unlocked version of protocol level close, will be used by
MPTCP to allow decouple orphaning and subflow level close.
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

Will be needed by the next patch, as MPTCP needs to handle
directly the error/memory-allocation-needed path.

No functional changes intended.

Additionally let MPTCP code access the tcp_remove_empty_skb()
helper.
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>

With SO_RCVLOWAT, under memory pressure,
it is possible to enter a state where:

1. We have not received enough bytes to satisfy SO_RCVLOWAT.
2. We have not entered buffer pressure (see tcp_rmem_pressure()).
3. But, we do not have enough buffer space to accept more packets.

In this case, we advertise 0 rwnd (due to #3) but the application does
not drain the receive queue (no wakeup because of #1 and #2) so the
flow stalls.

Modify the heuristic for SO_RCVLOWAT so that, if we are advertising
rwnd<=rcv_mss, force a wakeup to prevent a stall.

Without this patch, setting tcp_rmem to 6143 and disabling TCP
autotune causes a stalled flow. With this patch, no stall occurs. This
is with RPC-style traffic with large messages.

Fixes: 03f45c88 ("tcp: avoid extra wakeups for SO_RCVLOWAT users")
Signed-off-by: NArjun Roy <arjunroy@google.com>
Acked-by: NSoheil Hassas Yeganeh <soheil@google.com>
Acked-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/r/20201023184709.217614-1-arjunroy.kdev@gmail.comSigned-off-by: NJakub Kicinski <kuba@kernel.org>

commit a10674bf ("tcp: detecting the misuse of .sendpage for Slab
objects") adds the checks for Slab pages, but the pages don't have
page_count are still missing from the check.

Network layer's sendpage method is not designed to send page_count 0
pages neither, therefore both PageSlab() and page_count() should be
both checked for the sending page. This is exactly what sendpage_ok()
does.

This patch uses sendpage_ok() in do_tcp_sendpages() to detect misused
.sendpage, to make the code more robust.

Fixes: a10674bf ("tcp: detecting the misuse of .sendpage for Slab objects")
Suggested-by: NEric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: NColy Li <colyli@suse.de>
Cc: Vasily Averin <vvs@virtuozzo.com>
Cc: David S. Miller <davem@davemloft.net>
Cc: stable@vger.kernel.org
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

TCP has been using it to work around the possibility of tcp_delack_timer()
finding the socket owned by user.

After commit 6f458dfb ("tcp: improve latencies of timer triggered events")
we added TCP_DELACK_TIMER_DEFERRED atomic bit for more immediate recovery,
so we can get rid of icsk_ack.blocked

This frees space that following patch will reuse.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Acked-by: NSoheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

For EPOLLET, applications must call sendmsg until they get EAGAIN.
Otherwise, there is no guarantee that EPOLLOUT is sent if there was
a failure upon memory allocation.

As a result on high-speed NICs, userspace observes multiple small
sendmsgs after a partial sendmsg until EAGAIN, since TCP can send
1-2 TSOs in between two sendmsg syscalls:

// One large partial send due to memory allocation failure.
sendmsg(20MB)   = 2MB
// Many small sends until EAGAIN.
sendmsg(18MB)   = 64KB
sendmsg(17.9MB) = 128KB
sendmsg(17.8MB) = 64KB
...
sendmsg(...)    = EAGAIN
// At this point, userspace can assume an EPOLLOUT.

To fix this, set the SOCK_NOSPACE on all partial sendmsg scenarios
to guarantee that we send EPOLLOUT after partial sendmsg.

After this commit userspace can assume that it will receive an EPOLLOUT
after the first partial sendmsg. This EPOLLOUT will benefit from
sk_stream_write_space() logic delaying the EPOLLOUT until significant
space is available in write queue.
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NSoheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If there was any event available on the TCP socket, tcp_poll()
will be called to retrieve all the events.  In tcp_poll(), we call
sk_stream_is_writeable() which returns true as long as we are at least
one byte below notsent_lowat.  This will result in quite a few
spurious EPLLOUT and frequent tiny sendmsg() calls as a result.

Similar to sk_stream_write_space(), use __sk_stream_is_writeable
with a wake value of 1, so that we set EPOLLOUT only if half the
space is available for write.
Signed-off-by: NSoheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

That is needed to let the subflows announce promptly when new
space is available in the receive buffer.

tcp_cleanup_rbuf() is currently a static function, drop the
scope modifier and add a declaration in the TCP header.
Reviewed-by: NMat Martineau <mathew.j.martineau@linux.intel.com>
Signed-off-by: NPaolo Abeni <pabeni@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Now that the previous patches ensure that all call sites for
tcp_set_congestion_control() want to initialize congestion control, we
can simplify tcp_set_congestion_control() by removing the reinit
argument and the code to support it.
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NYuchung Cheng <ycheng@google.com>
Acked-by: NKevin Yang <yyd@google.com>
Cc: Lawrence Brakmo <brakmo@fb.com>

Change tcp_init_transfer() to only initialize congestion control if it
has not been initialized already.

