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![Christian Brauner](/assets/img/avatar_default.png)
In previous patches we added new and modified existing helpers to handle idmapped mounts of filesystems mounted with an idmapping. In this final patch we convert all relevant places in the vfs to actually pass the filesystem's idmapping into these helpers. With this the vfs is in shape to handle idmapped mounts of filesystems mounted with an idmapping. Note that this is just the generic infrastructure. Actually adding support for idmapped mounts to a filesystem mountable with an idmapping is follow-up work. In this patch we extend the definition of an idmapped mount from a mount that that has the initial idmapping attached to it to a mount that has an idmapping attached to it which is not the same as the idmapping the filesystem was mounted with. As before we do not allow the initial idmapping to be attached to a mount. In addition this patch prevents that the idmapping the filesystem was mounted with can be attached to a mount created based on this filesystem. This has multiple reasons and advantages. First, attaching the initial idmapping or the filesystem's idmapping doesn't make much sense as in both cases the values of the i_{g,u}id and other places where k{g,u}ids are used do not change. Second, a user that really wants to do this for whatever reason can just create a separate dedicated identical idmapping to attach to the mount. Third, we can continue to use the initial idmapping as an indicator that a mount is not idmapped allowing us to continue to keep passing the initial idmapping into the mapping helpers to tell them that something isn't an idmapped mount even if the filesystem is mounted with an idmapping. Link: https://lore.kernel.org/r/20211123114227.3124056-11-brauner@kernel.org (v1) Link: https://lore.kernel.org/r/20211130121032.3753852-11-brauner@kernel.org (v2) Link: https://lore.kernel.org/r/20211203111707.3901969-11-brauner@kernel.org Cc: Seth Forshee <sforshee@digitalocean.com> Cc: Amir Goldstein <amir73il@gmail.com> Cc: Christoph Hellwig <hch@lst.de> Cc: Al Viro <viro@zeniv.linux.org.uk> CC: linux-fsdevel@vger.kernel.org Reviewed-by: Seth Forshee <sforshee@digitalocean.com> Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>
1431 lines
35 KiB
C
1431 lines
35 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* linux/fs/open.c
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*
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* Copyright (C) 1991, 1992 Linus Torvalds
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*/
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#include <linux/string.h>
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#include <linux/mm.h>
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#include <linux/file.h>
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#include <linux/fdtable.h>
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#include <linux/fsnotify.h>
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#include <linux/module.h>
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#include <linux/tty.h>
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#include <linux/namei.h>
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#include <linux/backing-dev.h>
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#include <linux/capability.h>
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#include <linux/securebits.h>
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#include <linux/security.h>
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#include <linux/mount.h>
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#include <linux/fcntl.h>
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#include <linux/slab.h>
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#include <linux/uaccess.h>
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#include <linux/fs.h>
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#include <linux/personality.h>
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#include <linux/pagemap.h>
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#include <linux/syscalls.h>
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#include <linux/rcupdate.h>
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#include <linux/audit.h>
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#include <linux/falloc.h>
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#include <linux/fs_struct.h>
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#include <linux/ima.h>
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#include <linux/dnotify.h>
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#include <linux/compat.h>
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#include <linux/mnt_idmapping.h>
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#include "internal.h"
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int do_truncate(struct user_namespace *mnt_userns, struct dentry *dentry,
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loff_t length, unsigned int time_attrs, struct file *filp)
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{
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int ret;
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struct iattr newattrs;
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/* Not pretty: "inode->i_size" shouldn't really be signed. But it is. */
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if (length < 0)
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return -EINVAL;
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newattrs.ia_size = length;
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newattrs.ia_valid = ATTR_SIZE | time_attrs;
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if (filp) {
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newattrs.ia_file = filp;
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newattrs.ia_valid |= ATTR_FILE;
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}
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/* Remove suid, sgid, and file capabilities on truncate too */
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ret = dentry_needs_remove_privs(dentry);
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if (ret < 0)
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return ret;
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if (ret)
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newattrs.ia_valid |= ret | ATTR_FORCE;
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inode_lock(dentry->d_inode);
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/* Note any delegations or leases have already been broken: */
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ret = notify_change(mnt_userns, dentry, &newattrs, NULL);
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inode_unlock(dentry->d_inode);
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return ret;
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}
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long vfs_truncate(const struct path *path, loff_t length)
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{
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struct user_namespace *mnt_userns;
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struct inode *inode;
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long error;
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inode = path->dentry->d_inode;
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/* For directories it's -EISDIR, for other non-regulars - -EINVAL */
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if (S_ISDIR(inode->i_mode))
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return -EISDIR;
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if (!S_ISREG(inode->i_mode))
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return -EINVAL;
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error = mnt_want_write(path->mnt);
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if (error)
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goto out;
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mnt_userns = mnt_user_ns(path->mnt);
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error = inode_permission(mnt_userns, inode, MAY_WRITE);
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if (error)
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goto mnt_drop_write_and_out;
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error = -EPERM;
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if (IS_APPEND(inode))
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goto mnt_drop_write_and_out;
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error = get_write_access(inode);
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if (error)
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goto mnt_drop_write_and_out;
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/*
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* Make sure that there are no leases. get_write_access() protects
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* against the truncate racing with a lease-granting setlease().
