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Filename Latest commit message Latest commit date
Baokun Li 3638aa1c7d ext4: fix null-ptr-deref in ext4_write_info
commit f9c1f248607d5546075d3f731e7607d5571f2b60 upstream.

I caught a null-ptr-deref bug as follows:
==================================================================
KASAN: null-ptr-deref in range [0x0000000000000068-0x000000000000006f]
CPU: 1 PID: 1589 Comm: umount Not tainted 5.10.0-02219-dirty #339
RIP: 0010:ext4_write_info+0x53/0x1b0
[...]
Call Trace:
 dquot_writeback_dquots+0x341/0x9a0
 ext4_sync_fs+0x19e/0x800
 __sync_filesystem+0x83/0x100
 sync_filesystem+0x89/0xf0
 generic_shutdown_super+0x79/0x3e0
 kill_block_super+0xa1/0x110
 deactivate_locked_super+0xac/0x130
 deactivate_super+0xb6/0xd0
 cleanup_mnt+0x289/0x400
 __cleanup_mnt+0x16/0x20
 task_work_run+0x11c/0x1c0
 exit_to_user_mode_prepare+0x203/0x210
 syscall_exit_to_user_mode+0x5b/0x3a0
 do_syscall_64+0x59/0x70
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
 ==================================================================

Above issue may happen as follows:
-------------------------------------
exit_to_user_mode_prepare
 task_work_run
  __cleanup_mnt
   cleanup_mnt
    deactivate_super
     deactivate_locked_super
      kill_block_super
       generic_shutdown_super
        shrink_dcache_for_umount
         dentry = sb->s_root
         sb->s_root = NULL              <--- Here set NULL
        sync_filesystem
         __sync_filesystem
          sb->s_op->sync_fs > ext4_sync_fs
           dquot_writeback_dquots
            sb->dq_op->write_info > ext4_write_info
             ext4_journal_start(d_inode(sb->s_root), EXT4_HT_QUOTA, 2)
              d_inode(sb->s_root)
               s_root->d_inode          <--- Null pointer dereference

To solve this problem, we use ext4_journal_start_sb directly
to avoid s_root being used.

Cc: stable@kernel.org
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Link: https://lore.kernel.org/r/20220805123947.565152-1-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-10-26 13:22:18 +02:00
arch powerpc/boot: Explicitly disable usage of SPE instructions 2022-10-26 13:22:16 +02:00
block blk-mq: don't create hctx debugfs dir until q->debugfs_dir is created 2022-08-25 11:17:36 +02:00
certs certs/blacklist_hashes.c: fix const confusion in certs blacklist 2022-06-22 14:11:22 +02:00
crypto crypto: drbg - make reseeding from get_random_bytes() synchronous 2022-06-22 14:11:18 +02:00
Documentation ARM: dts: fix Moxa SDIO 'compatible', remove 'sdhci' misnomer 2022-10-15 07:54:37 +02:00
drivers fbdev: smscufx: Fix use-after-free in ufx_ops_open() 2022-10-26 13:22:16 +02:00
fs ext4: fix null-ptr-deref in ext4_write_info 2022-10-26 13:22:18 +02:00
include scsi: stex: Properly zero out the passthrough command structure 2022-10-15 07:54:39 +02:00
init random: handle latent entropy and command line from random_init() 2022-06-22 14:11:17 +02:00
ipc ipc/mqueue: use get_tree_nodev() in mqueue_get_tree() 2022-06-14 18:11:41 +02:00
kernel workqueue: don't skip lockdep work dependency in cancel_work_sync() 2022-09-28 11:04:09 +02:00
lib lib/vdso: Mark do_hres() and do_coarse() as __always_inline 2022-09-05 10:27:47 +02:00
LICENSES
mm mm: pagewalk: Fix race between unmap and page walker 2022-10-15 07:54:36 +02:00
net wifi: mac80211: fix MBSSID parsing use-after-free 2022-10-17 17:24:32 +02:00
samples samples/kretprobes: Fix return value if register_kretprobe() failed 2021-11-17 09:48:39 +01:00
scripts Makefile.extrawarn: Move -Wcast-function-type-strict to W=1 2022-10-07 09:16:57 +02:00
security efi: Correct Macmini DMI match in uefi cert quirk 2022-10-15 07:54:39 +02:00
sound ASoC: wcd9335: fix order of Slimbus unprepare/disable 2022-10-26 13:22:14 +02:00
tools perf tools: Fixup get_current_dir_name() compilation 2022-10-15 07:54:36 +02:00
usr
virt KVM: Add infrastructure and macro to mark VM as bugged 2022-08-25 11:18:16 +02:00
.clang-format
.cocciconfig
.get_maintainer.ignore
.gitattributes
.gitignore
.mailmap
COPYING
CREDITS
Kbuild
Kconfig
MAINTAINERS MAINTAINERS: add Chandan as xfs maintainer for 5.4.y 2022-09-28 11:03:58 +02:00
Makefile Linux 5.4.219 2022-10-17 17:24:32 +02:00
README

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.