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linux/fs
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Eric W. Biederman a2a1be2de7 signal: Extend exec_id to 64bits 
commit d1e7fd6462 upstream.

Replace the 32bit exec_id with a 64bit exec_id to make it impossible
to wrap the exec_id counter.  With care an attacker can cause exec_id
wrap and send arbitrary signals to a newly exec'd parent.  This
bypasses the signal sending checks if the parent changes their
credentials during exec.

The severity of this problem can been seen that in my limited testing
of a 32bit exec_id it can take as little as 19s to exec 65536 times.
Which means that it can take as little as 14 days to wrap a 32bit
exec_id.  Adam Zabrocki has succeeded wrapping the self_exe_id in 7
days.  Even my slower timing is in the uptime of a typical server.
Which means self_exec_id is simply a speed bump today, and if exec
gets noticably faster self_exec_id won't even be a speed bump.

Extending self_exec_id to 64bits introduces a problem on 32bit
architectures where reading self_exec_id is no longer atomic and can
take two read instructions.  Which means that is is possible to hit
a window where the read value of exec_id does not match the written
value.  So with very lucky timing after this change this still
remains expoiltable.

I have updated the update of exec_id on exec to use WRITE_ONCE
and the read of exec_id in do_notify_parent to use READ_ONCE
to make it clear that there is no locking between these two
locations.

