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-rw-r--r--fs/xattr.c480
1 files changed, 480 insertions, 0 deletions
diff --git a/fs/xattr.c b/fs/xattr.c
new file mode 100644
index 00000000000..93dee70a1db
--- /dev/null
+++ b/fs/xattr.c
@@ -0,0 +1,480 @@
+/*
+ File: fs/xattr.c
+
+ Extended attribute handling.
+
+ Copyright (C) 2001 by Andreas Gruenbacher <a.gruenbacher@computer.org>
+ Copyright (C) 2001 SGI - Silicon Graphics, Inc <linux-xfs@oss.sgi.com>
+ Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com>
+ */
+#include <linux/fs.h>
+#include <linux/slab.h>
+#include <linux/smp_lock.h>
+#include <linux/file.h>
+#include <linux/xattr.h>
+#include <linux/namei.h>
+#include <linux/security.h>
+#include <linux/syscalls.h>
+#include <linux/module.h>
+#include <asm/uaccess.h>
+
+/*
+ * Extended attribute SET operations
+ */
+static long
+setxattr(struct dentry *d, char __user *name, void __user *value,
+ size_t size, int flags)
+{
+ int error;
+ void *kvalue = NULL;
+ char kname[XATTR_NAME_MAX + 1];
+
+ if (flags & ~(XATTR_CREATE|XATTR_REPLACE))
+ return -EINVAL;
+
+ error = strncpy_from_user(kname, name, sizeof(kname));
+ if (error == 0 || error == sizeof(kname))
+ error = -ERANGE;
+ if (error < 0)
+ return error;
+
+ if (size) {
+ if (size > XATTR_SIZE_MAX)
+ return -E2BIG;
+ kvalue = kmalloc(size, GFP_KERNEL);
+ if (!kvalue)
+ return -ENOMEM;
+ if (copy_from_user(kvalue, value, size)) {
+ kfree(kvalue);
+ return -EFAULT;
+ }
+ }
+
+ error = -EOPNOTSUPP;
+ if (d->d_inode->i_op && d->d_inode->i_op->setxattr) {
+ down(&d->d_inode->i_sem);
+ error = security_inode_setxattr(d, kname, kvalue, size, flags);
+ if (error)
+ goto out;
+ error = d->d_inode->i_op->setxattr(d, kname, kvalue, size, flags);
+ if (!error)
+ security_inode_post_setxattr(d, kname, kvalue, size, flags);
+out:
+ up(&d->d_inode->i_sem);
+ }
+ if (kvalue)
+ kfree(kvalue);
+ return error;
+}
+
+asmlinkage long
+sys_setxattr(char __user *path, char __user *name, void __user *value,
+ size_t size, int flags)
+{
+ struct nameidata nd;
+ int error;
+
+ error = user_path_walk(path, &nd);
+ if (error)
+ return error;
+ error = setxattr(nd.dentry, name, value, size, flags);
+ path_release(&nd);
+ return error;
+}
+
+asmlinkage long
+sys_lsetxattr(char __user *path, char __user *name, void __user *value,
+ size_t size, int flags)
+{
+ struct nameidata nd;
+ int error;
+
+ error = user_path_walk_link(path, &nd);
+ if (error)
+ return error;
+ error = setxattr(nd.dentry, name, value, size, flags);
+ path_release(&nd);
+ return error;
+}
+
+asmlinkage long
+sys_fsetxattr(int fd, char __user *name, void __user *value,
+ size_t size, int flags)
+{
+ struct file *f;
+ int error = -EBADF;
+
+ f = fget(fd);
+ if (!f)
+ return error;
+ error = setxattr(f->f_dentry, name, value, size, flags);
+ fput(f);
+ return error;
+}
+
+/*
+ * Extended attribute GET operations
+ */
+static ssize_t
+getxattr(struct dentry *d, char __user *name, void __user *value, size_t size)
+{
+ ssize_t error;
+ void *kvalue = NULL;
+ char kname[XATTR_NAME_MAX + 1];
+
+ error = strncpy_from_user(kname, name, sizeof(kname));
+ if (error == 0 || error == sizeof(kname))
+ error = -ERANGE;
+ if (error < 0)
+ return error;
+
+ if (size) {
+ if (size > XATTR_SIZE_MAX)
+ size = XATTR_SIZE_MAX;
+ kvalue = kmalloc(size, GFP_KERNEL);
+ if (!kvalue)
+ return -ENOMEM;
+ }
+
+ error = -EOPNOTSUPP;
+ if (d->d_inode->i_op && d->d_inode->i_op->getxattr) {
+ error = security_inode_getxattr(d, kname);
+ if (error)
+ goto out;
+ error = d->d_inode->i_op->getxattr(d, kname, kvalue, size);
+ if (error > 0) {
+ if (size && copy_to_user(value, kvalue, error))
+ error = -EFAULT;
+ } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) {
+ /* The file system tried to returned a value bigger
+ than XATTR_SIZE_MAX bytes. Not possible. */
+ error = -E2BIG;
+ }
+ }
+out:
+ if (kvalue)
+ kfree(kvalue);
+ return error;
+}
+
+asmlinkage ssize_t
+sys_getxattr(char __user *path, char __user *name, void __user *value,
+ size_t size)
+{
+ struct nameidata nd;
+ ssize_t error;
+
+ error = user_path_walk(path, &nd);
+ if (error)
+ return error;
+ error = getxattr(nd.dentry, name, value, size);
