linux-stable.git/fs, branch v4.14.78

Revert "vfs: fix freeze protection in mnt_want_write_file() for overlayfs"

2018-10-20T07:48:52+00:00

This reverts commit 4f4374a9bd25b333971e6f2656b642d29e2efe7b which was
commit a6795a585929d94ca3e931bc8518f8deb8bbe627 upstream.

Turns out this causes problems and was to fix a patch only in the 4.19
and newer tree.

Reported-by: Amir Goldstein 
Cc: Miklos Szeredi 
Cc: Christoph Hellwig 
Cc: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

dcache: account external names as indirectly reclaimable memory

2018-10-18T07:16:25+00:00

commit f1782c9bc547754f4bd3043fe8cfda53db85f13f upstream.

I received a report about suspicious growth of unreclaimable slabs on
some machines.  I've found that it happens on machines with low memory
pressure, and these unreclaimable slabs are external names attached to
dentries.

External names are allocated using generic kmalloc() function, so they
are accounted as unreclaimable.  But they are held by dentries, which
are reclaimable, and they will be reclaimed under the memory pressure.

In particular, this breaks MemAvailable calculation, as it doesn't take
unreclaimable slabs into account.  This leads to a silly situation, when
a machine is almost idle, has no memory pressure and therefore has a big
dentry cache.  And the resulting MemAvailable is too low to start a new
workload.

To address the issue, the NR_INDIRECTLY_RECLAIMABLE_BYTES counter is
used to track the amount of memory, consumed by external names.  The
counter is increased in the dentry allocation path, if an external name
structure is allocated; and it's decreased in the dentry freeing path.

To reproduce the problem I've used the following Python script:

  import os

  for iter in range (0, 10000000):
      try:
          name = ("/some_long_name_%d" % iter) + "_" * 220
          os.stat(name)
      except Exception:
          pass

Without this patch:
  $ cat /proc/meminfo | grep MemAvailable
  MemAvailable:    7811688 kB
  $ python indirect.py
  $ cat /proc/meminfo | grep MemAvailable
  MemAvailable:    2753052 kB

With the patch:
  $ cat /proc/meminfo | grep MemAvailable
  MemAvailable:    7809516 kB
  $ python indirect.py
  $ cat /proc/meminfo | grep MemAvailable
  MemAvailable:    7749144 kB

[guro@fb.com: fix indirectly reclaimable memory accounting for CONFIG_SLOB]
  Link: http://lkml.kernel.org/r/20180312194140.19517-1-guro@fb.com
[guro@fb.com: fix indirectly reclaimable memory accounting]
  Link: http://lkml.kernel.org/r/20180313125701.7955-1-guro@fb.com
Link: http://lkml.kernel.org/r/20180305133743.12746-5-guro@fb.com
Signed-off-by: Roman Gushchin 
Reviewed-by: Andrew Morton 
Cc: Alexander Viro 
Cc: Michal Hocko 
Cc: Johannes Weiner 
Cc: Mel Gorman 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

ubifs: Check for name being NULL while mounting

2018-10-13T07:27:29+00:00

commit 37f31b6ca4311b94d985fb398a72e5399ad57925 upstream.

The requested device name can be NULL or an empty string.
Check for that and refuse to continue. UBIFS has to do this manually
since we cannot use mount_bdev(), which checks for this condition.

Fixes: 1e51764a3c2ac ("UBIFS: add new flash file system")
Reported-by: syzbot+38bd0f7865e5c6379280@syzkaller.appspotmail.com
Signed-off-by: Richard Weinberger 
Signed-off-by: Greg Kroah-Hartman

f2fs: fix invalid memory access

2018-10-13T07:27:29+00:00

commit d3f07c049dab1a3f1740f476afd3d5e5b738c21c upstream.

syzbot found the following crash on:

HEAD commit:    d9bd94c0bcaa Add linux-next specific files for 20180801
git tree:       linux-next
console output: https://syzkaller.appspot.com/x/log.txt?x=1001189c400000
kernel config:  https://syzkaller.appspot.com/x/.config?x=cc8964ea4d04518c
dashboard link: https://syzkaller.appspot.com/bug?extid=c966a82db0b14aa37e81
compiler:       gcc (GCC) 8.0.1 20180413 (experimental)

Unfortunately, I don't have any reproducer for this crash yet.

