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  1. 19 May, 2016 8 commits
    • David Howells's avatar
      KEYS: Fix ASN.1 indefinite length object parsing · 012d8158
      David Howells authored 
      commit 23c8a812 upstream.

This fixes CVE-2016-0758.

In the ASN.1 decoder, when the length field of an ASN.1 value is extracted,
it isn't validated against the remaining amount of data before being added
to the cursor.  With a sufficiently large size indicated, the check:

	datalen - dp < 2

may then fail due to integer overflow.

Fix this by checking the length indicated against the amount of remaining
data in both places a definite length is determined.

Whilst we're at it, make the following changes:

 (1) Check the maximum size of extended length does not exceed the capacity
     of the variable it's being stored in (len) rather than the type that
     variable is assumed to be (size_t).

 (2) Compare the EOC tag to the symbolic constant ASN1_EOC rather than the
     integer 0.

 (3) To reduce confusion, move the initialisation of len outside of:

	for (len = 0; n > 0; n--) {

     since it doesn't have anything to do with the loop counter n.
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Reviewed-by: default avatarMimi Zohar <zohar@linux.vnet.ibm.com>
Acked-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
Acked-by: default avatarPeter Jones <pjones@redhat.com>
Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
      012d8158
    • David Howells's avatar
      ASN.1: Fix non-match detection failure on data overrun · abce1538
      David Howells authored 
      commit 0d62e9dd upstream.

If the ASN.1 decoder is asked to parse a sequence of objects, non-optional
matches get skipped if there's no more data to be had rather than a
data-overrun error being reported.

This is due to the code segment that decides whether to skip optional
matches (ie. matches that could get ignored because an element is marked
OPTIONAL in the grammar) due to a lack of data also skips non-optional
elements if the data pointer has reached the end of the buffer.

This can be tested with the data decoder for the new RSA akcipher algorithm
that takes three non-optional integers.  Currently, it skips the last
integer if there is insufficient data.

Without the fix, #defining DEBUG in asn1_decoder.c will show something
like:

	next_op: pc=0/13 dp=0/270 C=0 J=0
	- match? 30 30 00
	- TAG: 30 266 CONS
	next_op: pc=2/13 dp=4/270 C=1 J=0
	- match? 02 02 00
	- TAG: 02 257
	- LEAF: 257
	next_op: pc=5/13 dp=265/270 C=1 J=0
	- match? 02 02 00
	- TAG: 02 3
	- LEAF: 3
	next_op: pc=8/13 dp=270/270 C=1 J=0
	next_op: pc=11/13 dp=270/270 C=1 J=0
	- end cons t=4 dp=270 l=270/270

The next_op line for pc=8/13 should be followed by a match line.

This is not exploitable for X.509 certificates by means of shortening the
message and fixing up the ASN.1 CONS tags because:

 (1) The relevant records being built up are cleared before use.

 (2) If the message is shortened sufficiently to remove the public key, the
     ASN.1 parse of the RSA key will fail quickly due to a lack of data.

 (3) Extracted signature data is either turned into MPIs (which cope with a
     0 length) or is simpler integers specifying algoritms and suchlike
     (which can validly be 0); and

 (4) The AKID and SKID extensions are optional and their removal is handled
     without risking passing a NULL to asymmetric_key_generate_id().

 (5) If the certificate is truncated sufficiently to remove the subject,
     issuer or serialNumber then the ASN.1 decoder will fail with a 'Cons
     stack underflow' return.

This is not exploitable for PKCS#7 messages by means of removal of elements
from such a message from the tail end of a sequence:

 (1) Any shortened X.509 certs embedded in the PKCS#7 message are survivable
     as detailed above.

 (2) The message digest content isn't used if it shows a NULL pointer,
     similarly, the authattrs aren't used if that shows a NULL pointer.

 (3) A missing signature results in a NULL MPI - which the MPI routines deal
     with.

 (4) If data is NULL, it is expected that the message has detached content and
     that is handled appropriately.

 (5) If the serialNumber is excised, the unconditional action associated
     with it will pick up the containing SEQUENCE instead, so no NULL
     pointer will be seen here.

     If both the issuer and the serialNumber are excised, the ASN.1 decode
     will fail with an 'Unexpected tag' return.

     In either case, there's no way to get to asymmetric_key_generate_id()
     with a NULL pointer.

 (6) Other fields are decoded to simple integers.  Shortening the message
     to omit an algorithm ID field will cause checks on this to fail early
     in the verification process.

