linux/fs
Linus Torvalds 53a41cb7ed Revert "x86/fault: BUG() when uaccess helpers fault on kernel addresses"
This reverts commit 9da3f2b740.

It was well-intentioned, but wrong.  Overriding the exception tables for
instructions for random reasons is just wrong, and that is what the new
code did.

It caused problems for tracing, and it caused problems for strncpy_from_user(),
because the new checks made perfectly valid use cases break, rather than
catch things that did bad things.

Unchecked user space accesses are a problem, but that's not a reason to
add invalid checks that then people have to work around with silly flags
(in this case, that 'kernel_uaccess_faults_ok' flag, which is just an
odd way to say "this commit was wrong" and was sprinked into random
places to hide the wrongness).

The real fix to unchecked user space accesses is to get rid of the
special "let's not check __get_user() and __put_user() at all" logic.
Make __{get|put}_user() be just aliases to the regular {get|put}_user()
functions, and make it impossible to access user space without having
the proper checks in places.

The raison d'être of the special double-underscore versions used to be
that the range check was expensive, and if you did multiple user
accesses, you'd do the range check up front (like the signal frame
handling code, for example).  But SMAP (on x86) and PAN (on ARM) have
made that optimization pointless, because the _real_ expense is the "set
CPU flag to allow user space access".

Do let's not break the valid cases to catch invalid cases that shouldn't
even exist.

Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Kees Cook <keescook@chromium.org>
Cc: Tobin C. Harding <tobin@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Jann Horn <jannh@google.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-02-25 09:10:51 -08:00
..
9p Merge branch 'work.afs' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-11-01 19:58:52 -07:00
adfs adfs: use timespec64 for time conversion 2018-08-22 10:52:51 -07:00
affs affs: fix potential memory leak when parsing option 'prefix' 2018-05-28 12:36:41 +02:00
afs afs: Fix race in async call refcounting 2019-01-17 15:17:28 +00:00
autofs autofs: fix error return in autofs_fill_super() 2019-02-01 15:46:24 -08:00
befs fix a series of Documentation/ broken file name references 2018-06-15 18:10:01 -03:00
bfs bfs: extra sanity checking and static inode bitmap 2019-01-04 13:13:47 -08:00
btrfs for-5.0-rc4-tag 2019-02-03 08:48:33 -08:00
cachefiles fscache, cachefiles: remove redundant variable 'cache' 2018-11-30 16:00:58 +00:00
ceph ceph: avoid repeatedly adding inode to mdsc->snap_flush_list 2019-02-18 18:08:29 +01:00
cifs cifs: update internal module version number 2019-01-31 07:05:06 -06:00
coda vfs: change inode times to use struct timespec64 2018-06-05 16:57:31 -07:00
configfs configfs: fix registered group removal 2018-07-17 06:14:07 -07:00
cramfs Make the Cramfs code more robust against filesystem corruptions, 2018-10-30 12:46:25 -07:00
crypto fscrypt: add Adiantum support 2019-01-06 08:36:21 -05:00
debugfs debugfs: debugfs_lookup() should return NULL if not found 2019-01-30 12:39:49 +01:00
devpts devpts: Convert to new IDA API 2018-08-21 23:54:17 -04:00
dlm dlm: fix invalid cluster name warning 2018-12-03 15:30:24 -06:00
ecryptfs ecryptfs_rename(): verify that lower dentries are still OK after lock_rename() 2018-10-09 23:33:17 -04:00
efivarfs efivars: Call guid_parse() against guid_t type of variable 2018-07-22 14:13:44 +02:00
efs
exofs exofs_mount(): fix leaks on failure exits 2018-12-17 18:36:33 -05:00
exportfs exportfs: do not read dentry after free 2018-11-23 09:08:17 -05:00
ext2 \n 2018-12-27 17:00:35 -08:00
ext4 Revert "ext4: use ext4_write_inode() when fsyncing w/o a journal" 2019-01-31 23:41:11 -05:00
f2fs f2fs-for-4.21-rc1 2018-12-31 09:41:37 -08:00
fat Merge branch 'akpm' (patches from Andrew) 2019-01-05 09:16:18 -08:00
freevxfs freevxfs_lookup(): use d_splice_alias() 2018-05-22 14:27:51 -04:00
fscache fscache: fix race between enablement and dropping of object 2018-11-30 15:57:31 +00:00
fuse fuse: decrement NR_WRITEBACK_TEMP on the right page 2019-01-16 10:27:59 +01:00
gfs2 Revert "gfs2: read journal in large chunks to locate the head" 2019-02-14 09:52:51 -08:00
hfs hfs: do not free node before using 2018-11-30 14:56:14 -08:00
hfsplus hfsplus: return file attributes on statx 2019-01-04 13:13:47 -08:00
hostfs vfs: discard ATTR_ATTR_FLAG 2018-08-17 16:20:28 -07:00
hpfs hpfs: remove unnecessary checks on the value of r when assigning error code 2018-08-25 12:42:33 -07:00
hugetlbfs hugetlbfs: revert "Use i_mmap_rwsem to fix page fault/truncate race" 2019-01-08 17:15:11 -08:00
isofs Update email address 2018-09-29 22:47:48 -04:00
jbd2 jbd2: clean up indentation issue, replace spaces with tab 2018-12-04 00:20:10 -05:00
jffs2 jffs2: Fix use of uninitialized delayed_work, lockdep breakage 2018-12-02 09:20:34 +01:00
jfs jfs: remove redundant dquot_initialize() in jfs_evict_inode() 2018-09-20 09:28:49 -05:00
kernfs kernfs: Improve kernfs_notify() poll notification latency 2018-11-27 11:59:33 +01:00
lockd NFS client updates for Linux 4.21 2019-01-02 16:35:23 -08:00
minix minix_lookup: use d_splice_alias() 2018-05-22 14:27:52 -04:00
nfs Merge branch 'fixes-v5.1-rc6' of git://git.kernel.org/pub/scm/linux/kernel/git/jmorris/linux-security 2019-02-20 09:09:33 -08:00
nfs_common
nfsd Revert "nfsd4: return default lease period" 2019-02-14 12:33:19 -05:00
nilfs2 nilfs2: Use xa_erase_irq 2018-11-05 14:57:05 -05:00
nls
notify inotify: Fix fd refcount leak in inotify_add_watch(). 2019-01-02 18:28:37 +01:00
ntfs mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
ocfs2 Merge branch 'akpm' (patches from Andrew) 2019-01-05 09:16:18 -08:00
omfs omfs_lookup(): report IO errors, use d_splice_alias() 2018-05-22 14:27:58 -04:00
openpromfs fs/openpromfs: Use of_node_name_eq for node name comparisons 2018-11-18 13:35:19 -08:00
orangefs fs: don't open code lru_to_page() 2019-01-04 13:13:48 -08:00
overlayfs Revert "ovl: relax permission checking on underlying layers" 2018-12-04 11:31:30 +01:00
proc proc, oom: do not report alien mms when setting oom_score_adj 2019-02-21 09:01:00 -08:00
pstore pstore/ram: Avoid allocation and leak of platform data 2019-01-20 14:44:52 -08:00
qnx4 qnx4_lookup: use d_splice_alias() 2018-05-22 14:27:52 -04:00
qnx6 qnx6_lookup: switch to d_splice_alias() 2018-05-22 14:27:54 -04:00
quota quota: Lock s_umount in exclusive mode for Q_XQUOTA{ON,OFF} quotactls. 2018-12-18 18:29:15 +01:00
ramfs
reiserfs reiserfs: remove workaround code for GCC 3.x 2018-10-31 08:54:14 -07:00
romfs romfs_lookup: switch to d_splice_alias() 2018-05-22 14:27:55 -04:00
squashfs Squashfs: Compute expected length from inode size rather than block length 2018-08-02 09:34:02 -07:00
sysfs sysfs: convert BUG_ON to WARN_ON 2019-01-07 08:53:32 +01:00
