linux-stable.git/fs/ext4, branch v5.4.233

ext4: Fix function prototype mismatch for ext4_feat_ktype

2023-02-25T10:53:27+00:00

commit 118901ad1f25d2334255b3d50512fa20591531cd upstream.

With clang's kernel control flow integrity (kCFI, CONFIG_CFI_CLANG),
indirect call targets are validated against the expected function
pointer prototype to make sure the call target is valid to help mitigate
ROP attacks. If they are not identical, there is a failure at run time,
which manifests as either a kernel panic or thread getting killed.

ext4_feat_ktype was setting the "release" handler to "kfree", which
doesn't have a matching function prototype. Add a simple wrapper
with the correct prototype.

This was found as a result of Clang's new -Wcast-function-type-strict
flag, which is more sensitive than the simpler -Wcast-function-type,
which only checks for type width mismatches.

Note that this code is only reached when ext4 is a loadable module and
it is being unloaded:

 CFI failure at kobject_put+0xbb/0x1b0 (target: kfree+0x0/0x180; expected type: 0x7c4aa698)
 ...
 RIP: 0010:kobject_put+0xbb/0x1b0
 ...
 Call Trace:
  
  ext4_exit_sysfs+0x14/0x60 [ext4]
  cleanup_module+0x67/0xedb [ext4]

Fixes: b99fee58a20a ("ext4: create ext4_feat kobject dynamically")
Cc: Theodore Ts'o 
Cc: Eric Biggers 
Cc: stable@vger.kernel.org
Build-tested-by: Gustavo A. R. Silva 
Reviewed-by: Gustavo A. R. Silva 
Reviewed-by: Nathan Chancellor 
Link: https://lore.kernel.org/r/20230103234616.never.915-kees@kernel.org
Signed-off-by: Kees Cook 
Reviewed-by: Eric Biggers 
Link: https://lore.kernel.org/r/20230104210908.gonna.388-kees@kernel.org
Signed-off-by: Greg Kroah-Hartman

ext4: fix uninititialized value in 'ext4_evict_inode'

2023-01-18T10:42:03+00:00

[ Upstream commit 7ea71af94eaaaf6d9aed24bc94a05b977a741cb9 ]

Syzbot found the following issue:
=====================================================
BUG: KMSAN: uninit-value in ext4_evict_inode+0xdd/0x26b0 fs/ext4/inode.c:180
 ext4_evict_inode+0xdd/0x26b0 fs/ext4/inode.c:180
 evict+0x365/0x9a0 fs/inode.c:664
 iput_final fs/inode.c:1747 [inline]
 iput+0x985/0xdd0 fs/inode.c:1773
 __ext4_new_inode+0xe54/0x7ec0 fs/ext4/ialloc.c:1361
 ext4_mknod+0x376/0x840 fs/ext4/namei.c:2844
 vfs_mknod+0x79d/0x830 fs/namei.c:3914
 do_mknodat+0x47d/0xaa0
 __do_sys_mknodat fs/namei.c:3992 [inline]
 __se_sys_mknodat fs/namei.c:3989 [inline]
 __ia32_sys_mknodat+0xeb/0x150 fs/namei.c:3989
 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
 __do_fast_syscall_32+0xa2/0x100 arch/x86/entry/common.c:178
 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
 do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:246
 entry_SYSENTER_compat_after_hwframe+0x70/0x82

