linux.git/fs/jffs2, branch v5.11

jffs2: Fix NULL pointer dereference in rp_size fs option parsing

2020-12-13T20:57:21+00:00

syzkaller found the following JFFS2 splat:

  Unable to handle kernel paging request at virtual address dfffa00000000001
  Mem abort info:
    ESR = 0x96000004
    EC = 0x25: DABT (current EL), IL = 32 bits
    SET = 0, FnV = 0
    EA = 0, S1PTW = 0
  Data abort info:
    ISV = 0, ISS = 0x00000004
    CM = 0, WnR = 0
  [dfffa00000000001] address between user and kernel address ranges
  Internal error: Oops: 96000004 [#1] SMP
  Dumping ftrace buffer:
     (ftrace buffer empty)
  Modules linked in:
  CPU: 0 PID: 12745 Comm: syz-executor.5 Tainted: G S                5.9.0-rc8+ #98
  Hardware name: linux,dummy-virt (DT)
  pstate: 20400005 (nzCv daif +PAN -UAO BTYPE=--)
  pc : jffs2_parse_param+0x138/0x308 fs/jffs2/super.c:206
  lr : jffs2_parse_param+0x108/0x308 fs/jffs2/super.c:205
  sp : ffff000022a57910
  x29: ffff000022a57910 x28: 0000000000000000
  x27: ffff000057634008 x26: 000000000000d800
  x25: 000000000000d800 x24: ffff0000271a9000
  x23: ffffa0001adb5dc0 x22: ffff000023fdcf00
  x21: 1fffe0000454af2c x20: ffff000024cc9400
  x19: 0000000000000000 x18: 0000000000000000
  x17: 0000000000000000 x16: ffffa000102dbdd0
  x15: 0000000000000000 x14: ffffa000109e44bc
  x13: ffffa00010a3a26c x12: ffff80000476e0b3
  x11: 1fffe0000476e0b2 x10: ffff80000476e0b2
  x9 : ffffa00010a3ad60 x8 : ffff000023b70593
  x7 : 0000000000000003 x6 : 00000000f1f1f1f1
  x5 : ffff000023fdcf00 x4 : 0000000000000002
  x3 : ffffa00010000000 x2 : 0000000000000001
  x1 : dfffa00000000000 x0 : 0000000000000008
  Call trace:
   jffs2_parse_param+0x138/0x308 fs/jffs2/super.c:206
   vfs_parse_fs_param+0x234/0x4e8 fs/fs_context.c:117
   vfs_parse_fs_string+0xe8/0x148 fs/fs_context.c:161
   generic_parse_monolithic+0x17c/0x208 fs/fs_context.c:201
   parse_monolithic_mount_data+0x7c/0xa8 fs/fs_context.c:649
   do_new_mount fs/namespace.c:2871 [inline]
   path_mount+0x548/0x1da8 fs/namespace.c:3192
   do_mount+0x124/0x138 fs/namespace.c:3205
   __do_sys_mount fs/namespace.c:3413 [inline]
   __se_sys_mount fs/namespace.c:3390 [inline]
   __arm64_sys_mount+0x164/0x238 fs/namespace.c:3390
   __invoke_syscall arch/arm64/kernel/syscall.c:36 [inline]
   invoke_syscall arch/arm64/kernel/syscall.c:48 [inline]
   el0_svc_common.constprop.0+0x15c/0x598 arch/arm64/kernel/syscall.c:149
   do_el0_svc+0x60/0x150 arch/arm64/kernel/syscall.c:195
   el0_svc+0x34/0xb0 arch/arm64/kernel/entry-common.c:226
   el0_sync_handler+0xc8/0x5b4 arch/arm64/kernel/entry-common.c:236
   el0_sync+0x15c/0x180 arch/arm64/kernel/entry.S:663
  Code: d2d40001 f2fbffe1 91002260 d343fc02 (38e16841)
  ---[ end trace 4edf690313deda44 ]---

This is because since ec10a24f10c8, the option parsing happens before
fill_super and so the MTD device isn't associated with the filesystem.
Defer the size check until there is a valid association.

Fixes: ec10a24f10c8 ("vfs: Convert jffs2 to use the new mount API")
Cc: 
Cc: David Howells 
Signed-off-by: Jamie Iles 
Signed-off-by: Richard Weinberger

jffs2: remove trailing semicolon in macro definition

2020-12-13T20:57:20+00:00

The macro use will already have a semicolon.

Signed-off-by: Tom Rix 
Signed-off-by: Richard Weinberger

jffs2: Allow setting rp_size to zero during remounting

2020-12-13T20:56:24+00:00

Set rp_size to zero will be ignore during remounting.

