[CRYPTO] Allow multiple implementations of the same algorithm

This is the first step on the road towards asynchronous support in the Crypto API. It adds support for having multiple crypto_alg objects for the same algorithm registered in the system. For example, each device driver would register a crypto_alg object for each algorithm that it supports. While at the same time the user may load software implementations of those same algorithms. Users of the Crypto API may then select a specific implementation by name, or choose any implementation for a given algorithm with the highest priority. The priority field is a 32-bit signed integer. In future it will be possible to modify it from user-space. This also provides a solution to the problem of selecting amongst various AES implementations, that is, aes vs. aes-i586 vs. aes-padlock. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

[CRYPTO] Allow multiple implementations of the same algorithm
This is the first step on the road towards asynchronous support in the Crypto API. It adds support for having multiple crypto_alg objects for the same algorithm registered in the system. For example, each device driver would register a crypto_alg object for each algorithm that it supports. While at the same time the user may load software implementations of those same algorithms. Users of the Crypto API may then select a specific implementation by name, or choose any implementation for a given algorithm with the highest priority. The priority field is a 32-bit signed integer. In future it will be possible to modify it from user-space. This also provides a solution to the problem of selecting amongst various AES implementations, that is, aes vs. aes-i586 vs. aes-padlock. Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Herbert Xu · David S. Miller
1 parent 06ace7a9ba
Showing 4 changed files with 60 additions and 9 deletions Side-by-side Diff
crypto/api.c
crypto/internal.h
crypto/proc.c
include/linux/crypto.h
@@ -3,6 +3,7 @@
  *
  * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
  * Copyright (c) 2002 David S. Miller (davem@redhat.com)
+ * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
  *
  * Portions derived from Cryptoapi, by Alexander Kjeldaas <astor@fast.no>
  * and Nettle, by Niels Möller.
  
@@ -18,9 +19,11 @@
 #include <linux/init.h>
 #include <linux/crypto.h>
 #include <linux/errno.h>
+#include <linux/kernel.h>
 #include <linux/kmod.h>
 #include <linux/rwsem.h>
 #include <linux/slab.h>
+#include <linux/string.h>
 #include "internal.h"
  
 LIST_HEAD(crypto_alg_list);
@@ -39,6 +42,7 @@
 static struct crypto_alg *crypto_alg_lookup(const char *name)
 {
 	struct crypto_alg *q, *alg = NULL;
+	int best = -1;
  
 	if (!name)
 		return NULL;
  
@@ -46,11 +50,23 @@
 	down_read(&crypto_alg_sem);
  
 	list_for_each_entry(q, &crypto_alg_list, cra_list) {
-		if (!(strcmp(q->cra_name, name))) {
-			if (crypto_alg_get(q))
-				alg = q;
+		int exact, fuzzy;
+
+		exact = !strcmp(q->cra_driver_name, name);
+		fuzzy = !strcmp(q->cra_name, name);
+		if (!exact && !(fuzzy && q->cra_priority > best))
+			continue;
+
+		if (unlikely(!crypto_alg_get(q)))
+			continue;
+
+		best = q->cra_priority;
+		if (alg)
+			crypto_alg_put(alg);
+		alg = q;
+
+		if (exact)
 			break;
-		}
 	}
  
 	up_read(&crypto_alg_sem);
  
@@ -207,9 +223,26 @@
 	kfree(tfm);
 }
  
+static inline int crypto_set_driver_name(struct crypto_alg *alg)
+{
+	static const char suffix[] = "-generic";
+	char *driver_name = (char *)alg->cra_driver_name;
+	int len;
+
+	if (*driver_name)
+		return 0;
+
+	len = strlcpy(driver_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);
+	if (len + sizeof(suffix) > CRYPTO_MAX_ALG_NAME)
+		return -ENAMETOOLONG;
+
+	memcpy(driver_name + len, suffix, sizeof(suffix));
+	return 0;
+}
+
 int crypto_register_alg(struct crypto_alg *alg)
 {
-	int ret = 0;
+	int ret;
 	struct crypto_alg *q;
  
 	if (alg->cra_alignmask & (alg->cra_alignmask + 1))
  
  
@@ -220,11 +253,18 @@
  
 	if (alg->cra_blocksize > PAGE_SIZE)
 		return -EINVAL;
+
+	if (alg->cra_priority < 0)
+		return -EINVAL;
  