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*/
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error = break_lease(inode, O_WRONLY);
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if (error)
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goto put_write_and_out;
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error = security_path_truncate(path);
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if (!error)
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error = do_truncate(mnt_userns, path->dentry, length, 0, NULL);
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put_write_and_out:
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put_write_access(inode);
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mnt_drop_write_and_out:
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mnt_drop_write(path->mnt);
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out:
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return error;
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}
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EXPORT_SYMBOL_GPL(vfs_truncate);
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long do_sys_truncate(const char __user *pathname, loff_t length)
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{
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unsigned int lookup_flags = LOOKUP_FOLLOW;
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struct path path;
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int error;
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if (length < 0) /* sorry, but loff_t says... */
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return -EINVAL;
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retry:
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error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path);
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if (!error) {
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error = vfs_truncate(&path, length);
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path_put(&path);
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}
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if (retry_estale(error, lookup_flags)) {
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lookup_flags |= LOOKUP_REVAL;
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goto retry;
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}
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return error;
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}
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SYSCALL_DEFINE2(truncate, const char __user *, path, long, length)
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{
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return do_sys_truncate(path, length);
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}
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#ifdef CONFIG_COMPAT
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COMPAT_SYSCALL_DEFINE2(truncate, const char __user *, path, compat_off_t, length)
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{
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return do_sys_truncate(path, length);
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}
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#endif
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long do_sys_ftruncate(unsigned int fd, loff_t length, int small)
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{
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struct inode *inode;
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struct dentry *dentry;
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struct fd f;
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int error;
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error = -EINVAL;
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if (length < 0)
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goto out;
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error = -EBADF;
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f = fdget(fd);
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if (!f.file)
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goto out;
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/* explicitly opened as large or we are on 64-bit box */
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if (f.file->f_flags & O_LARGEFILE)
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small = 0;
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dentry = f.file->f_path.dentry;
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inode = dentry->d_inode;
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error = -EINVAL;
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if (!S_ISREG(inode->i_mode) || !(f.file->f_mode & FMODE_WRITE))
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goto out_putf;
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error = -EINVAL;
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/* Cannot ftruncate over 2^31 bytes without large file support */
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if (small && length > MAX_NON_LFS)
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goto out_putf;
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error = -EPERM;
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/* Check IS_APPEND on real upper inode */
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if (IS_APPEND(file_inode(f.file)))
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goto out_putf;
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sb_start_write(inode->i_sb);
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error = security_path_truncate(&f.file->f_path);
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if (!error)
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error = do_truncate(file_mnt_user_ns(f.file), dentry, length,
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ATTR_MTIME | ATTR_CTIME, f.file);
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sb_end_write(inode->i_sb);
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out_putf:
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fdput(f);
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out:
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return error;
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}
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SYSCALL_DEFINE2(ftruncate, unsigned int, fd, unsigned long, length)
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{
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return do_sys_ftruncate(fd, length, 1);
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}
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#ifdef CONFIG_COMPAT
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COMPAT_SYSCALL_DEFINE2(ftruncate, unsigned int, fd, compat_ulong_t, length)
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{
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return do_sys_ftruncate(fd, length, 1);
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}
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#endif
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/* LFS versions of truncate are only needed on 32 bit machines */
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#if BITS_PER_LONG == 32
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SYSCALL_DEFINE2(truncate64, const char __user *, path, loff_t, length)
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{
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return do_sys_truncate(path, length);
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}
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SYSCALL_DEFINE2(ftruncate64, unsigned int, fd, loff_t, length)
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{
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return do_sys_ftruncate(fd, length, 0);
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}
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#endif /* BITS_PER_LONG == 32 */
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int vfs_fallocate(struct file *file, int mode, loff_t offset, loff_t len)
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{
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struct inode *inode = file_inode(file);
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long ret;
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if (offset < 0 || len <= 0)
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return -EINVAL;
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/* Return error if mode is not supported */
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if (mode & ~FALLOC_FL_SUPPORTED_MASK)
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return -EOPNOTSUPP;
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/* Punch hole and zero range are mutually exclusive */
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if ((mode & (FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE)) ==
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(FALLOC_FL_PUNCH_HOLE | FALLOC_FL_ZERO_RANGE))
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return -EOPNOTSUPP;
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/* Punch hole must have keep size set */
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if ((mode & FALLOC_FL_PUNCH_HOLE) &&
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!(mode & FALLOC_FL_KEEP_SIZE))
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return -EOPNOTSUPP;
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/* Collapse range should only be used exclusively. */
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if ((mode & FALLOC_FL_COLLAPSE_RANGE) &&
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(mode & ~FALLOC_FL_COLLAPSE_RANGE))
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return -EINVAL;
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/* Insert range should only be used exclusively. */
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if ((mode & FALLOC_FL_INSERT_RANGE) &&
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(mode & ~FALLOC_FL_INSERT_RANGE))
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return -EINVAL;
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/* Unshare range should only be used with allocate mode. */
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if ((mode & FALLOC_FL_UNSHARE_RANGE) &&
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(mode & ~(FALLOC_FL_UNSHARE_RANGE | FALLOC_FL_KEEP_SIZE)))
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return -EINVAL;
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if (!(file->f_mode & FMODE_WRITE))
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return -EBADF;
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/*
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* We can only allow pure fallocate on append only files
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*/
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if ((mode & ~FALLOC_FL_KEEP_SIZE) && IS_APPEND(inode))
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return -EPERM;
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if (IS_IMMUTABLE(inode))
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return -EPERM;
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/*
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* We cannot allow any fallocate operation on an active swapfile
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*/
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if (IS_SWAPFILE(inode))
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return -ETXTBSY;
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/*
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* Revalidate the write permissions, in case security policy has
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* changed since the files were opened.
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*/
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ret = security_file_permission(file, MAY_WRITE);
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if (ret)
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return ret;
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if (S_ISFIFO(inode->i_mode))
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return -ESPIPE;
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if (S_ISDIR(inode->i_mode))
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return -EISDIR;
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if (!S_ISREG(inode->i_mode) && !S_ISBLK(inode->i_mode))
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return -ENODEV;
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/* Check for wrap through zero too */
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if (((offset + len) > inode->i_sb->s_maxbytes) || ((offset + len) < 0))
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return -EFBIG;
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if (!file->f_op->fallocate)
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return -EOPNOTSUPP;
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file_start_write(file);
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ret = file->f_op->fallocate(file, mode, offset, len);
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/*
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* Create inotify and fanotify events.
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*
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* To keep the logic simple always create events if fallocate succeeds.
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* This implies that events are even created if the file size remains
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* unchanged, e.g. when using flag FALLOC_FL_KEEP_SIZE.
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*/
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if (ret == 0)
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fsnotify_modify(file);
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file_end_write(file);
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return ret;
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}
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EXPORT_SYMBOL_GPL(vfs_fallocate);
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int ksys_fallocate(int fd, int mode, loff_t offset, loff_t len)
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{
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struct fd f = fdget(fd);
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int error = -EBADF;
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if (f.file) {
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error = vfs_fallocate(f.file, mode, offset, len);
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fdput(f);
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}
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return error;
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}
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SYSCALL_DEFINE4(fallocate, int, fd, int, mode, loff_t, offset, loff_t, len)
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{
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return ksys_fallocate(fd, mode, offset, len);
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}
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/*
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* access() needs to use the real uid/gid, not the effective uid/gid.
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* We do this by temporarily clearing all FS-related capabilities and
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* switching the fsuid/fsgid around to the real ones.
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*/
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static const struct cred *access_override_creds(void)
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{
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const struct cred *old_cred;
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struct cred *override_cred;
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override_cred = prepare_creds();
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if (!override_cred)
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return NULL;
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override_cred->fsuid = override_cred->uid;
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override_cred->fsgid = override_cred->gid;
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if (!issecure(SECURE_NO_SETUID_FIXUP)) {
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/* Clear the capabilities if we switch to a non-root user */
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kuid_t root_uid = make_kuid(override_cred->user_ns, 0);
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if (!uid_eq(override_cred->uid, root_uid))
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cap_clear(override_cred->cap_effective);
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else
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override_cred->cap_effective =
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override_cred->cap_permitted;
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}
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|
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/*
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* The new set of credentials can *only* be used in
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* task-synchronous circumstances, and does not need
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* RCU freeing, unless somebody then takes a separate
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* reference to it.
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*
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* NOTE! This is _only_ true because this credential
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* is used purely for override_creds() that installs
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* it as the subjective cred. Other threads will be
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* accessing ->real_cred, not the subjective cred.
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*
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* If somebody _does_ make a copy of this (using the
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* 'get_current_cred()' function), that will clear the
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* non_rcu field, because now that other user may be
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* expecting RCU freeing. But normal thread-synchronous
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* cred accesses will keep things non-RCY.
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*/
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override_cred->non_rcu = 1;
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old_cred = override_creds(override_cred);
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/* override_cred() gets its own ref */
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put_cred(override_cred);
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return old_cred;
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}
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|
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static long do_faccessat(int dfd, const char __user *filename, int mode, int flags)
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|
{
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struct path path;
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struct inode *inode;
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int res;
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unsigned int lookup_flags = LOOKUP_FOLLOW;
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const struct cred *old_cred = NULL;
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|
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if (mode & ~S_IRWXO) /* where's F_OK, X_OK, W_OK, R_OK? */
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return -EINVAL;
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|
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if (flags & ~(AT_EACCESS | AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH))
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return -EINVAL;
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|
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if (flags & AT_SYMLINK_NOFOLLOW)
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lookup_flags &= ~LOOKUP_FOLLOW;
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if (flags & AT_EMPTY_PATH)
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lookup_flags |= LOOKUP_EMPTY;
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|
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if (!(flags & AT_EACCESS)) {
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old_cred = access_override_creds();
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if (!old_cred)
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return -ENOMEM;
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}
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|
|
retry:
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res = user_path_at(dfd, filename, lookup_flags, &path);
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if (res)
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goto out;
|
|
|
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inode = d_backing_inode(path.dentry);
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|
|
|
if ((mode & MAY_EXEC) && S_ISREG(inode->i_mode)) {
|
|
/*
|
|
* MAY_EXEC on regular files is denied if the fs is mounted
|
|
* with the "noexec" flag.
|
|
*/
|
|
res = -EACCES;
|
|
if (path_noexec(&path))
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goto out_path_release;
|
|
}
|
|
|
|
res = inode_permission(mnt_user_ns(path.mnt), inode, mode | MAY_ACCESS);
|
|
/* SuS v2 requires we report a read only fs too */
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|
if (res || !(mode & S_IWOTH) || special_file(inode->i_mode))
|
|
goto out_path_release;
|
|
/*
|
|
* This is a rare case where using __mnt_is_readonly()
|
|
* is OK without a mnt_want/drop_write() pair. Since
|
|
* no actual write to the fs is performed here, we do
|
|
* not need to telegraph to that to anyone.
|
|
*
|
|
* By doing this, we accept that this access is
|
|
* inherently racy and know that the fs may change
|
|
* state before we even see this result.
|
|
*/
|
|
if (__mnt_is_readonly(path.mnt))
|
|
res = -EROFS;
|
|
|
|
out_path_release:
|
|
path_put(&path);
|
|
if (retry_estale(res, lookup_flags)) {
|
|
lookup_flags |= LOOKUP_REVAL;
|
|
goto retry;
|
|
}
|
|
out:
|
|
if (old_cred)
|
|
revert_creds(old_cred);
|
|
|
|
return res;
|
|
}
|
|
|
|
SYSCALL_DEFINE3(faccessat, int, dfd, const char __user *, filename, int, mode)
|
|
{
|
|
return do_faccessat(dfd, filename, mode, 0);
|
|
}
|
|
|
|
SYSCALL_DEFINE4(faccessat2, int, dfd, const char __user *, filename, int, mode,
|
|
int, flags)
|
|
{
|
|
return do_faccessat(dfd, filename, mode, flags);
|
|
}
|
|
|
|
SYSCALL_DEFINE2(access, const char __user *, filename, int, mode)
|
|
{
|
|
return do_faccessat(AT_FDCWD, filename, mode, 0);
|
|
}
|
|
|
|
SYSCALL_DEFINE1(chdir, const char __user *, filename)