The method to identify whether we input a remounting option of
rp_size is to check if the rp_size input is zero. It can not work
well if we pass "rp_size=0".

This patch add a bool variable "set_rp_size" to fix this problem.

Reported-by: Jubin Zhong 
Signed-off-by: lizhe 
Signed-off-by: Richard Weinberger

jffs2: Fix ignoring mounting options problem during remounting

2020-12-13T20:55:59+00:00

The jffs2 mount options will be ignored when remounting jffs2.
It can be easily reproduced with the steps listed below.
1. mount -t jffs2 -o compr=none /dev/mtdblockx /mnt
2. mount -o remount compr=zlib /mnt

Since ec10a24f10c8, the option parsing happens before fill_super and
then pass fc, which contains the options parsing results, to function
jffs2_reconfigure during remounting. But function jffs2_reconfigure do
not update c->mount_opts.

This patch add a function jffs2_update_mount_opts to fix this problem.

By the way, I notice that tmpfs use the same way to update remounting
options. If it is necessary to unify them?

Cc: 
Fixes: ec10a24f10c8 ("vfs: Convert jffs2 to use the new mount API")
Signed-off-by: lizhe 
Signed-off-by: Richard Weinberger

jffs2: Fix GC exit abnormally

2020-12-13T20:55:39+00:00

The log of this problem is:
jffs2: Error garbage collecting node at 0x***!
jffs2: No space for garbage collection. Aborting GC thread

This is because GC believe that it do nothing, so it abort.

After going over the image of jffs2, I find a scene that
can trigger this problem stably.
The scene is: there is a normal dirent node at summary-area,
but abnormal at corresponding not-summary-area with error
name_crc.

The reason that GC exit abnormally is because it find that
abnormal dirent node to GC, but when it goes to function
jffs2_add_fd_to_list, it cannot meet the condition listed
below:

if ((*prev)->nhash == new->nhash && !strcmp((*prev)->name, new->name))

So no node is marked obsolete, statistical information of
erase_block do not change, which cause GC exit abnormally.

The root cause of this problem is: we do not check the
name_crc of the abnormal dirent node with summary is enabled.

Noticed that in function jffs2_scan_dirent_node, we use
function jffs2_scan_dirty_space to deal with the dirent
node with error name_crc. So this patch add a checking
code in function read_direntry to ensure the correctness
of dirent node. If checked failed, the dirent node will
be marked obsolete so GC will pass this node and this
problem will be fixed.

Cc: 
Signed-off-by: Zhe Li 
Signed-off-by: Richard Weinberger

jffs2: Fix if/else empty body warnings

2020-12-13T20:51:54+00:00

When debug (print) macros are not enabled, change them to use the
no_printk() macro instead of . This fixes gcc warnings when
-Wextra is used:

../fs/jffs2/nodelist.c:255:37: warning: suggest braces around empty body in an ‘else’ statement [-Wempty-body]
../fs/jffs2/nodelist.c:278:38: warning: suggest braces around empty body in an ‘else’ statement [-Wempty-body]
../fs/jffs2/nodelist.c:558:52: warning: suggest braces around empty body in an ‘else’ statement [-Wempty-body]
../fs/jffs2/xattr.c:1247:58: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]
../fs/jffs2/xattr.c:1281:65: warning: suggest braces around empty body in an ‘if’ statement [-Wempty-body]

Builds without warnings on all 3 levels of CONFIG_JFFS2_FS_DEBUG.

Signed-off-by: Randy Dunlap 
Cc: David Woodhouse 
Cc: Richard Weinberger 
Cc: linux-mtd@lists.infradead.org
Signed-off-by: Richard Weinberger

treewide: Use fallthrough pseudo-keyword

2020-08-23T22:36:59+00:00

Replace the existing /* fall through */ comments and its variants with
the new pseudo-keyword macro fallthrough[1]. Also, remove unnecessary
fall-through markings when it is the case.

[1] https://www.kernel.org/doc/html/v5.7/process/deprecated.html?highlight=fallthrough#implicit-switch-case-fall-through

Signed-off-by: Gustavo A. R. Silva

Merge tag 'for-linus-5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/ubifs

2020-08-11T01:20:04+00:00

Pull JFFS2, UBI and UBIFS updates from Richard Weinberger:
 "JFFS2:
   - Fix for a corner case while mounting
   - Fix for an use-after-free issue

  UBI:
   - Fix for a memory load while attaching
   - Don't produce an anchor PEB with fastmap being disabled

  UBIFS:
   - Fix for orphan inode logic
   - Spelling fixes
   - New mount option to specify filesystem version"