With this new approach, we can arrange things so that if the EBPF code
sets the congestion control by calling setsockopt(TCP_CONGESTION) then
tcp_init_transfer() will not re-initialize the CC module.

This is an approach that has the following beneficial properties:

(1) This allows CC module customizations made by the EBPF called in
    tcp_init_transfer() to persist, and not be wiped out by a later
    call to tcp_init_congestion_control() in tcp_init_transfer().

(2) Does not flip the order of EBPF and CC init, to avoid causing bugs
    for existing code upstream that depends on the current order.

(3) Does not cause 2 initializations for for CC in the case where the
    EBPF called in tcp_init_transfer() wants to set the CC to a new CC
    algorithm.

(4) Allows follow-on simplifications to the code in net/core/filter.c
    and net/ipv4/tcp_cong.c, which currently both have some complexity
    to special-case CC initialization to avoid double CC
    initialization if EBPF sets the CC.
Signed-off-by: NNeal Cardwell <ncardwell@google.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Acked-by: NYuchung Cheng <ycheng@google.com>
Acked-by: NKevin Yang <yyd@google.com>
Cc: Lawrence Brakmo <brakmo@fb.com>

This patch is adapted from Eric's patch in an earlier discussion [1].

The TCP_SAVE_SYN currently only stores the network header and
tcp header.  This patch allows it to optionally store
the mac header also if the setsockopt's optval is 2.

It requires one more bit for the "save_syn" bit field in tcp_sock.
This patch achieves this by moving the syn_smc bit next to the is_mptcp.
The syn_smc is currently used with the TCP experimental option.  Since
syn_smc is only used when CONFIG_SMC is enabled, this patch also puts
the "IS_ENABLED(CONFIG_SMC)" around it like the is_mptcp did
with "IS_ENABLED(CONFIG_MPTCP)".

The mac_hdrlen is also stored in the "struct saved_syn"
to allow a quick offset from the bpf prog if it chooses to start
getting from the network header or the tcp header.

[1]: https://lore.kernel.org/netdev/CANn89iLJNWh6bkH7DNhy_kmcAexuUCccqERqe7z2QsvPhGrYPQ@mail.gmail.com/Suggested-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NMartin KaFai Lau <kafai@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Reviewed-by: NEric Dumazet <edumazet@google.com>
Link: https://lore.kernel.org/bpf/20200820190123.2886935-1-kafai@fb.com

This patch adds bpf_setsockopt(TCP_BPF_RTO_MIN) to allow bpf prog
to set the min rto of a connection.  It could be used together
with the earlier patch which has added bpf_setsockopt(TCP_BPF_DELACK_MAX).

A later selftest patch will communicate the max delay ack in a
bpf tcp header option and then the receiving side can use
bpf_setsockopt(TCP_BPF_RTO_MIN) to set a shorter rto.
Signed-off-by: NMartin KaFai Lau <kafai@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Reviewed-by: NEric Dumazet <edumazet@google.com>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200820190027.2884170-1-kafai@fb.com

This change is mostly from an internal patch and adapts it from sysctl
config to the bpf_setsockopt setup.

The bpf_prog can set the max delay ack by using
bpf_setsockopt(TCP_BPF_DELACK_MAX).  This max delay ack can be communicated
to its peer through bpf header option.  The receiving peer can then use
this max delay ack and set a potentially lower rto by using
bpf_setsockopt(TCP_BPF_RTO_MIN) which will be introduced
in the next patch.

Another later selftest patch will also use it like the above to show
how to write and parse bpf tcp header option.
Signed-off-by: NMartin KaFai Lau <kafai@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Reviewed-by: NEric Dumazet <edumazet@google.com>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200820190021.2884000-1-kafai@fb.com

The TCP_SAVE_SYN has both the network header and tcp header.
The total length of the saved syn packet is currently stored in
the first 4 bytes (u32) of an array and the actual packet data is
stored after that.