+ path_release(&nd);
+ return error;
+}
+
+asmlinkage ssize_t
+sys_lgetxattr(char __user *path, char __user *name, void __user *value,
+ size_t size)
+{
+ struct nameidata nd;
+ ssize_t error;
+
+ error = user_path_walk_link(path, &nd);
+ if (error)
+ return error;
+ error = getxattr(nd.dentry, name, value, size);
+ path_release(&nd);
+ return error;
+}
+
+asmlinkage ssize_t
+sys_fgetxattr(int fd, char __user *name, void __user *value, size_t size)
+{
+ struct file *f;
+ ssize_t error = -EBADF;
+
+ f = fget(fd);
+ if (!f)
+ return error;
+ error = getxattr(f->f_dentry, name, value, size);
+ fput(f);
+ return error;
+}
+
+/*
+ * Extended attribute LIST operations
+ */
+static ssize_t
+listxattr(struct dentry *d, char __user *list, size_t size)
+{
+ ssize_t error;
+ char *klist = NULL;
+
+ if (size) {
+ if (size > XATTR_LIST_MAX)
+ size = XATTR_LIST_MAX;
+ klist = kmalloc(size, GFP_KERNEL);
+ if (!klist)
+ return -ENOMEM;
+ }
+
+ error = -EOPNOTSUPP;
+ if (d->d_inode->i_op && d->d_inode->i_op->listxattr) {
+ error = security_inode_listxattr(d);
+ if (error)
+ goto out;
+ error = d->d_inode->i_op->listxattr(d, klist, size);
+ if (error > 0) {
+ if (size && copy_to_user(list, klist, error))
+ error = -EFAULT;
+ } else if (error == -ERANGE && size >= XATTR_LIST_MAX) {
+ /* The file system tried to returned a list bigger
+ than XATTR_LIST_MAX bytes. Not possible. */
+ error = -E2BIG;
+ }
+ }
+out:
+ if (klist)
+ kfree(klist);
+ return error;
+}
+
+asmlinkage ssize_t
+sys_listxattr(char __user *path, char __user *list, size_t size)
+{
+ struct nameidata nd;
+ ssize_t error;
+
+ error = user_path_walk(path, &nd);
+ if (error)
+ return error;
+ error = listxattr(nd.dentry, list, size);
+ path_release(&nd);
+ return error;
+}
+
+asmlinkage ssize_t
+sys_llistxattr(char __user *path, char __user *list, size_t size)
+{
+ struct nameidata nd;
+ ssize_t error;
+
+ error = user_path_walk_link(path, &nd);
+ if (error)
+ return error;
+ error = listxattr(nd.dentry, list, size);
+ path_release(&nd);
+ return error;
+}
+
+asmlinkage ssize_t
+sys_flistxattr(int fd, char __user *list, size_t size)
+{
+ struct file *f;
+ ssize_t error = -EBADF;
+
+ f = fget(fd);
+ if (!f)
+ return error;
+ error = listxattr(f->f_dentry, list, size);
+ fput(f);
+ return error;
+}
+
+/*
+ * Extended attribute REMOVE operations
+ */
+static long
+removexattr(struct dentry *d, char __user *name)
+{
+ int error;
+ char kname[XATTR_NAME_MAX + 1];
+
+ error = strncpy_from_user(kname, name, sizeof(kname));
+ if (error == 0 || error == sizeof(kname))
+ error = -ERANGE;
+ if (error < 0)
+ return error;
+
+ error = -EOPNOTSUPP;
+ if (d->d_inode->i_op && d->d_inode->i_op->removexattr) {
+ error = security_inode_removexattr(d, kname);
+ if (error)
+ goto out;
+ down(&d->d_inode->i_sem);
+ error = d->d_inode->i_op->removexattr(d, kname);
+ up(&d->d_inode->i_sem);
+ }
+out:
+ return error;
+}
+
+asmlinkage long
+sys_removexattr(char __user *path, char __user *name)
+{
+ struct nameidata nd;
+ int error;
+
+ error = user_path_walk(path, &nd);
+ if (error)
+ return error;
+ error = removexattr(nd.dentry, name);
+ path_release(&nd);
+ return error;
+}
+
+asmlinkage long
+sys_lremovexattr(char __user *path, char __user *name)
+{
+ struct nameidata nd;
+ int error;
+
+ error = user_path_walk_link(path, &nd);
+ if (error)
+ return error;
+ error = removexattr(nd.dentry, name);
+ path_release(&nd);
+ return error;
+}
+
+asmlinkage long
+sys_fremovexattr(int fd, char __user *name)
+{
+ struct file *f;
+ int error = -EBADF;
+
+ f = fget(fd);
+ if (!f)
+ return error;
+ error = removexattr(f->f_dentry, name);
+ fput(f);
+ return error;
+}
+
+
+static const char *
+strcmp_prefix(const char *a, const char *a_prefix)
+{
+ while (*a_prefix && *a == *a_prefix) {
+ a++;
+ a_prefix++;
+ }
+ return *a_prefix ? NULL : a;
+}
+
+/*
+ * In order to implement different sets of xattr operations for each xattr
+ * prefix with the generic xattr API, a filesystem should create a
+ * null-terminated array of struct xattr_handler (one for each prefix) and
+ * hang a pointer to it off of the s_xattr field of the superblock.
