ima: use new crypto_shash API instead of old crypto_hash
Dmitry Kasatkin [Fri, 8 Jun 2012 07:42:30 +0000 (10:42 +0300)]
Old crypto hash API internally uses shash API.
Using shash API directly is more efficient.

Signed-off-by: Dmitry Kasatkin <dmitry.kasatkin@intel.com>
Signed-off-by: Mimi Zohar <zohar@linux.vnet.ibm.com>

security/integrity/ima/ima.h
security/integrity/ima/ima_crypto.c
security/integrity/ima/ima_init.c

index ab68bed..5a94f9c 100644 (file)
@@ -89,6 +89,7 @@ int ima_calc_template_hash(int template_len, void *template, char *digest);
 int ima_calc_boot_aggregate(char *digest);
 void ima_add_violation(struct inode *inode, const unsigned char *filename,
                       const char *op, const char *cause);
+int ima_init_crypto(void);
 
 /*
  * used to protect h_table and sha_table
index b21ee5b..920f49c 100644 (file)
 #include <linux/scatterlist.h>
 #include <linux/err.h>
 #include <linux/slab.h>
+#include <crypto/hash.h>
 #include "ima.h"
 
-static int init_desc(struct hash_desc *desc)
+static struct crypto_shash *ima_shash_tfm;
+
+int ima_init_crypto(void)
 {
-       int rc;
+       long rc;
 
-       desc->tfm = crypto_alloc_hash(ima_hash, 0, CRYPTO_ALG_ASYNC);
-       if (IS_ERR(desc->tfm)) {
-               pr_info("IMA: failed to load %s transform: %ld\n",
-                       ima_hash, PTR_ERR(desc->tfm));
-               rc = PTR_ERR(desc->tfm);
+       ima_shash_tfm = crypto_alloc_shash(ima_hash, 0, 0);
+       if (IS_ERR(ima_shash_tfm)) {
+               rc = PTR_ERR(ima_shash_tfm);
+               pr_err("Can not allocate %s (reason: %ld)\n", ima_hash, rc);
                return rc;
        }
-       desc->flags = 0;
-       rc = crypto_hash_init(desc);
-       if (rc)
-               crypto_free_hash(desc->tfm);
-       return rc;
+       return 0;
 }
 
 /*
@@ -44,13 +42,18 @@ static int init_desc(struct hash_desc *desc)
  */
 int ima_calc_hash(struct file *file, char *digest)
 {
-       struct hash_desc desc;
-       struct scatterlist sg[1];
        loff_t i_size, offset = 0;
        char *rbuf;
        int rc, read = 0;
+       struct {
+               struct shash_desc shash;
+               char ctx[crypto_shash_descsize(ima_shash_tfm)];
+       } desc;
 
-       rc = init_desc(&desc);
+       desc.shash.tfm = ima_shash_tfm;
+       desc.shash.flags = 0;
+
+       rc = crypto_shash_init(&desc.shash);
        if (rc != 0)
                return rc;
 
@@ -75,19 +78,17 @@ int ima_calc_hash(struct file *file, char *digest)
                if (rbuf_len == 0)
                        break;
                offset += rbuf_len;
-               sg_init_one(sg, rbuf, rbuf_len);
 
-               rc = crypto_hash_update(&desc, sg, rbuf_len);
+               rc = crypto_shash_update(&desc.shash, rbuf, rbuf_len);
                if (rc)
                        break;
        }
        kfree(rbuf);
        if (!rc)
-               rc = crypto_hash_final(&desc, digest);
+               rc = crypto_shash_final(&desc.shash, digest);
        if (read)
                file->f_mode &= ~FMODE_READ;
 out:
-       crypto_free_hash(desc.tfm);
        return rc;
 }
 
@@ -96,20 +97,15 @@ out:
  */
 int ima_calc_template_hash(int template_len, void *template, char *digest)
 {
-       struct hash_desc desc;
-       struct scatterlist sg[1];
-       int rc;
+       struct {
+               struct shash_desc shash;
+               char ctx[crypto_shash_descsize(ima_shash_tfm)];
+       } desc;
 
-       rc = init_desc(&desc);
-       if (rc != 0)
-               return rc;
+       desc.shash.tfm = ima_shash_tfm;
+       desc.shash.flags = 0;
 
-       sg_init_one(sg, template, template_len);
-       rc = crypto_hash_update(&desc, sg, template_len);
-       if (!rc)
-               rc = crypto_hash_final(&desc, digest);
-       crypto_free_hash(desc.tfm);
-       return rc;
+       return crypto_shash_digest(&desc.shash, template, template_len, digest);
 }
 
 static void __init ima_pcrread(int idx, u8 *pcr)
@@ -126,12 +122,17 @@ static void __init ima_pcrread(int idx, u8 *pcr)
  */
 int __init ima_calc_boot_aggregate(char *digest)
 {
-       struct hash_desc desc;
-       struct scatterlist sg;
        u8 pcr_i[IMA_DIGEST_SIZE];
        int rc, i;
+       struct {
+               struct shash_desc shash;
+               char ctx[crypto_shash_descsize(ima_shash_tfm)];
+       } desc;
+
+       desc.shash.tfm = ima_shash_tfm;
+       desc.shash.flags = 0;
 
-       rc = init_desc(&desc);
+       rc = crypto_shash_init(&desc.shash);
        if (rc != 0)
                return rc;
 
@@ -139,11 +140,9 @@ int __init ima_calc_boot_aggregate(char *digest)
        for (i = TPM_PCR0; i < TPM_PCR8; i++) {
                ima_pcrread(i, pcr_i);
                /* now accumulate with current aggregate */
-               sg_init_one(&sg, pcr_i, IMA_DIGEST_SIZE);
-               rc = crypto_hash_update(&desc, &sg, IMA_DIGEST_SIZE);
+               rc = crypto_shash_update(&desc.shash, pcr_i, IMA_DIGEST_SIZE);
        }
        if (!rc)
-               crypto_hash_final(&desc, digest);
-       crypto_free_hash(desc.tfm);
+               crypto_shash_final(&desc.shash, digest);
        return rc;
 }
index b5dfd53..162ea72 100644 (file)
@@ -85,6 +85,9 @@ int __init ima_init(void)
        if (!ima_used_chip)
                pr_info("IMA: No TPM chip found, activating TPM-bypass!\n");
 
+       rc = ima_init_crypto();
+       if (rc)
+               return rc;
        ima_add_boot_aggregate();       /* boot aggregate must be first entry */
        ima_init_policy();