linux-stable.git/fs, branch v4.4.217

jbd2: fix data races at struct journal_head

2020-03-20T08:06:34+00:00

[ Upstream commit 6c5d911249290f41f7b50b43344a7520605b1acb ]

journal_head::b_transaction and journal_head::b_next_transaction could
be accessed concurrently as noticed by KCSAN,

 LTP: starting fsync04
 /dev/zero: Can't open blockdev
 EXT4-fs (loop0): mounting ext3 file system using the ext4 subsystem
 EXT4-fs (loop0): mounted filesystem with ordered data mode. Opts: (null)
 ==================================================================
 BUG: KCSAN: data-race in __jbd2_journal_refile_buffer [jbd2] / jbd2_write_access_granted [jbd2]

 write to 0xffff99f9b1bd0e30 of 8 bytes by task 25721 on cpu 70:
  __jbd2_journal_refile_buffer+0xdd/0x210 [jbd2]
  __jbd2_journal_refile_buffer at fs/jbd2/transaction.c:2569
  jbd2_journal_commit_transaction+0x2d15/0x3f20 [jbd2]
  (inlined by) jbd2_journal_commit_transaction at fs/jbd2/commit.c:1034
  kjournald2+0x13b/0x450 [jbd2]
  kthread+0x1cd/0x1f0
  ret_from_fork+0x27/0x50

 read to 0xffff99f9b1bd0e30 of 8 bytes by task 25724 on cpu 68:
  jbd2_write_access_granted+0x1b2/0x250 [jbd2]
  jbd2_write_access_granted at fs/jbd2/transaction.c:1155
  jbd2_journal_get_write_access+0x2c/0x60 [jbd2]
  __ext4_journal_get_write_access+0x50/0x90 [ext4]
  ext4_mb_mark_diskspace_used+0x158/0x620 [ext4]
  ext4_mb_new_blocks+0x54f/0xca0 [ext4]
  ext4_ind_map_blocks+0xc79/0x1b40 [ext4]
  ext4_map_blocks+0x3b4/0x950 [ext4]
  _ext4_get_block+0xfc/0x270 [ext4]
  ext4_get_block+0x3b/0x50 [ext4]
  __block_write_begin_int+0x22e/0xae0
  __block_write_begin+0x39/0x50
  ext4_write_begin+0x388/0xb50 [ext4]
  generic_perform_write+0x15d/0x290
  ext4_buffered_write_iter+0x11f/0x210 [ext4]
  ext4_file_write_iter+0xce/0x9e0 [ext4]
  new_sync_write+0x29c/0x3b0
  __vfs_write+0x92/0xa0
  vfs_write+0x103/0x260
  ksys_write+0x9d/0x130
  __x64_sys_write+0x4c/0x60
  do_syscall_64+0x91/0xb05
  entry_SYSCALL_64_after_hwframe+0x49/0xbe

 5 locks held by fsync04/25724:
  #0: ffff99f9911093f8 (sb_writers#13){.+.+}, at: vfs_write+0x21c/0x260
  #1: ffff99f9db4c0348 (&sb->s_type->i_mutex_key#15){+.+.}, at: ext4_buffered_write_iter+0x65/0x210 [ext4]
  #2: ffff99f5e7dfcf58 (jbd2_handle){++++}, at: start_this_handle+0x1c1/0x9d0 [jbd2]
  #3: ffff99f9db4c0168 (&ei->i_data_sem){++++}, at: ext4_map_blocks+0x176/0x950 [ext4]
  #4: ffffffff99086b40 (rcu_read_lock){....}, at: jbd2_write_access_granted+0x4e/0x250 [jbd2]
 irq event stamp: 1407125
 hardirqs last  enabled at (1407125): [] __find_get_block+0x107/0x790
 hardirqs last disabled at (1407124): [] __find_get_block+0x49/0x790
 softirqs last  enabled at (1405528): [] __do_softirq+0x34c/0x57c
 softirqs last disabled at (1405521): [] irq_exit+0xa2/0xc0

 Reported by Kernel Concurrency Sanitizer on:
 CPU: 68 PID: 25724 Comm: fsync04 Tainted: G L 5.6.0-rc2-next-20200221+ #7
 Hardware name: HPE ProLiant DL385 Gen10/ProLiant DL385 Gen10, BIOS A40 07/10/2019

The plain reads are outside of jh->b_state_lock critical section which result
in data races. Fix them by adding pairs of READ|WRITE_ONCE().