+ *
+ * The generic_fooxattr() functions will use this list to dispatch xattr
+ * operations to the correct xattr_handler.
+ */
+#define for_each_xattr_handler(handlers, handler) \
+ for ((handler) = *(handlers)++; \
+ (handler) != NULL; \
+ (handler) = *(handlers)++)
+
+/*
+ * Find the xattr_handler with the matching prefix.
+ */
+static struct xattr_handler *
+xattr_resolve_name(struct xattr_handler **handlers, const char **name)
+{
+ struct xattr_handler *handler;
+
+ if (!*name)
+ return NULL;
+
+ for_each_xattr_handler(handlers, handler) {
+ const char *n = strcmp_prefix(*name, handler->prefix);
+ if (n) {
+ *name = n;
+ break;
+ }
+ }
+ return handler;
+}
+
+/*
+ * Find the handler for the prefix and dispatch its get() operation.
+ */
+ssize_t
+generic_getxattr(struct dentry *dentry, const char *name, void *buffer, size_t size)
+{
+ struct xattr_handler *handler;
+ struct inode *inode = dentry->d_inode;
+
+ handler = xattr_resolve_name(inode->i_sb->s_xattr, &name);
+ if (!handler)
+ return -EOPNOTSUPP;
+ return handler->get(inode, name, buffer, size);
+}
+
+/*
+ * Combine the results of the list() operation from every xattr_handler in the
+ * list.
+ */
+ssize_t
+generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size)
+{
+ struct inode *inode = dentry->d_inode;
+ struct xattr_handler *handler, **handlers = inode->i_sb->s_xattr;
+ unsigned int size = 0;
+
+ if (!buffer) {
+ for_each_xattr_handler(handlers, handler)
+ size += handler->list(inode, NULL, 0, NULL, 0);
+ } else {
+ char *buf = buffer;
+
+ for_each_xattr_handler(handlers, handler) {
+ size = handler->list(inode, buf, buffer_size, NULL, 0);
+ if (size > buffer_size)
+ return -ERANGE;
+ buf += size;
+ buffer_size -= size;
+ }
+ size = buf - buffer;
+ }
+ return size;
+}
+
+/*
+ * Find the handler for the prefix and dispatch its set() operation.
+ */
+int
+generic_setxattr(struct dentry *dentry, const char *name, const void *value, size_t size, int flags)
+{
+ struct xattr_handler *handler;
+ struct inode *inode = dentry->d_inode;
+
+ if (size == 0)
+ value = ""; /* empty EA, do not remove */
+ handler = xattr_resolve_name(inode->i_sb->s_xattr, &name);
+ if (!handler)
+ return -EOPNOTSUPP;
+ return handler->set(inode, name, value, size, flags);
+}
+
+/*
+ * Find the handler for the prefix and dispatch its set() operation to remove
+ * any associated extended attribute.
+ */
+int
+generic_removexattr(struct dentry *dentry, const char *name)
+{
+ struct xattr_handler *handler;
+ struct inode *inode = dentry->d_inode;
+
+ handler = xattr_resolve_name(inode->i_sb->s_xattr, &name);
+ if (!handler)
+ return -EOPNOTSUPP;
+ return handler->set(inode, name, NULL, 0, XATTR_REPLACE);
+}
+
+EXPORT_SYMBOL(generic_getxattr);
+EXPORT_SYMBOL(generic_listxattr);
+EXPORT_SYMBOL(generic_setxattr);
+EXPORT_SYMBOL(generic_removexattr);