|
|
{
|
|
struct path path;
|
|
int error;
|
|
unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
|
|
retry:
|
|
error = user_path_at(AT_FDCWD, filename, lookup_flags, &path);
|
|
if (error)
|
|
goto out;
|
|
|
|
error = path_permission(&path, MAY_EXEC | MAY_CHDIR);
|
|
if (error)
|
|
goto dput_and_out;
|
|
|
|
set_fs_pwd(current->fs, &path);
|
|
|
|
dput_and_out:
|
|
path_put(&path);
|
|
if (retry_estale(error, lookup_flags)) {
|
|
lookup_flags |= LOOKUP_REVAL;
|
|
goto retry;
|
|
}
|
|
out:
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE1(fchdir, unsigned int, fd)
|
|
{
|
|
struct fd f = fdget_raw(fd);
|
|
int error;
|
|
|
|
error = -EBADF;
|
|
if (!f.file)
|
|
goto out;
|
|
|
|
error = -ENOTDIR;
|
|
if (!d_can_lookup(f.file->f_path.dentry))
|
|
goto out_putf;
|
|
|
|
error = file_permission(f.file, MAY_EXEC | MAY_CHDIR);
|
|
if (!error)
|
|
set_fs_pwd(current->fs, &f.file->f_path);
|
|
out_putf:
|
|
fdput(f);
|
|
out:
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE1(chroot, const char __user *, filename)
|
|
{
|
|
struct path path;
|
|
int error;
|
|
unsigned int lookup_flags = LOOKUP_FOLLOW | LOOKUP_DIRECTORY;
|
|
retry:
|
|
error = user_path_at(AT_FDCWD, filename, lookup_flags, &path);
|
|
if (error)
|
|
goto out;
|
|
|
|
error = path_permission(&path, MAY_EXEC | MAY_CHDIR);
|
|
if (error)
|
|
goto dput_and_out;
|
|
|
|
error = -EPERM;
|
|
if (!ns_capable(current_user_ns(), CAP_SYS_CHROOT))
|
|
goto dput_and_out;
|
|
error = security_path_chroot(&path);
|
|
if (error)
|
|
goto dput_and_out;
|
|
|
|
set_fs_root(current->fs, &path);
|
|
error = 0;
|
|
dput_and_out:
|
|
path_put(&path);
|
|
if (retry_estale(error, lookup_flags)) {
|
|
lookup_flags |= LOOKUP_REVAL;
|
|
goto retry;
|
|
}
|
|
out:
|
|
return error;
|
|
}
|
|
|
|
int chmod_common(const struct path *path, umode_t mode)
|
|
{
|
|
struct inode *inode = path->dentry->d_inode;
|
|
struct inode *delegated_inode = NULL;
|
|
struct iattr newattrs;
|
|
int error;
|
|
|
|
error = mnt_want_write(path->mnt);
|
|
if (error)
|
|
return error;
|
|
retry_deleg:
|
|
inode_lock(inode);
|
|
error = security_path_chmod(path, mode);
|
|
if (error)
|
|
goto out_unlock;
|
|
newattrs.ia_mode = (mode & S_IALLUGO) | (inode->i_mode & ~S_IALLUGO);
|
|
newattrs.ia_valid = ATTR_MODE | ATTR_CTIME;
|
|
error = notify_change(mnt_user_ns(path->mnt), path->dentry,
|
|
&newattrs, &delegated_inode);
|
|
out_unlock:
|
|
inode_unlock(inode);
|
|
if (delegated_inode) {
|
|
error = break_deleg_wait(&delegated_inode);
|
|
if (!error)
|
|
goto retry_deleg;
|
|
}
|
|
mnt_drop_write(path->mnt);
|
|
return error;
|
|
}
|
|
|
|
int vfs_fchmod(struct file *file, umode_t mode)
|
|
{
|
|
audit_file(file);
|
|
return chmod_common(&file->f_path, mode);
|
|
}
|
|
|
|
SYSCALL_DEFINE2(fchmod, unsigned int, fd, umode_t, mode)
|
|
{
|
|
struct fd f = fdget(fd);
|
|
int err = -EBADF;
|
|
|
|
if (f.file) {
|
|
err = vfs_fchmod(f.file, mode);
|
|
fdput(f);
|
|
}
|
|
return err;
|
|
}
|
|
|
|
static int do_fchmodat(int dfd, const char __user *filename, umode_t mode)
|
|
{
|
|
struct path path;
|
|
int error;
|
|
unsigned int lookup_flags = LOOKUP_FOLLOW;
|
|
retry:
|
|
error = user_path_at(dfd, filename, lookup_flags, &path);
|
|
if (!error) {
|
|
error = chmod_common(&path, mode);
|
|
path_put(&path);
|
|
if (retry_estale(error, lookup_flags)) {
|
|
lookup_flags |= LOOKUP_REVAL;
|
|
goto retry;
|
|
}
|
|
}
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE3(fchmodat, int, dfd, const char __user *, filename,
|
|
umode_t, mode)
|
|
{
|
|
return do_fchmodat(dfd, filename, mode);
|
|
}
|
|
|
|
SYSCALL_DEFINE2(chmod, const char __user *, filename, umode_t, mode)
|
|
{
|
|
return do_fchmodat(AT_FDCWD, filename, mode);
|
|
}
|
|
|
|
int chown_common(const struct path *path, uid_t user, gid_t group)
|
|
{
|
|
struct user_namespace *mnt_userns, *fs_userns;
|
|
struct inode *inode = path->dentry->d_inode;
|
|
struct inode *delegated_inode = NULL;
|
|
int error;
|
|
struct iattr newattrs;
|
|
kuid_t uid;
|
|
kgid_t gid;
|
|
|
|
uid = make_kuid(current_user_ns(), user);
|
|
gid = make_kgid(current_user_ns(), group);
|
|
|
|
mnt_userns = mnt_user_ns(path->mnt);
|
|
fs_userns = i_user_ns(inode);
|
|
uid = mapped_kuid_user(mnt_userns, fs_userns, uid);
|
|
gid = mapped_kgid_user(mnt_userns, fs_userns, gid);
|
|
|
|
retry_deleg:
|
|
newattrs.ia_valid = ATTR_CTIME;
|
|
if (user != (uid_t) -1) {
|
|
if (!uid_valid(uid))
|
|
return -EINVAL;
|
|
newattrs.ia_valid |= ATTR_UID;
|
|
newattrs.ia_uid = uid;
|
|
}
|
|
if (group != (gid_t) -1) {
|
|
if (!gid_valid(gid))
|
|
return -EINVAL;
|
|
newattrs.ia_valid |= ATTR_GID;
|
|
newattrs.ia_gid = gid;
|
|
}
|
|
if (!S_ISDIR(inode->i_mode))
|
|
newattrs.ia_valid |=
|
|
ATTR_KILL_SUID | ATTR_KILL_SGID | ATTR_KILL_PRIV;
|
|
inode_lock(inode);
|
|
error = security_path_chown(path, uid, gid);
|
|
if (!error)
|
|
error = notify_change(mnt_userns, path->dentry, &newattrs,
|
|
&delegated_inode);
|
|
inode_unlock(inode);
|
|
if (delegated_inode) {
|
|
error = break_deleg_wait(&delegated_inode);
|
|
if (!error)
|
|
goto retry_deleg;
|
|
}
|
|
return error;
|
|
}
|
|
|
|
int do_fchownat(int dfd, const char __user *filename, uid_t user, gid_t group,
|
|
int flag)
|
|
{
|
|
struct path path;
|
|
int error = -EINVAL;
|
|
int lookup_flags;
|
|
|
|
if ((flag & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0)
|
|
goto out;
|
|
|
|
lookup_flags = (flag & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW;
|
|
if (flag & AT_EMPTY_PATH)
|
|
lookup_flags |= LOOKUP_EMPTY;
|
|
retry:
|
|
error = user_path_at(dfd, filename, lookup_flags, &path);
|
|
if (error)
|
|
goto out;
|
|
error = mnt_want_write(path.mnt);
|
|
if (error)
|
|
goto out_release;