This can also be tested by snipping objects off of the end of the ASN.1 stream
such that mandatory tags are removed - or even from the end of internal
SEQUENCEs.  If any mandatory tag is missing, the error EBADMSG *should* be
produced.  Without this patch ERANGE or ENOPKG might be produced or the parse
may apparently succeed, perhaps with ENOKEY or EKEYREJECTED being produced
later, depending on what gets snipped.

Just snipping off the final BIT_STRING or OCTET_STRING from either sample
should be a start since both are mandatory and neither will cause an EBADMSG
without the patches
Reported-by: default avatarMarcel Holtmann <marcel@holtmann.org>
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Tested-by: default avatarMarcel Holtmann <marcel@holtmann.org>
Reviewed-by: default avatarDavid Woodhouse <David.Woodhouse@intel.com>
Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
      abce1538
    • Kangjie Lu's avatar
      net: fix a kernel infoleak in x25 module · aeb14f17
      Kangjie Lu authored 
      [ Upstream commit 79e48650 ]

Stack object "dte_facilities" is allocated in x25_rx_call_request(),
which is supposed to be initialized in x25_negotiate_facilities.
However, 5 fields (8 bytes in total) are not initialized. This
object is then copied to userland via copy_to_user, thus infoleak
occurs.
Signed-off-by: default avatarKangjie Lu <kjlu@gatech.edu>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
      aeb14f17
    • Nikolay Aleksandrov's avatar
      net: bridge: fix old ioctl unlocked net device walk · cf5ae3f3
      Nikolay Aleksandrov authored 
      [ Upstream commit 31ca0458 ]

get_bridge_ifindices() is used from the old "deviceless" bridge ioctl
calls which aren't called with rtnl held. The comment above says that it is
called with rtnl but that is not really the case.
Here's a sample output from a test ASSERT_RTNL() which I put in
get_bridge_ifindices and executed "brctl show":
[  957.422726] RTNL: assertion failed at net/bridge//br_ioctl.c (30)
[  957.422925] CPU: 0 PID: 1862 Comm: brctl Tainted: G        W  O
4.6.0-rc4+ #157
[  957.423009] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996),
BIOS 1.8.1-20150318_183358- 04/01/2014
[  957.423009]  0000000000000000 ffff880058adfdf0 ffffffff8138dec5
0000000000000400
[  957.423009]  ffffffff81ce8380 ffff880058adfe58 ffffffffa05ead32
0000000000000001
[  957.423009]  00007ffec1a444b0 0000000000000400 ffff880053c19130
0000000000008940
[  957.423009] Call Trace:
[  957.423009]  [<ffffffff8138dec5>] dump_stack+0x85/0xc0
[  957.423009]  [<ffffffffa05ead32>]
br_ioctl_deviceless_stub+0x212/0x2e0 [bridge]
[  957.423009]  [<ffffffff81515beb>] sock_ioctl+0x22b/0x290
[  957.423009]  [<ffffffff8126ba75>] do_vfs_ioctl+0x95/0x700
[  957.423009]  [<ffffffff8126c159>] SyS_ioctl+0x79/0x90
[  957.423009]  [<ffffffff8163a4c0>] entry_SYSCALL_64_fastpath+0x23/0xc1

Since it only reads bridge ifindices, we can use rcu to safely walk the net
device list. Also remove the wrong rtnl comment above.
Signed-off-by: default avatarNikolay Aleksandrov <nikolay@cumulusnetworks.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
      cf5ae3f3
    • Ian Campbell's avatar
      VSOCK: do not disconnect socket when peer has shutdown SEND only · fa9ba455
      Ian Campbell authored 
      [ Upstream commit dedc58e0 ]

The peer may be expecting a reply having sent a request and then done a
shutdown(SHUT_WR), so tearing down the whole socket at this point seems
wrong and breaks for me with a client which does a SHUT_WR.

Looking at other socket family's stream_recvmsg callbacks doing a shutdown
here does not seem to be the norm and removing it does not seem to have
had any adverse effects that I can see.

