Andy Lutomirski bb2314b479 fs: Allow unprivileged linkat(..., AT_EMPTY_PATH) aka flink ...

Every now and then someone proposes a new flink syscall, and this spawns
a long discussion of whether it would be a security problem.  I think
that this is missing the point: flink is *already* allowed without
privilege as long as /proc is mounted -- it's called AT_SYMLINK_FOLLOW.

Now that O_TMPFILE is here, the ability to create a file with O_TMPFILE,
write it, and link it in is very convenient.  The only problem is that
it requires that /proc be mounted so that you can do:

linkat(AT_FDCWD, "/proc/self/fd/<tmpfd>", dfd, path, AT_SYMLINK_NOFOLLOW)

This sucks -- it's much nicer to do:

linkat(tmpfd, "", dfd, path, AT_EMPTY_PATH)

Let's allow it.

If this turns out to be excessively scary, it we could instead require
that the inode in question be I_LINKABLE, but this seems pointless given
the /proc situation

Signed-off-by: Andy Lutomirski <luto@amacapital.net>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2013-08-05 18:24:11 +04:00

..

9p

Second round of 9p patches for the 3.11 merge window.

2013-07-11 10:21:23 -07:00

adfs

Don't pass inode to ->d_hash() and ->d_compare()

2013-06-29 12:57:36 +04:00

affs

Don't pass inode to ->d_hash() and ->d_compare()

2013-06-29 12:57:36 +04:00

afs

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2013-07-03 09:10:19 -07:00

autofs4

helper for reading ->d_count

2013-07-05 18:59:33 +04:00

befs

[readdir] convert befs

2013-06-29 12:56:55 +04:00

bfs

[readdir] convert bfs

2013-06-29 12:56:33 +04:00

btrfs

Btrfs: fix wrong write offset when replacing a device

2013-07-19 15:07:26 -04:00

cachefiles

mm: remove lru parameter from __pagevec_lru_add and remove parts of pagevec API

2013-07-03 16:07:31 -07:00

ceph

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/sage/ceph-client

2013-07-09 12:39:10 -07:00

cifs

CIFS: Fix a deadlock when a file is reopened

2013-07-11 18:05:41 -05:00

coda

helper for reading ->d_count

2013-07-05 18:59:33 +04:00

configfs

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2013-07-14 11:42:26 -07:00

cramfs

[readdir] convert f2fs

2013-06-29 12:56:46 +04:00

debugfs

debugfs: write_file_bool() - ensure strtobool() operates on valid data

2013-06-03 13:55:02 -07:00

devpts

fs: Limit sys_mount to only request filesystem modules (Part 2).

2013-03-07 01:08:55 -08:00

dlm

dlm: Avoid LVB truncation

2013-06-26 11:38:02 -05:00

ecryptfs

Code cleanups and improved buffer handling during page crypto operations

2013-07-11 10:20:18 -07:00

efivarfs

efivarfs: we can use simple_lookup() now

2013-07-14 17:48:35 +04:00

efs

[readdir] convert efs

2013-06-29 12:56:31 +04:00

exofs

Lots of bug fixes, cleanups and optimizations. In the bug fixes

2013-07-02 09:39:34 -07:00

exportfs

[readdir] constify ->actor

2013-06-29 12:57:05 +04:00

ext2

[O_TMPFILE] it's still short a few helpers, but infrastructure should be OK now...

