#include <linux/security.h>
#include <linux/syscalls.h>
#include <linux/module.h>
+#include <linux/fsnotify.h>
+#include <linux/audit.h>
+#include <linux/mount.h>
#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)
+{
+ 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)
+ goto out;
+ error = -EOPNOTSUPP;
+ if (inode->i_op->setxattr) {
+ error = inode->i_op->setxattr(dentry, name, value, size, flags);
+ if (!error) {
+ fsnotify_xattr(dentry);
+ security_inode_post_setxattr(dentry, name, value,
+ size, flags);
+ }
+ } else if (!strncmp(name, XATTR_SECURITY_PREFIX,
+ XATTR_SECURITY_PREFIX_LEN)) {
+ const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
+ error = security_inode_setsecurity(inode, suffix, value,
+ size, flags);
+ if (!error)
+ fsnotify_xattr(dentry);
+ }
+out:
+ mutex_unlock(&inode->i_mutex);
+ return error;
+}
+EXPORT_SYMBOL_GPL(vfs_setxattr);
+
+ssize_t
+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;
+
+ if (inode->i_op->getxattr)
+ error = inode->i_op->getxattr(dentry, name, value, size);
+ else
+ error = -EOPNOTSUPP;
+
+ if (!strncmp(name, XATTR_SECURITY_PREFIX,
+ XATTR_SECURITY_PREFIX_LEN)) {
+ const char *suffix = name + XATTR_SECURITY_PREFIX_LEN;
+ int ret = security_inode_getsecurity(inode, suffix, value,
+ size, error);
+ /*
+ * Only overwrite the return value if a security module
+ * is actually active.
+ */
+ if (ret != -EOPNOTSUPP)
+ error = ret;
+ }
+
+ return error;
+}
+EXPORT_SYMBOL_GPL(vfs_getxattr);
+
+int
+vfs_removexattr(struct dentry *dentry, char *name)
+{
+ struct inode *inode = dentry->d_inode;
+ int error;
+
+ 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;
+
+ mutex_lock(&inode->i_mutex);
+ error = inode->i_op->removexattr(dentry, name);
+ mutex_unlock(&inode->i_mutex);
+
+ if (!error)
+ fsnotify_xattr(dentry);
+ return error;
+}
+EXPORT_SYMBOL_GPL(vfs_removexattr);
+
+
/*
* Extended attribute SET operations
*/
static long
setxattr(struct dentry *d, char __user *name, void __user *value,
- size_t size, int flags)
+ size_t size, int flags, struct vfsmount *mnt)
{
int error;
void *kvalue = NULL;
}
}
- 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);
+ if (MNT_IS_RDONLY(mnt))
+ return -EROFS;
+
+ error = vfs_setxattr(d, kname, kvalue, size, flags);
+ kfree(kvalue);
return error;
}
error = user_path_walk(path, &nd);
if (error)
return error;
- error = setxattr(nd.dentry, name, value, size, flags);
+ error = setxattr(nd.dentry, name, value, size, flags, nd.mnt);
path_release(&nd);
return error;
}
error = user_path_walk_link(path, &nd);
if (error)
return error;
- error = setxattr(nd.dentry, name, value, size, flags);
+ error = setxattr(nd.dentry, name, value, size, flags, nd.mnt);
path_release(&nd);
return error;
}
size_t size, int flags)
{
struct file *f;
+ struct dentry *dentry;
int error = -EBADF;
f = fget(fd);
if (!f)
return error;
- error = setxattr(f->f_dentry, name, value, size, flags);
+ dentry = f->f_dentry;
+ audit_inode(NULL, dentry->d_inode, 0);
+ error = setxattr(dentry, name, value, size, flags, f->f_vfsmnt);
fput(f);
return error;
}
if (size) {
if (size > XATTR_SIZE_MAX)
size = XATTR_SIZE_MAX;
- kvalue = kmalloc(size, GFP_KERNEL);
+ kvalue = kzalloc(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;
- }
+ error = vfs_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);
+ kfree(kvalue);
return error;
}
return -ENOMEM;
}
+ error = security_inode_listxattr(d);
+ if (error)
+ goto out;
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;
- }
+ } else {
+ error = security_inode_listsecurity(d->d_inode, klist, size);
+ if (size && error > size)
+ error = -ERANGE;
+ }
+ 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);
+ kfree(klist);
return error;
}
* Extended attribute REMOVE operations
*/
static long
-removexattr(struct dentry *d, char __user *name)
+removexattr(struct dentry *d, char __user *name, struct vfsmount *mnt)
{
int error;
char kname[XATTR_NAME_MAX + 1];
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;
+ if (MNT_IS_RDONLY(mnt))
+ return -EROFS;
+
+ return vfs_removexattr(d, kname);
}
asmlinkage long
error = user_path_walk(path, &nd);
if (error)
return error;
- error = removexattr(nd.dentry, name);
+ error = removexattr(nd.dentry, name, nd.mnt);
path_release(&nd);
return error;
}
error = user_path_walk_link(path, &nd);
if (error)
return error;
- error = removexattr(nd.dentry, name);
+ error = removexattr(nd.dentry, name, nd.mnt);
path_release(&nd);
return error;
}
sys_fremovexattr(int fd, char __user *name)
{
struct file *f;
+ struct dentry *dentry;
int error = -EBADF;
f = fget(fd);
if (!f)
return error;
- error = removexattr(f->f_dentry, name);
+ dentry = f->f_dentry;
+ audit_inode(NULL, dentry->d_inode, 0);
+ error = removexattr(dentry, name, f->f_vfsmnt);
fput(f);
return error;
}
git://git.onelab.eu / linux-2.6.git / blobdiff