A later patch will add a bpf helper that allows to get the tcp header
alone from the saved syn without the network header.  It will be more
convenient to have a direct offset to a specific header instead of
re-parsing it.  This requires to separately store the network hdrlen.
The total header length (i.e. network + tcp) is still needed for the
current usage in getsockopt.  Although this total length can be obtained
by looking into the tcphdr and then get the (th->doff << 2), this patch
chooses to directly store the tcp hdrlen in the second four bytes of
this newly created "struct saved_syn".  By using a new struct, it can
give a readable name to each individual header length.
Signed-off-by: NMartin KaFai Lau <kafai@fb.com>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Reviewed-by: NEric Dumazet <edumazet@google.com>
Acked-by: NJohn Fastabend <john.fastabend@gmail.com>
Link: https://lore.kernel.org/bpf/20200820190014.2883694-1-kafai@fb.com

When TFO keys are read back on big endian systems either via the global
sysctl interface or via getsockopt() using TCP_FASTOPEN_KEY, the values
don't match what was written.

For example, on s390x:

# echo "1-2-3-4" > /proc/sys/net/ipv4/tcp_fastopen_key
# cat /proc/sys/net/ipv4/tcp_fastopen_key
02000000-01000000-04000000-03000000

Instead of:

# cat /proc/sys/net/ipv4/tcp_fastopen_key
00000001-00000002-00000003-00000004

Fix this by converting to the correct endianness on read. This was
reported by Colin Ian King when running the 'tcp_fastopen_backup_key' net
selftest on s390x, which depends on the read value matching what was
written. I've confirmed that the test now passes on big and little endian
systems.
Signed-off-by: NJason Baron <jbaron@akamai.com>
Fixes: 438ac880 ("net: fastopen: robustness and endianness fixes for SipHash")
Cc: Ard Biesheuvel <ard.biesheuvel@linaro.org>
Cc: Eric Dumazet <edumazet@google.com>
Reported-and-tested-by: NColin Ian King <colin.king@canonical.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This change adds TCP_NLA_EDT to SCM_TIMESTAMPING_OPT_STATS that reports
the earliest departure time(EDT) of the timestamped skb. By tracking EDT
values of the skb from different timestamps, we can observe when and how
much the value changed. This allows to measure the precise delay
injected on the sender host e.g. by a bpf-base throttler.
Signed-off-by: NYousuk Seung <ysseung@google.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Acked-by: NNeal Cardwell <ncardwell@google.com>
Acked-by: NSoheil Hassas Yeganeh <soheil@google.com>
Acked-by: NYuchung Cheng <ycheng@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

sockptr_advance never properly worked.  Replace it with _offset variants
of copy_from_sockptr and copy_to_sockptr.

Fixes: ba423fda ("net: add a new sockptr_t type")
Reported-by: NJason A. Donenfeld <Jason@zx2c4.com>
Reported-by: NIdo Schimmel <idosch@idosch.org>
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NJason A. Donenfeld <Jason@zx2c4.com>
Tested-by: NIdo Schimmel <idosch@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Rework the remaining setsockopt code to pass a sockptr_t instead of a
plain user pointer.  This removes the last remaining set_fs(KERNEL_DS)
outside of architecture specific code.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: Stefan Schmidt <stefan@datenfreihafen.org> [ieee802154]
Acked-by: NMatthieu Baerts <matthieu.baerts@tessares.net>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Pass a sockptr_t to prepare for set_fs-less handling of the kernel
pointer from bpf-cgroup.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Pass a sockptr_t to prepare for set_fs-less handling of the kernel
pointer from bpf-cgroup.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Handle the few cases that need special treatment in-line using
in_compat_syscall().  This also removes all the now unused
compat_{get,set}sockopt methods.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

syzkaller found its way into setsockopt with TCP_CONGESTION "cdg".
tcp_cdg_init() does a kcalloc to store the gradients. As sk_clone_lock
just copies all the memory, the allocated pointer will be copied as
well, if the app called setsockopt(..., TCP_CONGESTION) on the listener.
If now the socket will be destroyed before the congestion-control
has properly been initialized (through a call to tcp_init_transfer), we
will end up freeing memory that does not belong to that particular
socket, opening the door to a double-free:

