linux-stable.git/fs/f2fs, branch linux-5.14.y

f2fs: fix UAF in f2fs_available_free_memory

2021-11-17T10:04:46+00:00

commit 5429c9dbc9025f9a166f64e22e3a69c94fd5b29b upstream.

if2fs_fill_super
-> f2fs_build_segment_manager
   -> create_discard_cmd_control
      -> f2fs_start_discard_thread

It invokes kthread_run to create a thread and run issue_discard_thread.

However, if f2fs_build_node_manager fails, the control flow goes to
free_nm and calls f2fs_destroy_node_manager. This function will free
sbi->nm_info. However, if issue_discard_thread accesses sbi->nm_info
after the deallocation, but before the f2fs_stop_discard_thread, it will
cause UAF(Use-after-free).

-> f2fs_destroy_segment_manager
   -> destroy_discard_cmd_control
      -> f2fs_stop_discard_thread

Fix this by stopping discard thread before f2fs_destroy_node_manager.

Note that, the commit d6d2b491a82e1 introduces the call of
f2fs_available_free_memory into issue_discard_thread.

Cc: stable@vger.kernel.org
Fixes: d6d2b491a82e ("f2fs: allow to change discard policy based on cached discard cmds")
Signed-off-by: Dongliang Mu 
Reviewed-by: Chao Yu 
Signed-off-by: Jaegeuk Kim 
Signed-off-by: Greg Kroah-Hartman

f2fs: include non-compressed blocks in compr_written_block

2021-11-17T10:04:46+00:00

commit 09631cf3234d32156e7cae32275f5a4144c683c5 upstream.

Need to include non-compressed blocks in compr_written_block to
estimate average compression ratio more accurately.

Fixes: 5ac443e26a09 ("f2fs: add sysfs nodes to get runtime compression stat")
Cc: stable@vger.kernel.org
Signed-off-by: Daeho Jeong 
Signed-off-by: Jaegeuk Kim 
Signed-off-by: Greg Kroah-Hartman

f2fs: should use GFP_NOFS for directory inodes

2021-11-17T10:04:45+00:00

commit 92d602bc7177325e7453189a22e0c8764ed3453e upstream.

We use inline_dentry which requires to allocate dentry page when adding a link.
If we allow to reclaim memory from filesystem, we do down_read(&sbi->cp_rwsem)
twice by f2fs_lock_op(). I think this should be okay, but how about stopping
the lockdep complaint [1]?

f2fs_create()
 - f2fs_lock_op()
 - f2fs_do_add_link()
  - __f2fs_find_entry
   - f2fs_get_read_data_page()
   -> kswapd
    - shrink_node
     - f2fs_evict_inode
      - f2fs_lock_op()

[1]

fs_reclaim
){+.+.}-{0:0}
:
kswapd0:        lock_acquire+0x114/0x394
kswapd0:        __fs_reclaim_acquire+0x40/0x50
kswapd0:        prepare_alloc_pages+0x94/0x1ec
kswapd0:        __alloc_pages_nodemask+0x78/0x1b0
kswapd0:        pagecache_get_page+0x2e0/0x57c
kswapd0:        f2fs_get_read_data_page+0xc0/0x394
kswapd0:        f2fs_find_data_page+0xa4/0x23c
kswapd0:        find_in_level+0x1a8/0x36c
kswapd0:        __f2fs_find_entry+0x70/0x100
kswapd0:        f2fs_do_add_link+0x84/0x1ec
kswapd0:        f2fs_mkdir+0xe4/0x1e4
kswapd0:        vfs_mkdir+0x110/0x1c0
kswapd0:        do_mkdirat+0xa4/0x160
kswapd0:        __arm64_sys_mkdirat+0x24/0x34
kswapd0:        el0_svc_common.llvm.17258447499513131576+0xc4/0x1e8
kswapd0:        do_el0_svc+0x28/0xa0
kswapd0:        el0_svc+0x24/0x38
kswapd0:        el0_sync_handler+0x88/0xec
kswapd0:        el0_sync+0x1c0/0x200
kswapd0:
-> #1
(
&sbi->cp_rwsem
){++++}-{3:3}
:
kswapd0:        lock_acquire+0x114/0x394
kswapd0:        down_read+0x7c/0x98
kswapd0:        f2fs_do_truncate_blocks+0x78/0x3dc
kswapd0:        f2fs_truncate+0xc8/0x128
kswapd0:        f2fs_evict_inode+0x2b8/0x8b8
kswapd0:        evict+0xd4/0x2f8
kswapd0:        iput+0x1c0/0x258
kswapd0:        do_unlinkat+0x170/0x2a0
kswapd0:        __arm64_sys_unlinkat+0x4c/0x68
kswapd0:        el0_svc_common.llvm.17258447499513131576+0xc4/0x1e8
kswapd0:        do_el0_svc+0x28/0xa0
kswapd0:        el0_svc+0x24/0x38
kswapd0:        el0_sync_handler+0x88/0xec
kswapd0:        el0_sync+0x1c0/0x200

