linux-toradex.git/net, branch v3.12.15

net: unix socket code abuses csum_partial

2014-03-24T08:45:00+00:00

commit 0a13404dd3bf4ea870e3d96270b5a382edca85c0 upstream.

The unix socket code is using the result of csum_partial to
hash into a lookup table:

	unix_hash_fold(csum_partial(sunaddr, len, 0));

csum_partial is only guaranteed to produce something that can be
folded into a checksum, as its prototype explains:

 * returns a 32-bit number suitable for feeding into itself
 * or csum_tcpudp_magic

The 32bit value should not be used directly.

Depending on the alignment, the ppc64 csum_partial will return
different 32bit partial checksums that will fold into the same
16bit checksum.

This difference causes the following testcase (courtesy of
Gustavo) to sometimes fail:

#include 
#include 

int main()
{
	int fd = socket(PF_LOCAL, SOCK_STREAM|SOCK_CLOEXEC, 0);

	int i = 1;
	setsockopt(fd, SOL_SOCKET, SO_REUSEADDR, &i, 4);

	struct sockaddr addr;
	addr.sa_family = AF_LOCAL;
	bind(fd, &addr, 2);

	listen(fd, 128);

	struct sockaddr_storage ss;
	socklen_t sslen = (socklen_t)sizeof(ss);
	getsockname(fd, (struct sockaddr*)&ss, &sslen);

	fd = socket(PF_LOCAL, SOCK_STREAM|SOCK_CLOEXEC, 0);

	if (connect(fd, (struct sockaddr*)&ss, sslen) == -1){
		perror(NULL);
		return 1;
	}
	printf("OK\n");
	return 0;
}

As suggested by davem, fix this by using csum_fold to fold the
partial 32bit checksum into a 16bit checksum before using it.

Signed-off-by: Anton Blanchard 
Signed-off-by: David S. Miller 
Signed-off-by: Jiri Slaby

mac80211: clear sequence/fragment number in QoS-null frames

2014-03-22T21:01:49+00:00

commit 864a6040f395464003af8dd0d8ca86fed19866d4 upstream.

Avoid leaking data by sending uninitialized memory and setting an
invalid (non-zero) fragment number (the sequence number is ignored
anyway) by setting the seq_ctrl field to zero.

Fixes: 3f52b7e328c5 ("mac80211: mesh power save basics")
Fixes: ce662b44ce22 ("mac80211: send (QoS) Null if no buffered frames")
Reviewed-by: Emmanuel Grumbach 
Signed-off-by: Johannes Berg 
Signed-off-by: Jiri Slaby

mac80211: fix association to 20/40 MHz VHT networks

2014-03-22T21:01:49+00:00

commit cb664981607a6b5b3d670ad57bbda893b2528d96 upstream.

When a VHT network uses 20 or 40 MHz as per the HT operation
information, the channel center frequency segment 0 field in
the VHT operation information is reserved, so ignore it.

This fixes association with such networks when the AP puts 0
into the field, previously we'd disconnect due to an invalid
channel with the message
wlan0: AP VHT information is invalid, disable VHT

Fixes: f2d9d270c15ae ("mac80211: support VHT association")
Reported-by: Tim Nelson 
Signed-off-by: Johannes Berg 
Signed-off-by: Jiri Slaby

mac80211: don't validate unchanged AP bandwidth while tracking

2014-03-22T21:01:49+00:00

commit 963a1852fbac4f75a2d938fa2e734ef1e6d4c044 upstream.

The MLME code in mac80211 must track whether or not the AP changed
bandwidth, but if there's no change while tracking it shouldn't do
anything, otherwise regulatory updates can make it impossible to
connect to certain APs if the regulatory database doesn't match the
information from the AP. See the precise scenario described in the
code.

This still leaves some possible problems with CSA or if the AP
actually changed bandwidth, but those cases are less common and
won't completely prevent using it.

This fixes https://bugzilla.kernel.org/show_bug.cgi?id=70881

Reported-and-tested-by: Nate Carlson 
Signed-off-by: Johannes Berg 
Signed-off-by: Jiri Slaby

mac80211: fix AP powersave TX vs. wakeup race

2014-03-22T21:01:49+00:00

commit 1d147bfa64293b2723c4fec50922168658e613ba upstream.