Reviewed-by: Jan Kara 
Signed-off-by: Qian Cai 
Link: https://lore.kernel.org/r/20200222043111.2227-1-cai@lca.pw
Signed-off-by: Theodore Ts'o 
Signed-off-by: Sasha Levin

gfs2_atomic_open(): fix O_EXCL|O_CREAT handling on cold dcache

2020-03-20T08:06:22+00:00

commit 21039132650281de06a169cbe8a0f7e5c578fd8b upstream.

with the way fs/namei.c:do_last() had been done, ->atomic_open()
instances needed to recognize the case when existing file got
found with O_EXCL|O_CREAT, either by falling back to finish_no_open()
or failing themselves.  gfs2 one didn't.

Fixes: 6d4ade986f9c (GFS2: Add atomic_open support)
Cc: stable@kernel.org # v3.11
Signed-off-by: Al Viro 
Signed-off-by: Greg Kroah-Hartman

NFS: Remove superfluous kmap in nfs_readdir_xdr_to_array

2020-03-20T08:06:18+00:00

Array is mapped by nfs_readdir_get_array(), the further kmap is a result
of a bad merge and should be removed.

This resource leakage can be exploited for DoS by receptively reading
a content of a directory on NFS (e.g. by running ls).

Fixes: 67a56e9743171 ("NFS: Fix memory leaks and corruption in readdir")
Signed-off-by: Petr Malat 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

fat: fix uninit-memory access for partial initialized inode

2020-03-11T06:51:17+00:00

commit bc87302a093f0eab45cd4e250c2021299f712ec6 upstream.

When get an error in the middle of reading an inode, some fields in the
inode might be still not initialized.  And then the evict_inode path may
access those fields via iput().

To fix, this makes sure that inode fields are initialized.

Reported-by: syzbot+9d82b8de2992579da5d0@syzkaller.appspotmail.com
Signed-off-by: Andrew Morton 
Signed-off-by: OGAWA Hirofumi 
Cc: 
Link: http://lkml.kernel.org/r/871rqnreqx.fsf@mail.parknet.co.jp
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

cifs: don't leak -EAGAIN for stat() during reconnect

2020-03-11T06:51:17+00:00

commit fc513fac56e1b626ae48a74d7551d9c35c50129e upstream.

If from cifs_revalidate_dentry_attr() the SMB2/QUERY_INFO call fails with an
error, such as STATUS_SESSION_EXPIRED, causing the session to be reconnected
it is possible we will leak -EAGAIN back to the application even for
system calls such as stat() where this is not a valid error.

Fix this by re-trying the operation from within cifs_revalidate_dentry_attr()
if cifs_get_inode_info*() returns -EAGAIN.

This fixes stat() and possibly also other system calls that uses
cifs_revalidate_dentry*().

Signed-off-by: Ronnie Sahlberg 
Signed-off-by: Steve French 
Reviewed-by: Pavel Shilovsky 
Reviewed-by: Aurelien Aptel 
CC: Stable 
Signed-off-by: Greg Kroah-Hartman

fs: prevent page refcount overflow in pipe_buf_get

2020-03-11T06:51:15+00:00

commit 15fab63e1e57be9fdb5eec1bbc5916e9825e9acb upstream.

Change pipe_buf_get() to return a bool indicating whether it succeeded
in raising the refcount of the page (if the thing in the pipe is a page).
This removes another mechanism for overflowing the page refcount.  All
callers converted to handle a failure.

Reported-by: Jann Horn 
Signed-off-by: Matthew Wilcox 
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds 
[ 4.4.y backport notes:
  Regarding the change in generic_pipe_buf_get(), note that
  page_cache_get() is the same as get_page(). See mainline commit
  09cbfeaf1a5a6 "mm, fs: get rid of PAGE_CACHE_* and
  page_cache_{get,release} macros" for context. ]
Signed-off-by: Ajay Kaher 
Signed-off-by: Vlastimil Babka 
Signed-off-by: Greg Kroah-Hartman

pipe: add pipe_buf_get() helper

2020-03-11T06:51:15+00:00

commit 7bf2d1df80822ec056363627e2014990f068f7aa upstream.