IMPORTANT: if you fix the bug, please add the following tag to the commit:
Reported-by: syzbot+c966a82db0b14aa37e81@syzkaller.appspotmail.com

loop7: rw=12288, want=8200, limit=20
netlink: 65342 bytes leftover after parsing attributes in process `syz-executor4'.
openvswitch: netlink: Message has 8 unknown bytes.
kasan: CONFIG_KASAN_INLINE enabled
kasan: GPF could be caused by NULL-ptr deref or user memory access
general protection fault: 0000 [#1] SMP KASAN
CPU: 1 PID: 7615 Comm: syz-executor7 Not tainted 4.18.0-rc7-next-20180801+ #29
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
RIP: 0010:__read_once_size include/linux/compiler.h:188 [inline]
RIP: 0010:compound_head include/linux/page-flags.h:142 [inline]
RIP: 0010:PageLocked include/linux/page-flags.h:272 [inline]
RIP: 0010:f2fs_put_page fs/f2fs/f2fs.h:2011 [inline]
RIP: 0010:validate_checkpoint+0x66d/0xec0 fs/f2fs/checkpoint.c:835
Code: e8 58 05 7f fe 4c 8d 6b 80 4d 8d 74 24 08 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 c6 04 02 00 4c 89 f2 48 c1 ea 03 <80> 3c 02 00 0f 85 f4 06 00 00 4c 89 ea 4d 8b 7c 24 08 48 b8 00 00
RSP: 0018:ffff8801937cebe8 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffff8801937cef30 RCX: ffffc90006035000
RDX: 0000000000000000 RSI: ffffffff82fd9658 RDI: 0000000000000005
RBP: ffff8801937cef58 R08: ffff8801ab254700 R09: fffff94000d9e026
R10: fffff94000d9e026 R11: ffffea0006cf0137 R12: fffffffffffffffb
R13: ffff8801937ceeb0 R14: 0000000000000003 R15: ffff880193419b40
FS:  00007f36a61d5700(0000) GS:ffff8801db100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc04ff93000 CR3: 00000001d0562000 CR4: 00000000001426e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400
Call Trace:
 f2fs_get_valid_checkpoint+0x436/0x1ec0 fs/f2fs/checkpoint.c:860
 f2fs_fill_super+0x2d42/0x8110 fs/f2fs/super.c:2883
 mount_bdev+0x314/0x3e0 fs/super.c:1344
 f2fs_mount+0x3c/0x50 fs/f2fs/super.c:3133
 legacy_get_tree+0x131/0x460 fs/fs_context.c:729
 vfs_get_tree+0x1cb/0x5c0 fs/super.c:1743
 do_new_mount fs/namespace.c:2603 [inline]
 do_mount+0x6f2/0x1e20 fs/namespace.c:2927
 ksys_mount+0x12d/0x140 fs/namespace.c:3143
 __do_sys_mount fs/namespace.c:3157 [inline]
 __se_sys_mount fs/namespace.c:3154 [inline]
 __x64_sys_mount+0xbe/0x150 fs/namespace.c:3154
 do_syscall_64+0x1b9/0x820 arch/x86/entry/common.c:290
 entry_SYSCALL_64_after_hwframe+0x49/0xbe
RIP: 0033:0x45943a
Code: b8 a6 00 00 00 0f 05 48 3d 01 f0 ff ff 0f 83 bd 8a fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 49 89 ca b8 a5 00 00 00 0f 05 <48> 3d 01 f0 ff ff 0f 83 9a 8a fb ff c3 66 0f 1f 84 00 00 00 00 00
RSP: 002b:00007f36a61d4a88 EFLAGS: 00000206 ORIG_RAX: 00000000000000a5
RAX: ffffffffffffffda RBX: 00007f36a61d4b30 RCX: 000000000045943a
RDX: 00007f36a61d4ad0 RSI: 0000000020000100 RDI: 00007f36a61d4af0
RBP: 0000000020000100 R08: 00007f36a61d4b30 R09: 00007f36a61d4ad0
R10: 0000000000000000 R11: 0000000000000206 R12: 0000000000000013
R13: 0000000000000000 R14: 00000000004c8ea0 R15: 0000000000000000
Modules linked in:
Dumping ftrace buffer:
   (ftrace buffer empty)
---[ end trace bd8550c129352286 ]---
RIP: 0010:__read_once_size include/linux/compiler.h:188 [inline]
RIP: 0010:compound_head include/linux/page-flags.h:142 [inline]
RIP: 0010:PageLocked include/linux/page-flags.h:272 [inline]
RIP: 0010:f2fs_put_page fs/f2fs/f2fs.h:2011 [inline]
RIP: 0010:validate_checkpoint+0x66d/0xec0 fs/f2fs/checkpoint.c:835
Code: e8 58 05 7f fe 4c 8d 6b 80 4d 8d 74 24 08 48 b8 00 00 00 00 00 fc ff df 4c 89 ea 48 c1 ea 03 c6 04 02 00 4c 89 f2 48 c1 ea 03 <80> 3c 02 00 0f 85 f4 06 00 00 4c 89 ea 4d 8b 7c 24 08 48 b8 00 00
RSP: 0018:ffff8801937cebe8 EFLAGS: 00010246
RAX: dffffc0000000000 RBX: ffff8801937cef30 RCX: ffffc90006035000
RDX: 0000000000000000 RSI: ffffffff82fd9658 RDI: 0000000000000005
netlink: 65342 bytes leftover after parsing attributes in process `syz-executor4'.
RBP: ffff8801937cef58 R08: ffff8801ab254700 R09: fffff94000d9e026
openvswitch: netlink: Message has 8 unknown bytes.
R10: fffff94000d9e026 R11: ffffea0006cf0137 R12: fffffffffffffffb
R13: ffff8801937ceeb0 R14: 0000000000000003 R15: ffff880193419b40
FS:  00007f36a61d5700(0000) GS:ffff8801db100000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 00007fc04ff93000 CR3: 00000001d0562000 CR4: 00000000001426e0
DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000
DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400