There is a race between the TX path and the STA wakeup: while
a station is sleeping, mac80211 buffers frames until it wakes
up, then the frames are transmitted. However, the RX and TX
path are concurrent, so the packet indicating wakeup can be
processed while a packet is being transmitted.

This can lead to a situation where the buffered frames list
is emptied on the one side, while a frame is being added on
the other side, as the station is still seen as sleeping in
the TX path.

As a result, the newly added frame will not be send anytime
soon. It might be sent much later (and out of order) when the
station goes to sleep and wakes up the next time.

Additionally, it can lead to the crash below.

Fix all this by synchronising both paths with a new lock.
Both path are not fastpath since they handle PS situations.

In a later patch we'll remove the extra skb queue locks to
reduce locking overhead.

BUG: unable to handle kernel
NULL pointer dereference at 000000b0
IP: [] ieee80211_report_used_skb+0x11/0x3e0 [mac80211]
*pde = 00000000
Oops: 0000 [#1] SMP DEBUG_PAGEALLOC
EIP: 0060:[] EFLAGS: 00210282 CPU: 1
EIP is at ieee80211_report_used_skb+0x11/0x3e0 [mac80211]
EAX: e5900da0 EBX: 00000000 ECX: 00000001 EDX: 00000000
ESI: e41d00c0 EDI: e5900da0 EBP: ebe458e4 ESP: ebe458b0
 DS: 007b ES: 007b FS: 00d8 GS: 00e0 SS: 0068
CR0: 8005003b CR2: 000000b0 CR3: 25a78000 CR4: 000407d0
DR0: 00000000 DR1: 00000000 DR2: 00000000 DR3: 00000000
DR6: ffff0ff0 DR7: 00000400
Process iperf (pid: 3934, ti=ebe44000 task=e757c0b0 task.ti=ebe44000)
iwlwifi 0000:02:00.0: I iwl_pcie_enqueue_hcmd Sending command LQ_CMD (#4e), seq: 0x0903, 92 bytes at 3[3]:9
Stack:
 e403b32c ebe458c4 00200002 00200286 e403b338 ebe458cc c10960bb e5900da0
 ff76a6ec ebe458d8 00000000 e41d00c0 e5900da0 ebe458f0 ff6f1b75 e403b210
 ebe4598c ff723dc1 00000000 ff76a6ec e597c978 e403b758 00000002 00000002
Call Trace:
 [] ieee80211_free_txskb+0x15/0x20 [mac80211]
 [] invoke_tx_handlers+0x1661/0x1780 [mac80211]
 [] ieee80211_tx+0x75/0x100 [mac80211]
 [] ieee80211_xmit+0x8f/0xc0 [mac80211]
 [] ieee80211_subif_start_xmit+0x4fe/0xe20 [mac80211]
 [] dev_hard_start_xmit+0x450/0x950
 [] sch_direct_xmit+0xa9/0x250
 [] __qdisc_run+0x4b/0x150
 [] dev_queue_xmit+0x2c2/0xca0

Reported-by: Yaara Rozenblum 
Signed-off-by: Emmanuel Grumbach 
Reviewed-by: Stanislaw Gruszka 
[reword commit log, use a separate lock]
Signed-off-by: Johannes Berg 
Signed-off-by: Jiri Slaby

mac80211: send control port protocol frames to the VO queue

2014-03-22T21:01:49+00:00

commit 1bf4bbb4024dcdab5e57634dd8ae1072d42a53ac upstream.

Improves reliability of wifi connections with WPA, since authentication
frames are prioritized over normal traffic and also typically exempt
from aggregation.

Signed-off-by: Felix Fietkau 
Signed-off-by: Johannes Berg 
Signed-off-by: Jiri Slaby

tcp: syncookies: reduce mss table to four values

2014-03-14T22:01:53+00:00

commit 086293542b991fb88a2e41ae7b4f82ac65a20e1a upstream.