Uninit was created at:
 __alloc_pages+0x9f1/0xe80 mm/page_alloc.c:5578
 alloc_pages+0xaae/0xd80 mm/mempolicy.c:2285
 alloc_slab_page mm/slub.c:1794 [inline]
 allocate_slab+0x1b5/0x1010 mm/slub.c:1939
 new_slab mm/slub.c:1992 [inline]
 ___slab_alloc+0x10c3/0x2d60 mm/slub.c:3180
 __slab_alloc mm/slub.c:3279 [inline]
 slab_alloc_node mm/slub.c:3364 [inline]
 slab_alloc mm/slub.c:3406 [inline]
 __kmem_cache_alloc_lru mm/slub.c:3413 [inline]
 kmem_cache_alloc_lru+0x6f3/0xb30 mm/slub.c:3429
 alloc_inode_sb include/linux/fs.h:3117 [inline]
 ext4_alloc_inode+0x5f/0x860 fs/ext4/super.c:1321
 alloc_inode+0x83/0x440 fs/inode.c:259
 new_inode_pseudo fs/inode.c:1018 [inline]
 new_inode+0x3b/0x430 fs/inode.c:1046
 __ext4_new_inode+0x2a7/0x7ec0 fs/ext4/ialloc.c:959
 ext4_mkdir+0x4d5/0x1560 fs/ext4/namei.c:2992
 vfs_mkdir+0x62a/0x870 fs/namei.c:4035
 do_mkdirat+0x466/0x7b0 fs/namei.c:4060
 __do_sys_mkdirat fs/namei.c:4075 [inline]
 __se_sys_mkdirat fs/namei.c:4073 [inline]
 __ia32_sys_mkdirat+0xc4/0x120 fs/namei.c:4073
 do_syscall_32_irqs_on arch/x86/entry/common.c:112 [inline]
 __do_fast_syscall_32+0xa2/0x100 arch/x86/entry/common.c:178
 do_fast_syscall_32+0x33/0x70 arch/x86/entry/common.c:203
 do_SYSENTER_32+0x1b/0x20 arch/x86/entry/common.c:246
 entry_SYSENTER_compat_after_hwframe+0x70/0x82

CPU: 1 PID: 4625 Comm: syz-executor.2 Not tainted 6.1.0-rc4-syzkaller-62821-gcb231e2f67ec #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 10/26/2022
=====================================================

Now, 'ext4_alloc_inode()' didn't init 'ei->i_flags'. If new inode failed
before set 'ei->i_flags' in '__ext4_new_inode()', then do 'iput()'. As after
6bc0d63dad7f commit will access 'ei->i_flags' in 'ext4_evict_inode()' which
will lead to access uninit-value.
To solve above issue just init 'ei->i_flags' in 'ext4_alloc_inode()'.

Reported-by: syzbot+57b25da729eb0b88177d@syzkaller.appspotmail.com
Signed-off-by: Ye Bin 
Fixes: 6bc0d63dad7f ("ext4: remove EA inode entry from mbcache on inode eviction")
Reviewed-by: Jan Kara 
Reviewed-by: Eric Biggers 
Link: https://lore.kernel.org/r/20221117073603.2598882-1-yebin@huaweicloud.com
Signed-off-by: Theodore Ts'o 
Cc: stable@kernel.org
Signed-off-by: Sasha Levin

ext4: fix use-after-free in ext4_orphan_cleanup

2023-01-18T10:42:03+00:00

[ Upstream commit a71248b1accb2b42e4980afef4fa4a27fa0e36f5 ]

I caught a issue as follows:
==================================================================
 BUG: KASAN: use-after-free in __list_add_valid+0x28/0x1a0
 Read of size 8 at addr ffff88814b13f378 by task mount/710

 CPU: 1 PID: 710 Comm: mount Not tainted 6.1.0-rc3-next #370
 Call Trace:
  
  dump_stack_lvl+0x73/0x9f
  print_report+0x25d/0x759
  kasan_report+0xc0/0x120
  __asan_load8+0x99/0x140
  __list_add_valid+0x28/0x1a0
  ext4_orphan_cleanup+0x564/0x9d0 [ext4]
  __ext4_fill_super+0x48e2/0x5300 [ext4]
  ext4_fill_super+0x19f/0x3a0 [ext4]
  get_tree_bdev+0x27b/0x450
  ext4_get_tree+0x19/0x30 [ext4]
  vfs_get_tree+0x49/0x150
  path_mount+0xaae/0x1350
  do_mount+0xe2/0x110
  __x64_sys_mount+0xf0/0x190
  do_syscall_64+0x35/0x80
  entry_SYSCALL_64_after_hwframe+0x63/0xcd
  
 [...]
==================================================================

Above issue may happen as follows:
-------------------------------------
ext4_fill_super
  ext4_orphan_cleanup
   --- loop1: assume last_orphan is 12 ---
    list_add(&EXT4_I(inode)->i_orphan, &EXT4_SB(sb)->s_orphan)
    ext4_truncate --> return 0
      ext4_inode_attach_jinode --> return -ENOMEM
    iput(inode) --> free inode<12>
   --- loop2: last_orphan is still 12 ---
    list_add(&EXT4_I(inode)->i_orphan, &EXT4_SB(sb)->s_orphan);
    // use inode<12> and trigger UAF

To solve this issue, we need to propagate the return value of
ext4_inode_attach_jinode() appropriately.