|
|
error = chown_common(&path, user, group);
|
|
mnt_drop_write(path.mnt);
|
|
out_release:
|
|
path_put(&path);
|
|
if (retry_estale(error, lookup_flags)) {
|
|
lookup_flags |= LOOKUP_REVAL;
|
|
goto retry;
|
|
}
|
|
out:
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE5(fchownat, int, dfd, const char __user *, filename, uid_t, user,
|
|
gid_t, group, int, flag)
|
|
{
|
|
return do_fchownat(dfd, filename, user, group, flag);
|
|
}
|
|
|
|
SYSCALL_DEFINE3(chown, const char __user *, filename, uid_t, user, gid_t, group)
|
|
{
|
|
return do_fchownat(AT_FDCWD, filename, user, group, 0);
|
|
}
|
|
|
|
SYSCALL_DEFINE3(lchown, const char __user *, filename, uid_t, user, gid_t, group)
|
|
{
|
|
return do_fchownat(AT_FDCWD, filename, user, group,
|
|
AT_SYMLINK_NOFOLLOW);
|
|
}
|
|
|
|
int vfs_fchown(struct file *file, uid_t user, gid_t group)
|
|
{
|
|
int error;
|
|
|
|
error = mnt_want_write_file(file);
|
|
if (error)
|
|
return error;
|
|
audit_file(file);
|
|
error = chown_common(&file->f_path, user, group);
|
|
mnt_drop_write_file(file);
|
|
return error;
|
|
}
|
|
|
|
int ksys_fchown(unsigned int fd, uid_t user, gid_t group)
|
|
{
|
|
struct fd f = fdget(fd);
|
|
int error = -EBADF;
|
|
|
|
if (f.file) {
|
|
error = vfs_fchown(f.file, user, group);
|
|
fdput(f);
|
|
}
|
|
return error;
|
|
}
|
|
|
|
SYSCALL_DEFINE3(fchown, unsigned int, fd, uid_t, user, gid_t, group)
|
|
{
|
|
return ksys_fchown(fd, user, group);
|
|
}
|
|
|
|
static int do_dentry_open(struct file *f,
|
|
struct inode *inode,
|
|
int (*open)(struct inode *, struct file *))
|
|
{
|
|
static const struct file_operations empty_fops = {};
|
|
int error;
|
|
|
|
path_get(&f->f_path);
|
|
f->f_inode = inode;
|
|
f->f_mapping = inode->i_mapping;
|
|
f->f_wb_err = filemap_sample_wb_err(f->f_mapping);
|
|
f->f_sb_err = file_sample_sb_err(f);
|
|
|
|
if (unlikely(f->f_flags & O_PATH)) {
|
|
f->f_mode = FMODE_PATH | FMODE_OPENED;
|
|
f->f_op = &empty_fops;
|
|
return 0;
|
|
}
|
|
|
|
if (f->f_mode & FMODE_WRITE && !special_file(inode->i_mode)) {
|
|
error = get_write_access(inode);
|
|
if (unlikely(error))
|
|
goto cleanup_file;
|
|
error = __mnt_want_write(f->f_path.mnt);
|
|
if (unlikely(error)) {
|
|
put_write_access(inode);
|
|
goto cleanup_file;
|
|
}
|
|
f->f_mode |= FMODE_WRITER;
|
|
}
|
|
|
|
/* POSIX.1-2008/SUSv4 Section XSI 2.9.7 */
|
|
if (S_ISREG(inode->i_mode) || S_ISDIR(inode->i_mode))
|
|
f->f_mode |= FMODE_ATOMIC_POS;
|
|
|
|
f->f_op = fops_get(inode->i_fop);
|
|
if (WARN_ON(!f->f_op)) {
|
|
error = -ENODEV;
|
|
goto cleanup_all;
|
|
}
|
|
|
|
error = security_file_open(f);
|
|
if (error)
|
|
goto cleanup_all;
|
|
|
|
error = break_lease(locks_inode(f), f->f_flags);
|
|
if (error)
|
|
goto cleanup_all;
|
|
|
|
/* normally all 3 are set; ->open() can clear them if needed */
|
|
f->f_mode |= FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE;
|
|
if (!open)
|
|
open = f->f_op->open;
|
|
if (open) {
|
|
error = open(inode, f);
|
|
if (error)
|
|
goto cleanup_all;
|
|
}
|
|
f->f_mode |= FMODE_OPENED;
|
|
if ((f->f_mode & (FMODE_READ | FMODE_WRITE)) == FMODE_READ)
|
|
i_readcount_inc(inode);
|
|
if ((f->f_mode & FMODE_READ) &&
|
|
likely(f->f_op->read || f->f_op->read_iter))
|
|
f->f_mode |= FMODE_CAN_READ;
|
|
if ((f->f_mode & FMODE_WRITE) &&
|
|
likely(f->f_op->write || f->f_op->write_iter))
|
|
f->f_mode |= FMODE_CAN_WRITE;
|
|
|
|
f->f_write_hint = WRITE_LIFE_NOT_SET;
|
|
f->f_flags &= ~(O_CREAT | O_EXCL | O_NOCTTY | O_TRUNC);
|
|
|
|
file_ra_state_init(&f->f_ra, f->f_mapping->host->i_mapping);
|
|
|
|
/* NB: we're sure to have correct a_ops only after f_op->open */
|
|
if (f->f_flags & O_DIRECT) {
|
|
if (!f->f_mapping->a_ops || !f->f_mapping->a_ops->direct_IO)
|
|
return -EINVAL;
|
|
}
|
|
|
|
/*
|
|
* XXX: Huge page cache doesn't support writing yet. Drop all page
|
|
* cache for this file before processing writes.
|
|
*/
|
|
if (f->f_mode & FMODE_WRITE) {
|
|
/*
|
|
* Paired with smp_mb() in collapse_file() to ensure nr_thps
|
|
* is up to date and the update to i_writecount by
|
|
* get_write_access() is visible. Ensures subsequent insertion
|
|
* of THPs into the page cache will fail.
|
|
*/
|
|
smp_mb();
|
|
if (filemap_nr_thps(inode->i_mapping)) {
|
|
struct address_space *mapping = inode->i_mapping;
|
|
|
|
filemap_invalidate_lock(inode->i_mapping);
|
|
/*
|
|
* unmap_mapping_range just need to be called once
|
|
* here, because the private pages is not need to be
|
|
* unmapped mapping (e.g. data segment of dynamic
|
|
* shared libraries here).
|
|
*/
|
|
unmap_mapping_range(mapping, 0, 0, 0);
|
|
truncate_inode_pages(mapping, 0);
|
|
filemap_invalidate_unlock(inode->i_mapping);
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
|
|
cleanup_all:
|
|
if (WARN_ON_ONCE(error > 0))
|
|
error = -EINVAL;
|
|
fops_put(f->f_op);
|
|
if (f->f_mode & FMODE_WRITER) {
|
|
put_write_access(inode);
|
|
__mnt_drop_write(f->f_path.mnt);
|
|
}
|
|
cleanup_file:
|
|
path_put(&f->f_path);
|
|
f->f_path.mnt = NULL;
|
|
f->f_path.dentry = NULL;
|
|
f->f_inode = NULL;
|
|
return error;
|
|
}
|
|
|
|
/**
|
|
* finish_open - finish opening a file
|
|
* @file: file pointer
|
|
* @dentry: pointer to dentry
|
|
* @open: open callback
|
|
* @opened: state of open
|
|
*
|
|
* This can be used to finish opening a file passed to i_op->atomic_open().
|
|
*
|
|
* If the open callback is set to NULL, then the standard f_op->open()
|
|
* filesystem callback is substituted.
|
|
*
|
|
* NB: the dentry reference is _not_ consumed. If, for example, the dentry is
|
|
* the return value of d_splice_alias(), then the caller needs to perform dput()
|
|
* on it after finish_open().
|
|
*
|
|
* Returns zero on success or -errno if the open failed.