Cc: stable@vger.kernel.org
Fixes: bdbc90fa55af ("f2fs: don't put dentry page in pagecache into highmem")
Reviewed-by: Chao Yu 
Reviewed-by: Stanley Chu 
Reviewed-by: Light Hsieh 
Tested-by: Light Hsieh 
Signed-off-by: Jaegeuk Kim 
Signed-off-by: Greg Kroah-Hartman

f2fs: should put a page beyond EOF when preparing a write

2021-09-18T11:43:34+00:00

[ Upstream commit 9605f75cf36e0bcc0f4ada07b5be712d30107607 ]

The prepare_compress_overwrite() gets/locks a page to prepare a read, and calls
f2fs_read_multi_pages() which checks EOF first. If there's any page beyond EOF,
we unlock the page and set cc->rpages[i] = NULL, which we can't put the page
anymore. This makes page leak, so let's fix by putting that page.

Fixes: a949dc5f2c5c ("f2fs: compress: fix race condition of overwrite vs truncate")
Reviewed-by: Chao Yu 
Signed-off-by: Jaegeuk Kim 
Signed-off-by: Sasha Levin

f2fs: deallocate compressed pages when error happens

2021-09-18T11:43:34+00:00

[ Upstream commit 827f02842e40ea2e00f401e8f4cb1bccf3b8cd86 ]

In f2fs_write_multi_pages(), f2fs_compress_pages() allocates pages for
compression work in cc->cpages[]. Then, f2fs_write_compressed_pages() initiates
bio submission. But, if there's any error before submitting the IOs like early
f2fs_cp_error(), previously it didn't free cpages by f2fs_compress_free_page().
Let's fix memory leak by putting that just before deallocating cc->cpages.

Fixes: 4c8ff7095bef ("f2fs: support data compression")
Reviewed-by: Chao Yu 
Signed-off-by: Jaegeuk Kim 
Signed-off-by: Sasha Levin

f2fs: fix to unmap pages from userspace process in punch_hole()

2021-09-18T11:43:34+00:00

[ Upstream commit c8dc3047c48540183744f959412d44b08c5435e1 ]

We need to unmap pages from userspace process before removing pagecache
in punch_hole() like we did in f2fs_setattr().

Similar change:
commit 5e44f8c374dc ("ext4: hole-punch use truncate_pagecache_range")

Fixes: fbfa2cc58d53 ("f2fs: add file operations")
Signed-off-by: Chao Yu 
Signed-off-by: Jaegeuk Kim 
Signed-off-by: Sasha Levin

f2fs: fix unexpected ENOENT comes from f2fs_map_blocks()

2021-09-18T11:43:34+00:00

[ Upstream commit adf9ea89c719c1d23794e363f631e376b3ff8cbc ]

In below path, it will return ENOENT if filesystem is shutdown:

- f2fs_map_blocks
 - f2fs_get_dnode_of_data
  - f2fs_get_node_page
   - __get_node_page
    - read_node_page
     - is_sbi_flag_set(sbi, SBI_IS_SHUTDOWN)
       return -ENOENT
 - force return value from ENOENT to 0

It should be fine for read case, since it indicates a hole condition,
and caller could use .m_next_pgofs to skip the hole and continue the
lookup.

However it may cause confusing for write case, since leaving a hole
there, and said nothing was wrong doesn't help.

There is at least one case from dax_iomap_actor() will complain that,
so fix this in prior to supporting dax in f2fs.

xfstest generic/388 reports below warning:

ubuntu godown: xfstests-induced forced shutdown of /mnt/scratch_f2fs:
------------[ cut here ]------------
WARNING: CPU: 0 PID: 485833 at fs/dax.c:1127 dax_iomap_actor+0x339/0x370
Call Trace:
 iomap_apply+0x1c4/0x7b0
 ? dax_iomap_rw+0x1c0/0x1c0
 dax_iomap_rw+0xad/0x1c0
 ? dax_iomap_rw+0x1c0/0x1c0
 f2fs_file_write_iter+0x5ab/0x970 [f2fs]
 do_iter_readv_writev+0x273/0x2e0
 do_iter_write+0xab/0x1f0
 vfs_iter_write+0x21/0x40
 iter_file_splice_write+0x287/0x540
 do_splice+0x37c/0xa60
 __x64_sys_splice+0x15f/0x3a0
 do_syscall_64+0x3b/0x90
 entry_SYSCALL_64_after_hwframe+0x44/0xae