Signed-off-by: Baokun Li 
Reviewed-by: Jan Kara 
Link: https://lore.kernel.org/r/20221102080633.1630225-1-libaokun1@huawei.com
Signed-off-by: Theodore Ts'o 
Cc: stable@kernel.org
Signed-off-by: Sasha Levin

ext4: lost matching-pair of trace in ext4_truncate

2023-01-18T10:42:03+00:00

[ Upstream commit 9a5d265fed014115f35e598022c956e5d2fb863e ]

It should call trace exit in all return path for ext4_truncate.

Signed-off-by: zhengliang 
Reviewed-by: Andreas Dilger 
Reviewed-by: Ritesh Harjani 
Link: https://lore.kernel.org/r/20200701083027.45996-1-zhengliang6@huawei.com
Signed-off-by: Theodore Ts'o 
Stable-dep-of: a71248b1accb ("ext4: fix use-after-free in ext4_orphan_cleanup")
Signed-off-by: Sasha Levin

ext4: don't allow journal inode to have encrypt flag

2023-01-18T10:41:59+00:00

commit 105c78e12468413e426625831faa7db4284e1fec upstream.

Mounting a filesystem whose journal inode has the encrypt flag causes a
NULL dereference in fscrypt_limit_io_blocks() when the 'inlinecrypt'
mount option is used.

The problem is that when jbd2_journal_init_inode() calls bmap(), it
eventually finds its way into ext4_iomap_begin(), which calls
fscrypt_limit_io_blocks().  fscrypt_limit_io_blocks() requires that if
the inode is encrypted, then its encryption key must already be set up.
That's not the case here, since the journal inode is never "opened" like
a normal file would be.  Hence the crash.

A reproducer is:

    mkfs.ext4 -F /dev/vdb
    debugfs -w /dev/vdb -R "set_inode_field <8> flags 0x80808"
    mount /dev/vdb /mnt -o inlinecrypt

To fix this, make ext4 consider journal inodes with the encrypt flag to
be invalid.  (Note, maybe other flags should be rejected on the journal
inode too.  For now, this is just the minimal fix for the above issue.)

I've marked this as fixing the commit that introduced the call to
fscrypt_limit_io_blocks(), since that's what made an actual crash start
being possible.  But this fix could be applied to any version of ext4
that supports the encrypt feature.

Reported-by: syzbot+ba9dac45bc76c490b7c3@syzkaller.appspotmail.com
Fixes: 38ea50daa7a4 ("ext4: support direct I/O with fscrypt using blk-crypto")
Cc: stable@vger.kernel.org
Signed-off-by: Eric Biggers 
Link: https://lore.kernel.org/r/20221102053312.189962-1-ebiggers@kernel.org
Signed-off-by: Theodore Ts'o 
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman

ext4: fix deadlock due to mbcache entry corruption

2023-01-18T10:41:56+00:00

[ Upstream commit a44e84a9b7764c72896f7241a0ec9ac7e7ef38dd ]

When manipulating xattr blocks, we can deadlock infinitely looping
inside ext4_xattr_block_set() where we constantly keep finding xattr
block for reuse in mbcache but we are unable to reuse it because its
reference count is too big. This happens because cache entry for the
xattr block is marked as reusable (e_reusable set) although its
reference count is too big. When this inconsistency happens, this
inconsistent state is kept indefinitely and so ext4_xattr_block_set()
keeps retrying indefinitely.

The inconsistent state is caused by non-atomic update of e_reusable bit.
e_reusable is part of a bitfield and e_reusable update can race with
update of e_referenced bit in the same bitfield resulting in loss of one
of the updates. Fix the problem by using atomic bitops instead.

This bug has been around for many years, but it became *much* easier
to hit after commit 65f8b80053a1 ("ext4: fix race when reusing xattr
blocks").

Cc: stable@vger.kernel.org
Fixes: 6048c64b2609 ("mbcache: add reusable flag to cache entries")
Fixes: 65f8b80053a1 ("ext4: fix race when reusing xattr blocks")
Reported-and-tested-by: Jeremi Piotrowski 
Reported-by: Thilo Fromm 
Link: https://lore.kernel.org/r/c77bf00f-4618-7149-56f1-b8d1664b9d07@linux.microsoft.com/
Signed-off-by: Jan Kara 
Reviewed-by: Andreas Dilger 
Link: https://lore.kernel.org/r/20221123193950.16758-1-jack@suse.cz
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

ext4: fix race when reusing xattr blocks

2023-01-18T10:41:56+00:00

[ Upstream commit 65f8b80053a1b2fd602daa6814e62d6fa90e5e9b ]

