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Ye Bin 0be698ecbe ext4: fix use-after-free in ext4_rename_dir_prepare
We got issue as follows:
EXT4-fs (loop0): mounted filesystem without journal. Opts: ,errors=continue
ext4_get_first_dir_block: bh->b_data=0xffff88810bee6000 len=34478
ext4_get_first_dir_block: *parent_de=0xffff88810beee6ae bh->b_data=0xffff88810bee6000
ext4_rename_dir_prepare: [1] parent_de=0xffff88810beee6ae
==================================================================
BUG: KASAN: use-after-free in ext4_rename_dir_prepare+0x152/0x220
Read of size 4 at addr ffff88810beee6ae by task rep/1895

CPU: 13 PID: 1895 Comm: rep Not tainted 5.10.0+ #241
Call Trace:
 dump_stack+0xbe/0xf9
 print_address_description.constprop.0+0x1e/0x220
 kasan_report.cold+0x37/0x7f
 ext4_rename_dir_prepare+0x152/0x220
 ext4_rename+0xf44/0x1ad0
 ext4_rename2+0x11c/0x170
 vfs_rename+0xa84/0x1440
 do_renameat2+0x683/0x8f0
 __x64_sys_renameat+0x53/0x60
 do_syscall_64+0x33/0x40
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x7f45a6fc41c9
RSP: 002b:00007ffc5a470218 EFLAGS: 00000246 ORIG_RAX: 0000000000000108
RAX: ffffffffffffffda RBX: 0000000000000000 RCX: 00007f45a6fc41c9
RDX: 0000000000000005 RSI: 0000000020000180 RDI: 0000000000000005
RBP: 00007ffc5a470240 R08: 00007ffc5a470160 R09: 0000000020000080
R10: 00000000200001c0 R11: 0000000000000246 R12: 0000000000400bb0
R13: 00007ffc5a470320 R14: 0000000000000000 R15: 0000000000000000

The buggy address belongs to the page:
page:00000000440015ce refcount:0 mapcount:0 mapping:0000000000000000 index:0x1 pfn:0x10beee
flags: 0x200000000000000()
raw: 0200000000000000 ffffea00043ff4c8 ffffea0004325608 0000000000000000
raw: 0000000000000001 0000000000000000 00000000ffffffff 0000000000000000
page dumped because: kasan: bad access detected

Memory state around the buggy address:
 ffff88810beee580: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88810beee600: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
>ffff88810beee680: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
                                  ^
 ffff88810beee700: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
 ffff88810beee780: ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff ff
==================================================================
Disabling lock debugging due to kernel taint
ext4_rename_dir_prepare: [2] parent_de->inode=3537895424
ext4_rename_dir_prepare: [3] dir=0xffff888124170140
ext4_rename_dir_prepare: [4] ino=2
ext4_rename_dir_prepare: ent->dir->i_ino=2 parent=-757071872

Reason is first directory entry which 'rec_len' is 34478, then will get illegal
parent entry. Now, we do not check directory entry after read directory block
in 'ext4_get_first_dir_block'.
To solve this issue, check directory entry in 'ext4_get_first_dir_block'.

[ Trigger an ext4_error() instead of just warning if the directory is
  missing a '.' or '..' entry.   Also make sure we return an error code
  if the file system is corrupted.  -TYT ]

Signed-off-by: Ye Bin <yebin10@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220414025223.4113128-1-yebin10@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
2022-05-17 14:16:56 -04:00
arch ARM: 2022-05-01 11:49:32 -07:00
block bfq: Fix warning in bfqq_request_over_limit() 2022-04-29 06:45:37 -06:00
certs Kbuild updates for v5.18 2022-03-31 11:59:03 -07:00
crypto for-5.18/64bit-pi-2022-03-25 2022-03-26 12:01:35 -07:00
Documentation ARM: 2022-05-01 11:49:32 -07:00
drivers - Fix locking when accessing device MSI descriptors 2022-05-01 09:30:47 -07:00
fs ext4: fix use-after-free in ext4_rename_dir_prepare 2022-05-17 14:16:56 -04:00
include ARM: 2022-05-01 11:49:32 -07:00
init Kbuild updates for v5.18 2022-03-31 11:59:03 -07:00
ipc fs: allocate inode by using alloc_inode_sb() 2022-03-22 15:57:03 -07:00
kernel Networking fixes for 5.18-rc5, including fixes from bluetooth, bpf 2022-04-28 12:34:50 -07:00
lib - A fix to disable PCI/MSI[-X] masking for XEN_HVM guests as that is 2022-05-01 10:03:36 -07:00
LICENSES LICENSES/LGPL-2.1: Add LGPL-2.1-or-later as valid identifiers 2021-12-16 14:33:10 +01:00
mm kasan: prevent cpu_quarantine corruption when CPU offline and cache shrink occur at same time 2022-04-27 13:28:48 -07:00
net A fix for a NULL dereference that turns out to be easily triggerable 2022-04-29 14:37:35 -07:00
samples dma-mapping updates for Linux 5.18 2022-03-29 08:50:14 -07:00
scripts objtool: Enable unreachable warnings for CLANG LTO 2022-04-19 21:58:48 +02:00
security hardening updates for v5.18-rc1-fix1 2022-03-31 11:43:01 -07:00
sound ALSA: hda/realtek: Add quirk for Clevo NP70PNP 2022-04-21 21:23:47 +02:00
tools - A fix to disable PCI/MSI[-X] masking for XEN_HVM guests as that is 2022-05-01 10:03:36 -07:00
usr Kbuild updates for v5.18 2022-03-31 11:59:03 -07:00
virt Merge branch 'kvm-fixes-for-5.18-rc5' into HEAD 2022-04-29 12:39:34 -04:00
.clang-format genirq/msi: Make interrupt allocation less convoluted 2021-12-16 22:22:20 +01:00
.cocciconfig
.get_maintainer.ignore Opt out of scripts/get_maintainer.pl 2019-05-16 10:53:40 -07:00
.gitattributes .gitattributes: use 'dts' diff driver for dts files 2019-12-04 19:44:11 -08:00
.gitignore .gitignore: ignore only top-level modules.builtin 2021-05-02 00:43:35 +09:00
.mailmap mailmap: update Vasily Averin's email address 2022-04-08 14:20:36 -10:00
COPYING COPYING: state that all contributions really are covered by this file 2020-02-10 13:32:20 -08:00
CREDITS MAINTAINERS: replace a Microchip AT91 maintainer 2022-02-09 11:30:01 +01:00
Kbuild kbuild: rename hostprogs-y/always to hostprogs/always-y 2020-02-04 01:53:07 +09:00
Kconfig kbuild: ensure full rebuild when the compiler is updated 2020-05-12 13:28:33 +09:00
MAINTAINERS - A fix to disable PCI/MSI[-X] masking for XEN_HVM guests as that is 2022-05-01 10:03:36 -07:00
Makefile Linux 5.18-rc5 2022-05-01 13:57:58 -07:00
README Drop all 00-INDEX files from Documentation/ 2018-09-09 15:08:58 -06:00

Linux kernel
============

There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.

In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``.  The formatted documentation can also be read online at:

    https://www.kernel.org/doc/html/latest/

There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.

Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.