linux.git/net/core/sock.c, branch v4.14

net: call cgroup_sk_alloc() earlier in sk_clone_lock()

2017-10-11T03:24:29+00:00

If for some reason, the newly allocated child need to be freed,
we will call cgroup_put() (via sk_free_unlock_clone()) while the
corresponding cgroup_get() was not yet done, and we will free memory
too soon.

Fixes: d979a39d7242 ("cgroup: duplicate cgroup reference when cloning sockets")
Signed-off-by: Eric Dumazet 
Cc: Johannes Weiner 
Cc: Tejun Heo 
Signed-off-by: David S. Miller

Revert "net: defer call to cgroup_sk_alloc()"

2017-10-11T03:24:29+00:00

This reverts commit fbb1fb4ad415cb31ce944f65a5ca700aaf73a227.

This was not the proper fix, lets cleanly revert it, so that
following patch can be carried to stable versions.

sock_cgroup_ptr() callers do not expect a NULL return value.

Signed-off-by: Eric Dumazet 
Cc: Johannes Weiner 
Cc: Tejun Heo 
Signed-off-by: David S. Miller

net: defer call to cgroup_sk_alloc()

2017-10-10T03:55:01+00:00

sk_clone_lock() might run while TCP/DCCP listener already vanished.

In order to prevent use after free, it is better to defer cgroup_sk_alloc()
to the point we know both parent and child exist, and from process context.

Fixes: e994b2f0fb92 ("tcp: do not lock listener to process SYN packets")
Signed-off-by: Eric Dumazet 
Cc: Johannes Weiner 
Cc: Tejun Heo 
Signed-off-by: David S. Miller

net: memcontrol: defer call to mem_cgroup_sk_alloc()

2017-10-10T03:55:01+00:00

Instead of calling mem_cgroup_sk_alloc() from BH context,
it is better to call it from inet_csk_accept() in process context.

Not only this removes code in mem_cgroup_sk_alloc(), but it also
fixes a bug since listener might have been dismantled and css_get()
might cause a use-after-free.

Fixes: e994b2f0fb92 ("tcp: do not lock listener to process SYN packets")
Signed-off-by: Eric Dumazet 
Cc: Johannes Weiner 
Cc: Tejun Heo 
Signed-off-by: David S. Miller

socket, bpf: fix possible use after free

2017-10-02T22:23:42+00:00

Starting from linux-4.4, 3WHS no longer takes the listener lock.

Since this time, we might hit a use-after-free in sk_filter_charge(),
if the filter we got in the memcpy() of the listener content
just happened to be replaced by a thread changing listener BPF filter.

To fix this, we need to make sure the filter refcount is not already
zero before incrementing it again.

Fixes: e994b2f0fb92 ("tcp: do not lock listener to process SYN packets")
Signed-off-by: Eric Dumazet 
Acked-by: Alexei Starovoitov 
Acked-by: Daniel Borkmann 
Signed-off-by: David S. Miller

net: Set sk_prot_creator when cloning sockets to the right proto

2017-09-28T17:33:22+00:00

sk->sk_prot and sk->sk_prot_creator can differ when the app uses
IPV6_ADDRFORM (transforming an IPv6-socket to an IPv4-one).
Which is why sk_prot_creator is there to make sure that sk_prot_free()
does the kmem_cache_free() on the right kmem_cache slab.

Now, if such a socket gets transformed back to a listening socket (using
connect() with AF_UNSPEC) we will allocate an IPv4 tcp_sock through
sk_clone_lock() when a new connection comes in. But sk_prot_creator will
still point to the IPv6 kmem_cache (as everything got copied in
sk_clone_lock()). When freeing, we will thus put this
memory back into the IPv6 kmem_cache although it was allocated in the
IPv4 cache. I have seen memory corruption happening because of this.

With slub-debugging and MEMCG_KMEM enabled this gives the warning
	"cache_from_obj: Wrong slab cache. TCPv6 but object is from TCP"

