[CRYPTO] padlock: Convert padlock-sha to use crypto_hash

This patch converts padlock-sha to use crypto_hash for its fallback.
It also changes the fallback selection to use selection by type instead
of name.  This is done through the new CRYPTO_ALG_NEED_FALLBACK bit,
which is set if and only if an algorithm needs a fallback of the same
type.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

2 files changed, 41 insertions, 56 deletions

diff --git a/drivers/crypto/padlock-sha.c b/drivers/crypto/padlock-sha.c
index b028db61c301..a781fd23b607 100644
--- a/drivers/crypto/padlock-sha.c
+++ b/drivers/crypto/padlock-sha.c
@@ -12,10 +12,11 @@
  *
  */
 
+#include <crypto/algapi.h>
+#include <linux/err.h>
 #include <linux/module.h>
 #include <linux/init.h>
 #include <linux/errno.h>
-#include <linux/crypto.h>
 #include <linux/cryptohash.h>
 #include <linux/interrupt.h>
 #include <linux/kernel.h>
@@ -30,28 +31,17 @@
 #define SHA256_DIGEST_SIZE      32
 #define SHA256_HMAC_BLOCK_SIZE  64
 
-static char *sha1_fallback = SHA1_DEFAULT_FALLBACK;
-static char *sha256_fallback = SHA256_DEFAULT_FALLBACK;
-
-module_param(sha1_fallback, charp, 0644);
-module_param(sha256_fallback, charp, 0644);
-
-MODULE_PARM_DESC(sha1_fallback, "Fallback driver for SHA1. Default is "
-                 SHA1_DEFAULT_FALLBACK);
-MODULE_PARM_DESC(sha256_fallback, "Fallback driver for SHA256. Default is "
-                 SHA256_DEFAULT_FALLBACK);
-
 struct padlock_sha_ctx {
         char            *data;
         size_t          used;
         int             bypass;
         void (*f_sha_padlock)(const char *in, char *out, int count);
-        struct crypto_tfm *fallback_tfm;
+        struct hash_desc fallback;
 };
 
 static inline struct padlock_sha_ctx *ctx(struct crypto_tfm *tfm)
 {
-        return (struct padlock_sha_ctx *)(crypto_tfm_ctx(tfm));
+        return crypto_tfm_ctx(tfm);
 }
 
 /* We'll need aligned address on the stack */
@@ -65,14 +55,12 @@ static void padlock_sha_bypass(struct crypto_tfm *tfm)
         if (ctx(tfm)->bypass)
                 return;
 
-        BUG_ON(!ctx(tfm)->fallback_tfm);
-
-        crypto_digest_init(ctx(tfm)->fallback_tfm);
+        crypto_hash_init(&ctx(tfm)->fallback);
         if (ctx(tfm)->data && ctx(tfm)->used) {
                 struct scatterlist sg;
 
                 sg_set_buf(&sg, ctx(tfm)->data, ctx(tfm)->used);
-                crypto_digest_update(ctx(tfm)->fallback_tfm, &sg, 1);
+                crypto_hash_update(&ctx(tfm)->fallback, &sg, sg.length);
         }
 
         ctx(tfm)->used = 0;
@@ -95,9 +83,8 @@ static void padlock_sha_update(struct crypto_tfm *tfm,
 
         if (unlikely(ctx(tfm)->bypass)) {
                 struct scatterlist sg;
-                BUG_ON(!ctx(tfm)->fallback_tfm);
                 sg_set_buf(&sg, (uint8_t *)data, length);
-                crypto_digest_update(ctx(tfm)->fallback_tfm, &sg, 1);
+                crypto_hash_update(&ctx(tfm)->fallback, &sg, length);
                 return;
         }
 
@@ -160,8 +147,7 @@ static void padlock_do_sha256(const char *in, char *out, int count)
 static void padlock_sha_final(struct crypto_tfm *tfm, uint8_t *out)
 {
         if (unlikely(ctx(tfm)->bypass)) {
-                BUG_ON(!ctx(tfm)->fallback_tfm);
-                crypto_digest_final(ctx(tfm)->fallback_tfm, out);
+                crypto_hash_final(&ctx(tfm)->fallback, out);
                 ctx(tfm)->bypass = 0;
                 return;
         }
@@ -172,8 +158,11 @@ static void padlock_sha_final(struct crypto_tfm *tfm, uint8_t *out)
         ctx(tfm)->used = 0;
 }
 
-static int padlock_cra_init(struct crypto_tfm *tfm, const char *fallback_driver_name)
+static int padlock_cra_init(struct crypto_tfm *tfm)
 {
+        const char *fallback_driver_name = tfm->__crt_alg->cra_name;
+        struct crypto_hash *fallback_tfm;
+
         /* For now we'll allocate one page. This
          * could eventually be configurable one day. */
         ctx(tfm)->data = (char *)__get_free_page(GFP_KERNEL);
@@ -181,14 +170,17 @@ static int padlock_cra_init(struct crypto_tfm *tfm, const char *fallback_driver_
                 return -ENOMEM;
 
         /* Allocate a fallback and abort if it failed. */
-        ctx(tfm)->fallback_tfm = crypto_alloc_tfm(fallback_driver_name, 0);
-        if (!ctx(tfm)->fallback_tfm) {
+        fallback_tfm = crypto_alloc_hash(fallback_driver_name, 0,
+                                         CRYPTO_ALG_ASYNC |
+                                         CRYPTO_ALG_NEED_FALLBACK);
+        if (IS_ERR(fallback_tfm)) {
                 printk(KERN_WARNING PFX "Fallback driver '%s' could not be loaded!\n",
                        fallback_driver_name);
                 free_page((unsigned long)(ctx(tfm)->data));
-                return -ENOENT;
+                return PTR_ERR(fallback_tfm);
         }
 
+        ctx(tfm)->fallback.tfm = fallback_tfm;
         return 0;
 }
 
@@ -196,14 +188,14 @@ static int padlock_sha1_cra_init(struct crypto_tfm *tfm)
 {
         ctx(tfm)->f_sha_padlock = padlock_do_sha1;
 
-        return padlock_cra_init(tfm, sha1_fallback);
+        return padlock_cra_init(tfm);
 }
 
 static int padlock_sha256_cra_init(struct crypto_tfm *tfm)
 {
         ctx(tfm)->f_sha_padlock = padlock_do_sha256;
 
-        return padlock_cra_init(tfm, sha256_fallback);
+        return padlock_cra_init(tfm);
 }
 
 static void padlock_cra_exit(struct crypto_tfm *tfm)
@@ -213,16 +205,16 @@ static void padlock_cra_exit(struct crypto_tfm *tfm)
                 ctx(tfm)->data = NULL;
         }
 
-        BUG_ON(!ctx(tfm)->fallback_tfm);
-        crypto_free_tfm(ctx(tfm)->fallback_tfm);
-        ctx(tfm)->fallback_tfm = NULL;
+        crypto_free_hash(ctx(tfm)->fallback.tfm);
+        ctx(tfm)->fallback.tfm = NULL;
 }
 
 static struct crypto_alg sha1_alg = {
         .cra_name               =       "sha1",
         .cra_driver_name        =       "sha1-padlock",
         .cra_priority           =       PADLOCK_CRA_PRIORITY,
-        .cra_flags              =       CRYPTO_ALG_TYPE_DIGEST,
+        .cra_flags              =       CRYPTO_ALG_TYPE_DIGEST |
+                                        CRYPTO_ALG_NEED_FALLBACK,
         .cra_blocksize          =       SHA1_HMAC_BLOCK_SIZE,
         .cra_ctxsize            =       sizeof(struct padlock_sha_ctx),
         .cra_module             =       THIS_MODULE,
@@ -243,7 +235,8 @@ static struct crypto_alg sha256_alg = {
         .cra_name               =       "sha256",
         .cra_driver_name        =       "sha256-padlock",
         .cra_priority           =       PADLOCK_CRA_PRIORITY,
-        .cra_flags              =       CRYPTO_ALG_TYPE_DIGEST,
+        .cra_flags              =       CRYPTO_ALG_TYPE_DIGEST |
+                                        CRYPTO_ALG_NEED_FALLBACK,
         .cra_blocksize          =       SHA256_HMAC_BLOCK_SIZE,
         .cra_ctxsize            =       sizeof(struct padlock_sha_ctx),
         .cra_module             =       THIS_MODULE,
@@ -262,29 +255,15 @@ static struct crypto_alg sha256_alg = {
 
 static void __init padlock_sha_check_fallbacks(void)
 {
-        struct crypto_tfm *tfm;
-
-        /* We'll try to allocate one TFM for each fallback
-         * to test that the modules are available. */
-        tfm = crypto_alloc_tfm(sha1_fallback, 0);
-        if (!tfm) {
-                printk(KERN_WARNING PFX "Couldn't load fallback module for '%s'. Tried '%s'.\n",
-                       sha1_alg.cra_name, sha1_fallback);
-        } else {
-                printk(KERN_NOTICE PFX "Fallback for '%s' is driver '%s' (prio=%d)\n", sha1_alg.cra_name,
-                       crypto_tfm_alg_driver_name(tfm), crypto_tfm_alg_priority(tfm));
-                crypto_free_tfm(tfm);
-        }
-
-        tfm = crypto_alloc_tfm(sha256_fallback, 0);
-        if (!tfm) {
-                printk(KERN_WARNING PFX "Couldn't load fallback module for '%s'. Tried '%s'.\n",
-                       sha256_alg.cra_name, sha256_fallback);
-        } else {
-                printk(KERN_NOTICE PFX "Fallback for '%s' is driver '%s' (prio=%d)\n", sha256_alg.cra_name,
-                       crypto_tfm_alg_driver_name(tfm), crypto_tfm_alg_priority(tfm));
-                crypto_free_tfm(tfm);
-        }
+        if (!crypto_has_hash("sha1", 0, CRYPTO_ALG_ASYNC |
+                                        CRYPTO_ALG_NEED_FALLBACK))
+                printk(KERN_WARNING PFX
+                       "Couldn't load fallback module for sha1.\n");
+
+        if (!crypto_has_hash("sha256", 0, CRYPTO_ALG_ASYNC |
+                                        CRYPTO_ALG_NEED_FALLBACK))
+                printk(KERN_WARNING PFX
+                       "Couldn't load fallback module for sha256.\n");
 }
 
 static int __init padlock_init(void)
diff --git a/include/linux/crypto.h b/include/linux/crypto.h
index d4f9948b64b1..187c6ea91959 100644
--- a/include/linux/crypto.h
+++ b/include/linux/crypto.h
@@ -43,6 +43,12 @@
 #define CRYPTO_ALG_ASYNC                0x00000080
 
 /*
+ * Set this bit if and only if the algorithm requires another algorithm of
+ * the same type to handle corner cases.
+ */
+#define CRYPTO_ALG_NEED_FALLBACK        0x00000100
+
+/*
  * Transform masks and values (for crt_flags).
  */
 #define CRYPTO_TFM_MODE_MASK            0x000000ff