linux-stable.git/fs/squashfs, branch linux-4.9.y

squashfs: fix divide error in calculate_skip()

2021-05-22T08:40:32+00:00

commit d6e621de1fceb3b098ebf435ef7ea91ec4838a1a upstream.

Sysbot has reported a "divide error" which has been identified as being
caused by a corrupted file_size value within the file inode.  This value
has been corrupted to a much larger value than expected.

Calculate_skip() is passed i_size_read(inode) >> msblk->block_log.  Due to
the file_size value corruption this overflows the int argument/variable in
that function, leading to the divide error.

This patch changes the function to use u64.  This will accommodate any
unexpectedly large values due to corruption.

The value returned from calculate_skip() is clamped to be never more than
SQUASHFS_CACHED_BLKS - 1, or 7.  So file_size corruption does not lead to
an unexpectedly large return result here.

Link: https://lkml.kernel.org/r/20210507152618.9447-1-phillip@squashfs.org.uk
Signed-off-by: Phillip Lougher 
Reported-by: 
Reported-by: 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

squashfs: fix xattr id and id lookup sanity checks

2021-03-30T12:41:40+00:00

commit 8b44ca2b634527151af07447a8090a5f3a043321 upstream.

The checks for maximum metadata block size is missing
SQUASHFS_BLOCK_OFFSET (the two byte length count).

Link: https://lkml.kernel.org/r/2069685113.2081245.1614583677427@webmail.123-reg.co.uk
Fixes: f37aa4c7366e23f ("squashfs: add more sanity checks in id lookup")
Signed-off-by: Phillip Lougher 
Cc: Sean Nyekjaer 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

squashfs: fix inode lookup sanity checks

2021-03-30T12:41:40+00:00

commit c1b2028315c6b15e8d6725e0d5884b15887d3daa upstream.

When mouting a squashfs image created without inode compression it fails
with: "unable to read inode lookup table"

It turns out that the BLOCK_OFFSET is missing when checking the
SQUASHFS_METADATA_SIZE agaist the actual size.

Link: https://lkml.kernel.org/r/20210226092903.1473545-1-sean@geanix.com
Fixes: eabac19e40c0 ("squashfs: add more sanity checks in inode lookup")
Signed-off-by: Sean Nyekjaer 
Acked-by: Phillip Lougher 
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

squashfs: add more sanity checks in xattr id lookup

2021-02-23T12:59:15+00:00

commit 506220d2ba21791314af569211ffd8870b8208fa upstream.

Sysbot has reported a warning where a kmalloc() attempt exceeds the
maximum limit.  This has been identified as corruption of the xattr_ids
count when reading the xattr id lookup table.

This patch adds a number of additional sanity checks to detect this
corruption and others.

1. It checks for a corrupted xattr index read from the inode.  This could
   be because the metadata block is uncompressed, or because the
   "compression" bit has been corrupted (turning a compressed block
   into an uncompressed block).  This would cause an out of bounds read.

2. It checks against corruption of the xattr_ids count.  This can either
   lead to the above kmalloc failure, or a smaller than expected
   table to be read.

3. It checks the contents of the index table for corruption.

[phillip@squashfs.org.uk: fix checkpatch issue]
  Link: https://lkml.kernel.org/r/270245655.754655.1612770082682@webmail.123-reg.co.uk

Link: https://lkml.kernel.org/r/20210204130249.4495-5-phillip@squashfs.org.uk
Signed-off-by: Phillip Lougher 
Reported-by: syzbot+2ccea6339d368360800d@syzkaller.appspotmail.com
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

squashfs: add more sanity checks in inode lookup

2021-02-23T12:59:15+00:00

commit eabac19e40c095543def79cb6ffeb3a8588aaff4 upstream.

Sysbot has reported an "slab-out-of-bounds read" error which has been
identified as being caused by a corrupted "ino_num" value read from the
inode.  This could be because the metadata block is uncompressed, or
because the "compression" bit has been corrupted (turning a compressed
block into an uncompressed block).

This patch adds additional sanity checks to detect this, and the
following corruption.

1. It checks against corruption of the inodes count.  This can either
   lead to a larger table to be read, or a smaller than expected
   table to be read.

   In the case of a too large inodes count, this would often have been
   trapped by the existing sanity checks, but this patch introduces
   a more exact check, which can identify too small values.

