 {
 	const struct serpent_ctx *ctx = c;
 	const u32 *k = ctx->expkey;
-	const __le32 *s = (const __le32 *)src;
-	__le32	*d = (__le32 *)dst;
 	u32	r0, r1, r2, r3, r4;
 
-	r0 = le32_to_cpu(s[0]);
-	r1 = le32_to_cpu(s[1]);
-	r2 = le32_to_cpu(s[2]);
-	r3 = le32_to_cpu(s[3]);
+	r0 = get_unaligned_le32(src);
+	r1 = get_unaligned_le32(src + 4);
+	r2 = get_unaligned_le32(src + 8);
+	r3 = get_unaligned_le32(src + 12);
 
 					K(r0, r1, r2, r3, 32);
 	SI7(r0, r1, r2, r3, r4);	KL(r1, r3, r0, r4, r2, 31);
@@ -557,10 +548,10 @@  void __serpent_decrypt(const void *c, u8 *dst, const u8 *src)
 	SI1(r3, r1, r2, r0, r4);	KL(r4, r1, r2, r0, r3, 1);
 	SI0(r4, r1, r2, r0, r3);	K(r2, r3, r1, r4, 0);
 
-	d[0] = cpu_to_le32(r2);
-	d[1] = cpu_to_le32(r3);
-	d[2] = cpu_to_le32(r1);
-	d[3] = cpu_to_le32(r4);
+	put_unaligned_le32(r2, dst);
+	put_unaligned_le32(r3, dst + 4);
+	put_unaligned_le32(r1, dst + 8);
+	put_unaligned_le32(r4, dst + 12);
 }
 EXPORT_SYMBOL_GPL(__serpent_decrypt);
 
@@ -578,7 +569,6 @@  static struct crypto_alg srp_alg = {
 	.cra_flags		=	CRYPTO_ALG_TYPE_CIPHER,
 	.cra_blocksize		=	SERPENT_BLOCK_SIZE,
 	.cra_ctxsize		=	sizeof(struct serpent_ctx),
-	.cra_alignmask		=	3,
 	.cra_module		=	THIS_MODULE,
 	.cra_u			=	{ .cipher = {
 	.cia_min_keysize	=	SERPENT_MIN_KEY_SIZE,