ima: add support for different security.ima data types
Mimi Zohar [Tue, 10 Jan 2012 03:59:36 +0000 (22:59 -0500)]
IMA-appraisal currently verifies the integrity of a file based on a
known 'good' measurement value.  This patch reserves the first byte
of 'security.ima' as a place holder for the type of method used for
verifying file data integrity.

Changelog v1:
- Use the newly defined 'struct evm_ima_xattr_data'

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

security/integrity/ima/ima_api.c
security/integrity/ima/ima_appraise.c
security/integrity/integrity.h

index 41cce84..33d4685 100644 (file)
@@ -147,8 +147,8 @@ int ima_collect_measurement(struct integrity_iint_cache *iint,
        if (!(iint->flags & IMA_COLLECTED)) {
                u64 i_version = file->f_dentry->d_inode->i_version;
 
-               memset(iint->digest, 0, IMA_DIGEST_SIZE);
-               result = ima_calc_hash(file, iint->digest);
+               iint->ima_xattr.type = IMA_XATTR_DIGEST;
+               result = ima_calc_hash(file, iint->ima_xattr.digest);
                if (!result) {
                        iint->version = i_version;
                        iint->flags |= IMA_COLLECTED;
@@ -196,7 +196,7 @@ void ima_store_measurement(struct integrity_iint_cache *iint,
                return;
        }
        memset(&entry->template, 0, sizeof(entry->template));
-       memcpy(entry->template.digest, iint->digest, IMA_DIGEST_SIZE);
+       memcpy(entry->template.digest, iint->ima_xattr.digest, IMA_DIGEST_SIZE);
        strcpy(entry->template.file_name,
               (strlen(filename) > IMA_EVENT_NAME_LEN_MAX) ?
               file->f_dentry->d_name.name : filename);
index becc7e0..f997997 100644 (file)
@@ -45,9 +45,9 @@ int ima_must_appraise(struct inode *inode, enum ima_hooks func, int mask)
 static void ima_fix_xattr(struct dentry *dentry,
                          struct integrity_iint_cache *iint)
 {
-       iint->digest[0] = IMA_XATTR_DIGEST;
-       __vfs_setxattr_noperm(dentry, XATTR_NAME_IMA,
-                             iint->digest, IMA_DIGEST_SIZE + 1, 0);
+       iint->ima_xattr.type = IMA_XATTR_DIGEST;
+       __vfs_setxattr_noperm(dentry, XATTR_NAME_IMA, (u8 *)&iint->ima_xattr,
+                             sizeof iint->ima_xattr, 0);
 }
 
 /*
@@ -63,7 +63,7 @@ int ima_appraise_measurement(struct integrity_iint_cache *iint,
 {
        struct dentry *dentry = file->f_dentry;
        struct inode *inode = dentry->d_inode;
-       u8 xattr_value[IMA_DIGEST_SIZE];
+       struct evm_ima_xattr_data xattr_value;
        enum integrity_status status = INTEGRITY_UNKNOWN;
        const char *op = "appraise_data";
        char *cause = "unknown";
@@ -77,8 +77,8 @@ int ima_appraise_measurement(struct integrity_iint_cache *iint,
        if (iint->flags & IMA_APPRAISED)
                return iint->ima_status;
 
-       rc = inode->i_op->getxattr(dentry, XATTR_NAME_IMA, xattr_value,
-                                  IMA_DIGEST_SIZE);
+       rc = inode->i_op->getxattr(dentry, XATTR_NAME_IMA, (u8 *)&xattr_value,
+                                  sizeof xattr_value);
        if (rc <= 0) {
                if (rc && rc != -ENODATA)
                        goto out;
@@ -89,7 +89,8 @@ int ima_appraise_measurement(struct integrity_iint_cache *iint,
                goto out;
        }
 
-       status = evm_verifyxattr(dentry, XATTR_NAME_IMA, xattr_value, rc, iint);
+       status = evm_verifyxattr(dentry, XATTR_NAME_IMA, (u8 *)&xattr_value,
+                                rc, iint);
        if ((status != INTEGRITY_PASS) && (status != INTEGRITY_UNKNOWN)) {
                if ((status == INTEGRITY_NOLABEL)
                    || (status == INTEGRITY_NOXATTRS))
@@ -99,14 +100,16 @@ int ima_appraise_measurement(struct integrity_iint_cache *iint,
                goto out;
        }
 
-       rc = memcmp(xattr_value, iint->digest, IMA_DIGEST_SIZE);
+       rc = memcmp(xattr_value.digest, iint->ima_xattr.digest,
+                   IMA_DIGEST_SIZE);
        if (rc) {
                status = INTEGRITY_FAIL;
                cause = "invalid-hash";
                print_hex_dump_bytes("security.ima: ", DUMP_PREFIX_NONE,
-                                    xattr_value, IMA_DIGEST_SIZE);
+                                    &xattr_value, sizeof xattr_value);
                print_hex_dump_bytes("collected: ", DUMP_PREFIX_NONE,
-                                    iint->digest, IMA_DIGEST_SIZE);
+                                    (u8 *)&iint->ima_xattr,
+                                    sizeof iint->ima_xattr);
                goto out;
        }
        status = INTEGRITY_PASS;
index dac6b68..91ccef1 100644 (file)
@@ -39,7 +39,7 @@ struct integrity_iint_cache {
        struct inode *inode;    /* back pointer to inode in question */
        u64 version;            /* track inode changes */
        unsigned char flags;
-       u8 digest[SHA1_DIGEST_SIZE];
+       struct evm_ima_xattr_data ima_xattr;
        enum integrity_status ima_status;
        enum integrity_status evm_status;
 };