In validate_checkpoint(), if we failed to call get_checkpoint_version(), we
will pass returned invalid page pointer into f2fs_put_page, cause accessing
invalid memory, this patch tries to handle error path correctly to fix this
issue.

Signed-off-by: Chao Yu 
Signed-off-by: Greg Kroah-Hartman 

Signed-off-by: Jaegeuk Kim

ocfs2: fix locking for res->tracking and dlm->tracking_list

2018-10-10T06:54:28+00:00

commit cbe355f57c8074bc4f452e5b6e35509044c6fa23 upstream.

In dlm_init_lockres() we access and modify res->tracking and
dlm->tracking_list without holding dlm->track_lock.  This can cause list
corruptions and can end up in kernel panic.

Fix this by locking res->tracking and dlm->tracking_list with
dlm->track_lock instead of dlm->spinlock.

Link: http://lkml.kernel.org/r/1529951192-4686-1-git-send-email-ashish.samant@oracle.com
Signed-off-by: Ashish Samant 
Reviewed-by: Changwei Ge 
Acked-by: Joseph Qi 
Acked-by: Jun Piao 
Cc: Mark Fasheh 
Cc: Joel Becker 
Cc: Junxiao Bi 
Cc: Changwei Ge 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

proc: restrict kernel stack dumps to root

2018-10-10T06:54:28+00:00

commit f8a00cef17206ecd1b30d3d9f99e10d9fa707aa7 upstream.

Currently, you can use /proc/self/task/*/stack to cause a stack walk on
a task you control while it is running on another CPU.  That means that
the stack can change under the stack walker.  The stack walker does
have guards against going completely off the rails and into random
kernel memory, but it can interpret random data from your kernel stack
as instruction pointers and stack pointers.  This can cause exposure of
kernel stack contents to userspace.

