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authorLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
committerLinus Torvalds <torvalds@ppc970.osdl.org>2005-04-16 15:20:36 -0700
commit1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 (patch)
tree0bba044c4ce775e45a88a51686b5d9f90697ea9d /crypto/cipher.c
downloadlinux-1da177e4c3f41524e886b7f1b8a0c1fc7321cac2.tar.gz
Linux-2.6.12-rc2
Initial git repository build. I'm not bothering with the full history,
even though we have it. We can create a separate "historical" git
archive of that later if we want to, and in the meantime it's about
3.2GB when imported into git - space that would just make the early
git days unnecessarily complicated, when we don't have a lot of good
infrastructure for it.

Let it rip!
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 000000000000..f434ce7c2d0b
--- /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);
+}