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Filename Latest commit message Latest commit date
Baokun Li 30bf7244ac jffs2: fix use-after-free in jffs2_clear_xattr_subsystem
commit 4c7c44ee1650677fbe89d86edbad9497b7679b5c upstream.

When we mount a jffs2 image, assume that the first few blocks of
the image are normal and contain at least one xattr-related inode,
but the next block is abnormal. As a result, an error is returned
in jffs2_scan_eraseblock(). jffs2_clear_xattr_subsystem() is then
called in jffs2_build_filesystem() and then again in
jffs2_do_fill_super().

Finally we can observe the following report:
 ==================================================================
 BUG: KASAN: use-after-free in jffs2_clear_xattr_subsystem+0x95/0x6ac
 Read of size 8 at addr ffff8881243384e0 by task mount/719

 Call Trace:
  dump_stack+0x115/0x16b
  jffs2_clear_xattr_subsystem+0x95/0x6ac
  jffs2_do_fill_super+0x84f/0xc30
  jffs2_fill_super+0x2ea/0x4c0
  mtd_get_sb+0x254/0x400
  mtd_get_sb_by_nr+0x4f/0xd0
  get_tree_mtd+0x498/0x840
  jffs2_get_tree+0x25/0x30
  vfs_get_tree+0x8d/0x2e0
  path_mount+0x50f/0x1e50
  do_mount+0x107/0x130
  __se_sys_mount+0x1c5/0x2f0
  __x64_sys_mount+0xc7/0x160
  do_syscall_64+0x45/0x70
  entry_SYSCALL_64_after_hwframe+0x44/0xa9

 Allocated by task 719:
  kasan_save_stack+0x23/0x60
  __kasan_kmalloc.constprop.0+0x10b/0x120
  kasan_slab_alloc+0x12/0x20
  kmem_cache_alloc+0x1c0/0x870
  jffs2_alloc_xattr_ref+0x2f/0xa0
  jffs2_scan_medium.cold+0x3713/0x4794
  jffs2_do_mount_fs.cold+0xa7/0x2253
  jffs2_do_fill_super+0x383/0xc30
  jffs2_fill_super+0x2ea/0x4c0
 [...]

 Freed by task 719:
  kmem_cache_free+0xcc/0x7b0
  jffs2_free_xattr_ref+0x78/0x98
  jffs2_clear_xattr_subsystem+0xa1/0x6ac
  jffs2_do_mount_fs.cold+0x5e6/0x2253
  jffs2_do_fill_super+0x383/0xc30
  jffs2_fill_super+0x2ea/0x4c0
 [...]

 The buggy address belongs to the object at ffff8881243384b8
  which belongs to the cache jffs2_xattr_ref of size 48
 The buggy address is located 40 bytes inside of
  48-byte region [ffff8881243384b8, ffff8881243384e8)
 [...]
 ==================================================================

The triggering of the BUG is shown in the following stack:
-----------------------------------------------------------
jffs2_fill_super
  jffs2_do_fill_super
    jffs2_do_mount_fs
      jffs2_build_filesystem
        jffs2_scan_medium
          jffs2_scan_eraseblock        <--- ERROR
        jffs2_clear_xattr_subsystem    <--- free
    jffs2_clear_xattr_subsystem        <--- free again
-----------------------------------------------------------

An error is returned in jffs2_do_mount_fs(). If the error is returned
by jffs2_sum_init(), the jffs2_clear_xattr_subsystem() does not need to
be executed. If the error is returned by jffs2_build_filesystem(), the
jffs2_clear_xattr_subsystem() also does not need to be executed again.
So move jffs2_clear_xattr_subsystem() from 'out_inohash' to 'out_root'
to fix this UAF problem.

Fixes: aa98d7cf59 ("[JFFS2][XATTR] XATTR support on JFFS2 (version. 5)")
Cc: stable@vger.kernel.org
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Baokun Li <libaokun1@huawei.com>
Signed-off-by: Richard Weinberger <richard@nod.at>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2022-04-15 14:17:59 +02:00
arch nds32: fix access_ok() checks in get/put_user 2022-03-28 08:46:48 +02:00
block block: Fix fsync always failed if once failed 2022-03-08 19:07:47 +01:00
certs certs: Trigger creation of RSA module signing key if it's not an RSA key 2021-09-15 09:47:29 +02:00
crypto crypto: pcrypt - Delay write to padata->info 2021-11-17 09:48:40 +01:00
Documentation Documentation: update stable tree link 2022-04-15 14:17:58 +02:00
drivers can: ems_usb: ems_usb_start_xmit(): fix double dev_kfree_skb() in error path 2022-04-15 14:17:59 +02:00
fs jffs2: fix use-after-free in jffs2_clear_xattr_subsystem 2022-04-15 14:17:59 +02:00
include NFSD: prevent integer overflow on 32 bit systems 2022-04-15 14:17:59 +02:00
init bpf: Add kconfig knob for disabling unpriv bpf by default 2022-02-16 12:52:49 +01:00
ipc shm: extend forced shm destroy to support objects from several IPC nses 2021-12-01 09:23:35 +01:00
kernel ptrace: Check PTRACE_O_SUSPEND_SECCOMP permission on PTRACE_SEIZE 2022-04-15 14:17:58 +02:00
lib ARM: 9178/1: fix unmet dependency on BITREVERSE for HAVE_ARCH_BITREVERSE 2022-03-19 13:40:16 +01:00
LICENSES
mm memfd: fix F_SEAL_WRITE after shmem huge page allocated 2022-03-08 19:07:49 +01:00
net SUNRPC: avoid race between mod_timer() and del_timer_sync() 2022-04-15 14:17:58 +02:00
samples samples/kretprobes: Fix return value if register_kretprobe() failed 2021-11-17 09:48:39 +01:00
scripts kconfig: fix failing to generate auto.conf 2022-02-23 12:00:01 +01:00
security KEYS: fix length validation in keyctl_pkey_params_get_2() 2022-04-15 14:17:58 +02:00
sound ALSA: hda/realtek: Add quirk for ASUS GA402 2022-03-28 08:46:46 +02:00
tools Revert "selftests/bpf: Add test for bpf_timer overwriting crash" 2022-03-23 09:12:08 +01:00
usr
virt KVM: arm64: Allow SMCCC_ARCH_WORKAROUND_3 to be discovered and migrated 2022-03-19 13:40:15 +01:00
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Makefile Linux 5.4.188 2022-03-28 08:46:49 +02:00
README

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

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

There are various text files in the Documentation/ subdirectory,
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Please read the Documentation/process/changes.rst file, as it contains the
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