[PATCH] fuse: move INIT handling to inode.c

[linux-2.6] / fs / xattr.c

diff --git a/fs/xattr.c b/fs/xattr.c
index fee804e69a9a40206fd55ca81dc3c31ace876eca..80eca7d3d69f68272a70b4a79bdc7c8f6d273ebf 100644 (file)
--- a/fs/xattr.c
+++ b/fs/xattr.c
@@ -20,6 +20,47 @@
 #include <asm/uaccess.h>
 
 
+/*
+ * Check permissions for extended attribute access.  This is a bit complicated
+ * because different namespaces have very different rules.
+ */
+static int
+xattr_permission(struct inode *inode, const char *name, int mask)
+{
+       /*
+        * We can never set or remove an extended attribute on a read-only
+        * filesystem  or on an immutable / append-only inode.
+        */
+       if (mask & MAY_WRITE) {
+               if (IS_RDONLY(inode))
+                       return -EROFS;
+               if (IS_IMMUTABLE(inode) || IS_APPEND(inode))
+                       return -EPERM;
+       }
+
+       /*
+        * No restriction for security.* and system.* from the VFS.  Decision
+        * on these is left to the underlying filesystem / security module.
+        */
+       if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN) ||
+           !strncmp(name, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN))
+               return 0;
+
+       /*
+        * The trusted.* namespace can only accessed by a privilegued user.
+        */
+       if (!strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN))
+               return (capable(CAP_SYS_ADMIN) ? 0 : -EPERM);
+
+       if (!strncmp(name, XATTR_USER_PREFIX, XATTR_USER_PREFIX_LEN)) {
+               if (!S_ISREG(inode->i_mode) &&
+                   (!S_ISDIR(inode->i_mode) || inode->i_mode & S_ISVTX))
+                       return -EPERM;
+       }
+
+       return permission(inode, mask, NULL);
+}
+
 int
 vfs_setxattr(struct dentry *dentry, char *name, void *value,
                size_t size, int flags)
@@ -27,6 +68,10 @@ vfs_setxattr(struct dentry *dentry, char *name, void *value,
        struct inode *inode = dentry->d_inode;
        int error;
 
+       error = xattr_permission(inode, name, MAY_WRITE);
+       if (error)
+               return error;
+
        mutex_lock(&inode->i_mutex);
        error = security_inode_setxattr(dentry, name, value, size, flags);
        if (error)
@@ -40,8 +85,8 @@ vfs_setxattr(struct dentry *dentry, char *name, void *value,
                                                     size, flags);
                }
        } else if (!strncmp(name, XATTR_SECURITY_PREFIX,
-                               sizeof XATTR_SECURITY_PREFIX - 1)) {
-               const char *suffix = name + sizeof XATTR_SECURITY_PREFIX - 1;
+                               XATTR_SECURITY_PREFIX_LEN)) {
+               const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
                error = security_inode_setsecurity(inode, suffix, value,
                                                   size, flags);
                if (!error)
@@ -59,6 +104,10 @@ vfs_getxattr(struct dentry *dentry, char *name, void *value, size_t size)
        struct inode *inode = dentry->d_inode;
        int error;
 
+       error = xattr_permission(inode, name, MAY_READ);
+       if (error)
+               return error;
+
        error = security_inode_getxattr(dentry, name);
        if (error)
                return error;
@@ -69,8 +118,8 @@ vfs_getxattr(struct dentry *dentry, char *name, void *value, size_t size)
                error = -EOPNOTSUPP;
 
        if (!strncmp(name, XATTR_SECURITY_PREFIX,
-                               sizeof XATTR_SECURITY_PREFIX - 1)) {
-               const char *suffix = name + sizeof XATTR_SECURITY_PREFIX - 1;
+                               XATTR_SECURITY_PREFIX_LEN)) {
+               const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
                int ret = security_inode_getsecurity(inode, suffix, value,
                                                     size, error);
                /*
@@ -94,6 +143,10 @@ vfs_removexattr(struct dentry *dentry, char *name)
        if (!inode->i_op->removexattr)
                return -EOPNOTSUPP;
 
+       error = xattr_permission(inode, name, MAY_WRITE);
+       if (error)
+               return error;
+
        error = security_inode_removexattr(dentry, name);
        if (error)
                return error;