* tag 'for-linus-5.9-rc1' of git://git.kernel.org/pub/scm/linux/kernel/git/rw/ubifs:
  jffs2: fix UAF problem
  jffs2: fix jffs2 mounting failure
  ubifs: Fix wrong orphan node deletion in ubifs_jnl_update|rename
  ubi: fastmap: Free fastmap next anchor peb during detach
  ubi: fastmap: Don't produce the initial next anchor PEB when fastmap is disabled
  ubifs: misc.h: delete a duplicated word
  ubifs: add option to specify version for new file systems

jffs2: fix UAF problem

2020-08-02T21:56:13+00:00

The log of UAF problem is listed below.
BUG: KASAN: use-after-free in jffs2_rmdir+0xa4/0x1cc [jffs2] at addr c1f165fc
Read of size 4 by task rm/8283
=============================================================================
BUG kmalloc-32 (Tainted: P    B      O   ): kasan: bad access detected
-----------------------------------------------------------------------------

INFO: Allocated in 0xbbbbbbbb age=3054364 cpu=0 pid=0
        0xb0bba6ef
        jffs2_write_dirent+0x11c/0x9c8 [jffs2]
        __slab_alloc.isra.21.constprop.25+0x2c/0x44
        __kmalloc+0x1dc/0x370
        jffs2_write_dirent+0x11c/0x9c8 [jffs2]
        jffs2_do_unlink+0x328/0x5fc [jffs2]
        jffs2_rmdir+0x110/0x1cc [jffs2]
        vfs_rmdir+0x180/0x268
        do_rmdir+0x2cc/0x300
        ret_from_syscall+0x0/0x3c
INFO: Freed in 0x205b age=3054364 cpu=0 pid=0
        0x2e9173
        jffs2_add_fd_to_list+0x138/0x1dc [jffs2]
        jffs2_add_fd_to_list+0x138/0x1dc [jffs2]
        jffs2_garbage_collect_dirent.isra.3+0x21c/0x288 [jffs2]
        jffs2_garbage_collect_live+0x16bc/0x1800 [jffs2]
        jffs2_garbage_collect_pass+0x678/0x11d4 [jffs2]
        jffs2_garbage_collect_thread+0x1e8/0x3b0 [jffs2]
        kthread+0x1a8/0x1b0
        ret_from_kernel_thread+0x5c/0x64
Call Trace:
[c17ddd20] [c02452d4] kasan_report.part.0+0x298/0x72c (unreliable)
[c17ddda0] [d2509680] jffs2_rmdir+0xa4/0x1cc [jffs2]
[c17dddd0] [c026da04] vfs_rmdir+0x180/0x268
[c17dde00] [c026f4e4] do_rmdir+0x2cc/0x300
[c17ddf40] [c001a658] ret_from_syscall+0x0/0x3c

The root cause is that we don't get "jffs2_inode_info.sem" before
we scan list "jffs2_inode_info.dents" in function jffs2_rmdir.
This patch add codes to get "jffs2_inode_info.sem" before we scan
"jffs2_inode_info.dents" to slove the UAF problem.

Signed-off-by: Zhe Li 
Reviewed-by: Hou Tao 
Signed-off-by: Richard Weinberger

jffs2: fix jffs2 mounting failure

2020-08-02T21:56:13+00:00

Thanks for the advice mentioned in the email.
This is my v3 patch for this problem.

Mounting jffs2 on nand flash will get message "failed: I/O error"
with the steps listed below.
1.umount jffs2
2.erase nand flash
3.mount jffs2 on it (this mounting operation will be successful)
4.do chown or chmod to the mount point directory
5.umount jffs2
6.mount jffs2 on nand flash
After step 6, we will get message "mount ... failed: I/O error".

Typical image of this problem is like:
Empty space found from 0x00000000 to 0x008a0000
Inode node at xx, totlen 0x00000044, #ino 1, version 1, isize 0...

The reason for this mounting failure is that at the end of function
jffs2_scan_medium(), jffs2 will check the used_size and some info
of nr_blocks.If conditions are met, it will return -EIO.

The detail is that, in the steps listed above, step 4 will write
jffs2_raw_inode into flash without jffs2_raw_dirent, which will
cause that there are some jffs2_raw_inode but no jffs2_raw_dirent
on flash. This will meet the condition at the end of function
jffs2_scan_medium() and return -EIO if we umount jffs2 and mount it
again.

We notice that jffs2 add the value of c->unchecked_size if we find
an inode node while mounting. And jffs2 will never add the value of
c->unchecked_size in other situations. So this patch add one more
condition about c->unchecked_size of the judgement to fix this problem.

Signed-off-by: Zhe Li 
Signed-off-by: Richard Weinberger