aboutsummaryrefslogtreecommitdiff
path: root/crypto/cipher.c
diff options
context:
space:
mode:
Diffstat (limited to 'crypto/cipher.c')
-rw-r--r--crypto/cipher.c341
1 files changed, 341 insertions, 0 deletions
diff --git a/crypto/cipher.c b/crypto/cipher.c
new file mode 100644
index 00000000000..f434ce7c2d0
--- /dev/null
+++ b/crypto/cipher.c
@@ -0,0 +1,341 @@
+/*
+ * Cryptographic API.
+ *
+ * Cipher operations.
+ *
+ * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
+ *
+ * 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/compiler.h>
+#include <linux/kernel.h>
+#include <linux/crypto.h>
+#include <linux/errno.h>
+#include <linux/mm.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <asm/scatterlist.h>
+#include "internal.h"
+#include "scatterwalk.h"
+
+typedef void (cryptfn_t)(void *, u8 *, const u8 *);
+typedef void (procfn_t)(struct crypto_tfm *, u8 *,
+ u8*, cryptfn_t, void *);
+
+static inline void xor_64(u8 *a, const u8 *b)
+{
+ ((u32 *)a)[0] ^= ((u32 *)b)[0];
+ ((u32 *)a)[1] ^= ((u32 *)b)[1];
+}
+
+static inline void xor_128(u8 *a, const u8 *b)
+{
+ ((u32 *)a)[0] ^= ((u32 *)b)[0];
+ ((u32 *)a)[1] ^= ((u32 *)b)[1];
+ ((u32 *)a)[2] ^= ((u32 *)b)[2];
+ ((u32 *)a)[3] ^= ((u32 *)b)[3];
+}
+
+static inline void *prepare_src(struct scatter_walk *walk, int bsize,
+ void *tmp, int in_place)
+{
+ void *src = walk->data;
+ int n = bsize;
+
+ if (unlikely(scatterwalk_across_pages(walk, bsize))) {
+ src = tmp;
+ n = scatterwalk_copychunks(src, walk, bsize, 0);
+ }
+ scatterwalk_advance(walk, n);
+ return src;
+}
+
+static inline void *prepare_dst(struct scatter_walk *walk, int bsize,
+ void *tmp, int in_place)
+{
+ void *dst = walk->data;
+
+ if (unlikely(scatterwalk_across_pages(walk, bsize)) || in_place)
+ dst = tmp;
+ return dst;
+}
+
+static inline void complete_src(struct scatter_walk *walk, int bsize,
+ void *src, int in_place)
+{
+}
+
+static inline void complete_dst(struct scatter_walk *walk, int bsize,
+ void *dst, int in_place)
+{
+ int n = bsize;
+
+ if (unlikely(scatterwalk_across_pages(walk, bsize)))
+ n = scatterwalk_copychunks(dst, walk, bsize, 1);
+ else if (in_place)
+ memcpy(walk->data, dst, bsize);
+ scatterwalk_advance(walk, n);
+}
+
+/*
+ * Generic encrypt/decrypt wrapper for ciphers, handles operations across
+ * multiple page boundaries by using temporary blocks. In user context,
+ * the kernel is given a chance to schedule us once per block.
