linux-toradex.git/fs, branch v2.6.27.23

proc: avoid information leaks to non-privileged processes

2009-05-08T21:54:36+00:00

commit f83ce3e6b02d5e48b3a43b001390e2b58820389d upstream.

By using the same test as is used for /proc/pid/maps and /proc/pid/smaps,
only allow processes that can ptrace() a given process to see information
that might be used to bypass address space layout randomization (ASLR).
These include eip, esp, wchan, and start_stack in /proc/pid/stat as well
as the non-symbolic output from /proc/pid/wchan.

ASLR can be bypassed by sampling eip as shown by the proof-of-concept
code at http://code.google.com/p/fuzzyaslr/ As part of a presentation
(http://www.cr0.org/paper/to-jt-linux-alsr-leak.pdf) esp and wchan were
also noted as possibly usable information leaks as well.  The
start_stack address also leaks potentially useful information.

Cc: Stable Team 
Signed-off-by: Jake Edge 
Acked-by: Arjan van de Ven 
Acked-by: "Eric W. Biederman" 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

pagemap: require aligned-length, non-null reads of /proc/pid/pagemap

2009-05-08T21:54:34+00:00

commit 0816178638c15ce5472d39d771a96860dff4141a upstream.

The intention of commit aae8679b0ebcaa92f99c1c3cb0cd651594a43915
("pagemap: fix bug in add_to_pagemap, require aligned-length reads of
/proc/pid/pagemap") was to force reads of /proc/pid/pagemap to be a
multiple of 8 bytes, but now it allows to read 0 bytes, which actually
puts some data to user's buffer.  According to POSIX, if count is zero,
read() should return zero and has no other results.

Signed-off-by: Vitaly Mayatskikh 
Cc: Thomas Tuttle 
Acked-by: Matt Mackall 
Cc: Alexey Dobriyan 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

fs core fixes

2009-05-02T17:25:00+00:00

Please add the following 4 commits to 2.6.27-stable and 2.6.28-stable.
However, there has been a lot of change here between 2.6.28 and 2.6.29:
in particular, fs/exec.c's unsafe_exec() grew into the more complicated
check_unsafe_exec().  So applying the original patches gives too many
rejects: at the bottom is the diffstat and the combined patch required.

1
Commit: 53e9309e01277ec99c38e84e0ca16921287cf470
Author: Hugh Dickins 
Date: Sat, 28 Mar 2009 23:16:03 +0000 (+0000)
Subject: compat_do_execve should unshare_files

2
Commit: e426b64c412aaa3e9eb3e4b261dc5be0d5a83e78
Author: Hugh Dickins 
Date: Sat, 28 Mar 2009 23:20:19 +0000 (+0000)
Subject: fix setuid sometimes doesn't

3
Commit: 7c2c7d993044cddc5010f6f429b100c63bc7dffb
Author: Hugh Dickins 
Date: Sat, 28 Mar 2009 23:21:27 +0000 (+0000)
Subject: fix setuid sometimes wouldn't

4
Commit: f1191b50ec11c8e2ca766d6d99eb5bb9d2c084a3
Author: Al Viro 
Date: Mon, 30 Mar 2009 11:35:18 +0000 (-0400)
Subject: check_unsafe_exec() doesn't care about signal handlers sharing

Signed-off-by: Hugh Dickins 
Signed-off-by: Greg Kroah-Hartman

block: revert part of 18ce3751ccd488c78d3827e9f6bf54e6322676fb

2009-05-02T17:24:38+00:00

commit 78f707bfc723552e8309b7c38a8d0cc51012e813 upstream.

The above commit added WRITE_SYNC and switched various places to using
that for committing writes that will be waited upon immediately after
submission. However, this causes a performance regression with AS and CFQ
for ext3 at least, since sync_dirty_buffer() will submit some writes with
WRITE_SYNC while ext3 has sumitted others dependent writes without the sync
flag set. This causes excessive anticipation/idling in the IO scheduler
because sync and async writes get interleaved, causing a big performance
regression for the below test case (which is meant to simulate sqlite
like behaviour).

---- test case ----

int main(int argc, char **argv)
{

	int fdes, i;
	FILE *fp;
	struct timeval start;
	struct timeval end;
	struct timeval res;

	gettimeofday(&start, NULL);
	for (i=0; i
Signed-off-by: Greg Kroah-Hartman

hugetlbfs: return negative error code for bad mount option

2009-05-02T17:24:36+00:00

upstream commit: c12ddba09394c60e1120e6997794fa6ed52da884

This fixes the following BUG:

  # mount -o size=MM -t hugetlbfs none /huge
  hugetlbfs: Bad value 'MM' for mount option 'size=MM'
  ------------[ cut here ]------------
  kernel BUG at fs/super.c:996!

Due to

	BUG_ON(!mnt->mnt_sb);

in vfs_kern_mount().