|
|
*/
|
|
int finish_open(struct file *file, struct dentry *dentry,
|
|
int (*open)(struct inode *, struct file *))
|
|
{
|
|
BUG_ON(file->f_mode & FMODE_OPENED); /* once it's opened, it's opened */
|
|
|
|
file->f_path.dentry = dentry;
|
|
return do_dentry_open(file, d_backing_inode(dentry), open);
|
|
}
|
|
EXPORT_SYMBOL(finish_open);
|
|
|
|
/**
|
|
* finish_no_open - finish ->atomic_open() without opening the file
|
|
*
|
|
* @file: file pointer
|
|
* @dentry: dentry or NULL (as returned from ->lookup())
|
|
*
|
|
* This can be used to set the result of a successful lookup in ->atomic_open().
|
|
*
|
|
* NB: unlike finish_open() this function does consume the dentry reference and
|
|
* the caller need not dput() it.
|
|
*
|
|
* Returns "0" which must be the return value of ->atomic_open() after having
|
|
* called this function.
|
|
*/
|
|
int finish_no_open(struct file *file, struct dentry *dentry)
|
|
{
|
|
file->f_path.dentry = dentry;
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL(finish_no_open);
|
|
|
|
char *file_path(struct file *filp, char *buf, int buflen)
|
|
{
|
|
return d_path(&filp->f_path, buf, buflen);
|
|
}
|
|
EXPORT_SYMBOL(file_path);
|
|
|
|
/**
|
|
* vfs_open - open the file at the given path
|
|
* @path: path to open
|
|
* @file: newly allocated file with f_flag initialized
|
|
* @cred: credentials to use
|
|
*/
|
|
int vfs_open(const struct path *path, struct file *file)
|
|
{
|
|
file->f_path = *path;
|
|
return do_dentry_open(file, d_backing_inode(path->dentry), NULL);
|
|
}
|
|
|
|
struct file *dentry_open(const struct path *path, int flags,
|
|
const struct cred *cred)
|
|
{
|
|
int error;
|
|
struct file *f;
|
|
|
|
validate_creds(cred);
|
|
|
|
/* We must always pass in a valid mount pointer. */
|
|
BUG_ON(!path->mnt);
|
|
|
|
f = alloc_empty_file(flags, cred);
|
|
if (!IS_ERR(f)) {
|
|
error = vfs_open(path, f);
|
|
if (error) {
|
|
fput(f);
|
|
f = ERR_PTR(error);
|
|
}
|
|
}
|
|
return f;
|
|
}
|
|
EXPORT_SYMBOL(dentry_open);
|
|
|
|
struct file *open_with_fake_path(const struct path *path, int flags,
|
|
struct inode *inode, const struct cred *cred)
|
|
{
|
|
struct file *f = alloc_empty_file_noaccount(flags, cred);
|
|
if (!IS_ERR(f)) {
|
|
int error;
|
|
|
|
f->f_path = *path;
|
|
error = do_dentry_open(f, inode, NULL);
|
|
if (error) {
|
|
fput(f);
|
|
f = ERR_PTR(error);
|
|
}
|
|
}
|
|
return f;
|
|
}
|
|
EXPORT_SYMBOL(open_with_fake_path);
|
|
|
|
#define WILL_CREATE(flags) (flags & (O_CREAT | __O_TMPFILE))
|
|
#define O_PATH_FLAGS (O_DIRECTORY | O_NOFOLLOW | O_PATH | O_CLOEXEC)
|
|
|
|
inline struct open_how build_open_how(int flags, umode_t mode)
|
|
{
|
|
struct open_how how = {
|
|
.flags = flags & VALID_OPEN_FLAGS,
|
|
.mode = mode & S_IALLUGO,
|
|
};
|
|
|
|
/* O_PATH beats everything else. */
|
|
if (how.flags & O_PATH)
|
|
how.flags &= O_PATH_FLAGS;
|
|
/* Modes should only be set for create-like flags. */
|
|
if (!WILL_CREATE(how.flags))
|
|
how.mode = 0;
|
|
return how;
|
|
}
|
|
|
|
inline int build_open_flags(const struct open_how *how, struct open_flags *op)
|
|
{
|
|
u64 flags = how->flags;
|
|
u64 strip = FMODE_NONOTIFY | O_CLOEXEC;
|
|
int lookup_flags = 0;
|
|
int acc_mode = ACC_MODE(flags);
|
|
|
|
BUILD_BUG_ON_MSG(upper_32_bits(VALID_OPEN_FLAGS),
|
|
"struct open_flags doesn't yet handle flags > 32 bits");
|
|
|
|
/*
|
|
* Strip flags that either shouldn't be set by userspace like
|
|
* FMODE_NONOTIFY or that aren't relevant in determining struct
|
|
* open_flags like O_CLOEXEC.
|
|
*/
|
|
flags &= ~strip;
|
|
|
|
/*
|
|
* Older syscalls implicitly clear all of the invalid flags or argument
|
|
* values before calling build_open_flags(), but openat2(2) checks all
|
|
* of its arguments.
|
|
*/
|
|
if (flags & ~VALID_OPEN_FLAGS)
|
|
return -EINVAL;
|
|
if (how->resolve & ~VALID_RESOLVE_FLAGS)
|
|
return -EINVAL;
|
|
|
|
/* Scoping flags are mutually exclusive. */
|
|
if ((how->resolve & RESOLVE_BENEATH) && (how->resolve & RESOLVE_IN_ROOT))
|
|
return -EINVAL;
|
|
|
|
/* Deal with the mode. */
|
|
if (WILL_CREATE(flags)) {
|
|
if (how->mode & ~S_IALLUGO)
|
|
return -EINVAL;
|
|
op->mode = how->mode | S_IFREG;
|
|
} else {
|
|
if (how->mode != 0)
|
|
return -EINVAL;
|
|
op->mode = 0;
|
|
}
|
|
|
|
/*
|
|
* In order to ensure programs get explicit errors when trying to use
|
|
* O_TMPFILE on old kernels, O_TMPFILE is implemented such that it
|
|
* looks like (O_DIRECTORY|O_RDWR & ~O_CREAT) to old kernels. But we
|
|
* have to require userspace to explicitly set it.
|
|
*/
|
|
if (flags & __O_TMPFILE) {
|
|
if ((flags & O_TMPFILE_MASK) != O_TMPFILE)
|
|
return -EINVAL;
|
|
if (!(acc_mode & MAY_WRITE))
|
|
return -EINVAL;
|
|
}
|
|
if (flags & O_PATH) {
|
|
/* O_PATH only permits certain other flags to be set. */
|
|
if (flags & ~O_PATH_FLAGS)
|
|
return -EINVAL;
|
|
acc_mode = 0;
|
|
}
|
|
|
|
/*
|
|
* O_SYNC is implemented as __O_SYNC|O_DSYNC. As many places only
|
|
* check for O_DSYNC if the need any syncing at all we enforce it's
|
|
* always set instead of having to deal with possibly weird behaviour
|
|
* for malicious applications setting only __O_SYNC.