When ext4_xattr_block_set() decides to remove xattr block the following
race can happen:

CPU1                                    CPU2
ext4_xattr_block_set()                  ext4_xattr_release_block()
  new_bh = ext4_xattr_block_cache_find()

                                          lock_buffer(bh);
                                          ref = le32_to_cpu(BHDR(bh)->h_refcount);
                                          if (ref == 1) {
                                            ...
                                            mb_cache_entry_delete();
                                            unlock_buffer(bh);
                                            ext4_free_blocks();
                                              ...
                                              ext4_forget(..., bh, ...);
                                                jbd2_journal_revoke(..., bh);

  ext4_journal_get_write_access(..., new_bh, ...)
    do_get_write_access()
      jbd2_journal_cancel_revoke(..., new_bh);

Later the code in ext4_xattr_block_set() finds out the block got freed
and cancels reusal of the block but the revoke stays canceled and so in
case of block reuse and journal replay the filesystem can get corrupted.
If the race works out slightly differently, we can also hit assertions
in the jbd2 code.

Fix the problem by making sure that once matching mbcache entry is
found, code dropping the last xattr block reference (or trying to modify
xattr block in place) waits until the mbcache entry reference is
dropped. This way code trying to reuse xattr block is protected from
someone trying to drop the last reference to xattr block.

Reported-and-tested-by: Ritesh Harjani 
CC: stable@vger.kernel.org
Fixes: 82939d7999df ("ext4: convert to mbcache2")
Signed-off-by: Jan Kara 
Link: https://lore.kernel.org/r/20220712105436.32204-5-jack@suse.cz
Signed-off-by: Theodore Ts'o 
Stable-dep-of: a44e84a9b776 ("ext4: fix deadlock due to mbcache entry corruption")
Signed-off-by: Sasha Levin

ext4: unindent codeblock in ext4_xattr_block_set()

2023-01-18T10:41:56+00:00

[ Upstream commit fd48e9acdf26d0cbd80051de07d4a735d05d29b2 ]

Remove unnecessary else (and thus indentation level) from a code block
in ext4_xattr_block_set(). It will also make following code changes
easier. No functional changes.

CC: stable@vger.kernel.org
Fixes: 82939d7999df ("ext4: convert to mbcache2")
Signed-off-by: Jan Kara 
Link: https://lore.kernel.org/r/20220712105436.32204-4-jack@suse.cz
Signed-off-by: Theodore Ts'o 
Stable-dep-of: a44e84a9b776 ("ext4: fix deadlock due to mbcache entry corruption")
Signed-off-by: Sasha Levin

ext4: remove EA inode entry from mbcache on inode eviction

2023-01-18T10:41:55+00:00

[ Upstream commit 6bc0d63dad7f9f54d381925ee855b402f652fa39 ]

Currently we remove EA inode from mbcache as soon as its xattr refcount
drops to zero. However there can be pending attempts to reuse the inode
and thus refcount handling code has to handle the situation when
refcount increases from zero anyway. So save some work and just keep EA
inode in mbcache until it is getting evicted. At that moment we are sure
following iget() of EA inode will fail anyway (or wait for eviction to
finish and load things from the disk again) and so removing mbcache
entry at that moment is fine and simplifies the code a bit.

CC: stable@vger.kernel.org
Fixes: 82939d7999df ("ext4: convert to mbcache2")
Signed-off-by: Jan Kara 
Link: https://lore.kernel.org/r/20220712105436.32204-3-jack@suse.cz
Signed-off-by: Theodore Ts'o 
Stable-dep-of: a44e84a9b776 ("ext4: fix deadlock due to mbcache entry corruption")
Signed-off-by: Sasha Levin

ext4: use kmemdup() to replace kmalloc + memcpy

2023-01-18T10:41:55+00:00

[ Upstream commit 4efd9f0d120c55b08852ee5605dbb02a77089a5d ]

Replace kmalloc + memcpy with kmemdup()

Signed-off-by: Shuqi Zhang 
Reviewed-by: Ritesh Harjani 
Link: https://lore.kernel.org/r/20220525030120.803330-1-zhangshuqi3@huawei.com
Signed-off-by: Theodore Ts'o 
Stable-dep-of: a44e84a9b776 ("ext4: fix deadlock due to mbcache entry corruption")
Signed-off-by: Sasha Levin