sysv sysv: return 'err' instead of 0 in __sysv_write_inode 2018-11-10 08:02:40 -05:00
tracefs tracefs: Annotate tracefs_ops with __ro_after_init 2018-07-31 11:32:44 -04:00
ubifs mm: migrate: drop unused argument of migrate_page_move_mapping() 2018-12-28 12:11:51 -08:00
udf \n 2018-12-27 17:00:35 -08:00
ufs fs/ufs: use ktime_get_real_seconds for sb and cg timestamps 2018-08-17 16:20:27 -07:00
xfs xfs: set buffer ops when repair probes for btree type 2019-02-03 14:03:59 -08:00
Kconfig autofs: remove left-over autofs4 stubs 2018-06-11 08:22:34 -07:00
Kconfig.binfmt kconfig: move the "Executable file formats" menu to fs/Kconfig.binfmt 2018-08-02 08:06:55 +09:00
Makefile autofs: remove left-over autofs4 stubs 2018-06-11 08:22:34 -07:00
aio.c aio: initialize kiocb private in case any filesystems expect it. 2019-02-06 08:04:22 -07:00
anon_inodes.c anon_inode_getfile(): switch to alloc_file_pseudo() 2018-07-12 10:04:27 -04:00
attr.c fs: Fix attr.c kernel-doc 2018-07-03 16:44:45 -04:00
bad_inode.c get rid of 'opened' argument of ->atomic_open() - part 3 2018-07-12 10:04:20 -04:00
binfmt_aout.c Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
binfmt_elf.c signal: Distinguish between kernel_siginfo and siginfo 2018-10-03 16:47:43 +02:00
binfmt_elf_fdpic.c treewide: kmalloc() -> kmalloc_array() 2018-06-12 16:19:22 -07:00
binfmt_em86.c
binfmt_flat.c
binfmt_misc.c turn filp_clone_open() into inline wrapper for dentry_open() 2018-07-10 23:29:03 -04:00
binfmt_script.c exec: load_script: Do not exec truncated interpreter path 2019-02-18 16:49:36 -08:00
block_dev.c blockdev: Fix livelocks on loop device 2019-01-15 07:30:56 -07:00
buffer.c fs: ratelimit __find_get_block_slow() failure message. 2019-02-06 12:58:56 -07:00
char_dev.c
compat.c ncpfs: remove compat functionality 2018-06-05 19:23:26 +02:00
compat_binfmt_elf.c y2038: globally rename compat_time to old_time32 2018-08-27 14:48:48 +02:00
compat_ioctl.c media updates for v4.20-rc1 2018-10-29 14:29:58 -07:00
coredump.c signal: Distinguish between kernel_siginfo and siginfo 2018-10-03 16:47:43 +02:00
d_path.c
dax.c dax fix 4.21 2018-12-31 09:46:39 -08:00
dcache.c fs/dcache: Track & report number of negative dentries 2019-01-30 11:02:11 -08:00
dcookies.c
direct-io.c direct-io: allow direct writes to empty inodes 2019-01-22 08:26:44 -07:00
drop_caches.c fs/drop_caches.c: avoid softlockups in drop_pagecache_sb() 2019-02-01 15:46:24 -08:00
eventfd.c Revert changes to convert to ->poll_mask() and aio IOCB_CMD_POLL 2018-06-28 10:40:47 -07:00
eventpoll.c Merge branch 'akpm' (patches from Andrew) 2019-01-05 09:16:18 -08:00
exec.c Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2019-01-05 13:18:59 -08:00
fcntl.c signal: Distinguish between kernel_siginfo and siginfo 2018-10-03 16:47:43 +02:00
fhandle.c
file.c Char/Misc driver patches for 4.21-rc1 2018-12-28 20:54:57 -08:00
file_table.c mm: convert totalram_pages and totalhigh_pages variables to atomic 2018-12-28 12:11:47 -08:00
filesystems.c
fs-writeback.c writeback: synchronize sync(2) against cgroup writeback membership switches 2019-01-22 14:39:38 -07:00
fs_pin.c
fs_struct.c
inode.c Revert "mm: don't reclaim inodes with many attached pages" 2019-02-12 16:33:18 -08:00
internal.h overlayfs update for 4.19 2018-08-21 18:19:09 -07:00
ioctl.c Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
iomap.c iomap: fix a use after free in iomap_dio_rw 2019-01-27 08:47:42 -08:00
libfs.c
locks.c locks: fix error in locks_move_blocks() 2019-01-02 20:14:50 -05:00
mbcache.c treewide: kmalloc() -> kmalloc_array() 2018-06-12 16:19:22 -07:00
mount.h
mpage.c mpage: mpage_readpages() should submit IO as read-ahead 2018-08-17 16:20:29 -07:00
namei.c Revert "vfs: Allow userns root to call mknod on owned filesystems." 2018-12-22 14:18:34 -08:00
namespace.c Revert "x86/fault: BUG() when uaccess helpers fault on kernel addresses" 2019-02-25 09:10:51 -08:00
no-block.c
nsfs.c
open.c overlayfs update for 4.19 2018-08-21 18:19:09 -07:00
pipe.c Merge branch 'work.open3' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-08-13 19:58:36 -07:00
pnode.c vfs: Suppress MS_* flag defs within the kernel unless explicitly enabled 2018-12-20 16:32:56 +00:00
pnode.h
posix_acl.c
proc_namespace.c
read_write.c Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
readdir.c Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
select.c Remove 'type' argument from access_ok() function 2019-01-03 18:57:57 -08:00
seq_file.c fs/seq_file.c: simplify seq_file iteration code and interface 2018-08-17 16:20:28 -07:00
signalfd.c signal: Distinguish between kernel_siginfo and siginfo 2018-10-03 16:47:43 +02:00
splice.c splice: don't read more than available pipe space 2018-12-04 08:50:49 -08:00
stack.c
stat.c y2038: Remove newstat family from default syscall set 2018-08-29 15:42:20 +02:00
statfs.c kernel: add kcompat_sys_{f,}statfs64() 2018-07-12 14:49:48 +01:00
super.c mount_fs: suppress MAC on MS_SUBMOUNT as well as MS_KERNMOUNT 2018-12-21 11:51:23 -05:00
sync.c
timerfd.c y2038: globally rename compat_time to old_time32 2018-08-27 14:48:48 +02:00
userfaultfd.c userfaultfd: clear flag if remap event not enabled 2018-12-28 12:11:51 -08:00
utimes.c y2038: utimes: Rework #ifdef guards for compat syscalls 2018-08-29 15:42:23 +02:00
xattr.c sysfs: Do not return POSIX ACL xattrs via listxattr 2018-09-18 07:30:48 -04:00