2013-06-29 12:57:10 +04:00

ext3

ext3: fix a BUG when opening a file with O_TMPFILE flag

2013-07-20 22:03:20 -04:00

ext4

ext4: fix a BUG when opening a file with O_TMPFILE flag

2013-07-20 21:58:38 -04:00

f2fs

f2fs: fix readdir incorrectness

2013-07-08 13:35:48 +04:00

fat

fatfs: add FAT_IOCTL_GET_VOLUME_ID

2013-07-09 10:33:25 -07:00

freevxfs

[readdir] convert freevxfs

2013-06-29 12:56:53 +04:00

fscache

FS-Cache: Don't use spin_is_locked() in assertions

2013-06-19 14:16:47 +01:00

fuse

fuse: readdirplus: cleanup

2013-07-17 14:53:54 +02:00

gfs2

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2013-07-03 09:10:19 -07:00

hfs

Don't pass inode to ->d_hash() and ->d_compare()

2013-06-29 12:57:36 +04:00

hfsplus

Don't pass inode to ->d_hash() and ->d_compare()

2013-06-29 12:57:36 +04:00

hostfs

[readdir] convert hostfs

2013-06-29 12:56:59 +04:00

hpfs

Merge branch 'hpfs' from Mikulas Patocka

2013-07-04 11:22:55 -07:00

hppfs

clean up scary strncpy(dst, src, strlen(src)) uses

2013-07-03 16:07:41 -07:00

hugetlbfs

hugetlbfs: fix mmap failure in unaligned size request

2013-05-07 18:38:27 -07:00

isofs

Don't pass inode to ->d_hash() and ->d_compare()

2013-06-29 12:57:36 +04:00

jbd

jbd: change journal_invalidatepage() to accept length

2013-05-21 23:26:36 -04:00

jbd2

jbd2: invalidate handle if jbd2_journal_restart() fails

2013-07-01 08:12:41 -04:00

jffs2

[readdir] convert jffs2

2013-06-29 12:56:47 +04:00

jfs

A couple cleanups to JFS for 3.11

2013-07-11 10:19:34 -07:00

lockd

Merge branch 'for-3.11' of git://linux-nfs.org/~bfields/linux

2013-07-17 13:43:55 -07:00

logfs

Lots of bug fixes, cleanups and optimizations. In the bug fixes

2013-07-02 09:39:34 -07:00

minix

minix: bug widening a binary "not" operation

2013-06-29 12:57:35 +04:00

ncpfs

ncpfs: fix error return code in ncp_parse_options()

2013-07-09 10:33:25 -07:00

nfs

NFSv4: Fix brainfart in attribute length calculation

2013-07-23 14:24:59 -07:00

nfs_common

nfs_common: Update the translation between nfsv3 acls linux posix acls

2013-02-13 06:15:14 -08:00

nfsd

nfsd: nfsd_open: when dentry_open returns an error do not propagate as struct file

2013-07-23 12:15:32 -04:00

nilfs2

helper for reading ->d_count

2013-07-05 18:59:33 +04:00

nls

…

notify

fsnotify: update comments concerning locking scheme

2013-07-09 10:33:20 -07:00

ntfs

Lots of bug fixes, cleanups and optimizations. In the bug fixes

2013-07-02 09:39:34 -07:00

ocfs2

ocfs2/refcounttree: add the missing NULL check of the return value of find_or_create_page()

2013-07-31 14:41:02 -07:00

omfs

[readdir] convert omfs

2013-06-29 12:56:37 +04:00

openpromfs

[readdir] convert openpromfs

2013-06-29 12:56:32 +04:00

proc

s390/kdump: Disable mmap for s390

2013-07-18 13:40:18 +02:00

pstore

Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc

2013-07-04 10:29:23 -07:00

qnx4

[readdir] convert qnx4

2013-06-29 12:56:38 +04:00

qnx6

[readdir] convert qnx6

2013-06-29 12:56:39 +04:00

quota

quota: Convert use of typedef ctl_table to struct ctl_table

2013-07-04 19:22:55 +02:00

ramfs

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2013-02-26 20:16:07 -08:00

reiserfs

reiserfs: fix deadlock in umount

2013-08-05 17:37:37 +04:00

romfs

[readdir] convert romfs

2013-06-29 12:56:29 +04:00

squashfs

[readdir] convert squashfs

2013-06-29 12:56:28 +04:00

sysfs

sysfs: prevent warning when only using binary attributes

2013-07-16 10:57:36 -07:00

sysv

Don't pass inode to ->d_hash() and ->d_compare()

2013-06-29 12:57:36 +04:00

ubifs

Only a single patch which fixes a message.