A C-program to trigger this:

void main(void)
{
        int fd = socket(AF_INET6, SOCK_STREAM, IPPROTO_TCP);
        int new_fd, newest_fd, client_fd;
        struct sockaddr_in6 bind_addr;
        struct sockaddr_in bind_addr4, client_addr1, client_addr2;
        struct sockaddr unsp;
        int val;

        memset(&bind_addr, 0, sizeof(bind_addr));
        bind_addr.sin6_family = AF_INET6;
        bind_addr.sin6_port = ntohs(42424);

        memset(&client_addr1, 0, sizeof(client_addr1));
        client_addr1.sin_family = AF_INET;
        client_addr1.sin_port = ntohs(42424);
        client_addr1.sin_addr.s_addr = inet_addr("127.0.0.1");

        memset(&client_addr2, 0, sizeof(client_addr2));
        client_addr2.sin_family = AF_INET;
        client_addr2.sin_port = ntohs(42421);
        client_addr2.sin_addr.s_addr = inet_addr("127.0.0.1");

        memset(&unsp, 0, sizeof(unsp));
        unsp.sa_family = AF_UNSPEC;

        bind(fd, (struct sockaddr *)&bind_addr, sizeof(bind_addr));

        listen(fd, 5);

        client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
        connect(client_fd, (struct sockaddr *)&client_addr1, sizeof(client_addr1));
        new_fd = accept(fd, NULL, NULL);
        close(fd);

        val = AF_INET;
        setsockopt(new_fd, SOL_IPV6, IPV6_ADDRFORM, &val, sizeof(val));

        connect(new_fd, &unsp, sizeof(unsp));

        memset(&bind_addr4, 0, sizeof(bind_addr4));
        bind_addr4.sin_family = AF_INET;
        bind_addr4.sin_port = ntohs(42421);
        bind(new_fd, (struct sockaddr *)&bind_addr4, sizeof(bind_addr4));

        listen(new_fd, 5);

        client_fd = socket(AF_INET, SOCK_STREAM, IPPROTO_TCP);
        connect(client_fd, (struct sockaddr *)&client_addr2, sizeof(client_addr2));

        newest_fd = accept(new_fd, NULL, NULL);
        close(new_fd);

        close(client_fd);
        close(new_fd);
}

As far as I can see, this bug has been there since the beginning of the
git-days.

Signed-off-by: Christoph Paasch 
Reviewed-by: Eric Dumazet 
Signed-off-by: David S. Miller

neigh: increase queue_len_bytes to match wmem_default

2017-08-29T23:10:50+00:00

Florian reported UDP xmit drops that could be root caused to the
too small neigh limit.

Current limit is 64 KB, meaning that even a single UDP socket would hit
it, since its default sk_sndbuf comes from net.core.wmem_default
(~212992 bytes on 64bit arches).

Once ARP/ND resolution is in progress, we should allow a little more
packets to be queued, at least for one producer.

Once neigh arp_queue is filled, a rogue socket should hit its sk_sndbuf
limit and either block in sendmsg() or return -EAGAIN.

Signed-off-by: Eric Dumazet 
Reported-by: Florian Fainelli 
Signed-off-by: David S. Miller

net/sock: allow the user to set negative peek offset

2017-08-24T05:18:44+00:00

This is necessary to allow the user to disable peeking with
offset once it's enabled.
Unix sockets already allow the above, with this patch we
permit it for udp[6] sockets, too.

Fixes: 627d2d6b5500 ("udp: enable MSG_PEEK at non-zero offset")
Signed-off-by: Paolo Abeni 
Acked-by: Willem de Bruijn 
Signed-off-by: David S. Miller

Merge branch 'master' of git://git.kernel.org/pub/scm/linux/kernel/git/klassert/ipsec-next

2017-08-21T16:29:47+00:00

Steffen Klassert says:

====================
pull request (net-next): ipsec-next 2017-08-21

1) Support RX checksum with IPsec crypto offload for esp4/esp6.
   From Ilan Tayari.

2) Fixup IPv6 checksums when doing IPsec crypto offload.
   From Yossi Kuperman.

3) Auto load the xfrom offload modules if a user installs
   a SA that requests IPsec offload. From Ilan Tayari.

4) Clear RX offload informations in xfrm_input to not
   confuse the TX path with stale offload informations.
   From Ilan Tayari.

5) Allow IPsec GSO for local sockets if the crypto operation
   will be offloaded.

6) Support setting of an output mark to the xfrm_state.
   This mark can be used to to do the tunnel route lookup.
   From Lorenzo Colitti.
====================

Signed-off-by: David S. Miller

sock: add SOCK_ZEROCOPY sockopt

2017-08-04T04:37:29+00:00

The send call ignores unknown flags. Legacy applications may already
unwittingly pass MSG_ZEROCOPY. Continue to ignore this flag unless a
socket opts in to zerocopy.

Introduce socket option SO_ZEROCOPY to enable MSG_ZEROCOPY processing.
Processes can also query this socket option to detect kernel support
for the feature. Older kernels will return ENOPROTOOPT.

Signed-off-by: Willem de Bruijn 
Signed-off-by: David S. Miller