xref: /linux/arch/x86/crypto/ecb_cbc_helpers.h (revision 9a87ffc99ec8eb8d35eed7c4f816d75f5cc9662e)
1 /* SPDX-License-Identifier: GPL-2.0 */
2 
3 #ifndef _CRYPTO_ECB_CBC_HELPER_H
4 #define _CRYPTO_ECB_CBC_HELPER_H
5 
6 #include <crypto/internal/skcipher.h>
7 #include <asm/fpu/api.h>
8 
9 /*
10  * Mode helpers to instantiate parameterized skcipher ECB/CBC modes without
11  * having to rely on indirect calls and retpolines.
12  */
13 
14 #define ECB_WALK_START(req, bsize, fpu_blocks) do {			\
15 	void *ctx = crypto_skcipher_ctx(crypto_skcipher_reqtfm(req));	\
16 	const int __fpu_blocks = (fpu_blocks);				\
17 	const int __bsize = (bsize);					\
18 	struct skcipher_walk walk;					\
19 	int err = skcipher_walk_virt(&walk, (req), false);		\
20 	while (walk.nbytes > 0) {					\
21 		unsigned int nbytes = walk.nbytes;			\
22 		bool do_fpu = __fpu_blocks != -1 &&			\
23 			      nbytes >= __fpu_blocks * __bsize;		\
24 		const u8 *src = walk.src.virt.addr;			\
25 		u8 *dst = walk.dst.virt.addr;				\
26 		u8 __maybe_unused buf[(bsize)];				\
27 		if (do_fpu) kernel_fpu_begin()
28 
29 #define CBC_WALK_START(req, bsize, fpu_blocks)				\
30 	ECB_WALK_START(req, bsize, fpu_blocks)
31 
32 #define ECB_WALK_ADVANCE(blocks) do {					\
33 	dst += (blocks) * __bsize;					\
34 	src += (blocks) * __bsize;					\
35 	nbytes -= (blocks) * __bsize;					\
36 } while (0)
37 
38 #define ECB_BLOCK(blocks, func) do {					\
39 	const int __blocks = (blocks);					\
40 	if (do_fpu && __blocks < __fpu_blocks) {			\
41 		kernel_fpu_end();					\
42 		do_fpu = false;						\
43 	}								\
44 	while (nbytes >= __blocks * __bsize) {				\
45 		(func)(ctx, dst, src);					\
46 		ECB_WALK_ADVANCE(blocks);				\
47 	}								\
48 } while (0)
49 
50 #define CBC_ENC_BLOCK(func) do {					\
51 	const u8 *__iv = walk.iv;					\
52 	while (nbytes >= __bsize) {					\
53 		crypto_xor_cpy(dst, src, __iv, __bsize);		\
54 		(func)(ctx, dst, dst);					\
55 		__iv = dst;						\
56 		ECB_WALK_ADVANCE(1);					\
57 	}								\
58 	memcpy(walk.iv, __iv, __bsize);					\
59 } while (0)
60 
61 #define CBC_DEC_BLOCK(blocks, func) do {				\
62 	const int __blocks = (blocks);					\
63 	if (do_fpu && __blocks <  __fpu_blocks) {			\
64 		kernel_fpu_end();					\
65 		do_fpu = false;						\
66 	}								\
67 	while (nbytes >= __blocks * __bsize) {				\
68 		const u8 *__iv = src + ((blocks) - 1) * __bsize;	\
69 		if (dst == src)						\
70 			__iv = memcpy(buf, __iv, __bsize);		\
71 		(func)(ctx, dst, src);					\
72 		crypto_xor(dst, walk.iv, __bsize);			\
73 		memcpy(walk.iv, __iv, __bsize);				\
74 		ECB_WALK_ADVANCE(blocks);				\
75 	}								\
76 } while (0)
77 
78 #define ECB_WALK_END()							\
79 		if (do_fpu) kernel_fpu_end();				\
80 		err = skcipher_walk_done(&walk, nbytes);		\
81 	}								\
82 	return err;							\
83 } while (0)
84 
85 #define CBC_WALK_END() ECB_WALK_END()
86 
87 #endif
88