Link: https://lore.kernel.org/kernel-hardening/20200324215049.GA3710@pi3.com.pl
Fixes: 2.3.23pre2
Cc: stable@vger.kernel.org
Signed-off-by: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2020-04-17 10:48:47 +02:00
..
9p 9p: avoid attaching writeback_fid on mmap with type PRIVATE 2019-10-11 18:21:13 +02:00
adfs fs/adfs: super: fix use-after-free bug 2019-08-06 19:06:49 +02:00
affs affs: fix a memory leak in affs_remount 2020-01-27 14:51:21 +01:00
afs afs: Fix some tracing details 2020-04-02 15:28:19 +02:00
autofs autofs: fix a leak in autofs_expire_indirect() 2019-12-13 08:51:01 +01:00
befs fix a series of Documentation/ broken file name references 2018-06-15 18:10:01 -03:00
bfs bfs: add sanity check at bfs_fill_super() 2018-12-01 09:37:27 +01:00
btrfs btrfs: track reloc roots based on their commit root bytenr 2020-04-17 10:48:42 +02:00
cachefiles fscache, cachefiles: remove redundant variable 'cache' 2018-12-17 09:24:40 +01:00
ceph ceph: canonicalize server path in place 2020-04-13 10:45:12 +02:00
cifs cifs_atomic_open(): fix double-put on late allocation failure 2020-03-18 07:14:21 +01:00
coda coda: add error handling for fget 2019-08-06 19:06:51 +02:00
configfs configfs: fix a deadlock in configfs_symlink() 2019-11-12 19:20:47 +01:00
cramfs Cramfs: fix abad comparison when wrap-arounds occur 2018-11-13 11:08:55 -08:00
crypto fscrypt: clean up some BUG_ON()s in block encryption/decryption 2019-07-26 09:14:02 +02:00
debugfs debugfs: fix use-after-free on symlink traversal 2019-05-08 07:21:48 +02:00
devpts fs/devpts: always delete dcache dentry-s in dput() 2019-03-23 20:09:59 +01:00
dlm dlm: fix invalid cluster name warning 2019-12-13 08:52:23 +01:00
ecryptfs ecryptfs: replace BUG_ON with error handling code 2020-02-28 16:38:59 +01:00
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 2019-12-05 09:20:32 +01:00
exportfs exportfs: fix 'passing zero to ERR_PTR()' warning 2020-01-27 14:50:02 +01:00
ext2 ext2: Adjust indentation in ext2_fill_super 2020-02-11 04:34:12 -08:00
ext4 ext4: potential crash on allocation error in ext4_alloc_flex_bg_array() 2020-03-05 16:42:17 +01:00
f2fs f2fs: fix memleak of kobject 2020-02-24 08:34:49 +01:00
fat fat: fix uninit-memory access for partial initialized inode 2020-03-11 14:15:01 +01:00
freevxfs
fscache fscache: fix race between enablement and dropping of object 2018-12-17 09:24:40 +01:00
fuse fuse: verify attributes 2019-12-13 08:52:36 +01:00
gfs2 gfs2: Don't demote a glock until its revokes are written 2020-04-17 10:48:41 +02:00
hfs fs/hfs/extent.c: fix array out of bounds read of array extent 2019-12-01 09:17:10 +01:00
hfsplus hfsplus: update timestamps on truncate() 2019-12-01 09:17:09 +01:00
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 hugetlb: use same fault hash key for shared and private mappings 2019-05-22 07:37:40 +02:00
isofs isofs: reject hardware sector size > 2048 bytes 2018-08-21 11:37:41 +02:00
jbd2 jbd2: fix data races at struct journal_head 2020-03-20 11:55:56 +01:00
jffs2 jffs2: fix use-after-free on symlink traversal 2019-05-08 07:21:48 +02:00
jfs jfs: fix bogus variable self-initialization 2020-01-27 14:50:33 +01:00
kernfs kernfs: fix ino wrap-around detection 2019-12-13 08:52:43 +01:00
lockd lockd: fix decoding of TEST results 2019-12-13 08:51:59 +01:00
minix
nfs nfs: add minor version to nfs_server_key for fscache 2020-04-02 15:28:14 +02:00
nfs_common
nfsd nfsd: Return the correct number of bytes written to the file 2020-02-11 04:34:13 -08:00
nilfs2 nilfs2: convert to SPDX license tags 2018-09-04 16:45:02 -07:00
nls
notify fs: avoid softlockups in s_inodes iterators 2020-01-12 12:17:20 +01:00
ntfs ntfs: mft: remove VLA usage 2018-08-17 16:20:27 -07:00
ocfs2 ocfs2: fix a NULL pointer dereference when call ocfs2_update_inode_fsync_trans() 2020-02-24 08:34:52 +01:00
omfs
openpromfs
orangefs help_next should increase position index 2020-02-24 08:34:53 +01:00
overlayfs ovl: fix wrong WARN_ON() in ovl_cache_update_ino() 2020-02-11 04:34:02 -08:00
proc mm, thp, proc: report THP eligibility for each vma 2019-12-17 20:35:45 +01:00
pstore pstore: pstore_ftrace_seq_next should increase position index 2020-04-17 10:48:47 +02:00
qnx4
qnx6
quota fs: avoid softlockups in s_inodes iterators 2020-01-12 12:17:20 +01:00
ramfs
reiserfs reiserfs: prevent NULL pointer dereference in reiserfs_insert_item() 2020-02-24 08:34:52 +01:00
romfs
squashfs Squashfs: Compute expected length from inode size rather than block length 2018-08-02 09:34:02 -07:00
sysfs Driver core patches for 4.19-rc1 2018-08-18 11:44:53 -07:00
sysv sysv: return 'err' instead of 0 in __sysv_write_inode 2018-12-17 09:24:30 +01:00
tracefs tracefs: Annotate tracefs_ops with __ro_after_init 2018-07-31 11:32:44 -04:00