ubuntu godown: xfstests-induced forced shutdown of /mnt/scratch_f2fs:
------------[ cut here ]------------
RIP: 0010:dax_iomap_pte_fault.isra.0+0x72e/0x14a0
Call Trace:
 dax_iomap_fault+0x44/0x70
 f2fs_dax_huge_fault+0x155/0x400 [f2fs]
 f2fs_dax_fault+0x18/0x30 [f2fs]
 __do_fault+0x4e/0x120
 do_fault+0x3cf/0x7a0
 __handle_mm_fault+0xa8c/0xf20
 ? find_held_lock+0x39/0xd0
 handle_mm_fault+0x1b6/0x480
 do_user_addr_fault+0x320/0xcd0
 ? rcu_read_lock_sched_held+0x67/0xc0
 exc_page_fault+0x77/0x3f0
 ? asm_exc_page_fault+0x8/0x30
 asm_exc_page_fault+0x1e/0x30

Fixes: 83a3bfdb5a8a ("f2fs: indicate shutdown f2fs to allow unmount successfully")
Signed-off-by: Chao Yu 
Signed-off-by: Jaegeuk Kim 
Signed-off-by: Sasha Levin

f2fs: fix to account missing .skipped_gc_rwsem

2021-09-18T11:43:34+00:00

[ Upstream commit ad126ebddecbf696e0cf214ff56c7b170fa9f0f7 ]

There is a missing place we forgot to account .skipped_gc_rwsem, fix it.

Fixes: 6f8d4455060d ("f2fs: avoid fi->i_gc_rwsem[WRITE] lock in f2fs_gc")
Signed-off-by: Chao Yu 
Signed-off-by: Jaegeuk Kim 
Signed-off-by: Sasha Levin

f2fs: fix to keep compatibility of fault injection interface

2021-09-18T11:43:31+00:00

[ Upstream commit b96d9b3b09f0427b289332c6f6bfbf747a19b654 ]

The value of FAULT_* macros and its description in f2fs.rst became
inconsistent, fix this to keep compatibility of fault injection
interface.

Fixes: 67883ade7a98 ("f2fs: remove FAULT_ALLOC_BIO")
Signed-off-by: Chao Yu 
Signed-off-by: Jaegeuk Kim 
Signed-off-by: Sasha Levin

f2fs: reduce the scope of setting fsck tag when de->name_len is zero

2021-09-18T11:43:28+00:00

[ Upstream commit d4bf15a7ce172d186d400d606adf4f34a59130d6 ]

I recently found a case where de->name_len is 0 in f2fs_fill_dentries()
easily reproduced, and finally set the fsck flag.

Thread A			Thread B
- f2fs_readdir
 - f2fs_read_inline_dir
  - ctx->pos = d.max
				- f2fs_add_dentry
				 - f2fs_add_inline_entry
				  - do_convert_inline_dir
				 - f2fs_add_regular_entry
- f2fs_readdir
 - f2fs_fill_dentries
  - set_sbi_flag(sbi, SBI_NEED_FSCK)

Process A opens the folder, and has been reading without closing it.
During this period, Process B created a file under the folder (occupying
multiple f2fs_dir_entry, exceeding the d.max of the inline dir). After
creation, process A uses the d.max of inline dir to read it again, and
it will read that de->name_len is 0.

And Chao pointed out that w/o inline conversion, the race condition still
can happen as below:

dir_entry1: A
dir_entry2: B
dir_entry3: C
free slot: _
ctx->pos: ^

Thread A is traversing directory,
ctx-pos moves to below position after readdir() by thread A:
AAAABBBB___
        ^

Then thread B delete dir_entry2, and create dir_entry3.

Thread A calls readdir() to lookup dirents starting from middle
of new dirent slots as below:
AAAACCCCCC_
        ^
In these scenarios, the file system is not damaged, and it's hard to
avoid it. But we can bypass tagging FSCK flag if:
a) bit_pos (:= ctx->pos % d->max) is non-zero and
b) before bit_pos moves to first valid dir_entry.

Fixes: ddf06b753a85 ("f2fs: fix to trigger fsck if dirent.name_len is zero")
Signed-off-by: Yangtao Li 
[Chao: clean up description]
Reviewed-by: Chao Yu 
Signed-off-by: Jaegeuk Kim 
Signed-off-by: Sasha Levin