ima: separate 'security.ima' reading functionality from collect

Instead of passing pointers to pointers to ima_collect_measurent() to
read and return the 'security.ima' xattr value, this patch moves the
functionality to the calling process_measurement() to directly read
the xattr and pass only the hash algo to the ima_collect_measurement().

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

security/integrity/ima/ima.h

@@ -23,6 +23,7 @@
 #include <linux/hash.h>
 #include <linux/tpm.h>
 #include <linux/audit.h>
+#include <crypto/hash_info.h>
 
 #include "../integrity.h"
 
@@ -140,9 +141,7 @@ static inline unsigned long ima_hash_key(u8 *digest)
 int ima_get_action(struct inode *inode, int mask, int function);
 int ima_must_measure(struct inode *inode, int mask, int function);
 int ima_collect_measurement(struct integrity_iint_cache *iint,
-			    struct file *file,
-			    struct evm_ima_xattr_data **xattr_value,
-			    int *xattr_len);
+			    struct file *file, enum hash_algo algo);
 void ima_store_measurement(struct integrity_iint_cache *iint, struct file *file,
 			   const unsigned char *filename,
 			   struct evm_ima_xattr_data *xattr_value,
@@ -188,8 +187,8 @@ int ima_must_appraise(struct inode *inode, int mask, enum ima_hooks func);
 void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file);
 enum integrity_status ima_get_cache_status(struct integrity_iint_cache *iint,
 					   int func);
-void ima_get_hash_algo(struct evm_ima_xattr_data *xattr_value, int xattr_len,
-		       struct ima_digest_data *hash);
+enum hash_algo ima_get_hash_algo(struct evm_ima_xattr_data *xattr_value,
+				 int xattr_len);
 int ima_read_xattr(struct dentry *dentry,
 		   struct evm_ima_xattr_data **xattr_value);
 
@@ -221,10 +220,10 @@ static inline enum integrity_status ima_get_cache_status(struct integrity_iint_c
 	return INTEGRITY_UNKNOWN;
 }
 
-static inline void ima_get_hash_algo(struct evm_ima_xattr_data *xattr_value,
-				     int xattr_len,
-				     struct ima_digest_data *hash)
+static inline enum hash_algo
+ima_get_hash_algo(struct evm_ima_xattr_data *xattr_value, int xattr_len)
 {
+	return ima_hash_algo;
 }
 
 static inline int ima_read_xattr(struct dentry *dentry,

security/integrity/ima/ima_api.c

@@ -18,7 +18,7 @@
 #include <linux/fs.h>
 #include <linux/xattr.h>
 #include <linux/evm.h>
-#include <crypto/hash_info.h>
+
 #include "ima.h"
 
 /*
@@ -188,9 +188,7 @@ int ima_get_action(struct inode *inode, int mask, int function)
  * Return 0 on success, error code otherwise
  */
 int ima_collect_measurement(struct integrity_iint_cache *iint,
-			    struct file *file,
-			    struct evm_ima_xattr_data **xattr_value,
-			    int *xattr_len)
+			    struct file *file, enum hash_algo algo)
 {
 	const char *audit_cause = "failed";
 	struct inode *inode = file_inode(file);
@@ -201,9 +199,6 @@ int ima_collect_measurement(struct integrity_iint_cache *iint,
 		char digest[IMA_MAX_DIGEST_SIZE];
 	} hash;
 
-	if (xattr_value)
-		*xattr_len = ima_read_xattr(file->f_path.dentry, xattr_value);
-
 	if (!(iint->flags & IMA_COLLECTED)) {
 		u64 i_version = file_inode(file)->i_version;
 
@@ -213,11 +208,7 @@ int ima_collect_measurement(struct integrity_iint_cache *iint,
 			goto out;
 		}
 
-		/* use default hash algorithm */
-		hash.hdr.algo = ima_hash_algo;
-
-		if (xattr_value)
-			ima_get_hash_algo(*xattr_value, *xattr_len, &hash.hdr);
+		hash.hdr.algo = algo;
 
 		result = ima_calc_file_hash(file, &hash.hdr);
 		if (!result) {

security/integrity/ima/ima_appraise.c

@@ -15,7 +15,6 @@
 #include <linux/magic.h>
 #include <linux/ima.h>
 #include <linux/evm.h>
-#include <crypto/hash_info.h>
 
 #include "ima.h"
 
@@ -130,36 +129,40 @@ static void ima_cache_flags(struct integrity_iint_cache *iint, int func)
 	}
 }
 
-void ima_get_hash_algo(struct evm_ima_xattr_data *xattr_value, int xattr_len,
-		       struct ima_digest_data *hash)
+enum hash_algo ima_get_hash_algo(struct evm_ima_xattr_data *xattr_value,
+				 int xattr_len)
 {
 	struct signature_v2_hdr *sig;
 
 	if (!xattr_value || xattr_len < 2)
-		return;
+		/* return default hash algo */
+		return ima_hash_algo;
 
 	switch (xattr_value->type) {
 	case EVM_IMA_XATTR_DIGSIG:
 		sig = (typeof(sig))xattr_value;
 		if (sig->version != 2 || xattr_len <= sizeof(*sig))
-			return;
-		hash->algo = sig->hash_algo;
+			return ima_hash_algo;
+		return sig->hash_algo;
 		break;
 	case IMA_XATTR_DIGEST_NG:
-		hash->algo = xattr_value->digest[0];
+		return xattr_value->digest[0];
 		break;
 	case IMA_XATTR_DIGEST:
 		/* this is for backward compatibility */
 		if (xattr_len == 21) {
 			unsigned int zero = 0;
 			if (!memcmp(&xattr_value->digest[16], &zero, 4))
-				hash->algo = HASH_ALGO_MD5;
+				return HASH_ALGO_MD5;
 			else
-				hash->algo = HASH_ALGO_SHA1;
+				return HASH_ALGO_SHA1;
 		} else if (xattr_len == 17)
-			hash->algo = HASH_ALGO_MD5;
+			return HASH_ALGO_MD5;
 		break;
 	}
+
+	/* return default hash algo */
+	return ima_hash_algo;
 }
 
 int ima_read_xattr(struct dentry *dentry,
@@ -296,7 +299,7 @@ void ima_update_xattr(struct integrity_iint_cache *iint, struct file *file)
 	if (iint->flags & IMA_DIGSIG)
 		return;
 
-	rc = ima_collect_measurement(iint, file, NULL, NULL);
+	rc = ima_collect_measurement(iint, file, ima_hash_algo);
 	if (rc < 0)
 		return;
 

security/integrity/ima/ima_crypto.c

@@ -24,7 +24,7 @@
 #include <linux/err.h>
 #include <linux/slab.h>
 #include <crypto/hash.h>
-#include <crypto/hash_info.h>
+
 #include "ima.h"
 
 struct ahash_completion {

security/integrity/ima/ima_init.c

@@ -21,7 +21,7 @@
 #include <linux/scatterlist.h>
 #include <linux/slab.h>
 #include <linux/err.h>
-#include <crypto/hash_info.h>
+
 #include "ima.h"
 
 /* name for boot aggregate entry */

security/integrity/ima/ima_main.c

@@ -24,7 +24,6 @@
 #include <linux/slab.h>
 #include <linux/xattr.h>
 #include <linux/ima.h>
-#include <crypto/hash_info.h>
 
 #include "ima.h"
 
@@ -163,9 +162,10 @@ static int process_measurement(struct file *file, int mask, int function,
 	char *pathbuf = NULL;
 	const char *pathname = NULL;
 	int rc = -ENOMEM, action, must_appraise;
-	struct evm_ima_xattr_data *xattr_value = NULL, **xattr_ptr = NULL;
+	struct evm_ima_xattr_data *xattr_value = NULL;
 	int xattr_len = 0;
 	bool violation_check;
+	enum hash_algo hash_algo;
 
 	if (!ima_policy_flag || !S_ISREG(inode->i_mode))
 		return 0;
@@ -221,9 +221,12 @@ static int process_measurement(struct file *file, int mask, int function,
 	template_desc = ima_template_desc_current();
 	if ((action & IMA_APPRAISE_SUBMASK) ||
 		    strcmp(template_desc->name, IMA_TEMPLATE_IMA_NAME) != 0)
-		xattr_ptr = &xattr_value;
+		/* read 'security.ima' */
+		xattr_len = ima_read_xattr(file->f_path.dentry, &xattr_value);
 
-	rc = ima_collect_measurement(iint, file, xattr_ptr, &xattr_len);
+	hash_algo = ima_get_hash_algo(xattr_value, xattr_len);
+
+	rc = ima_collect_measurement(iint, file, hash_algo);
 	if (rc != 0) {
 		if (file->f_flags & O_DIRECT)
 			rc = (iint->flags & IMA_PERMIT_DIRECTIO) ? 0 : -EACCES;

security/integrity/ima/ima_template.c

@@ -15,8 +15,6 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
-#include <crypto/hash_info.h>
-
 #include "ima.h"
 #include "ima_template_lib.h"
 

security/integrity/ima/ima_template_lib.c

@@ -12,7 +12,6 @@
  * File: ima_template_lib.c
  *      Library of supported template fields.
  */
-#include <crypto/hash_info.h>
 
 #include "ima_template_lib.h"