+	ret = crypto_set_driver_name(alg);
+	if (unlikely(ret))
+		return ret;
+
 	down_write(&crypto_alg_sem);
  
 	list_for_each_entry(q, &crypto_alg_list, cra_list) {
-		if (!(strcmp(q->cra_name, alg->cra_name))) {
+		if (!strcmp(q->cra_driver_name, alg->cra_driver_name)) {
 			ret = -EEXIST;
 			goto out;
 		}
@@ -2,6 +2,7 @@
  * Cryptographic API.
  *
  * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
+ * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.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
  
  
@@ -16,9 +17,14 @@
 #include <linux/highmem.h>
 #include <linux/interrupt.h>
 #include <linux/init.h>
+#include <linux/list.h>
 #include <linux/kernel.h>
+#include <linux/rwsem.h>
 #include <linux/slab.h>
 #include <asm/kmap_types.h>
+
+extern struct list_head crypto_alg_list;
+extern struct rw_semaphore crypto_alg_sem;
  
 extern enum km_type crypto_km_types[];
  
@@ -4,6 +4,7 @@
  * Procfs information.
  *
  * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
+ * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.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
@@ -18,9 +19,6 @@
 #include <linux/seq_file.h>
 #include "internal.h"
  
-extern struct list_head crypto_alg_list;
-extern struct rw_semaphore crypto_alg_sem;
-
 static void *c_start(struct seq_file *m, loff_t *pos)
 {
 	struct list_head *v;
  
@@ -53,7 +51,9 @@
 	struct crypto_alg *alg = (struct crypto_alg *)p;
  
 	seq_printf(m, "name         : %s\n", alg->cra_name);
+	seq_printf(m, "driver       : %s\n", alg->cra_driver_name);
 	seq_printf(m, "module       : %s\n", module_name(alg->cra_module));
+	seq_printf(m, "priority     : %d\n", alg->cra_priority);
  
 	switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
 	case CRYPTO_ALG_TYPE_CIPHER:
@@ -3,6 +3,7 @@
  *
  * Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
  * Copyright (c) 2002 David S. Miller (davem@redhat.com)
+ * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
  *
  * Portions derived from Cryptoapi, by Alexander Kjeldaas <astor@fast.no>
  * and Nettle, by Niels Möller.
  
@@ -126,7 +127,11 @@
 	unsigned int cra_blocksize;
 	unsigned int cra_ctxsize;
 	unsigned int cra_alignmask;
+
+	int cra_priority;
+
 	const char cra_name[CRYPTO_MAX_ALG_NAME];
+	const char cra_driver_name[CRYPTO_MAX_ALG_NAME];
  