I'm using Stefan's RFC virtio transport patches, I'm unsure of the impact
on the vmci transport.
Signed-off-by: default avatarIan Campbell <ian.campbell@docker.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Stefan Hajnoczi <stefanha@redhat.com>
Cc: Claudio Imbrenda <imbrenda@linux.vnet.ibm.com>
Cc: Andy King <acking@vmware.com>
Cc: Dmitry Torokhov <dtor@vmware.com>
Cc: Jorgen Hansen <jhansen@vmware.com>
Cc: Adit Ranadive <aditr@vmware.com>
Cc: netdev@vger.kernel.org
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
      fa9ba455
    • Kangjie Lu's avatar
      net: fix infoleak in rtnetlink · 3248734d
      Kangjie Lu authored 
      [ Upstream commit 5f8e4474 ]

The stack object “map” has a total size of 32 bytes. Its last 4
bytes are padding generated by compiler. These padding bytes are
not initialized and sent out via “nla_put”.
Signed-off-by: default avatarKangjie Lu <kjlu@gatech.edu>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
      3248734d
    • Kangjie Lu's avatar
      net: fix infoleak in llc · 734b9658
      Kangjie Lu authored 
      [ Upstream commit b8670c09 ]

The stack object “info” has a total size of 12 bytes. Its last byte
is padding which is not initialized and leaked via “put_cmsg”.
Signed-off-by: default avatarKangjie Lu <kjlu@gatech.edu>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
      734b9658
    • Neil Horman's avatar
      netem: Segment GSO packets on enqueue · 521a3b41
      Neil Horman authored 
      [ Upstream commit 6071bd1a ]

This was recently reported to me, and reproduced on the latest net kernel,
when attempting to run netperf from a host that had a netem qdisc attached
to the egress interface:

[  788.073771] ---------------------[ cut here ]---------------------------
[  788.096716] WARNING: at net/core/dev.c:2253 skb_warn_bad_offload+0xcd/0xda()
[  788.129521] bnx2: caps=(0x00000001801949b3, 0x0000000000000000) len=2962
data_len=0 gso_size=1448 gso_type=1 ip_summed=3
[  788.182150] Modules linked in: sch_netem kvm_amd kvm crc32_pclmul ipmi_ssif
ghash_clmulni_intel sp5100_tco amd64_edac_mod aesni_intel lrw gf128mul
glue_helper ablk_helper edac_mce_amd cryptd pcspkr sg edac_core hpilo ipmi_si
i2c_piix4 k10temp fam15h_power hpwdt ipmi_msghandler shpchp acpi_power_meter
pcc_cpufreq nfsd auth_rpcgss nfs_acl lockd grace sunrpc ip_tables xfs libcrc32c
sd_mod crc_t10dif crct10dif_generic mgag200 syscopyarea sysfillrect sysimgblt
i2c_algo_bit drm_kms_helper ahci ata_generic pata_acpi ttm libahci
crct10dif_pclmul pata_atiixp tg3 libata crct10dif_common drm crc32c_intel ptp
serio_raw bnx2 r8169 hpsa pps_core i2c_core mii dm_mirror dm_region_hash dm_log
dm_mod
[  788.465294] CPU: 16 PID: 0 Comm: swapper/16 Tainted: G        W
------------   3.10.0-327.el7.x86_64 #1
[  788.511521] Hardware name: HP ProLiant DL385p Gen8, BIOS A28 12/17/2012
[  788.542260]  ffff880437c036b8 f7afc56532a53db9 ffff880437c03670
ffffffff816351f1
[  788.576332]  ffff880437c036a8 ffffffff8107b200 ffff880633e74200
ffff880231674000
[  788.611943]  0000000000000001 0000000000000003 0000000000000000
ffff880437c03710
[  788.647241] Call Trace:
[  788.658817]  <IRQ>  [<ffffffff816351f1>] dump_stack+0x19/0x1b
[  788.686193]  [<ffffffff8107b200>] warn_slowpath_common+0x70/0xb0
[  788.713803]  [<ffffffff8107b29c>] warn_slowpath_fmt+0x5c/0x80
[  788.741314]  [<ffffffff812f92f3>] ? ___ratelimit+0x93/0x100
[  788.767018]  [<ffffffff81637f49>] skb_warn_bad_offload+0xcd/0xda
[  788.796117]  [<ffffffff8152950c>] skb_checksum_help+0x17c/0x190
[  788.823392]  [<ffffffffa01463a1>] netem_enqueue+0x741/0x7c0 [sch_netem]
[  788.854487]  [<ffffffff8152cb58>] dev_queue_xmit+0x2a8/0x570
[  788.880870]  [<ffffffff8156ae1d>] ip_finish_output+0x53d/0x7d0
...

The problem occurs because netem is not prepared to handle GSO packets (as it
uses skb_checksum_help in its enqueue path, which cannot manipulate these
frames).