Restrict the ability to inspect kernel stacks of arbitrary tasks to root
in order to prevent a local attacker from exploiting racy stack unwinding
to leak kernel task stack contents.  See the added comment for a longer
rationale.

There don't seem to be any users of this userspace API that can't
gracefully bail out if reading from the file fails.  Therefore, I believe
that this change is unlikely to break things.  In the case that this patch
does end up needing a revert, the next-best solution might be to fake a
single-entry stack based on wchan.

Link: http://lkml.kernel.org/r/20180927153316.200286-1-jannh@google.com
Fixes: 2ec220e27f50 ("proc: add /proc/*/stack")
Signed-off-by: Jann Horn 
Acked-by: Kees Cook 
Cc: Alexey Dobriyan 
Cc: Ken Chen 
Cc: Will Deacon 
Cc: Laura Abbott 
Cc: Andy Lutomirski 
Cc: Catalin Marinas 
Cc: Josh Poimboeuf 
Cc: Thomas Gleixner 
Cc: Ingo Molnar 
Cc: "H . Peter Anvin" 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Greg Kroah-Hartman

smb2: fix missing files in root share directory listing

2018-10-10T06:54:27+00:00

commit 0595751f267994c3c7027377058e4185b3a28e75 upstream.

When mounting a Windows share that is the root of a drive (eg. C$)
the server does not return . and .. directory entries. This results in
the smb2 code path erroneously skipping the 2 first entries.

Pseudo-code of the readdir() code path:

cifs_readdir(struct file, struct dir_context)
    initiate_cifs_search            <-- if no reponse cached yet
        server->ops->query_dir_first

    dir_emit_dots
        dir_emit                    <-- adds "." and ".." if we're at pos=0

    find_cifs_entry
        initiate_cifs_search        <-- if pos < start of current response
                                         (restart search)
        server->ops->query_dir_next <-- if pos > end of current response
                                         (fetch next search res)

    for(...)                        <-- loops over cur response entries
                                          starting at pos
        cifs_filldir                <-- skip . and .., emit entry
            cifs_fill_dirent
            dir_emit
	pos++

A) dir_emit_dots() always adds . & ..
   and sets the current dir pos to 2 (0 and 1 are done).

Therefore we always want the index_to_find to be 2 regardless of if
the response has . and ..

B) smb1 code initializes index_of_last_entry with a +2 offset

  in cifssmb.c CIFSFindFirst():
		psrch_inf->index_of_last_entry = 2 /* skip . and .. */ +
			psrch_inf->entries_in_buffer;

Later in find_cifs_entry() we want to find the next dir entry at pos=2
as a result of (A)

	first_entry_in_buffer = cfile->srch_inf.index_of_last_entry -
					cfile->srch_inf.entries_in_buffer;

This var is the dir pos that the first entry in the buffer will
have therefore it must be 2 in the first call.

If we don't offset index_of_last_entry by 2 (like in (B)),
first_entry_in_buffer=0 but we were instructed to get pos=2 so this
code in find_cifs_entry() skips the 2 first which is ok for non-root
shares, as it skips . and .. from the response but is not ok for root
shares where the 2 first are actual files

		pos_in_buf = index_to_find - first_entry_in_buffer;
                // pos_in_buf=2
		// we skip 2 first response entries :(
		for (i = 0; (i < (pos_in_buf)) && (cur_ent != NULL); i++) {
			/* go entry by entry figuring out which is first */
			cur_ent = nxt_dir_entry(cur_ent, end_of_smb,
						cfile->srch_inf.info_level);
		}

C) cifs_filldir() skips . and .. so we can safely ignore them for now.

