linux-stable.git/net/ipv4, branch v3.2.69

tcp: avoid looping in tcp_send_fin()

2015-05-09T22:16:40+00:00

[ Upstream commit 845704a535e9b3c76448f52af1b70e4422ea03fd ]

Presence of an unbound loop in tcp_send_fin() had always been hard
to explain when analyzing crash dumps involving gigantic dying processes
with millions of sockets.

Lets try a different strategy :

In case of memory pressure, try to add the FIN flag to last packet
in write queue, even if packet was already sent. TCP stack will
be able to deliver this FIN after a timeout event. Note that this
FIN being delivered by a retransmit, it also carries a Push flag
given our current implementation.

By checking sk_under_memory_pressure(), we anticipate that cooking
many FIN packets might deplete tcp memory.

In the case we could not allocate a packet, even with __GFP_WAIT
allocation, then not sending a FIN seems quite reasonable if it allows
to get rid of this socket, free memory, and not block the process from
eventually doing other useful work.

Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.2:
 - Drop inapplicable change to sk_forced_wmem_schedule()
 - s/sk_under_memory_pressure(sk)/tcp_memory_pressure/]
Signed-off-by: Ben Hutchings

ip_forward: Drop frames with attached skb->sk

2015-05-09T22:16:40+00:00

[ Upstream commit 2ab957492d13bb819400ac29ae55911d50a82a13 ]

Initial discussion was:
[FYI] xfrm: Don't lookup sk_policy for timewait sockets

Forwarded frames should not have a socket attached. Especially
tw sockets will lead to panics later-on in the stack.

This was observed with TPROXY assigning a tw socket and broken
policy routing (misconfigured). As a result frame enters
forwarding path instead of input. We cannot solve this in
TPROXY as it cannot know that policy routing is broken.

v2:
Remove useless comment

Signed-off-by: Sebastian Poehn 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

tcp: make connect() mem charging friendly

2015-05-09T22:16:39+00:00

[ Upstream commit 355a901e6cf1b2b763ec85caa2a9f04fbcc4ab4a ]

While working on sk_forward_alloc problems reported by Denys
Fedoryshchenko, we found that tcp connect() (and fastopen) do not call
sk_wmem_schedule() for SYN packet (and/or SYN/DATA packet), so
sk_forward_alloc is negative while connect is in progress.

We can fix this by calling regular sk_stream_alloc_skb() both for the
SYN packet (in tcp_connect()) and the syn_data packet in
tcp_send_syn_data()

Then, tcp_send_syn_data() can avoid copying syn_data as we simply
can manipulate syn_data->cb[] to remove SYN flag (and increment seq)

Instead of open coding memcpy_fromiovecend(), simply use this helper.

This leaves in socket write queue clean fast clone skbs.

This was tested against our fastopen packetdrill tests.

Reported-by: Denys Fedoryshchenko 
Signed-off-by: Eric Dumazet 
Acked-by: Yuchung Cheng 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.2:
 - Drop the Fast Open changes
 - Adjust context]
Signed-off-by: Ben Hutchings

net: avoid to hang up on sending due to sysctl configuration overflow.

2015-05-09T22:16:38+00:00

commit cdda88912d62f9603d27433338a18be83ef23ac1 upstream.

    I found if we write a larger than 4GB value to some sysctl
variables, the sending syscall will hang up forever, because these
variables are 32 bits, such large values make them overflow to 0 or
negative.

    This patch try to fix overflow or prevent from zero value setup
of below sysctl variables:

net.core.wmem_default
net.core.rmem_default

net.core.rmem_max
net.core.wmem_max

net.ipv4.udp_rmem_min
net.ipv4.udp_wmem_min

net.ipv4.tcp_wmem
net.ipv4.tcp_rmem

Signed-off-by: Eric Dumazet 
Signed-off-by: Li Yu 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.2:
 - Adjust context
 - Delete now-unused 'zero' variable]
Signed-off-by: Ben Hutchings

net: ping: Return EAFNOSUPPORT when appropriate.

2015-05-09T22:16:38+00:00

[ Upstream commit 9145736d4862145684009d6a72a6e61324a9439e ]

1. For an IPv4 ping socket, ping_check_bind_addr does not check
   the family of the socket address that's passed in. Instead,
   make it behave like inet_bind, which enforces either that the
   address family is AF_INET, or that the family is AF_UNSPEC and
   the address is 0.0.0.0.
2. For an IPv6 ping socket, ping_check_bind_addr returns EINVAL
   if the socket family is not AF_INET6. Return EAFNOSUPPORT
   instead, for consistency with inet6_bind.
3. Make ping_v4_sendmsg and ping_v6_sendmsg return EAFNOSUPPORT
   instead of EINVAL if an incorrect socket address structure is
   passed in.
4. Make IPv6 ping sockets be IPv6-only. The code does not support
   IPv4, and it cannot easily be made to support IPv4 because
   the protocol numbers for ICMP and ICMPv6 are different. This
   makes connect(::ffff:192.0.2.1) fail with EAFNOSUPPORT instead
   of making the socket unusable.