+ */
+static int crypt(struct crypto_tfm *tfm,
+ struct scatterlist *dst,
+ struct scatterlist *src,
+ unsigned int nbytes, cryptfn_t crfn,
+ procfn_t prfn, void *info)
+{
+ struct scatter_walk walk_in, walk_out;
+ const unsigned int bsize = crypto_tfm_alg_blocksize(tfm);
+ u8 tmp_src[bsize];
+ u8 tmp_dst[bsize];
+
+ if (!nbytes)
+ return 0;
+
+ if (nbytes % bsize) {
+ tfm->crt_flags |= CRYPTO_TFM_RES_BAD_BLOCK_LEN;
+ return -EINVAL;
+ }
+
+ scatterwalk_start(&walk_in, src);
+ scatterwalk_start(&walk_out, dst);
+
+ for(;;) {
+ u8 *src_p, *dst_p;
+ int in_place;
+
+ scatterwalk_map(&walk_in, 0);
+ scatterwalk_map(&walk_out, 1);
+
+ in_place = scatterwalk_samebuf(&walk_in, &walk_out);
+
+ do {
+ src_p = prepare_src(&walk_in, bsize, tmp_src,
+ in_place);
+ dst_p = prepare_dst(&walk_out, bsize, tmp_dst,
+ in_place);
+
+ prfn(tfm, dst_p, src_p, crfn, info);
+
+ complete_src(&walk_in, bsize, src_p, in_place);
+ complete_dst(&walk_out, bsize, dst_p, in_place);
+
+ nbytes -= bsize;
+ } while (nbytes &&
+ !scatterwalk_across_pages(&walk_in, bsize) &&
+ !scatterwalk_across_pages(&walk_out, bsize));
+
+ scatterwalk_done(&walk_in, 0, nbytes);
+ scatterwalk_done(&walk_out, 1, nbytes);
+
+ if (!nbytes)
+ return 0;
+
+ crypto_yield(tfm);
+ }
+}
+
+static void cbc_process_encrypt(struct crypto_tfm *tfm, u8 *dst, u8 *src,
+ cryptfn_t fn, void *info)
+{
+ u8 *iv = info;
+
+ tfm->crt_u.cipher.cit_xor_block(iv, src);
+ fn(crypto_tfm_ctx(tfm), dst, iv);
+ memcpy(iv, dst, crypto_tfm_alg_blocksize(tfm));
+}
+
+static void cbc_process_decrypt(struct crypto_tfm *tfm, u8 *dst, u8 *src,
+ cryptfn_t fn, void *info)
+{
+ u8 *iv = info;
+
+ fn(crypto_tfm_ctx(tfm), dst, src);
+ tfm->crt_u.cipher.cit_xor_block(dst, iv);
+ memcpy(iv, src, crypto_tfm_alg_blocksize(tfm));
+}
+
+static void ecb_process(struct crypto_tfm *tfm, u8 *dst, u8 *src,
+ cryptfn_t fn, void *info)
+{
+ fn(crypto_tfm_ctx(tfm), dst, src);
+}
+
+static int setkey(struct crypto_tfm *tfm, const u8 *key, unsigned int keylen)
+{
+ struct cipher_alg *cia = &tfm->__crt_alg->cra_cipher;
+
+ if (keylen < cia->cia_min_keysize || keylen > cia->cia_max_keysize) {
+ tfm->crt_flags |= CRYPTO_TFM_RES_BAD_KEY_LEN;
+ return -EINVAL;
+ } else
+ return cia->cia_setkey(crypto_tfm_ctx(tfm), key, keylen,
+ &tfm->crt_flags);
+}
+
+static int ecb_encrypt(struct crypto_tfm *tfm,
+ struct scatterlist *dst,
+ struct scatterlist *src, unsigned int nbytes)
+{
+ return crypt(tfm, dst, src, nbytes,
+ tfm->__crt_alg->cra_cipher.cia_encrypt,
+ ecb_process, NULL);
+}
+
+static int ecb_decrypt(struct crypto_tfm *tfm,
+ struct scatterlist *dst,
+ struct scatterlist *src,
+ unsigned int nbytes)
+{
+ return crypt(tfm, dst, src, nbytes,
+ tfm->__crt_alg->cra_cipher.cia_decrypt,
+ ecb_process, NULL);
+}
+
+static int cbc_encrypt(struct crypto_tfm *tfm,
+ struct scatterlist *dst,
+ struct scatterlist *src,
+ unsigned int nbytes)
+{
+ return crypt(tfm, dst, src, nbytes,
+ tfm->__crt_alg->cra_cipher.cia_encrypt,