Halve mss table size to make blind cookie guessing more difficult.
This is sad since the tables were already small, but there
is little alternative except perhaps adding more precise mss information
in the tcp timestamp.  Timestamps are unfortunately not ubiquitous.

Guessing all possible cookie values still has 8-in 2**32 chance.

Reported-by: Jakob Lell 
Signed-off-by: Florian Westphal 
Signed-off-by: David S. Miller 
Signed-off-by: Jiri Slaby

tcp: syncookies: reduce cookie lifetime to 128 seconds

2014-03-14T22:00:54+00:00

commit 8c27bd75f04fb9cb70c69c3cfe24f4e6d8e15906 upstream.

We currently accept cookies that were created less than 4 minutes ago
(ie, cookies with counter delta 0-3).  Combined with the 8 mss table
values, this yields 32 possible values (out of 2**32) that will be valid.

Reducing the lifetime to < 2 minutes halves the guessing chance while
still providing a large enough period.

While at it, get rid of jiffies value -- they overflow too quickly on
32 bit platforms.

getnstimeofday is used to create a counter that increments every 64s.
perf shows getnstimeofday cost is negible compared to sha_transform;
normal tcp initial sequence number generation uses getnstimeofday, too.

Reported-by: Jakob Lell 
Signed-off-by: Florian Westphal 
Signed-off-by: David S. Miller 
Signed-off-by: Jiri Slaby

xfrm: prevent ipcomp scratch buffer race condition

2014-03-14T21:48:58+00:00

commit 12e3594698f6c3ab6ebacc79f2fb2ad2bb5952b5 upstream.

In ipcomp_compress(), sortirq is enabled too early, allowing the
per-cpu scratch buffer to be rewritten by ipcomp_decompress()
(called on the same CPU in softirq context) between populating
the buffer and copying the compressed data to the skb.

v2: as pointed out by Steffen Klassert, if we also move the
local_bh_disable() before reading the per-cpu pointers, we can
get rid of get_cpu()/put_cpu().

v3: removed ipcomp_decompress part (as explained by Herbert Xu,
it cannot be called from process context), get rid of cpu
variable (thanks to Eric Dumazet)

Signed-off-by: Michal Kubecek 
Reviewed-by: Eric Dumazet 
Acked-by: Herbert Xu 
Signed-off-by: Steffen Klassert 
Signed-off-by: Jiri Slaby

net: sctp: fix sctp_sf_do_5_1D_ce to verify if we/peer is AUTH capable

2014-03-13T22:19:40+00:00

[ Upstream commit ec0223ec48a90cb605244b45f7c62de856403729 ]

RFC4895 introduced AUTH chunks for SCTP; during the SCTP
handshake RANDOM; CHUNKS; HMAC-ALGO are negotiated (CHUNKS
being optional though):

  ---------- INIT[RANDOM; CHUNKS; HMAC-ALGO] ---------->
  <------- INIT-ACK[RANDOM; CHUNKS; HMAC-ALGO] ---------
  -------------------- COOKIE-ECHO -------------------->
  <-------------------- COOKIE-ACK ---------------------

A special case is when an endpoint requires COOKIE-ECHO
chunks to be authenticated:

  ---------- INIT[RANDOM; CHUNKS; HMAC-ALGO] ---------->
  <------- INIT-ACK[RANDOM; CHUNKS; HMAC-ALGO] ---------
  ------------------ AUTH; COOKIE-ECHO ---------------->
  <-------------------- COOKIE-ACK ---------------------

RFC4895, section 6.3. Receiving Authenticated Chunks says:

  The receiver MUST use the HMAC algorithm indicated in
  the HMAC Identifier field. If this algorithm was not
  specified by the receiver in the HMAC-ALGO parameter in
  the INIT or INIT-ACK chunk during association setup, the
  AUTH chunk and all the chunks after it MUST be discarded
  and an ERROR chunk SHOULD be sent with the error cause
  defined in Section 4.1. [...] If no endpoint pair shared
  key has been configured for that Shared Key Identifier,
  all authenticated chunks MUST be silently discarded. [...]