|
|
*/
|
|
if (flags & __O_SYNC)
|
|
flags |= O_DSYNC;
|
|
|
|
op->open_flag = flags;
|
|
|
|
/* O_TRUNC implies we need access checks for write permissions */
|
|
if (flags & O_TRUNC)
|
|
acc_mode |= MAY_WRITE;
|
|
|
|
/* Allow the LSM permission hook to distinguish append
|
|
access from general write access. */
|
|
if (flags & O_APPEND)
|
|
acc_mode |= MAY_APPEND;
|
|
|
|
op->acc_mode = acc_mode;
|
|
|
|
op->intent = flags & O_PATH ? 0 : LOOKUP_OPEN;
|
|
|
|
if (flags & O_CREAT) {
|
|
op->intent |= LOOKUP_CREATE;
|
|
if (flags & O_EXCL) {
|
|
op->intent |= LOOKUP_EXCL;
|
|
flags |= O_NOFOLLOW;
|
|
}
|
|
}
|
|
|
|
if (flags & O_DIRECTORY)
|
|
lookup_flags |= LOOKUP_DIRECTORY;
|
|
if (!(flags & O_NOFOLLOW))
|
|
lookup_flags |= LOOKUP_FOLLOW;
|
|
|
|
if (how->resolve & RESOLVE_NO_XDEV)
|
|
lookup_flags |= LOOKUP_NO_XDEV;
|
|
if (how->resolve & RESOLVE_NO_MAGICLINKS)
|
|
lookup_flags |= LOOKUP_NO_MAGICLINKS;
|
|
if (how->resolve & RESOLVE_NO_SYMLINKS)
|
|
lookup_flags |= LOOKUP_NO_SYMLINKS;
|
|
if (how->resolve & RESOLVE_BENEATH)
|
|
lookup_flags |= LOOKUP_BENEATH;
|
|
if (how->resolve & RESOLVE_IN_ROOT)
|
|
lookup_flags |= LOOKUP_IN_ROOT;
|
|
if (how->resolve & RESOLVE_CACHED) {
|
|
/* Don't bother even trying for create/truncate/tmpfile open */
|
|
if (flags & (O_TRUNC | O_CREAT | O_TMPFILE))
|
|
return -EAGAIN;
|
|
lookup_flags |= LOOKUP_CACHED;
|
|
}
|
|
|
|
op->lookup_flags = lookup_flags;
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* file_open_name - open file and return file pointer
|
|
*
|
|
* @name: struct filename containing path to open
|
|
* @flags: open flags as per the open(2) second argument
|
|
* @mode: mode for the new file if O_CREAT is set, else ignored
|
|
*
|
|
* This is the helper to open a file from kernelspace if you really
|
|
* have to. But in generally you should not do this, so please move
|
|
* along, nothing to see here..
|
|
*/
|
|
struct file *file_open_name(struct filename *name, int flags, umode_t mode)
|
|
{
|
|
struct open_flags op;
|
|
struct open_how how = build_open_how(flags, mode);
|
|
int err = build_open_flags(&how, &op);
|
|
if (err)
|
|
return ERR_PTR(err);
|
|
return do_filp_open(AT_FDCWD, name, &op);
|
|
}
|
|
|
|
/**
|
|
* filp_open - open file and return file pointer
|
|
*
|
|
* @filename: path to open
|
|
* @flags: open flags as per the open(2) second argument
|
|
* @mode: mode for the new file if O_CREAT is set, else ignored
|
|
*
|
|
* This is the helper to open a file from kernelspace if you really
|
|
* have to. But in generally you should not do this, so please move
|
|
* along, nothing to see here..
|
|
*/
|
|
struct file *filp_open(const char *filename, int flags, umode_t mode)
|
|
{
|
|
struct filename *name = getname_kernel(filename);
|
|
struct file *file = ERR_CAST(name);
|
|
|
|
if (!IS_ERR(name)) {
|
|
file = file_open_name(name, flags, mode);
|
|
putname(name);
|
|
}
|
|
return file;
|
|
}
|
|
EXPORT_SYMBOL(filp_open);
|
|
|
|
struct file *file_open_root(const struct path *root,
|
|
const char *filename, int flags, umode_t mode)
|
|
{
|
|
struct open_flags op;
|
|
struct open_how how = build_open_how(flags, mode);
|
|
int err = build_open_flags(&how, &op);
|
|
if (err)
|
|
return ERR_PTR(err);
|
|
return do_file_open_root(root, filename, &op);
|
|
}
|
|
EXPORT_SYMBOL(file_open_root);
|
|
|
|
static long do_sys_openat2(int dfd, const char __user *filename,
|
|
struct open_how *how)
|
|
{
|
|
struct open_flags op;
|
|
int fd = build_open_flags(how, &op);
|
|
struct filename *tmp;
|
|
|
|
if (fd)
|
|
return fd;
|
|
|
|
tmp = getname(filename);
|
|
if (IS_ERR(tmp))
|
|
return PTR_ERR(tmp);
|
|
|
|
fd = get_unused_fd_flags(how->flags);
|
|
if (fd >= 0) {
|
|
struct file *f = do_filp_open(dfd, tmp, &op);
|
|
if (IS_ERR(f)) {
|
|
put_unused_fd(fd);
|
|
fd = PTR_ERR(f);
|
|
} else {
|
|
fsnotify_open(f);
|
|
fd_install(fd, f);
|
|
}
|
|
}
|
|
putname(tmp);
|
|
return fd;
|
|
}
|
|
|
|
long do_sys_open(int dfd, const char __user *filename, int flags, umode_t mode)
|
|
{
|
|
struct open_how how = build_open_how(flags, mode);
|
|
return do_sys_openat2(dfd, filename, &how);
|
|
}
|
|
|
|
|
|
SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode)
|
|
{
|
|
if (force_o_largefile())
|
|
flags |= O_LARGEFILE;
|
|
return do_sys_open(AT_FDCWD, filename, flags, mode);
|
|
}
|
|
|
|
SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags,
|
|
umode_t, mode)
|
|
{
|
|
if (force_o_largefile())
|
|
flags |= O_LARGEFILE;
|
|
return do_sys_open(dfd, filename, flags, mode);
|
|
}
|
|
|
|
SYSCALL_DEFINE4(openat2, int, dfd, const char __user *, filename,
|
|
struct open_how __user *, how, size_t, usize)
|
|
{
|
|
int err;
|
|
struct open_how tmp;
|
|
|
|
BUILD_BUG_ON(sizeof(struct open_how) < OPEN_HOW_SIZE_VER0);
|
|
BUILD_BUG_ON(sizeof(struct open_how) != OPEN_HOW_SIZE_LATEST);
|
|
|
|
if (unlikely(usize < OPEN_HOW_SIZE_VER0))
|
|
return -EINVAL;
|
|
|
|
err = copy_struct_from_user(&tmp, sizeof(tmp), how, usize);
|
|
if (err)
|
|
return err;
|
|
|
|
audit_openat2_how(&tmp);
|
|
|
|
/* O_LARGEFILE is only allowed for non-O_PATH. */
|
|
if (!(tmp.flags & O_PATH) && force_o_largefile())
|
|
tmp.flags |= O_LARGEFILE;
|
|
|
|
return do_sys_openat2(dfd, filename, &tmp);
|
|
}
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
/*
|
|
* Exactly like sys_open(), except that it doesn't set the
|
|
* O_LARGEFILE flag.