Sample program:

int main(int argc, char **argv)
{
	const char *path = argc >= 2 ? argv[1] : ".";
	DIR *dh;
	struct dirent *de;

	printf("listing path <%s>\n", path);
	dh = opendir(path);
	if (!dh) {
		printf("opendir error %d\n", errno);
		return 1;
	}

	while (1) {
		de = readdir(dh);
		if (!de) {
			if (errno) {
				printf("readdir error %d\n", errno);
				return 1;
			}
			printf("end of listing\n");
			break;
		}
		printf("off=%lu <%s>\n", de->d_off, de->d_name);
	}

	return 0;
}

Before the fix with SMB1 on root shares:

<.>            off=1
<..>           off=2
<$Recycle.Bin> off=3
      off=4

and on non-root shares:

<.>    off=1
<..>   off=4  <-- after adding .., the offsets jumps to +2 because
<2536> off=5       we skipped . and .. from response buffer (C)
<411>  off=6       but still incremented pos
 off=7
  off=8

Therefore the fix for smb2 is to mimic smb1 behaviour and offset the
index_of_last_entry by 2.

Test results comparing smb1 and smb2 before/after the fix on root
share, non-root shares and on large directories (ie. multi-response
dir listing):

PRE FIX
=======
pre-1-root VS pre-2-root:
        ERR pre-2-root is missing [bootmgr, $Recycle.Bin]
pre-1-nonroot VS pre-2-nonroot:
        OK~ same files, same order, different offsets
pre-1-nonroot-large VS pre-2-nonroot-large:
        OK~ same files, same order, different offsets

POST FIX
========
post-1-root VS post-2-root:
        OK same files, same order, same offsets
post-1-nonroot VS post-2-nonroot:
        OK same files, same order, same offsets
post-1-nonroot-large VS post-2-nonroot-large:
        OK same files, same order, same offsets

REGRESSION?
===========
pre-1-root VS post-1-root:
        OK same files, same order, same offsets
pre-1-nonroot VS post-1-nonroot:
        OK same files, same order, same offsets

BugLink: https://bugzilla.samba.org/show_bug.cgi?id=13107
Signed-off-by: Aurelien Aptel 
Signed-off-by: Paulo Alcantara 
Reviewed-by: Ronnie Sahlberg 
Signed-off-by: Steve French 
CC: Stable 
Signed-off-by: Greg Kroah-Hartman

sysfs: Do not return POSIX ACL xattrs via listxattr

2018-10-10T06:54:27+00:00

commit ffc4c92227db5699493e43eb140b4cb5904c30ff upstream.

Commit 786534b92f3c introduced a regression that caused listxattr to
return the POSIX ACL attribute names even though sysfs doesn't support
POSIX ACLs.  This happens because simple_xattr_list checks for NULL
i_acl / i_default_acl, but inode_init_always initializes those fields
to ACL_NOT_CACHED ((void *)-1).  For example:
    $ getfattr -m- -d /sys
    /sys: system.posix_acl_access: Operation not supported
    /sys: system.posix_acl_default: Operation not supported
Fix this in simple_xattr_list by checking if the filesystem supports POSIX ACLs.

Fixes: 786534b92f3c ("tmpfs: listxattr should include POSIX ACL xattrs")
Reported-by:  Marc Aurèle La France 
Tested-by: Marc Aurèle La France 
Signed-off-by: Andreas Gruenbacher 
Cc: stable@vger.kernel.org # v4.5+
Signed-off-by: Al Viro 
Signed-off-by: Greg Kroah-Hartman

ovl: fix format of setxattr debug

2018-10-10T06:54:27+00:00

commit 1a8f8d2a443ef9ad9a3065ba8c8119df714240fa upstream.

Format has a typo: it was meant to be "%.*s", not "%*s".  But at some point
callers grew nonprintable values as well, so use "%*pE" instead with a
maximized length.

Reported-by: Amir Goldstein 
Signed-off-by: Miklos Szeredi 
Fixes: 3a1e819b4e80 ("ovl: store file handle of lower inode on copy up")
Cc:  # v4.12
Signed-off-by: Greg Kroah-Hartman

ovl: fix memory leak on unlink of indexed file

2018-10-10T06:54:27+00:00

commit 63e132528032ce937126aba591a7b37ec593a6bb upstream.

The memory leak was detected by kmemleak when running xfstests
overlay/051,053

Fixes: caf70cb2ba5d ("ovl: cleanup orphan index entries")
Cc:  # v4.13
Signed-off-by: Amir Goldstein 
Signed-off-by: Miklos Szeredi 
Signed-off-by: Greg Kroah-Hartman