  When an endpoint requires COOKIE-ECHO chunks to be
  authenticated, some special procedures have to be followed
  because the reception of a COOKIE-ECHO chunk might result
  in the creation of an SCTP association. If a packet arrives
  containing an AUTH chunk as a first chunk, a COOKIE-ECHO
  chunk as the second chunk, and possibly more chunks after
  them, and the receiver does not have an STCB for that
  packet, then authentication is based on the contents of
  the COOKIE-ECHO chunk. In this situation, the receiver MUST
  authenticate the chunks in the packet by using the RANDOM
  parameters, CHUNKS parameters and HMAC_ALGO parameters
  obtained from the COOKIE-ECHO chunk, and possibly a local
  shared secret as inputs to the authentication procedure
  specified in Section 6.3. If authentication fails, then
  the packet is discarded. If the authentication is successful,
  the COOKIE-ECHO and all the chunks after the COOKIE-ECHO
  MUST be processed. If the receiver has an STCB, it MUST
  process the AUTH chunk as described above using the STCB
  from the existing association to authenticate the
  COOKIE-ECHO chunk and all the chunks after it. [...]

Commit bbd0d59809f9 introduced the possibility to receive
and verification of AUTH chunk, including the edge case for
authenticated COOKIE-ECHO. On reception of COOKIE-ECHO,
the function sctp_sf_do_5_1D_ce() handles processing,
unpacks and creates a new association if it passed sanity
checks and also tests for authentication chunks being
present. After a new association has been processed, it
invokes sctp_process_init() on the new association and
walks through the parameter list it received from the INIT
chunk. It checks SCTP_PARAM_RANDOM, SCTP_PARAM_HMAC_ALGO
and SCTP_PARAM_CHUNKS, and copies them into asoc->peer
meta data (peer_random, peer_hmacs, peer_chunks) in case
sysctl -w net.sctp.auth_enable=1 is set. If in INIT's
SCTP_PARAM_SUPPORTED_EXT parameter SCTP_CID_AUTH is set,
peer_random != NULL and peer_hmacs != NULL the peer is to be
assumed asoc->peer.auth_capable=1, in any other case
asoc->peer.auth_capable=0.

Now, if in sctp_sf_do_5_1D_ce() chunk->auth_chunk is
available, we set up a fake auth chunk and pass that on to
sctp_sf_authenticate(), which at latest in
sctp_auth_calculate_hmac() reliably dereferences a NULL pointer
at position 0..0008 when setting up the crypto key in
crypto_hash_setkey() by using asoc->asoc_shared_key that is
NULL as condition key_id == asoc->active_key_id is true if
the AUTH chunk was injected correctly from remote. This
happens no matter what net.sctp.auth_enable sysctl says.

The fix is to check for net->sctp.auth_enable and for
asoc->peer.auth_capable before doing any operations like
sctp_sf_authenticate() as no key is activated in
sctp_auth_asoc_init_active_key() for each case.

Now as RFC4895 section 6.3 states that if the used HMAC-ALGO
passed from the INIT chunk was not used in the AUTH chunk, we
SHOULD send an error; however in this case it would be better
to just silently discard such a maliciously prepared handshake
as we didn't even receive a parameter at all. Also, as our
endpoint has no shared key configured, section 6.3 says that
MUST silently discard, which we are doing from now onwards.

Before calling sctp_sf_pdiscard(), we need not only to free
the association, but also the chunk->auth_chunk skb, as
commit bbd0d59809f9 created a skb clone in that case.

I have tested this locally by using netfilter's nfqueue and
re-injecting packets into the local stack after maliciously
modifying the INIT chunk (removing RANDOM; HMAC-ALGO param)
and the SCTP packet containing the COOKIE_ECHO (injecting
AUTH chunk before COOKIE_ECHO). Fixed with this patch applied.

Fixes: bbd0d59809f9 ("[SCTP]: Implement the receive and verification of AUTH chunk")
Signed-off-by: Daniel Borkmann 
Cc: Vlad Yasevich 
Cc: Neil Horman 
Acked-by: Vlad Yasevich 
Signed-off-by: David S. Miller 
Signed-off-by: Jiri Slaby