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author | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:02:30 +0000 |
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committer | Daniel Baumann <daniel.baumann@progress-linux.org> | 2024-05-06 01:02:30 +0000 |
commit | 76cb841cb886eef6b3bee341a2266c76578724ad (patch) | |
tree | f5892e5ba6cc11949952a6ce4ecbe6d516d6ce58 /crypto/arc4.c | |
parent | Initial commit. (diff) | |
download | linux-76cb841cb886eef6b3bee341a2266c76578724ad.tar.xz linux-76cb841cb886eef6b3bee341a2266c76578724ad.zip |
Adding upstream version 4.19.249.upstream/4.19.249
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
Diffstat (limited to 'crypto/arc4.c')
-rw-r--r-- | crypto/arc4.c | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/crypto/arc4.c b/crypto/arc4.c new file mode 100644 index 000000000..f1a819255 --- /dev/null +++ b/crypto/arc4.c @@ -0,0 +1,169 @@ +/* + * Cryptographic API + * + * ARC4 Cipher Algorithm + * + * Jon Oberheide <jon@oberheide.org> + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + */ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/crypto.h> +#include <crypto/algapi.h> + +#define ARC4_MIN_KEY_SIZE 1 +#define ARC4_MAX_KEY_SIZE 256 +#define ARC4_BLOCK_SIZE 1 + +struct arc4_ctx { + u32 S[256]; + u32 x, y; +}; + +static int arc4_set_key(struct crypto_tfm *tfm, const u8 *in_key, + unsigned int key_len) +{ + struct arc4_ctx *ctx = crypto_tfm_ctx(tfm); + int i, j = 0, k = 0; + + ctx->x = 1; + ctx->y = 0; + + for (i = 0; i < 256; i++) + ctx->S[i] = i; + + for (i = 0; i < 256; i++) { + u32 a = ctx->S[i]; + j = (j + in_key[k] + a) & 0xff; + ctx->S[i] = ctx->S[j]; + ctx->S[j] = a; + if (++k >= key_len) + k = 0; + } + + return 0; +} + +static void arc4_crypt(struct arc4_ctx *ctx, u8 *out, const u8 *in, + unsigned int len) +{ + u32 *const S = ctx->S; + u32 x, y, a, b; + u32 ty, ta, tb; + + if (len == 0) + return; + + x = ctx->x; + y = ctx->y; + + a = S[x]; + y = (y + a) & 0xff; + b = S[y]; + + do { + S[y] = a; + a = (a + b) & 0xff; + S[x] = b; + x = (x + 1) & 0xff; + ta = S[x]; + ty = (y + ta) & 0xff; + tb = S[ty]; + *out++ = *in++ ^ S[a]; + if (--len == 0) + break; + y = ty; + a = ta; + b = tb; + } while (true); + + ctx->x = x; + ctx->y = y; +} + +static void arc4_crypt_one(struct crypto_tfm *tfm, u8 *out, const u8 *in) +{ + arc4_crypt(crypto_tfm_ctx(tfm), out, in, 1); +} + +static int ecb_arc4_crypt(struct blkcipher_desc *desc, struct scatterlist *dst, + struct scatterlist *src, unsigned int nbytes) +{ + struct arc4_ctx *ctx = crypto_blkcipher_ctx(desc->tfm); + struct blkcipher_walk walk; + int err; + + blkcipher_walk_init(&walk, dst, src, nbytes); + + err = blkcipher_walk_virt(desc, &walk); + + while (walk.nbytes > 0) { + u8 *wsrc = walk.src.virt.addr; + u8 *wdst = walk.dst.virt.addr; + + arc4_crypt(ctx, wdst, wsrc, walk.nbytes); + + err = blkcipher_walk_done(desc, &walk, 0); + } + + return err; +} + +static struct crypto_alg arc4_algs[2] = { { + .cra_name = "arc4", + .cra_flags = CRYPTO_ALG_TYPE_CIPHER, + .cra_blocksize = ARC4_BLOCK_SIZE, + .cra_ctxsize = sizeof(struct arc4_ctx), + .cra_module = THIS_MODULE, + .cra_u = { + .cipher = { + .cia_min_keysize = ARC4_MIN_KEY_SIZE, + .cia_max_keysize = ARC4_MAX_KEY_SIZE, + .cia_setkey = arc4_set_key, + .cia_encrypt = arc4_crypt_one, + .cia_decrypt = arc4_crypt_one, + }, + }, +}, { + .cra_name = "ecb(arc4)", + .cra_priority = 100, + .cra_flags = CRYPTO_ALG_TYPE_BLKCIPHER, + .cra_blocksize = ARC4_BLOCK_SIZE, + .cra_ctxsize = sizeof(struct arc4_ctx), + .cra_alignmask = 0, + .cra_type = &crypto_blkcipher_type, + .cra_module = THIS_MODULE, + .cra_u = { + .blkcipher = { + .min_keysize = ARC4_MIN_KEY_SIZE, + .max_keysize = ARC4_MAX_KEY_SIZE, + .setkey = arc4_set_key, + .encrypt = ecb_arc4_crypt, + .decrypt = ecb_arc4_crypt, + }, + }, +} }; + +static int __init arc4_init(void) +{ + return crypto_register_algs(arc4_algs, ARRAY_SIZE(arc4_algs)); +} + +static void __exit arc4_exit(void) +{ + crypto_unregister_algs(arc4_algs, ARRAY_SIZE(arc4_algs)); +} + +module_init(arc4_init); +module_exit(arc4_exit); + +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("ARC4 Cipher Algorithm"); +MODULE_AUTHOR("Jon Oberheide <jon@oberheide.org>"); +MODULE_ALIAS_CRYPTO("arc4"); |