ubifs ubifs: Fix deadlock in concurrent bulk-read and writepage 2020-02-11 04:34:00 -08:00
udf udf: Fix free space reporting for metadata and virtual partitions 2020-02-24 08:34:45 +01:00
ufs ufs: fix braino in ufs_get_inode_gid() for solaris UFS flavour 2019-05-25 18:23:46 +02:00
xfs xfs: Sanity check flags of Q_XQUOTARM call 2020-01-27 14:49:51 +01:00
aio.c aio: prevent potential eventfd recursion on poll 2020-02-11 04:34:08 -08:00
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
binfmt_elf_fdpic.c treewide: kmalloc() -> kmalloc_array() 2018-06-12 16:19:22 -07:00
binfmt_elf.c binfmt_elf: Do not move brk for INTERP-less ET_EXEC 2019-10-05 13:10:06 +02:00
binfmt_em86.c
binfmt_flat.c fs/binfmt_flat.c: make load_flat_shared_library() work 2019-07-03 13:14:44 +02:00
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 2019-11-06 13:05:37 +01:00
block_dev.c bdev: Refresh bdev size for disks without partitioning 2020-01-09 10:19:07 +01:00
buffer.c fs: fix guard_bio_eod to check for real EOD errors 2019-04-05 22:33:00 +02:00
char_dev.c chardev: Avoid potential use-after-free in 'chrdev_open()' 2020-01-14 20:06:57 +01:00
compat_binfmt_elf.c
compat_ioctl.c fix compat handling of FICLONERANGE, FIDEDUPERANGE and FS_IOC_FIEMAP 2020-01-09 10:19:07 +01:00
compat.c ncpfs: remove compat functionality 2018-06-05 19:23:26 +02:00
coredump.c
d_path.c
dax.c dax: pass NOWAIT flag to iomap_apply 2020-03-05 16:42:12 +01:00
dcache.c dcache: sort the freeing-without-RCU-delay mess for good. 2019-05-25 18:23:26 +02:00
dcookies.c
direct-io.c direct-io: allow direct writes to empty inodes 2019-03-05 17:58:50 +01:00
drop_caches.c fs: avoid softlockups in s_inodes iterators 2020-01-12 12:17:20 +01:00
eventfd.c eventfd: track eventfd_signal() recursion depth 2020-02-11 04:34:08 -08:00
eventpoll.c fs/epoll: drop ovflist branch prediction 2019-02-12 19:47:19 +01:00
exec.c signal: Extend exec_id to 64bits 2020-04-17 10:48:47 +02:00
fcntl.c signal: Don't send signals to tasks that don't exist 2018-08-15 23:03:20 -05:00
fhandle.c
file_table.c overlayfs update for 4.19 2018-08-21 18:19:09 -07:00
file.c fs/file.c: initialize init_files.resize_wait 2019-04-05 22:32:59 +02:00
filesystems.c
fs_pin.c
fs_struct.c
fs-writeback.c cgroup,writeback: don't switch wbs immediately on dead wbs if the memcg is dead 2019-11-12 19:21:20 +01:00
inode.c futex: Fix inode life-time issue 2020-03-25 08:06:14 +01:00
internal.h acct_on(): don't mess with freeze protection 2019-05-31 06:46:05 -07:00
ioctl.c vfs: fix FIGETBSZ ioctl on an overlayfs file 2018-11-21 09:19:14 +01:00
iomap.c iomap: partially revert 4721a60109 (simulated directio short read on EFAULT) 2019-12-13 08:52:56 +01:00
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
libfs.c libfs: fix infoleak in simple_attr_read() 2020-04-02 15:28:21 +02:00
locks.c locks: print unsigned ino in /proc/locks 2020-01-09 10:19:00 +01:00
Makefile autofs: remove left-over autofs4 stubs 2018-06-11 08:22:34 -07:00
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 namei: only return -ECHILD from follow_dotdot_rcu() 2020-03-05 16:42:20 +01:00
namespace.c mnt: fix __detach_mounts infinite loop 2018-11-21 09:19:22 +01:00
no-block.c
nsfs.c dcache: sort the freeing-without-RCU-delay mess for good. 2019-05-25 18:23:26 +02:00
open.c cifs_atomic_open(): fix double-put on late allocation failure 2020-03-18 07:14:21 +01:00
pipe.c fs: prevent page refcount overflow in pipe_buf_get 2019-05-04 09:20:11 +02:00
pnode.c
pnode.h
posix_acl.c
proc_namespace.c
read_write.c vfs: avoid problematic remapping requests into partial EOF block 2019-12-01 09:17:04 +01:00
readdir.c filldir[64]: remove WARN_ON_ONCE() for bad directory entries 2020-01-04 19:13:26 +01:00
select.c Revert changes to convert to ->poll_mask() and aio IOCB_CMD_POLL 2018-06-28 10:40:47 -07:00
seq_file.c seq_file: fix problem when seeking mid-record 2019-08-25 10:47:43 +02:00
signalfd.c Merge branch 'work.compat' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-06-16 16:21:50 +09:00
splice.c splice: only read in as much information as there is pipe buffer space 2019-12-17 20:35:43 +01:00
stack.c
stat.c
statfs.c vfs: Fix EOVERFLOW testing in put_compat_statfs64 2019-10-11 18:21:39 +02:00
super.c Merge branch 'ida-4.19' of git://git.infradead.org/users/willy/linux-dax 2018-08-26 11:48:42 -07:00
sync.c
timerfd.c Merge branch 'work.aio' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs 2018-08-13 20:56:23 -07:00
userfaultfd.c userfaultfd: require CAP_SYS_PTRACE for UFFD_FEATURE_EVENT_FORK 2020-01-04 19:13:18 +01:00
utimes.c
xattr.c sysfs: Do not return POSIX ACL xattrs via listxattr 2018-09-18 07:30:48 -04:00