Signed-off-by: Miklos Szeredi 
Signed-off-by: Al Viro 
Signed-off-by: Ajay Kaher 
Signed-off-by: Vlastimil Babka 
Signed-off-by: Greg Kroah-Hartman

namei: only return -ECHILD from follow_dotdot_rcu()

2020-03-11T06:51:14+00:00

commit 2b98149c2377bff12be5dd3ce02ae0506e2dd613 upstream.

It's over-zealous to return hard errors under RCU-walk here, given that
a REF-walk will be triggered for all other cases handling ".." under
RCU.

The original purpose of this check was to ensure that if a rename occurs
such that a directory is moved outside of the bind-mount which the
resolution started in, it would be detected and blocked to avoid being
able to mess with paths outside of the bind-mount. However, triggering a
new REF-walk is just as effective a solution.

Cc: "Eric W. Biederman" 
Fixes: 397d425dc26d ("vfs: Test for and handle paths that are unreachable from their mnt_root")
Suggested-by: Al Viro 
Signed-off-by: Aleksa Sarai 
Signed-off-by: Al Viro 
Signed-off-by: Greg Kroah-Hartman

ecryptfs: Fix up bad backport of fe2e082f5da5b4a0a92ae32978f81507ef37ec66

2020-03-11T06:51:14+00:00

When doing the 4.9 merge into certain Android trees, I noticed a warning
from Android's deprecated GCC 4.9.4, which causes a build failure in
those trees due to basically -Werror:

fs/ecryptfs/keystore.c: In function 'ecryptfs_parse_packet_set':
fs/ecryptfs/keystore.c:1357:2: warning: 'auth_tok_list_item' may be used
uninitialized in this function [-Wmaybe-uninitialized]
  memset(auth_tok_list_item, 0,
  ^
fs/ecryptfs/keystore.c:1260:38: note: 'auth_tok_list_item' was declared
here
  struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
                                      ^

GCC 9.2.0 was not able to pick up this warning when I tested it.

Turns out that Clang warns as well when -Wuninitialized is used, which
is not the case in older stable trees at the moment (but shows value in
potentially backporting the various warning fixes currently in upstream
to get more coverage).

fs/ecryptfs/keystore.c:1284:6: warning: variable 'auth_tok_list_item' is
used uninitialized whenever 'if' condition is true
[-Wsometimes-uninitialized]
        if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
            ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/ecryptfs/keystore.c:1360:4: note: uninitialized use occurs here
                        auth_tok_list_item);
                        ^~~~~~~~~~~~~~~~~~
fs/ecryptfs/keystore.c:1284:2: note: remove the 'if' if its condition is
always false
        if (data[(*packet_size)++] != ECRYPTFS_TAG_1_PACKET_TYPE) {
        ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
fs/ecryptfs/keystore.c:1260:56: note: initialize the variable
'auth_tok_list_item' to silence this warning
        struct ecryptfs_auth_tok_list_item *auth_tok_list_item;
                                                              ^
                                                               = NULL
1 warning generated.

Somehow, commit fe2e082f5da5 ("ecryptfs: fix a memory leak bug in
parse_tag_1_packet()") upstream was not applied in the correct if block
in 4.4.215, 4.9.215, and 4.14.172, which will indeed lead to use of
uninitialized memory. Fix it up by undoing the bad backport in those
trees then reapplying the patch in the proper location.

Signed-off-by: Nathan Chancellor 
Signed-off-by: Greg Kroah-Hartman

ext4: potential crash on allocation error in ext4_alloc_flex_bg_array()

2020-03-11T06:51:13+00:00

commit 37b0b6b8b99c0e1c1f11abbe7cf49b6d03795b3f upstream.

If sbi->s_flex_groups_allocated is zero and the first allocation fails
then this code will crash.  The problem is that "i--" will set "i" to
-1 but when we compare "i >= sbi->s_flex_groups_allocated" then the -1
is type promoted to unsigned and becomes UINT_MAX.  Since UINT_MAX
is more than zero, the condition is true so we call kvfree(new_groups[-1]).
The loop will carry on freeing invalid memory until it crashes.

Fixes: 7c990728b99e ("ext4: fix potential race between s_flex_groups online resizing and access")
Reviewed-by: Suraj Jitindar Singh 
Signed-off-by: Dan Carpenter 
Cc: stable@kernel.org
Link: https://lore.kernel.org/r/20200228092142.7irbc44yaz3by7nb@kili.mountain
Signed-off-by: Theodore Ts'o 
Signed-off-by: Greg Kroah-Hartman