[Patch 1/7] integrity: new hooks

From: Mimi Zohar
Date: Fri Mar 23 2007 - 12:11:11 EST

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This patch adds integrity hooks used to implement an integrity service
provider and updates the previously submitted dummy provider to
support these new hooks.

signed-off-by: Mimi Zohar <zohar@xxxxxxxxxx>
signed-off-by: Kylene Hall <kjhall@xxxxxxxxxx>
---
Index: linux-2.6.21-rc4-mm1/security/integrity_dummy.c
===================================================================
--- linux-2.6.21-rc4-mm1.orig/security/integrity_dummy.c
+++ linux-2.6.21-rc4-mm1/security/integrity_dummy.c
@@ -3,7 +3,7 @@
*
* Instantiate integrity subsystem
*
- * Copyright (C) 2005,2006 IBM Corporation
+ * Copyright (C) 2005,2006,2007 IBM Corporation
* Author: Mimi Zohar <zohar@xxxxxxxxxx>
*
* This program is free software; you can redistribute it and/or modify
@@ -28,21 +28,24 @@ static int dummy_verify_metadata(struct
int size;
int error;

- if (!xattr_value || !xattr_value_len || !status)
+ if (!status)
return -EINVAL;

- size = vfs_getxattr(dentry, xattr_name, NULL, 0);
- if (size < 0) {
- if (size == -ENODATA)
- *status = INTEGRITY_NOLABEL;
- return size;
+ /* get requested extended attribute */
+ if (xattr_name && xattr_value && xattr_value_len) {
+ size = vfs_getxattr(dentry, xattr_name, NULL, 0);
+ if (size < 0) {
+ if (size == -ENODATA)
+ *status = INTEGRITY_NOLABEL;
+ return size;
+ }
+
+ value = kzalloc(size + 1, GFP_KERNEL);
+ if (!value)
+ return -ENOMEM;
+ error = vfs_getxattr(dentry, xattr_name, value, size);
}

- value = kzalloc(size + 1, GFP_KERNEL);
- if (!value)
- return -ENOMEM;
- error = vfs_getxattr(dentry, xattr_name, value, size);
-
*xattr_value_len = size;
*xattr_value = value;
*status = INTEGRITY_PASS;
@@ -62,9 +65,78 @@ static void dummy_measure(struct dentry
return;
}

+static int dummy_inode_alloc_integrity(struct inode *inode)
+{
+ return 0;
+}
+
+static void dummy_inode_free_integrity(struct inode *inode)
+{
+ return;
+}
+
+static void dummy_inode_init_integrity(struct inode *inode, struct inode *dir,
+ char **name, void **value, size_t * len)
+{
+ return;
+}
+
+static void dummy_file_free_integrity(struct file *file)
+{
+ return;
+}
+
+static int dummy_inode_setxattr(struct dentry *dentry, char *name, void *value,
+ size_t size, int flags)
+{
+ if (!strncmp(name, XATTR_SECURITY_PREFIX,
+ sizeof(XATTR_SECURITY_PREFIX) - 1) &&
+ !capable(CAP_SYS_ADMIN))
+ return -EPERM;
+ return 0;
+}
+
+static void dummy_inode_post_setxattr(struct dentry *dentry, char *name)
+{
+}
+
+static void dummy_d_instantiate(struct dentry *dentry, struct inode *inode)
+{
+ return;
+}
+
struct integrity_operations dummy_integrity_ops = {
.verify_metadata = dummy_verify_metadata,
.verify_data = dummy_verify_data,
- .measure = dummy_measure
+ .measure = dummy_measure,
+ .inode_setxattr = dummy_inode_setxattr,
+ .inode_post_setxattr = dummy_inode_post_setxattr,
+ .inode_alloc_integrity = dummy_inode_alloc_integrity,
+ .inode_init_integrity = dummy_inode_init_integrity,
+ .inode_free_integrity = dummy_inode_free_integrity,
+ .file_free_integrity = dummy_file_free_integrity,
+ .d_instantiate = dummy_d_instantiate
};

+#define set_to_dummy_if_null(ops, function) \
+ do { \
+ if (!ops->function) { \
+ ops->function = dummy_##function; \
+ printk(KERN_INFO "Had to override the " #function \
+ " security operation with the dummy one.\n");\
+ } \
+ } while (0)
+
+void integrity_fixup_ops(struct integrity_operations *ops)
+{
+ set_to_dummy_if_null(ops, verify_metadata);
+ set_to_dummy_if_null(ops, verify_data);
+ set_to_dummy_if_null(ops, measure);
+ set_to_dummy_if_null(ops, inode_setxattr);
+ set_to_dummy_if_null(ops, inode_post_setxattr);
+ set_to_dummy_if_null(ops, inode_alloc_integrity);
+ set_to_dummy_if_null(ops, inode_init_integrity);
+ set_to_dummy_if_null(ops, inode_free_integrity);
+ set_to_dummy_if_null(ops, file_free_integrity);
+ set_to_dummy_if_null(ops, d_instantiate);
+}
Index: linux-2.6.21-rc4-mm1/security/integrity_dummy.h
===================================================================
--- linux-2.6.21-rc4-mm1.orig/security/integrity_dummy.h
+++ linux-2.6.21-rc4-mm1/security/integrity_dummy.h
@@ -1,7 +1,7 @@
/*
* integrity_dummy.h
*
- * Copyright (C) 2005,2006 IBM Corporation
+ * Copyright (C) 2005,2006,2007 IBM Corporation
* Author: Mimi Zohar <zohar@xxxxxxxxxx>
*
* This program is free software; you can redistribute it and/or modify
@@ -10,3 +10,4 @@
*/

extern struct integrity_operations dummy_integrity_ops;
+extern void integrity_fixup_ops(struct integrity_operations *ops);
Index: linux-2.6.21-rc4-mm1/include/linux/integrity.h
===================================================================
--- linux-2.6.21-rc4-mm1.orig/include/linux/integrity.h
+++ linux-2.6.21-rc4-mm1/include/linux/integrity.h
@@ -1,7 +1,7 @@
/*
* integrity.h
*
- * Copyright (C) 2005,2006 IBM Corporation
+ * Copyright (C) 2005,2006,2007 IBM Corporation
* Author: Mimi Zohar <zohar@xxxxxxxxxx>
*
* This program is free software; you can redistribute it and/or modify
@@ -45,6 +45,45 @@
* @filename either contains the full pathname/short file name.
* @mask contains the filename permission status(i.e. read, write, append).
*
+ * @inode_setxattr:
+ * Check permission before permitting an integrity extended attribute
+ * to be set.
+ * @value identified by @name for @dentry.
+ * Return 0 if permission is granted.
+ *
+ * @inode_post_setxattr:
+ * Update inode integrity xattr after successful setxattr operation.
+ * identified by @name for @dentry.
+ *
+ * @inode_alloc_integrity:
+ * Allocate and attach an integrity structure to @inode->i_integrity. The
+ * i_integrity field is initialized to NULL when the inode structure is
+ * allocated.
+ * @inode contains the inode structure.
+ * Return 0 if operation was successful.
+ *
+ * @inode_free_integrity:
+ * @inode contains the inode structure.
+ * Deallocate the inode integrity structure and set @inode->i_integrity to
+ * NULL.
+ *
+ * @inode_init_integrity:
+ * Create inode integrity xattr for a new inode based on the new security
+ * xattr information.
+ * @inode contains the inode structure of the newly created inode.
+ * @dir contains the inode structure of the parent directory.
+ * @name contains the security xattr name suffix.
+ * @value contains the security attribute value.
+ * @len contains the length of the security attribute value.
+ *
+ * @file_free_integrity:
+ * Update the integrity xattr value as necessary.
+ * *file contains the file structure being closed.
+ *
+ * @d_instantiate:
+ * Initialize the integrity structure of an inode for a dentry.
+ * @dentry to complete.
+ * @inode to attach to this dentry.
*/

#define PASS_STR "INTEGRITY_PASS"
@@ -57,13 +96,22 @@ struct integrity_operations {
int (*verify_data) (struct dentry *dentry, int *status);
void (*measure) (struct dentry *dentry,
const unsigned char *filename, int mask);
+ int (*inode_setxattr) (struct dentry *dentry, char *name, void *value,
+ size_t size, int flags);
+ void (*inode_post_setxattr) (struct dentry *dentry, char *name);
+ int (*inode_alloc_integrity) (struct inode *inode);
+ void (*inode_free_integrity) (struct inode *inode);
+ void (*inode_init_integrity) (struct inode *inode, struct inode *dir,
+ char **name, void **value, size_t *len);
+ void (*file_free_integrity) (struct file * file);
+ void (*d_instantiate) (struct dentry *dentry, struct inode *inode);
};
extern int register_integrity(struct integrity_operations *ops);
extern int unregister_integrity(struct integrity_operations *ops);

/* global variables */
extern struct integrity_operations *integrity_ops;
-enum integrity_verify_status {
+enum integrity_status {
INTEGRITY_PASS = 0, INTEGRITY_FAIL = -1, INTEGRITY_NOLABEL = -2
};

@@ -77,8 +125,7 @@ static inline int integrity_verify_metad
xattr_value, xattr_val_len, status);
}

-static inline int integrity_verify_data(struct dentry *dentry,
- int *status)
+static inline int integrity_verify_data(struct dentry *dentry, int *status)
{
return integrity_ops->verify_data(dentry, status);
}
@@ -88,6 +135,55 @@ static inline void integrity_measure(str
{
integrity_ops->measure(dentry, filename, mask);
}
+
+static inline int integrity_inode_setxattr(struct dentry *dentry, char *name,
+ void *value, size_t size, int flags)
+{
+ if (unlikely (IS_PRIVATE (dentry->d_inode)))
+ return 0;
+ return integrity_ops->inode_setxattr(dentry, name, value, size, flags);
+}
+
+static inline void integrity_inode_post_setxattr(struct dentry *dentry, char *name)
+{
+ if (unlikely (IS_PRIVATE (dentry->d_inode)))
+ return;
+ integrity_ops->inode_post_setxattr(dentry, name);
+}
+
+static inline int integrity_inode_alloc(struct inode *inode)
+{
+ return integrity_ops->inode_alloc_integrity(inode);
+}
+
+static inline void integrity_inode_free(struct inode *inode)
+{
+ integrity_ops->inode_free_integrity(inode);
+}
+
+static inline void integrity_inode_init_integrity(struct inode *inode,
+ struct inode *dir,
+ char **name,
+ void **value,
+ size_t *len)
+{
+ if (unlikely (IS_PRIVATE (inode)))
+ return;
+ integrity_ops->inode_init_integrity(inode, dir, name, value, len);
+ return;
+}
+
+static inline void integrity_file_free(struct file *file)
+{
+ integrity_ops->file_free_integrity(file);
+}
+
+static inline void integrity_d_instantiate(struct dentry *dentry, struct inode *inode)
+{
+ if (unlikely (inode && IS_PRIVATE(inode)))
+ return;
+ integrity_ops->d_instantiate(dentry, inode);
+}
#else
static inline int integrity_verify_metadata(struct dentry *dentry,
char *xattr_name, char **xattr_value,
@@ -97,8 +193,7 @@ static inline int integrity_verify_metad
return 0;
}

-static inline int integrity_verify_data(struct dentry *dentry,
- int *status)
+static inline int integrity_verify_data(struct dentry *dentry, int *status)
{
status = INTEGRITY_PASS;
return 0;
@@ -108,5 +203,47 @@ static inline void integrity_measure(str
const unsigned char *filename, int mask)
{
}
+
+static inline int integrity_inode_setxattr(struct dentry *dentry, char *name,
+ void *value, size_t size, int flags)
+{
+ return 0;
+}
+
+static inline void integrity_inode_post_setxattr(struct dentry *dentry, char *name)
+{ }
+
+static inline int integrity_inode_alloc(struct inode *inode)
+{
+ return 0;
+}
+
+static inline void integrity_inode_free(struct inode *inode)
+{ }
+
+static inline int integrity_inode_init_integrity(struct inode *inode,
+ struct inode *dir,
+ char **name,
+ void **value,
+ size_t *len)
+{
+ return -EOPNOTSUPP;
+}
+
+static inline int integrity_file_permission(struct file *file, int mask)
+{
+ return 0;
+}
+
+static inline void integrity_file_free(struct file *file)
+{
+ return;
+}
+
+static inline void integrity_d_instantiate(struct dentry *dentry, struct inode *inode)
+{
+ return;
+}
+
#endif
#endif
Index: linux-2.6.21-rc4-mm1/security/integrity.c
===================================================================
--- linux-2.6.21-rc4-mm1.orig/security/integrity.c
+++ linux-2.6.21-rc4-mm1/security/integrity.c
@@ -3,7 +3,7 @@
*
* register integrity subsystem
*
- * Copyright (C) 2005,2006 IBM Corporation
+ * Copyright (C) 2005,2006,2007 IBM Corporation
* Author: Mimi Zohar <zohar@xxxxxxxxxx>
*
* This program is free software; you can redistribute it and/or modify
@@ -27,6 +27,7 @@ int register_integrity(struct integrity_
return -EAGAIN;

integrity_ops = ops;
+ integrity_fixup_ops(integrity_ops);
return 0;
}

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