linux-toradex.git/net/ipv4, branch v2.6.33.9

net: don't allow CAP_NET_ADMIN to load non-netdev kernel modules

2011-03-21T19:45:36+00:00

commit 8909c9ad8ff03611c9c96c9a92656213e4bb495b upstream.

Since a8f80e8ff94ecba629542d9b4b5f5a8ee3eb565c any process with
CAP_NET_ADMIN may load any module from /lib/modules/.  This doesn't mean
that CAP_NET_ADMIN is a superset of CAP_SYS_MODULE as modules are
limited to /lib/modules/**.  However, CAP_NET_ADMIN capability shouldn't
allow anybody load any module not related to networking.

This patch restricts an ability of autoloading modules to netdev modules
with explicit aliases.  This fixes CVE-2011-1019.

Arnd Bergmann suggested to leave untouched the old pre-v2.6.32 behavior
of loading netdev modules by name (without any prefix) for processes
with CAP_SYS_MODULE to maintain the compatibility with network scripts
that use autoloading netdev modules by aliases like "eth0", "wlan0".

Currently there are only three users of the feature in the upstream
kernel: ipip, ip_gre and sit.

    root@albatros:~# capsh --drop=$(seq -s, 0 11),$(seq -s, 13 34) --
    root@albatros:~# grep Cap /proc/$$/status
    CapInh:	0000000000000000
    CapPrm:	fffffff800001000
    CapEff:	fffffff800001000
    CapBnd:	fffffff800001000
    root@albatros:~# modprobe xfs
    FATAL: Error inserting xfs
    (/lib/modules/2.6.38-rc6-00001-g2bf4ca3/kernel/fs/xfs/xfs.ko): Operation not permitted
    root@albatros:~# lsmod | grep xfs
    root@albatros:~# ifconfig xfs
    xfs: error fetching interface information: Device not found
    root@albatros:~# lsmod | grep xfs
    root@albatros:~# lsmod | grep sit
    root@albatros:~# ifconfig sit
    sit: error fetching interface information: Device not found
    root@albatros:~# lsmod | grep sit
    root@albatros:~# ifconfig sit0
    sit0      Link encap:IPv6-in-IPv4
	      NOARP  MTU:1480  Metric:1

    root@albatros:~# lsmod | grep sit
    sit                    10457  0
    tunnel4                 2957  1 sit

For CAP_SYS_MODULE module loading is still relaxed:

    root@albatros:~# grep Cap /proc/$$/status
    CapInh:	0000000000000000
    CapPrm:	ffffffffffffffff
    CapEff:	ffffffffffffffff
    CapBnd:	ffffffffffffffff
    root@albatros:~# ifconfig xfs
    xfs: error fetching interface information: Device not found
    root@albatros:~# lsmod | grep xfs
    xfs                   745319  0

Reference: https://lkml.org/lkml/2011/2/24/203

Signed-off-by: Vasiliy Kulikov 
Signed-off-by: Michael Tokarev 
Acked-by: David S. Miller 
Acked-by: Kees Cook 
Signed-off-by: James Morris 
Signed-off-by: Greg Kroah-Hartman

tcp: fix inet_twsk_deschedule()

2011-03-21T19:45:17+00:00

commit 91035f0b7d89291af728b6f3e370c3be58fcbe1b upstream.

Eric W. Biederman reported a lockdep splat in inet_twsk_deschedule()

This is caused by inet_twsk_purge(), run from process context,
and commit 575f4cd5a5b6394577 (net: Use rcu lookups in inet_twsk_purge.)
removed the BH disabling that was necessary.

Add the BH disabling but fine grained, right before calling
inet_twsk_deschedule(), instead of whole function.

With help from Linus Torvalds and Eric W. Biederman

Reported-by: Eric W. Biederman 
Signed-off-by: Eric Dumazet 
CC: Daniel Lezcano 
CC: Pavel Emelyanov 
CC: Arnaldo Carvalho de Melo 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tcp: Make TCP_MAXSEG minimum more correct.

2011-03-21T19:45:09+00:00

commit c39508d6f118308355468314ff414644115a07f3 upstream.

Use TCP_MIN_MSS instead of constant 64.

Reported-by: Min Zhang 
Signed-off-by: David S. Miller 
Cc: Moritz Muehlenhoff 
Signed-off-by: Greg Kroah-Hartman

tcp: Increase TCP_MAXSEG socket option minimum.

2011-03-21T19:45:09+00:00

commit 7a1abd08d52fdeddb3e9a5a33f2f15cc6a5674d2 upstream.

As noted by Steve Chen, since commit
f5fff5dc8a7a3f395b0525c02ba92c95d42b7390 ("tcp: advertise MSS
requested by user") we can end up with a situation where
tcp_select_initial_window() does a divide by a zero (or
even negative) mss value.

The problem is that sometimes we effectively subtract
TCPOLEN_TSTAMP_ALIGNED and/or TCPOLEN_MD5SIG_ALIGNED from the mss.