The solution I think is to simply segment the skb in a simmilar fashion to the
way we do in __dev_queue_xmit (via validate_xmit_skb), with some minor changes.
When we decide to corrupt an skb, if the frame is GSO, we segment it, corrupt
the first segment, and enqueue the remaining ones.

tested successfully by myself on the latest net kernel, to which this applies

[js] backport to 3.12: no qdisc_qstats_drop yet, update directly. Also use
     qdisc_tree_decrease_qlen instead of qdisc_tree_reduce_backlog.
Signed-off-by: default avatarNeil Horman <nhorman@tuxdriver.com>
CC: Jamal Hadi Salim <jhs@mojatatu.com>
CC: "David S. Miller" <davem@davemloft.net>
CC: netem@lists.linux-foundation.org
CC: eric.dumazet@gmail.com
CC: stephen@networkplumber.org
Acked-by: default avatarEric Dumazet <edumazet@google.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
      521a3b41
  3. 18 May, 2016 10 commits
  5. 16 May, 2016 4 commits
  7. 13 May, 2016 2 commits
    • Konstantin Khlebnikov's avatar
      mm/balloon_compaction: fix deflation when compaction is disabled · 1f649733
      Konstantin Khlebnikov authored 
      commit 4d88e6f7 upstream.

If CONFIG_BALLOON_COMPACTION=n balloon_page_insert() does not link pages
with balloon and doesn't set PagePrivate flag, as a result
balloon_page_dequeue() cannot get any pages because it thinks that all
of them are isolated.  Without balloon compaction nobody can isolate
ballooned pages.  It's safe to remove this check.

Fixes: d6d86c0a ("mm/balloon_compaction: redesign ballooned pages management").
Signed-off-by: default avatarKonstantin Khlebnikov <k.khlebnikov@samsung.com>
Reported-by: default avatarMatt Mullins <mmullins@mmlx.us>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Cc: Gavin Guo <gavin.guo@canonical.com>
Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
      1f649733
    • Konstantin Khlebnikov's avatar
      mm/balloon_compaction: redesign ballooned pages management · 33904d89
      Konstantin Khlebnikov authored 
      commit d6d86c0a upstream.

Sasha Levin reported KASAN splash inside isolate_migratepages_range().
Problem is in the function __is_movable_balloon_page() which tests
AS_BALLOON_MAP in page->mapping->flags.  This function has no protection
against anonymous pages.  As result it tried to check address space flags
inside struct anon_vma.

Further investigation shows more problems in current implementation:

* Special branch in __unmap_and_move() never works:
  balloon_page_movable() checks page flags and page_count.  In
  __unmap_and_move() page is locked, reference counter is elevated, thus
  balloon_page_movable() always fails.  As a result execution goes to the
  normal migration path.  virtballoon_migratepage() returns
  MIGRATEPAGE_BALLOON_SUCCESS instead of MIGRATEPAGE_SUCCESS,
  move_to_new_page() thinks this is an error code and assigns
  newpage->mapping to NULL.  Newly migrated page lose connectivity with
  balloon an all ability for further migration.

* lru_lock erroneously required in isolate_migratepages_range() for
  isolation ballooned page.  This function releases lru_lock periodically,
  this makes migration mostly impossible for some pages.

* balloon_page_dequeue have a tight race with balloon_page_isolate:
  balloon_page_isolate could be executed in parallel with dequeue between
  picking page from list and locking page_lock.  Race is rare because they
  use trylock_page() for locking.

This patch fixes all of them.

Instead of fake mapping with special flag this patch uses special state of
page->_mapcount: PAGE_BALLOON_MAPCOUNT_VALUE = -256.  Buddy allocator uses
PAGE_BUDDY_MAPCOUNT_VALUE = -128 for similar purpose.  Storing mark
directly in struct page makes everything safer and easier.

PagePrivate is used to mark pages present in page list (i.e.  not
isolated, like PageLRU for normal pages).  It replaces special rules for
reference counter and makes balloon migration similar to migration of
normal pages.  This flag is protected by page_lock together with link to
the balloon device.

[js] backport to 3.12. MIGRATEPAGE_BALLOON_SUCCESS had to be removed
     from one more place. VM_BUG_ON_PAGE does not exist in 3.12 yet,
     use plain VM_BUG_ON.
Signed-off-by: default avatarKonstantin Khlebnikov <k.khlebnikov@samsung.com>
Reported-by: default avatarSasha Levin <sasha.levin@oracle.com>
Link: http://lkml.kernel.org/p/53E6CEAA.9020105@oracle.com
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
Cc: Gavin Guo <gavin.guo@canonical.com>
Signed-off-by: default avatarJiri Slaby <jslaby@suse.cz>
      33904d89
  9. 11 May, 2016 16 commits
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