[CRYPTO] Ensure cit_iv is aligned correctly

This patch ensures that cit_iv is aligned according to cra_alignmask
by allocating it as part of the tfm structure.  As a side effect the
crypto layer will also guarantee that the tfm ctx area has enough space
to be aligned by cra_alignmask.  This allows us to remove the extra
space reservation from the Padlock driver.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: David S. Miller <davem@davemloft.net>

5 files changed, 72 insertions, 11 deletions

diff --git a/crypto/api.c b/crypto/api.c
index 0b583d24f7fa..2d8d828c0ca2 100644
--- a/crypto/api.c
+++ b/crypto/api.c
@@ -125,20 +125,46 @@ static void crypto_exit_ops(struct crypto_tfm *tfm)
         }
 }
 
+static unsigned int crypto_ctxsize(struct crypto_alg *alg, int flags)
+{
+        unsigned int len;
+
+        switch (alg->cra_flags & CRYPTO_ALG_TYPE_MASK) {
+        default:
+                BUG();
+
+        case CRYPTO_ALG_TYPE_CIPHER:
+                len = crypto_cipher_ctxsize(alg, flags);
+                break;
+                
+        case CRYPTO_ALG_TYPE_DIGEST:
+                len = crypto_digest_ctxsize(alg, flags);
+                break;
+                
+        case CRYPTO_ALG_TYPE_COMPRESS:
+                len = crypto_compress_ctxsize(alg, flags);
+                break;
+        }
+
+        return len + alg->cra_alignmask;
+}
+
 struct crypto_tfm *crypto_alloc_tfm(const char *name, u32 flags)
 {
         struct crypto_tfm *tfm = NULL;
         struct crypto_alg *alg;
+        unsigned int tfm_size;
 
         alg = crypto_alg_mod_lookup(name);
         if (alg == NULL)
                 goto out;
-        
-        tfm = kmalloc(sizeof(*tfm) + alg->cra_ctxsize, GFP_KERNEL);
+
+        tfm_size = sizeof(*tfm) + crypto_ctxsize(alg, flags);
+        tfm = kmalloc(tfm_size, GFP_KERNEL);
         if (tfm == NULL)
                 goto out_put;
 
-        memset(tfm, 0, sizeof(*tfm) + alg->cra_ctxsize);
+        memset(tfm, 0, tfm_size);
         
         tfm->__crt_alg = alg;
         
diff --git a/crypto/cipher.c b/crypto/cipher.c
index 85eb12f8e564..d3295ce14a57 100644
--- a/crypto/cipher.c
+++ b/crypto/cipher.c
@@ -41,7 +41,7 @@ static unsigned int crypt_slow(const struct cipher_desc *desc,
                                struct scatter_walk *in,
                                struct scatter_walk *out, unsigned int bsize)
 {
-        unsigned int alignmask = desc->tfm->__crt_alg->cra_alignmask;
+        unsigned int alignmask = crypto_tfm_alg_alignmask(desc->tfm);
         u8 buffer[bsize * 2 + alignmask];
         u8 *src = (u8 *)ALIGN((unsigned long)buffer, alignmask + 1);
         u8 *dst = src + bsize;
@@ -98,7 +98,7 @@ static int crypt(const struct cipher_desc *desc,
         struct scatter_walk walk_in, walk_out;
         struct crypto_tfm *tfm = desc->tfm;
         const unsigned int bsize = crypto_tfm_alg_blocksize(tfm);
-        unsigned int alignmask = tfm->__crt_alg->cra_alignmask;
+        unsigned int alignmask = crypto_tfm_alg_alignmask(tfm);
         unsigned long buffer = 0;
 
         if (!nbytes)
@@ -399,6 +399,8 @@ int crypto_init_cipher_ops(struct crypto_tfm *tfm)
         }
         
         if (ops->cit_mode == CRYPTO_TFM_MODE_CBC) {
+                unsigned int align;
+                unsigned long addr;
                 
                 switch (crypto_tfm_alg_blocksize(tfm)) {
                 case 8:
@@ -418,9 +420,11 @@ int crypto_init_cipher_ops(struct crypto_tfm *tfm)
                 }
                 
                 ops->cit_ivsize = crypto_tfm_alg_blocksize(tfm);
-                ops->cit_iv = kmalloc(ops->cit_ivsize, GFP_KERNEL);
-                if (ops->cit_iv == NULL)
-                        ret = -ENOMEM;
+                align = crypto_tfm_alg_alignmask(tfm) + 1;
+                addr = (unsigned long)crypto_tfm_ctx(tfm);
+                addr = ALIGN(addr, align);
+                addr += ALIGN(tfm->__crt_alg->cra_ctxsize, align);
+                ops->cit_iv = (void *)addr;
         }
 
 out:    
@@ -429,5 +433,4 @@ out:
 
 void crypto_exit_cipher_ops(struct crypto_tfm *tfm)
 {
-        kfree(tfm->crt_cipher.cit_iv);
 }
diff --git a/crypto/internal.h b/crypto/internal.h
index 83b1b6d6d92b..68612874b5fd 100644
--- a/crypto/internal.h
+++ b/crypto/internal.h
@@ -16,6 +16,7 @@
 #include <linux/highmem.h>
 #include <linux/interrupt.h>
 #include <linux/init.h>
+#include <linux/kernel.h>
 #include <asm/kmap_types.h>
 
 extern enum km_type crypto_km_types[];
@@ -61,6 +62,33 @@ static inline void crypto_init_proc(void)
 { }
 #endif
 
+static inline unsigned int crypto_digest_ctxsize(struct crypto_alg *alg,
+                                                 int flags)
+{
+        return alg->cra_ctxsize;
+}
+
+static inline unsigned int crypto_cipher_ctxsize(struct crypto_alg *alg,
+                                                 int flags)
+{
+        unsigned int len = alg->cra_ctxsize;
+        
+        switch (flags & CRYPTO_TFM_MODE_MASK) {
+        case CRYPTO_TFM_MODE_CBC:
+                len = ALIGN(len, alg->cra_alignmask + 1);
+                len += alg->cra_blocksize;
+                break;
+        }
+
+        return len;
+}
+
+static inline unsigned int crypto_compress_ctxsize(struct crypto_alg *alg,
+                                                   int flags)
+{
+        return alg->cra_ctxsize;
+}
+
 int crypto_init_digest_flags(struct crypto_tfm *tfm, u32 flags);
 int crypto_init_cipher_flags(struct crypto_tfm *tfm, u32 flags);
 int crypto_init_compress_flags(struct crypto_tfm *tfm, u32 flags);
diff --git a/drivers/crypto/padlock-aes.c b/drivers/crypto/padlock-aes.c
index d2745ff4699c..c5b58fae95f2 100644
--- a/drivers/crypto/padlock-aes.c
+++ b/drivers/crypto/padlock-aes.c
@@ -465,8 +465,7 @@ static struct crypto_alg aes_alg = {
         .cra_name               =       "aes",
         .cra_flags              =       CRYPTO_ALG_TYPE_CIPHER,
         .cra_blocksize          =       AES_BLOCK_SIZE,
-        .cra_ctxsize            =       sizeof(struct aes_ctx) +
-                                        PADLOCK_ALIGNMENT,
+        .cra_ctxsize            =       sizeof(struct aes_ctx),
         .cra_alignmask          =       PADLOCK_ALIGNMENT - 1,
         .cra_module             =       THIS_MODULE,
         .cra_list               =       LIST_HEAD_INIT(aes_alg.cra_list),
diff --git a/include/linux/crypto.h b/include/linux/crypto.h
index ac9d49beecd3..5e2bcc636a02 100644
--- a/include/linux/crypto.h
+++ b/include/linux/crypto.h
@@ -288,6 +288,11 @@ static inline unsigned int crypto_tfm_alg_digestsize(struct crypto_tfm *tfm)
         return tfm->__crt_alg->cra_digest.dia_digestsize;
 }
 
+static inline unsigned int crypto_tfm_alg_alignmask(struct crypto_tfm *tfm)
+{
+        return tfm->__crt_alg->cra_alignmask;
+}
+
 static inline void *crypto_tfm_ctx(struct crypto_tfm *tfm)
 {
         return (void *)&tfm[1];