2. It checks the contents of the index table for corruption.

[phillip@squashfs.org.uk: fix checkpatch issue]
  Link: https://lkml.kernel.org/r/527909353.754618.1612769948607@webmail.123-reg.co.uk

Link: https://lkml.kernel.org/r/20210204130249.4495-4-phillip@squashfs.org.uk
Signed-off-by: Phillip Lougher 
Reported-by: syzbot+04419e3ff19d2970ea28@syzkaller.appspotmail.com
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

squashfs: add more sanity checks in id lookup

2021-02-23T12:59:15+00:00

commit f37aa4c7366e23f91b81d00bafd6a7ab54e4a381 upstream.

Sysbot has reported a number of "slab-out-of-bounds reads" and
"use-after-free read" errors which has been identified as being caused
by a corrupted index value read from the inode.  This could be because
the metadata block is uncompressed, or because the "compression" bit has
been corrupted (turning a compressed block into an uncompressed block).

This patch adds additional sanity checks to detect this, and the
following corruption.

1. It checks against corruption of the ids count.  This can either
   lead to a larger table to be read, or a smaller than expected
   table to be read.

   In the case of a too large ids count, this would often have been
   trapped by the existing sanity checks, but this patch introduces
   a more exact check, which can identify too small values.

2. It checks the contents of the index table for corruption.

Link: https://lkml.kernel.org/r/20210204130249.4495-3-phillip@squashfs.org.uk
Signed-off-by: Phillip Lougher 
Reported-by: syzbot+b06d57ba83f604522af2@syzkaller.appspotmail.com
Reported-by: syzbot+c021ba012da41ee9807c@syzkaller.appspotmail.com
Reported-by: syzbot+5024636e8b5fd19f0f19@syzkaller.appspotmail.com
Reported-by: syzbot+bcbc661df46657d0fa4f@syzkaller.appspotmail.com
Cc: 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

Squashfs: Compute expected length from inode size rather than block length

2018-09-05T07:20:03+00:00

[ Upstream commit a3f94cb99a854fa381fe7fadd97c4f61633717a5 ]

Previously in squashfs_readpage() when copying data into the page
cache, it used the length of the datablock read from the filesystem
(after decompression).  However, if the filesystem has been corrupted
this data block may be short, which will leave pages unfilled.

The fix for this is to compute the expected number of bytes to copy
from the inode size, and use this to detect if the block is short.

Signed-off-by: Phillip Lougher 
Tested-by: Willy Tarreau 
Cc: Анатолий Тросиненко 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

squashfs metadata 2: electric boogaloo

2018-09-05T07:20:03+00:00

[ Upstream commit cdbb65c4c7ead680ebe54f4f0d486e2847a500ea ]

Anatoly continues to find issues with fuzzed squashfs images.

This time, corrupt, missing, or undersized data for the page filling
wasn't checked for, because the squashfs_{copy,read}_cache() functions
did the squashfs_copy_data() call without checking the resulting data
size.

Which could result in the page cache pages being incompletely filled in,
and no error indication to the user space reading garbage data.

So make a helper function for the "fill in pages" case, because the
exact same incomplete sequence existed in two places.

[ I should have made a squashfs branch for these things, but I didn't
  intend to start doing them in the first place.

  My historical connection through cramfs is why I got into looking at
  these issues at all, and every time I (continue to) think it's a
  one-off.

  Because _this_ time is always the last time. Right?   - Linus ]

Reported-by: Anatoly Trosinenko 
Tested-by: Willy Tarreau 
Cc: Al Viro 
Cc: Phillip Lougher 
Signed-off-by: Linus Torvalds 
Signed-off-by: Sasha Levin 
Signed-off-by: Greg Kroah-Hartman

squashfs: more metadata hardenings

2018-08-06T14:23:03+00:00

commit 71755ee5350b63fb1f283de8561cdb61b47f4d1d upstream.

The squashfs fragment reading code doesn't actually verify that the
fragment is inside the fragment table.  The end result _is_ verified to
be inside the image when actually reading the fragment data, but before
that is done, we may end up taking a page fault because the fragment
table itself might not even exist.

Another report from Anatoly and his endless squashfs image fuzzing.

Reported-by: Анатолий Тросиненко 
Acked-by:: Phillip Lougher ,
Cc: Willy Tarreau 
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman

squashfs: more metadata hardening

2018-08-06T14:23:03+00:00

commit d512584780d3e6a7cacb2f482834849453d444a1 upstream.

Anatoly reports another squashfs fuzzing issue, where the decompression
parameters themselves are in a compressed block.

This causes squashfs_read_data() to be called in order to read the
decompression options before the decompression stream having been set
up, making squashfs go sideways.

Reported-by: Anatoly Trosinenko 
Acked-by: Phillip Lougher 
Cc: stable@kernel.org
Signed-off-by: Linus Torvalds 
Signed-off-by: Greg Kroah-Hartman