2013-07-05 12:08:47 -07:00

udf

udf: provide ->tmpfile()

2013-06-29 12:57:12 +04:00

ufs

[readdir] simple local unixlike: switch to ->iterate()

2013-06-29 12:46:47 +04:00

xfs

xfs: di_flushiter considered harmful

2013-07-25 10:41:42 -05:00

aio.c

aio: fix wrong comment in aio_complete()

2013-07-03 16:08:06 -07:00

anon_inodes.c

get_empty_filp()/alloc_file() leave both ->f_pos and ->f_version zero

2013-02-26 02:46:11 -05:00

attr.c

userns: Allow chown and setgid preservation

2012-11-20 04:17:24 -08:00

bad_inode.c

[readdir] ->readdir() is gone

2013-06-29 12:57:04 +04:00

binfmt_aout.c

mm: remove free_area_cache

2013-07-10 18:11:34 -07:00

binfmt_elf_fdpic.c

Merge branch 'next' of git://git.kernel.org/pub/scm/linux/kernel/git/benh/powerpc

2013-05-02 10:16:16 -07:00

binfmt_elf.c

mm: remove free_area_cache

2013-07-10 18:11:34 -07:00

binfmt_em86.c

exec: use -ELOOP for max recursion depth

2012-12-17 17:15:23 -08:00

binfmt_flat.c

new helper: read_code()

2013-04-29 15:40:23 -04:00

binfmt_misc.c

binfmt_misc: reuse string_unescape_inplace()

2013-04-30 17:04:03 -07:00

binfmt_script.c

exec: do not leave bprm->interp on stack

2012-12-20 17:40:19 -08:00

binfmt_som.c

get rid of pt_regs argument of ->load_binary()

2012-11-28 21:53:38 -05:00

bio-integrity.c

bio-integrity: Add explicit field for owner of bip_buf

2013-03-23 14:26:34 -07:00

bio.c

Merge branch 'for-3.10/core' of git://git.kernel.dk/linux-block

2013-05-08 10:13:35 -07:00

block_dev.c

Merge branch 'for-3.11/core' of git://git.kernel.dk/linux-block

2013-07-11 13:03:24 -07:00

buffer.c

mm: vmscan: take page buffers dirty and locked state into account

2013-07-03 16:07:29 -07:00

char_dev.c

…

compat_binfmt_elf.c

…

compat_ioctl.c

compat.c: LOOP_CLR_FD is taken care of in loop.c itself...

2013-06-29 12:46:44 +04:00

compat.c

[readdir] constify ->actor

2013-06-29 12:57:05 +04:00

coredump.c

coredump: '% at the end' shouldn't bypass core_uses_pid logic

2013-07-03 16:08:02 -07:00

coredump.h

…

dcache.c

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2013-07-03 09:10:19 -07:00

dcookies.c

consolidate compat lookup_dcookie()

2013-03-03 23:00:23 -05:00

direct-io.c

Merge branch 'for-3.10/core' of git://git.kernel.dk/linux-block

2013-05-08 10:13:35 -07:00

drop_caches.c

…

eventfd.c

fs, eventfd: add procfs fdinfo helper

2012-12-17 17:15:27 -08:00

eventpoll.c

Merge branch 'akpm' (updates from Andrew Morton)

2013-07-03 17:12:13 -07:00

exec.c

fs/exec.c:de_thread: mt-exec should update ->real_start_time

2013-07-03 16:08:03 -07:00

fcntl.c

new helper: file_inode(file)

2013-02-22 23:31:31 -05:00

fhandle.c

Merge branch 'for-3.8' of git://linux-nfs.org/~bfields/linux

2012-12-20 14:04:11 -08:00

file_table.c

fput: turn "list_head delayed_fput_list" into llist_head

2013-07-13 13:29:10 +04:00

file.c

don't bother with deferred freeing of fdtables

2013-05-01 17:31:42 -04:00

filesystems.c

fs: Limit sys_mount to only request filesystem modules.

2013-03-03 19:36:31 -08:00

fs_struct.c

constify path_get/path_put and fs_struct.c stuff

2013-03-01 23:51:07 -05:00

fs-writeback.c

mm/writeback: don't check force_wait to handle bdi->work_list

2013-07-09 10:33:22 -07:00

generic_acl.c

…

inode.c

allow the temp files created by open() to be linked to

2013-06-29 12:57:11 +04:00

internal.h

constify rw_verify_area()

2013-06-29 12:57:34 +04:00

ioctl.c

new helper: file_inode(file)

2013-02-22 23:31:31 -05:00

ioprio.c

…

Kconfig

efivarfs: Move to fs/efivarfs

2013-04-17 13:25:09 +01:00

Kconfig.binfmt

fs: make binfmt support for #! scripts modular and removable

2013-04-30 17:04:04 -07:00

libfs.c

make simple_lookup() usable for filesystems that set ->s_d_op

2013-07-14 17:43:25 +04:00

locks.c

locks: move file_lock_list to a set of percpu hlist_heads and convert file_lock_lock to an lglock

2013-07-08 13:36:42 +04:00

Makefile

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2013-05-01 17:51:54 -07:00

mbcache.c

…

mount.h

get rid of full-hash scan on detaching vfsmounts

2013-04-09 14:12:52 -04:00

mpage.c

…

namei.c

fs: Allow unprivileged linkat(..., AT_EMPTY_PATH) aka flink

2013-08-05 18:24:11 +04:00

namespace.c

create_mnt_ns: unidiomatic use of list_add()

2013-05-04 15:18:53 -04:00

no-block.c

…

open.c

fs: Fix file mode for O_TMPFILE

2013-08-05 18:24:10 +04:00

pipe.c

aio: don't include aio.h in sched.h

2013-05-07 20:16:25 -07:00

pnode.c

vfs: Fix invalid ida_remove() call

2013-05-31 15:16:33 -04:00

pnode.h

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2013-05-01 17:51:54 -07:00

posix_acl.c

…

proc_namespace.c

…

read_write.c

vfs: export lseek_execute() to modules

2013-07-03 16:23:27 +04:00

readdir.c

[readdir] constify ->actor

2013-06-29 12:57:05 +04:00

select.c

net: rename include/net/ll_poll.h to include/net/busy_poll.h

2013-07-10 17:08:27 -07:00

seq_file.c

seq_file: add seq_list_*_percpu helpers

2013-07-08 13:36:41 +04:00

signalfd.c

switch signalfd{,4}() to COMPAT_SYSCALL_DEFINE

2013-03-03 22:58:46 -05:00

splice.c

Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs

2013-07-03 09:10:19 -07:00

stack.c

…

stat.c

switch vfs_getattr() to struct path

2013-02-26 02:46:08 -05:00

statfs.c

vfs: fix user_statfs to retry once on ESTALE errors

2012-12-20 18:50:07 -05:00

super.c

livelock avoidance in sget()

2013-07-20 04:58:58 +04:00

sync.c

teach SYSCALL_DEFINE<n> how to deal with long long/unsigned long long

2013-03-03 22:46:22 -05:00

timerfd.c

timerfd: Add alarm timers

2013-05-29 12:57:34 -07:00

utimes.c

vfs: allow utimensat() calls to retry once on an ESTALE error

2012-12-20 18:50:08 -05:00

xattr_acl.c

…

xattr.c

vfs: make lremovexattr retry once on ESTALE error

2012-12-20 18:50:11 -05:00