Fix this by increasing the minimum from 8 to 64.

Reported-by: Steve Chen 
Signed-off-by: David S. Miller 
Cc: Moritz Muehlenhoff 
Signed-off-by: Greg Kroah-Hartman

udp: add rehash on connect()

2011-03-21T19:44:10+00:00

commit 719f835853a92f6090258114a72ffe41f09155cd upstream.

commit 30fff923 introduced in linux-2.6.33 (udp: bind() optimisation)
added a secondary hash on UDP, hashed on (local addr, local port).

Problem is that following sequence :

fd = socket(...)
connect(fd, &remote, ...)

not only selects remote end point (address and port), but also sets
local address, while UDP stack stored in secondary hash table the socket
while its local address was INADDR_ANY (or ipv6 equivalent)

Sequence is :
 - autobind() : choose a random local port, insert socket in hash tables
              [while local address is INADDR_ANY]
 - connect() : set remote address and port, change local address to IP
              given by a route lookup.

When an incoming UDP frame comes, if more than 10 sockets are found in
primary hash table, we switch to secondary table, and fail to find
socket because its local address changed.

One solution to this problem is to rehash datagram socket if needed.

We add a new rehash(struct socket *) method in "struct proto", and
implement this method for UDP v4 & v6, using a common helper.

This rehashing only takes care of secondary hash table, since primary
hash (based on local port only) is not changed.

Reported-by: Krzysztof Piotr Oledzki 
Signed-off-by: Eric Dumazet 
Tested-by: Krzysztof Piotr Oledzki 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

xfrm4: strip ECN and IP Precedence bits in policy lookup

2011-03-21T19:43:22+00:00

[ Upstream commit 94e2238969e89f5112297ad2a00103089dde7e8f ]

dont compare ECN and IP Precedence bits in find_bundle
and use ECN bit stripped TOS value in xfrm_lookup

Signed-off-by: Ulrich Weber 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tcp: Fix race in tcp_poll

2011-03-21T19:43:22+00:00

[ Upstream commit a4d258036ed9b2a1811c3670c6099203a0f284a0 ]

If a RST comes in immediately after checking sk->sk_err, tcp_poll will
return POLLIN but not POLLOUT.  Fix this by checking sk->sk_err at the end
of tcp_poll.  Additionally, ensure the correct order of operations on SMP
machines with memory barriers.

Signed-off-by: Tom Marshall 
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

tcp: Fix >4GB writes on 64-bit.

2011-03-21T19:43:21+00:00

[ Upstream commit 01db403cf99f739f86903314a489fb420e0e254f ]

Fixes kernel bugzilla #16603

tcp_sendmsg() truncates iov_len to an 'int' which a 4GB write to write
zero bytes, for example.

There is also the problem higher up of how verify_iovec() works.  It
wants to prevent the total length from looking like an error return
value.

However it does this using 'int', but syscalls return 'long' (and
thus signed 64-bit on 64-bit machines).  So it could trigger
false-positives on 64-bit as written.  So fix it to use 'long'.

Reported-by: Olaf Bonorden 
Reported-by: Daniel Büse 
Reported-by: Andrew Morton 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

net: blackhole route should always be recalculated

2011-03-21T19:43:19+00:00

[ Upstream commit ae2688d59b5f861dc70a091d003773975d2ae7fb ]

Blackhole routes are used when xfrm_lookup() returns -EREMOTE (error
triggered by IKE for example), hence this kind of route is always
temporary and so we should check if a better route exists for next
packets.
Bug has been introduced by commit d11a4dc18bf41719c9f0d7ed494d295dd2973b92.

Signed-off-by: Jianzhao Wang 
Signed-off-by: Nicolas Dichtel 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman

ip: fix truesize mismatch in ip fragmentation

2011-03-21T19:43:19+00:00

[ Upstream commit 3d13008e7345fa7a79d8f6438150dc15d6ba6e9d ]

Special care should be taken when slow path is hit in ip_fragment() :

When walking through frags, we transfert truesize ownership from skb to
frags. Then if we hit a slow_path condition, we must undo this or risk
uncharging frags->truesize twice, and in the end, having negative socket
sk_wmem_alloc counter, or even freeing socket sooner than expected.

Many thanks to Nick Bowler, who provided a very clean bug report and
test program.

Thanks to Jarek for reviewing my first patch and providing a V2

While Nick bisection pointed to commit 2b85a34e911 (net: No more
expensive sock_hold()/sock_put() on each tx), underlying bug is older
(2.6.12-rc5)

A side effect is to extend work done in commit b2722b1c3a893e
(ip_fragment: also adjust skb->truesize for packets not owned by a
socket) to ipv6 as well.

Reported-and-bisected-by: Nick Bowler 
Tested-by: Nick Bowler 
Signed-off-by: Eric Dumazet 
CC: Jarek Poplawski 
CC: Patrick McHardy 
Signed-off-by: David S. Miller 
Signed-off-by: Greg Kroah-Hartman