security: imbed evm calls in security hooks

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>

2 files changed, 15 insertions, 2 deletions

diff --git a/security/integrity/evm/evm_main.c b/security/integrity/evm/evm_main.c
index c0580dd15ec0..1746c3669c6f 100644
--- a/security/integrity/evm/evm_main.c
+++ b/security/integrity/evm/evm_main.c
@@ -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;
diff --git a/security/security.c b/security/security.c
index 947fdcfbc83e..21a79b3d1e8e 100644
--- a/security/security.c
+++ b/security/security.c
@@ -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)