+ cbc_process_encrypt, tfm->crt_cipher.cit_iv);
+}
+
+static int cbc_encrypt_iv(struct crypto_tfm *tfm,
+ struct scatterlist *dst,
+ struct scatterlist *src,
+ unsigned int nbytes, u8 *iv)
+{
+ return crypt(tfm, dst, src, nbytes,
+ tfm->__crt_alg->cra_cipher.cia_encrypt,
+ cbc_process_encrypt, iv);
+}
+
+static int cbc_decrypt(struct crypto_tfm *tfm,
+ struct scatterlist *dst,
+ struct scatterlist *src,
+ unsigned int nbytes)
+{
+ return crypt(tfm, dst, src, nbytes,
+ tfm->__crt_alg->cra_cipher.cia_decrypt,
+ cbc_process_decrypt, tfm->crt_cipher.cit_iv);
+}
+
+static int cbc_decrypt_iv(struct crypto_tfm *tfm,
+ struct scatterlist *dst,
+ struct scatterlist *src,
+ unsigned int nbytes, u8 *iv)
+{
+ return crypt(tfm, dst, src, nbytes,
+ tfm->__crt_alg->cra_cipher.cia_decrypt,
+ cbc_process_decrypt, iv);
+}
+
+static int nocrypt(struct crypto_tfm *tfm,
+ struct scatterlist *dst,
+ struct scatterlist *src,
+ unsigned int nbytes)
+{
+ return -ENOSYS;
+}
+
+static int nocrypt_iv(struct crypto_tfm *tfm,
+ struct scatterlist *dst,
+ struct scatterlist *src,
+ unsigned int nbytes, u8 *iv)
+{
+ return -ENOSYS;
+}
+
+int crypto_init_cipher_flags(struct crypto_tfm *tfm, u32 flags)
+{
+ u32 mode = flags & CRYPTO_TFM_MODE_MASK;
+
+ tfm->crt_cipher.cit_mode = mode ? mode : CRYPTO_TFM_MODE_ECB;
+ if (flags & CRYPTO_TFM_REQ_WEAK_KEY)
+ tfm->crt_flags = CRYPTO_TFM_REQ_WEAK_KEY;
+
+ return 0;
+}
+
+int crypto_init_cipher_ops(struct crypto_tfm *tfm)
+{
+ int ret = 0;
+ struct cipher_tfm *ops = &tfm->crt_cipher;
+
+ ops->cit_setkey = setkey;
+
+ switch (tfm->crt_cipher.cit_mode) {
+ case CRYPTO_TFM_MODE_ECB:
+ ops->cit_encrypt = ecb_encrypt;
+ ops->cit_decrypt = ecb_decrypt;
+ break;
+
+ case CRYPTO_TFM_MODE_CBC:
+ ops->cit_encrypt = cbc_encrypt;
+ ops->cit_decrypt = cbc_decrypt;
+ ops->cit_encrypt_iv = cbc_encrypt_iv;
+ ops->cit_decrypt_iv = cbc_decrypt_iv;
+ break;
+
+ case CRYPTO_TFM_MODE_CFB:
+ ops->cit_encrypt = nocrypt;
+ ops->cit_decrypt = nocrypt;
+ ops->cit_encrypt_iv = nocrypt_iv;
+ ops->cit_decrypt_iv = nocrypt_iv;
+ break;
+
+ case CRYPTO_TFM_MODE_CTR:
+ ops->cit_encrypt = nocrypt;
+ ops->cit_decrypt = nocrypt;
+ ops->cit_encrypt_iv = nocrypt_iv;
+ ops->cit_decrypt_iv = nocrypt_iv;
+ break;
+
+ default:
+ BUG();
+ }
+
+ if (ops->cit_mode == CRYPTO_TFM_MODE_CBC) {
+
+ switch (crypto_tfm_alg_blocksize(tfm)) {
+ case 8:
+ ops->cit_xor_block = xor_64;
+ break;
+
+ case 16:
+ ops->cit_xor_block = xor_128;
+ break;
+
+ default:
+ printk(KERN_WARNING "%s: block size %u not supported\n",
+ crypto_tfm_alg_name(tfm),
+ crypto_tfm_alg_blocksize(tfm));
+ ret = -EINVAL;
+ goto out;
+ }
+
+ ops->cit_ivsize = crypto_tfm_alg_blocksize(tfm);
+ ops->cit_iv = kmalloc(ops->cit_ivsize, GFP_KERNEL);
+ if (ops->cit_iv == NULL)
+ ret = -ENOMEM;
+ }
+
+out:
+ return ret;
+}
+
+void crypto_exit_cipher_ops(struct crypto_tfm *tfm)
+{
+ if (tfm->crt_cipher.cit_iv)
+ kfree(tfm->crt_cipher.cit_iv);
+}
generated by cgit v1.2.3-18-g5258 (git 2.32.0) at 2024-11-22 14:59:12 +0000