 	union {
 		struct cipher_alg cipher;
...	...	@@ -3,6 +3,7 @@
3	3	*
4	4	* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
5	5	* Copyright (c) 2002 David S. Miller (davem@redhat.com)
	6	+ * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
6	7	*
7	8	* Portions derived from Cryptoapi, by Alexander Kjeldaas <astor@fast.no>
8	9	* and Nettle, by Niels Möller.
9	10
...	...	@@ -18,9 +19,11 @@
18	19	#include <linux/init.h>
19	20	#include <linux/crypto.h>
20	21	#include <linux/errno.h>
	22	+#include <linux/kernel.h>
21	23	#include <linux/kmod.h>
22	24	#include <linux/rwsem.h>
23	25	#include <linux/slab.h>
	26	+#include <linux/string.h>
24	27	#include "internal.h"
25	28
26	29	LIST_HEAD(crypto_alg_list);
...	...	@@ -39,6 +42,7 @@
39	42	static struct crypto_alg crypto_alg_lookup(const char name)
40	43	{
41	44	struct crypto_alg q, alg = NULL;
	45	+ int best = -1;
42	46
43	47	if (!name)
44	48	return NULL;
45	49
...	...	@@ -46,11 +50,23 @@
46	50	down_read(&crypto_alg_sem);
47	51
48	52	list_for_each_entry(q, &crypto_alg_list, cra_list) {
49		- if (!(strcmp(q->cra_name, name))) {
50		- if (crypto_alg_get(q))
51		- alg = q;
	53	+ int exact, fuzzy;
	54	+
	55	+ exact = !strcmp(q->cra_driver_name, name);
	56	+ fuzzy = !strcmp(q->cra_name, name);
	57	+ if (!exact && !(fuzzy && q->cra_priority > best))
	58	+ continue;
	59	+
	60	+ if (unlikely(!crypto_alg_get(q)))
	61	+ continue;
	62	+
	63	+ best = q->cra_priority;
	64	+ if (alg)
	65	+ crypto_alg_put(alg);
	66	+ alg = q;
	67	+
	68	+ if (exact)
52	69	break;
53		- }
54	70	}
55	71
56	72	up_read(&crypto_alg_sem);
57	73
...	...	@@ -207,9 +223,26 @@
207	223	kfree(tfm);
208	224	}
209	225
	226	+static inline int crypto_set_driver_name(struct crypto_alg *alg)
	227	+{
	228	+ static const char suffix[] = "-generic";
	229	+ char driver_name = (char )alg->cra_driver_name;
	230	+ int len;
	231	+
	232	+ if (*driver_name)
	233	+ return 0;
	234	+
	235	+ len = strlcpy(driver_name, alg->cra_name, CRYPTO_MAX_ALG_NAME);
	236	+ if (len + sizeof(suffix) > CRYPTO_MAX_ALG_NAME)
	237	+ return -ENAMETOOLONG;
	238	+
	239	+ memcpy(driver_name + len, suffix, sizeof(suffix));
	240	+ return 0;
	241	+}
	242	+
210	243	int crypto_register_alg(struct crypto_alg *alg)
211	244	{
212		- int ret = 0;
	245	+ int ret;
213	246	struct crypto_alg *q;
214	247
215	248	if (alg->cra_alignmask & (alg->cra_alignmask + 1))
216	249
217	250
...	...	@@ -220,11 +253,18 @@
220	253
221	254	if (alg->cra_blocksize > PAGE_SIZE)
222	255	return -EINVAL;
	256	+
	257	+ if (alg->cra_priority < 0)
	258	+ return -EINVAL;
223	259
	260	+ ret = crypto_set_driver_name(alg);
	261	+ if (unlikely(ret))
	262	+ return ret;
	263	+
224	264	down_write(&crypto_alg_sem);
225	265
226	266	list_for_each_entry(q, &crypto_alg_list, cra_list) {
227		- if (!(strcmp(q->cra_name, alg->cra_name))) {
	267	+ if (!strcmp(q->cra_driver_name, alg->cra_driver_name)) {
228	268	ret = -EEXIST;
229	269	goto out;
230	270	}
...	...	@@ -2,6 +2,7 @@
2	2	* Cryptographic API.
3	3	*
4	4	* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
	5	+ * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
5	6	*
6	7	* This program is free software; you can redistribute it and/or modify it
7	8	* under the terms of the GNU General Public License as published by the Free
8	9
9	10
...	...	@@ -16,9 +17,14 @@
16	17	#include <linux/highmem.h>
17	18	#include <linux/interrupt.h>
18	19	#include <linux/init.h>
	20	+#include <linux/list.h>
19	21	#include <linux/kernel.h>
	22	+#include <linux/rwsem.h>
20	23	#include <linux/slab.h>
21	24	#include <asm/kmap_types.h>
	25	+
	26	+extern struct list_head crypto_alg_list;
	27	+extern struct rw_semaphore crypto_alg_sem;
22	28
23	29	extern enum km_type crypto_km_types[];
24	30
...	...	@@ -4,6 +4,7 @@
4	4	* Procfs information.
5	5	*
6	6	* Copyright (c) 2002 James Morris <jmorris@intercode.com.au>
	7	+ * Copyright (c) 2005 Herbert Xu <herbert@gondor.apana.org.au>
7	8	*
8	9	* This program is free software; you can redistribute it and/or modify it
9	10	* under the terms of the GNU General Public License as published by the Free
...	...	@@ -18,9 +19,6 @@
18	19	#include <linux/seq_file.h>
19	20	#include "internal.h"
20	21
21		-extern struct list_head crypto_alg_list;
22		-extern struct rw_semaphore crypto_alg_sem;
23		-
24	22	static void c_start(struct seq_file m, loff_t *pos)
25	23	{
26	24	struct list_head *v;
27	25
...	...	@@ -53,7 +51,9 @@
53	51	struct crypto_alg alg = (struct crypto_alg )p;
54	52
55	53	seq_printf(m, "name : %s\n", alg->cra_name);
	54	+ seq_printf(m, "driver : %s\n", alg->cra_driver_name);
56	55	seq_printf(m, "module : %s\n", module_name(alg->cra_module));
	56	+ seq_printf(m, "priority : %d\n", alg->cra_priority);
57	57
58	58	switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
59	59	case CRYPTO_ALG_TYPE_CIPHER: