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security: imbed evm calls in security hooks

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Imbed the evm calls evm_inode_setxattr(), evm_inode_post_setxattr(),
evm_inode_removexattr() in the security hooks.  evm_inode_setxattr()
protects security.evm xattr.  evm_inode_post_setxattr() and
evm_inode_removexattr() updates the hmac associated with an inode.

(Assumes an LSM module protects the setting/removing of xattr.)

Changelog:
  - Don't define evm_verifyxattr(), unless CONFIG_INTEGRITY is enabled.
  - xattr_name is a 'const', value is 'void *'

Signed-off-by: Mimi Zohar <zohar@us.ibm.com>
Acked-by: Serge Hallyn <serge.hallyn@ubuntu.com>
This commit is contained in:
Mimi Zohar 2011-03-09 14:38:26 -05:00
parent 6be5cc5246
commit 3e1be52d6c
3 changed files with 71 additions and 2 deletions
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56
include/linux/evm.h Normal file
View file

@ -0,0 +1,56 @@
/*
* evm.h
*
* Copyright (c) 2009 IBM Corporation
* Author: Mimi Zohar <zohar@us.ibm.com>
*/
#ifndef _LINUX_EVM_H
#define _LINUX_EVM_H
#include <linux/integrity.h>
#ifdef CONFIG_EVM
extern enum integrity_status evm_verifyxattr(struct dentry *dentry,
const char *xattr_name,
void *xattr_value,
size_t xattr_value_len);
extern int evm_inode_setxattr(struct dentry *dentry, const char *name,
const void *value, size_t size);
extern void evm_inode_post_setxattr(struct dentry *dentry,
const char *xattr_name,
const void *xattr_value,
size_t xattr_value_len);
extern int evm_inode_removexattr(struct dentry *dentry, const char *xattr_name);
#else
#ifdef CONFIG_INTEGRITY
static inline enum integrity_status evm_verifyxattr(struct dentry *dentry,
const char *xattr_name,
void *xattr_value,
size_t xattr_value_len)
{
return INTEGRITY_UNKNOWN;
}
#endif
static inline int evm_inode_setxattr(struct dentry *dentry, const char *name,
const void *value, size_t size)
{
return 0;
}
static inline void evm_inode_post_setxattr(struct dentry *dentry,
const char *xattr_name,
const void *xattr_value,
size_t xattr_value_len)
{
return;
}
static inline int evm_inode_removexattr(struct dentry *dentry,
const char *xattr_name)
{
return 0;
}
#endif /* CONFIG_EVM_H */
#endif /* LINUX_EVM_H */

1
security/integrity/evm/evm_main.c
View file

@ -18,6 +18,7 @@
#include <linux/crypto.h>
#include <linux/xattr.h>
#include <linux/integrity.h>
#include <linux/evm.h>
#include "evm.h"
int evm_initialized;

16
security/security.c
View file

@ -18,6 +18,7 @@
#include <linux/security.h>
#include <linux/integrity.h>
#include <linux/ima.h>
#include <linux/evm.h>
#define MAX_LSM_XATTR 1
@ -580,9 +581,14 @@ int security_inode_getattr(struct vfsmount *mnt, struct dentry *dentry)
int security_inode_setxattr(struct dentry *dentry, const char *name,
const void *value, size_t size, int flags)
{
int ret;
if (unlikely(IS_PRIVATE(dentry->d_inode)))
return 0;
return security_ops->inode_setxattr(dentry, name, value, size, flags);
ret = security_ops->inode_setxattr(dentry, name, value, size, flags);
if (ret)
return ret;
return evm_inode_setxattr(dentry, name, value, size);
}
void security_inode_post_setxattr(struct dentry *dentry, const char *name,
@ -591,6 +597,7 @@ void security_inode_post_setxattr(struct dentry *dentry, const char *name,
if (unlikely(IS_PRIVATE(dentry->d_inode)))
return;
security_ops->inode_post_setxattr(dentry, name, value, size, flags);
evm_inode_post_setxattr(dentry, name, value, size);
}
int security_inode_getxattr(struct dentry *dentry, const char *name)
@ -609,9 +616,14 @@ int security_inode_listxattr(struct dentry *dentry)
int security_inode_removexattr(struct dentry *dentry, const char *name)
{
int ret;
if (unlikely(IS_PRIVATE(dentry->d_inode)))
return 0;
return security_ops->inode_removexattr(dentry, name);
ret = security_ops->inode_removexattr(dentry, name);
if (ret)
return ret;
return evm_inode_removexattr(dentry, name);
}
int security_inode_need_killpriv(struct dentry *dentry)