Also, remove unused #include 

Cc: William Irwin 
Signed-off-by: Akinobu Mita 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Chris Wright 
Signed-off-by: Greg Kroah-Hartman

splice: fix deadlock in splicing to file

2009-05-02T17:24:09+00:00

upstream commit: 7bfac9ecf0585962fe13584f5cf526d8c8e76f17

There's a possible deadlock in generic_file_splice_write(),
splice_from_pipe() and ocfs2_file_splice_write():

 - task A calls generic_file_splice_write()
 - this calls inode_double_lock(), which locks i_mutex on both
   pipe->inode and target inode
 - ordering depends on inode pointers, can happen that pipe->inode is
   locked first
 - __splice_from_pipe() needs more data, calls pipe_wait()
 - this releases lock on pipe->inode, goes to interruptible sleep
 - task B calls generic_file_splice_write(), similarly to the first
 - this locks pipe->inode, then tries to lock inode, but that is
   already held by task A
 - task A is interrupted, it tries to lock pipe->inode, but fails, as
   it is already held by task B
 - ABBA deadlock

Fix this by explicitly ordering locks: the outer lock must be on
target inode and the inner lock (which is later unlocked and relocked)
must be on pipe->inode.  This is OK, pipe inodes and target inodes
form two nonoverlapping sets, generic_file_splice_write() and friends
are not called with a target which is a pipe.

Signed-off-by: Miklos Szeredi 
Acked-by: Mark Fasheh 
Acked-by: Jens Axboe 
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds 
Signed-off-by: Chris Wright 
Signed-off-by: Greg Kroah-Hartman

vfs: skip I_CLEAR state inodes

2009-05-02T17:24:01+00:00

upstream commit: b6fac63cc1f52ec27f29fe6c6c8494a2ffac33fd

clear_inode() will switch inode state from I_FREEING to I_CLEAR, and do so
_outside_ of inode_lock.  So any I_FREEING testing is incomplete without a
coupled testing of I_CLEAR.

So add I_CLEAR tests to drop_pagecache_sb(), generic_sync_sb_inodes() and
add_dquot_ref().

Masayoshi MIZUMA discovered the bug in drop_pagecache_sb() and Jan Kara
reminds fixing the other two cases.

Masayoshi MIZUMA has a nice panic flow:

=====================================================================
            [process A]               |        [process B]
 |                                    |
 |    prune_icache()                  | drop_pagecache()
 |      spin_lock(&inode_lock)        |   drop_pagecache_sb()
 |      inode->i_state |= I_FREEING;  |       |
 |      spin_unlock(&inode_lock)      |       V
 |          |                         |     spin_lock(&inode_lock)
 |          V                         |         |
 |      dispose_list()                |         |
 |        list_del()                  |         |
 |        clear_inode()               |         |
 |          inode->i_state = I_CLEAR  |         |
 |            |                       |         V
 |            |                       |      if (inode->i_state & (I_FREEING|I_WILL_FREE))
 |            |                       |              continue;           <==== NOT MATCH
 |            |                       |
 |            |                       | (DANGER from here on! Accessing disposing inode!)
 |            |                       |
 |            |                       |      __iget()
 |            |                       |        list_move() <===== PANIC on poisoned list !!
 V            V                       |
(time)
=====================================================================

Reported-by: Masayoshi MIZUMA 
Reviewed-by: Jan Kara 
Signed-off-by: Wu Fengguang 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
[chrisw: backport to 2.6.29]
Signed-off-by: Chris Wright 
Signed-off-by: Greg Kroah-Hartman

CIFS: Fix memory overwrite when saving nativeFileSystem field during mount

2009-05-02T17:23:35+00:00

upstream commit: b363b3304bcf68c4541683b2eff70b29f0446a5b

CIFS can allocate a few bytes to little for the nativeFileSystem field
during tree connect response processing during mount.  This can result
in a "Redzone overwritten" message to be logged.

Signed-off-by: Sridhar Vinay 
Acked-by: Shirish Pargaonkar 
CC: Stable 
Signed-off-by: Steve French 
[chrisw: minor backport to CHANGES file]
Signed-off-by: Chris Wright 
Signed-off-by: Greg Kroah-Hartman

cifs: fix buffer format byte on NT Rename/hardlink

2009-05-02T17:23:31+00:00

upstream commit: fcc7c09d94be7b75c9ea2beb22d0fae191c6b4b9

Discovered at Connnectathon 2009...

The buffer format byte and the pad are transposed in NT_RENAME calls
(which are used to set hardlinks). Most servers seem to ignore this
fact, but NetApp filers throw back an error due to this problem. This
patch fixes it.

CC: Stable 
Signed-off-by: Jeff Layton 
Signed-off-by: Steve French 
Signed-off-by: Chris Wright 
Signed-off-by: Greg Kroah-Hartman

eventfd: remove fput() call from possible IRQ context

2009-03-23T22:00:01+00:00

commit 87c3a86e1c220121d0ced59d1a71e78ed9abc6dd upstream.

Remove a source of fput() call from inside IRQ context.  Myself, like Eric,
wasn't able to reproduce an fput() call from IRQ context, but Jeff said he was
able to, with the attached test program.  Independently from this, the bug is
conceptually there, so we might be better off fixing it.  This patch adds an
optimization similar to the one we already do on ->ki_filp, on ->ki_eventfd.
Playing with ->f_count directly is not pretty in general, but the alternative
here would be to add a brand new delayed fput() infrastructure, that I'm not
sure is worth it.

Signed-off-by: Davide Libenzi 
Cc: Benjamin LaHaise 
Cc: Trond Myklebust 
Cc: Eric Dumazet 
Signed-off-by: Jeff Moyer 
Cc: Zach Brown 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman