Btrfs: selinux support

Add call to LSM security initialization and save
resulting security xattr for new inodes.

Add xattr support to symlink inode ops.

Set inode->i_op for existing special files.

Signed-off-by: jim owens <jowens@hp.com>

3 files changed, 53 insertions, 4 deletions

diff --git a/fs/btrfs/inode.c b/fs/btrfs/inode.c
index 2bb65e9b1448..4a79e1c5ebd0 100644
--- a/fs/btrfs/inode.c
+++ b/fs/btrfs/inode.c
@@ -90,6 +90,16 @@ static noinline int cow_file_range(struct inode *inode,
                                    u64 start, u64 end, int *page_started,
                                    unsigned long *nr_written, int unlock);
 
+static int btrfs_init_inode_security(struct inode *inode,  struct inode *dir)
+{
+        int err;
+
+        err = btrfs_init_acl(inode, dir);
+        if (!err)
+                err = btrfs_xattr_security_init(inode, dir);
+        return err;
+}
+
 /*
  * a very lame attempt at stopping writes when the FS is 85% full.  There
  * are countless ways this is incorrect, but it is better than nothing.
@@ -2037,6 +2047,7 @@ void btrfs_read_locked_inode(struct inode *inode)
                 inode->i_mapping->backing_dev_info = &root->fs_info->bdi;
                 break;
         default:
+                inode->i_op = &btrfs_special_inode_operations;
                 init_special_inode(inode, inode->i_mode, rdev);
                 break;
         }
@@ -3584,7 +3595,7 @@ static int btrfs_mknod(struct inode *dir, struct dentry *dentry,
         if (IS_ERR(inode))
                 goto out_unlock;
 
-        err = btrfs_init_acl(inode, dir);
+        err = btrfs_init_inode_security(inode, dir);
         if (err) {
                 drop_inode = 1;
                 goto out_unlock;
@@ -3647,7 +3658,7 @@ static int btrfs_create(struct inode *dir, struct dentry *dentry,
         if (IS_ERR(inode))
                 goto out_unlock;
 
-        err = btrfs_init_acl(inode, dir);
+        err = btrfs_init_inode_security(inode, dir);
         if (err) {
                 drop_inode = 1;
                 goto out_unlock;
@@ -3770,7 +3781,7 @@ static int btrfs_mkdir(struct inode *dir, struct dentry *dentry, int mode)
 
         drop_on_err = 1;
 
-        err = btrfs_init_acl(inode, dir);
+        err = btrfs_init_inode_security(inode, dir);
         if (err)
                 goto out_fail;
 
@@ -4732,7 +4743,7 @@ static int btrfs_symlink(struct inode *dir, struct dentry *dentry,
         if (IS_ERR(inode))
                 goto out_unlock;
 
-        err = btrfs_init_acl(inode, dir);
+        err = btrfs_init_inode_security(inode, dir);
         if (err) {
                 drop_inode = 1;
                 goto out_unlock;
@@ -5043,4 +5054,8 @@ static struct inode_operations btrfs_symlink_inode_operations = {
         .follow_link    = page_follow_link_light,
         .put_link       = page_put_link,
         .permission     = btrfs_permission,
+        .setxattr       = btrfs_setxattr,
+        .getxattr       = btrfs_getxattr,
+        .listxattr      = btrfs_listxattr,
+        .removexattr    = btrfs_removexattr,
 };
diff --git a/fs/btrfs/xattr.c b/fs/btrfs/xattr.c
index b4fa5f4b6ad1..312b9435e9f8 100644
--- a/fs/btrfs/xattr.c
+++ b/fs/btrfs/xattr.c
@@ -21,6 +21,7 @@
 #include <linux/slab.h>
 #include <linux/rwsem.h>
 #include <linux/xattr.h>
+#include <linux/security.h>
 #include "ctree.h"
 #include "btrfs_inode.h"
 #include "transaction.h"
@@ -330,3 +331,34 @@ int btrfs_removexattr(struct dentry *dentry, const char *name)
                 return -EOPNOTSUPP;
         return __btrfs_setxattr(dentry->d_inode, name, NULL, 0, XATTR_REPLACE);
 }
+
+int btrfs_xattr_security_init(struct inode *inode, struct inode *dir)
+{
+        int err;
+        size_t len;
+        void *value;
+        char *suffix;
+        char *name;
+
+        err = security_inode_init_security(inode, dir, &suffix, &value, &len);
+        if (err) {
+                if (err == -EOPNOTSUPP)
+                        return 0;
+                return err;
+        }
+
+        name = kmalloc(XATTR_SECURITY_PREFIX_LEN + strlen(suffix) + 1,
+                       GFP_NOFS);
+        if (!name) {
+                err = -ENOMEM;
+        } else {
+                strcpy(name, XATTR_SECURITY_PREFIX);
+                strcpy(name + XATTR_SECURITY_PREFIX_LEN, suffix);
+                err = __btrfs_setxattr(inode, name, value, len, 0);
+                kfree(name);
+        }
+
+        kfree(suffix);
+        kfree(value);
+        return err;
+}
diff --git a/fs/btrfs/xattr.h b/fs/btrfs/xattr.h
index 5b1d08f8e68d..c71e9c3cf3f7 100644
--- a/fs/btrfs/xattr.h
+++ b/fs/btrfs/xattr.h
@@ -36,4 +36,6 @@ extern int btrfs_setxattr(struct dentry *dentry, const char *name,
                 const void *value, size_t size, int flags);
 extern int btrfs_removexattr(struct dentry *dentry, const char *name);
 
+extern int btrfs_xattr_security_init(struct inode *inode, struct inode *dir);
+
 #endif /* __XATTR__ */