|
|
*/
|
|
COMPAT_SYSCALL_DEFINE3(open, const char __user *, filename, int, flags, umode_t, mode)
|
|
{
|
|
return do_sys_open(AT_FDCWD, filename, flags, mode);
|
|
}
|
|
|
|
/*
|
|
* Exactly like sys_openat(), except that it doesn't set the
|
|
* O_LARGEFILE flag.
|
|
*/
|
|
COMPAT_SYSCALL_DEFINE4(openat, int, dfd, const char __user *, filename, int, flags, umode_t, mode)
|
|
{
|
|
return do_sys_open(dfd, filename, flags, mode);
|
|
}
|
|
#endif
|
|
|
|
#ifndef __alpha__
|
|
|
|
/*
|
|
* For backward compatibility? Maybe this should be moved
|
|
* into arch/i386 instead?
|
|
*/
|
|
SYSCALL_DEFINE2(creat, const char __user *, pathname, umode_t, mode)
|
|
{
|
|
int flags = O_CREAT | O_WRONLY | O_TRUNC;
|
|
|
|
if (force_o_largefile())
|
|
flags |= O_LARGEFILE;
|
|
return do_sys_open(AT_FDCWD, pathname, flags, mode);
|
|
}
|
|
#endif
|
|
|
|
/*
|
|
* "id" is the POSIX thread ID. We use the
|
|
* files pointer for this..
|
|
*/
|
|
int filp_close(struct file *filp, fl_owner_t id)
|
|
{
|
|
int retval = 0;
|
|
|
|
if (!file_count(filp)) {
|
|
printk(KERN_ERR "VFS: Close: file count is 0\n");
|
|
return 0;
|
|
}
|
|
|
|
if (filp->f_op->flush)
|
|
retval = filp->f_op->flush(filp, id);
|
|
|
|
if (likely(!(filp->f_mode & FMODE_PATH))) {
|
|
dnotify_flush(filp, id);
|
|
locks_remove_posix(filp, id);
|
|
}
|
|
fput(filp);
|
|
return retval;
|
|
}
|
|
|
|
EXPORT_SYMBOL(filp_close);
|
|
|
|
/*
|
|
* Careful here! We test whether the file pointer is NULL before
|
|
* releasing the fd. This ensures that one clone task can't release
|
|
* an fd while another clone is opening it.
|
|
*/
|
|
SYSCALL_DEFINE1(close, unsigned int, fd)
|
|
{
|
|
int retval = close_fd(fd);
|
|
|
|
/* can't restart close syscall because file table entry was cleared */
|
|
if (unlikely(retval == -ERESTARTSYS ||
|
|
retval == -ERESTARTNOINTR ||
|
|
retval == -ERESTARTNOHAND ||
|
|
retval == -ERESTART_RESTARTBLOCK))
|
|
retval = -EINTR;
|
|
|
|
return retval;
|
|
}
|
|
|
|
/**
|
|
* close_range() - Close all file descriptors in a given range.
|
|
*
|
|
* @fd: starting file descriptor to close
|
|
* @max_fd: last file descriptor to close
|
|
* @flags: reserved for future extensions
|
|
*
|
|
* This closes a range of file descriptors. All file descriptors
|
|
* from @fd up to and including @max_fd are closed.
|
|
* Currently, errors to close a given file descriptor are ignored.
|
|
*/
|
|
SYSCALL_DEFINE3(close_range, unsigned int, fd, unsigned int, max_fd,
|
|
unsigned int, flags)
|
|
{
|
|
return __close_range(fd, max_fd, flags);
|
|
}
|
|
|
|
/*
|
|
* This routine simulates a hangup on the tty, to arrange that users
|
|
* are given clean terminals at login time.
|
|
*/
|
|
SYSCALL_DEFINE0(vhangup)
|
|
{
|
|
if (capable(CAP_SYS_TTY_CONFIG)) {
|
|
tty_vhangup_self();
|
|
return 0;
|
|
}
|
|
return -EPERM;
|
|
}
|
|
|
|
/*
|
|
* Called when an inode is about to be open.
|
|
* We use this to disallow opening large files on 32bit systems if
|
|
* the caller didn't specify O_LARGEFILE. On 64bit systems we force
|
|
* on this flag in sys_open.
|
|
*/
|
|
int generic_file_open(struct inode * inode, struct file * filp)
|
|
{
|
|
if (!(filp->f_flags & O_LARGEFILE) && i_size_read(inode) > MAX_NON_LFS)
|
|
return -EOVERFLOW;
|
|
return 0;
|
|
}
|
|
|
|
EXPORT_SYMBOL(generic_file_open);
|
|
|
|
/*
|
|
* This is used by subsystems that don't want seekable
|
|
* file descriptors. The function is not supposed to ever fail, the only
|
|
* reason it returns an 'int' and not 'void' is so that it can be plugged
|
|
* directly into file_operations structure.
|
|
*/
|
|
int nonseekable_open(struct inode *inode, struct file *filp)
|
|
{
|
|
filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE);
|
|
return 0;
|
|
}
|
|
|
|
EXPORT_SYMBOL(nonseekable_open);
|
|
|
|
/*
|
|
* stream_open is used by subsystems that want stream-like file descriptors.
|
|
* Such file descriptors are not seekable and don't have notion of position
|
|
* (file.f_pos is always 0 and ppos passed to .read()/.write() is always NULL).
|
|
* Contrary to file descriptors of other regular files, .read() and .write()
|
|
* can run simultaneously.
|
|
*
|
|
* stream_open never fails and is marked to return int so that it could be
|
|
* directly used as file_operations.open .
|
|
*/
|
|
int stream_open(struct inode *inode, struct file *filp)
|
|
{
|
|
filp->f_mode &= ~(FMODE_LSEEK | FMODE_PREAD | FMODE_PWRITE | FMODE_ATOMIC_POS);
|
|
filp->f_mode |= FMODE_STREAM;
|
|
return 0;
|
|
}
|
|
|
|
EXPORT_SYMBOL(stream_open);
|