Among other things, this fixes an oops that can be triggered by:

    int s = socket(AF_INET, SOCK_DGRAM, IPPROTO_ICMP);
    struct sockaddr_in6 sin6 = {
        .sin6_family = AF_INET6,
        .sin6_addr = in6addr_any,
    };
    bind(s, (struct sockaddr *) &sin6, sizeof(sin6));

Change-Id: If06ca86d9f1e4593c0d6df174caca3487c57a241
Signed-off-by: Lorenzo Colitti 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.2:
 - Drop the IPv6 part
 - Adjust context, indentation]
Signed-off-by: Ben Hutchings

udp: only allow UFO for packets from SOCK_DGRAM sockets

2015-05-09T22:16:38+00:00

[ Upstream commit acf8dd0a9d0b9e4cdb597c2f74802f79c699e802 ]

If an over-MTU UDP datagram is sent through a SOCK_RAW socket to a
UFO-capable device, ip_ufo_append_data() sets skb->ip_summed to
CHECKSUM_PARTIAL unconditionally as all GSO code assumes transport layer
checksum is to be computed on segmentation. However, in this case,
skb->csum_start and skb->csum_offset are never set as raw socket
transmit path bypasses udp_send_skb() where they are usually set. As a
result, driver may access invalid memory when trying to calculate the
checksum and store the result (as observed in virtio_net driver).

Moreover, the very idea of modifying the userspace provided UDP header
is IMHO against raw socket semantics (I wasn't able to find a document
clearly stating this or the opposite, though). And while allowing
CHECKSUM_NONE in the UFO case would be more efficient, it would be a bit
too intrusive change just to handle a corner case like this. Therefore
disallowing UFO for packets from SOCK_DGRAM seems to be the best option.

Signed-off-by: Michal Kubecek 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

ipv4: ip_check_defrag should not assume that skb_network_offset is zero

2015-05-09T22:16:37+00:00

[ Upstream commit 3e32e733d1bbb3f227259dc782ef01d5706bdae0 ]

ip_check_defrag() may be used by af_packet to defragment outgoing packets.
skb_network_offset() of af_packet's outgoing packets is not zero.

Signed-off-by: Alexander Drozdov 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

ping: Fix race in free in receive path

2015-05-09T22:16:37+00:00

[ Upstream commit fc752f1f43c1c038a2c6ae58cc739ebb5953ccb0 ]

An exception is seen in ICMP ping receive path where the skb
destructor sock_rfree() tries to access a freed socket. This happens
because ping_rcv() releases socket reference with sock_put() and this
internally frees up the socket. Later icmp_rcv() will try to free the
skb and as part of this, skb destructor is called and which leads
to a kernel panic as the socket is freed already in ping_rcv().

-->|exception
-007|sk_mem_uncharge
-007|sock_rfree
-008|skb_release_head_state
-009|skb_release_all
-009|__kfree_skb
-010|kfree_skb
-011|icmp_rcv
-012|ip_local_deliver_finish

Fix this incorrect free by cloning this skb and processing this cloned
skb instead.

This patch was suggested by Eric Dumazet

Signed-off-by: Subash Abhinov Kasiviswanathan 
Cc: Eric Dumazet 
Signed-off-by: Eric Dumazet 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings

ip: zero sockaddr returned on error queue

2015-05-09T22:16:36+00:00

[ Upstream commit f812116b174e59a350acc8e4856213a166a91222 ]

The sockaddr is returned in IP(V6)_RECVERR as part of errhdr. That
structure is defined and allocated on the stack as

    struct {
            struct sock_extended_err ee;
            struct sockaddr_in(6)    offender;
    } errhdr;

The second part is only initialized for certain SO_EE_ORIGIN values.
Always initialize it completely.

An MTU exceeded error on a SOCK_RAW/IPPROTO_RAW is one example that
would return uninitialized bytes.

Signed-off-by: Willem de Bruijn 

----

Also verified that there is no padding between errhdr.ee and
errhdr.offender that could leak additional kernel data.
Acked-by: Eric Dumazet 
Signed-off-by: David S. Miller 
[bwh: Backported to 3.2: adjust context]
Signed-off-by: Ben Hutchings

ipv4: Missing sk_nulls_node_init() in ping_unhash().

2015-05-09T22:16:36+00:00

commit a134f083e79fb4c3d0a925691e732c56911b4326 upstream.

If we don't do that, then the poison value is left in the ->pprev
backlink.

This can cause crashes if we do a disconnect, followed by a connect().

Tested-by: Linus Torvalds 
Reported-by: Wen Xu 
Signed-off-by: David S. Miller 
Signed-off-by: Ben Hutchings