[   11.413102] ==================================================================
[   11.414181] BUG: KASAN: double-free or invalid-free in tcp_cleanup_congestion_control+0x58/0xd0
[   11.415329]
[   11.415560] CPU: 3 PID: 4884 Comm: syz-executor.5 Not tainted 5.8.0-rc2 #80
[   11.416544] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.12.1-0-ga5cab58e9a3f-prebuilt.qemu.org 04/01/2014
[   11.418148] Call Trace:
[   11.418534]  <IRQ>
[   11.418834]  dump_stack+0x7d/0xb0
[   11.419297]  print_address_description.constprop.0+0x1a/0x210
[   11.422079]  kasan_report_invalid_free+0x51/0x80
[   11.423433]  __kasan_slab_free+0x15e/0x170
[   11.424761]  kfree+0x8c/0x230
[   11.425157]  tcp_cleanup_congestion_control+0x58/0xd0
[   11.425872]  tcp_v4_destroy_sock+0x57/0x5a0
[   11.426493]  inet_csk_destroy_sock+0x153/0x2c0
[   11.427093]  tcp_v4_syn_recv_sock+0xb29/0x1100
[   11.427731]  tcp_get_cookie_sock+0xc3/0x4a0
[   11.429457]  cookie_v4_check+0x13d0/0x2500
[   11.433189]  tcp_v4_do_rcv+0x60e/0x780
[   11.433727]  tcp_v4_rcv+0x2869/0x2e10
[   11.437143]  ip_protocol_deliver_rcu+0x23/0x190
[   11.437810]  ip_local_deliver+0x294/0x350
[   11.439566]  __netif_receive_skb_one_core+0x15d/0x1a0
[   11.441995]  process_backlog+0x1b1/0x6b0
[   11.443148]  net_rx_action+0x37e/0xc40
[   11.445361]  __do_softirq+0x18c/0x61a
[   11.445881]  asm_call_on_stack+0x12/0x20
[   11.446409]  </IRQ>
[   11.446716]  do_softirq_own_stack+0x34/0x40
[   11.447259]  do_softirq.part.0+0x26/0x30
[   11.447827]  __local_bh_enable_ip+0x46/0x50
[   11.448406]  ip_finish_output2+0x60f/0x1bc0
[   11.450109]  __ip_queue_xmit+0x71c/0x1b60
[   11.451861]  __tcp_transmit_skb+0x1727/0x3bb0
[   11.453789]  tcp_rcv_state_process+0x3070/0x4d3a
[   11.456810]  tcp_v4_do_rcv+0x2ad/0x780
[   11.457995]  __release_sock+0x14b/0x2c0
[   11.458529]  release_sock+0x4a/0x170
[   11.459005]  __inet_stream_connect+0x467/0xc80
[   11.461435]  inet_stream_connect+0x4e/0xa0
[   11.462043]  __sys_connect+0x204/0x270
[   11.465515]  __x64_sys_connect+0x6a/0xb0
[   11.466088]  do_syscall_64+0x3e/0x70
[   11.466617]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[   11.467341] RIP: 0033:0x7f56046dc469
[   11.467844] Code: Bad RIP value.
[   11.468282] RSP: 002b:00007f5604dccdd8 EFLAGS: 00000246 ORIG_RAX: 000000000000002a
[   11.469326] RAX: ffffffffffffffda RBX: 000000000068bf00 RCX: 00007f56046dc469
[   11.470379] RDX: 0000000000000010 RSI: 0000000020000000 RDI: 0000000000000004
[   11.471311] RBP: 00000000ffffffff R08: 0000000000000000 R09: 0000000000000000
[   11.472286] R10: 0000000000000000 R11: 0000000000000246 R12: 0000000000000000
[   11.473341] R13: 000000000041427c R14: 00007f5604dcd5c0 R15: 0000000000000003
[   11.474321]
[   11.474527] Allocated by task 4884:
[   11.475031]  save_stack+0x1b/0x40
[   11.475548]  __kasan_kmalloc.constprop.0+0xc2/0xd0
[   11.476182]  tcp_cdg_init+0xf0/0x150
[   11.476744]  tcp_init_congestion_control+0x9b/0x3a0
[   11.477435]  tcp_set_congestion_control+0x270/0x32f
[   11.478088]  do_tcp_setsockopt.isra.0+0x521/0x1a00
[   11.478744]  __sys_setsockopt+0xff/0x1e0
[   11.479259]  __x64_sys_setsockopt+0xb5/0x150
[   11.479895]  do_syscall_64+0x3e/0x70
[   11.480395]  entry_SYSCALL_64_after_hwframe+0x44/0xa9
[   11.481097]
[   11.481321] Freed by task 4872:
[   11.481783]  save_stack+0x1b/0x40
[   11.482230]  __kasan_slab_free+0x12c/0x170
[   11.482839]  kfree+0x8c/0x230
[   11.483240]  tcp_cleanup_congestion_control+0x58/0xd0
[   11.483948]  tcp_v4_destroy_sock+0x57/0x5a0
[   11.484502]  inet_csk_destroy_sock+0x153/0x2c0
[   11.485144]  tcp_close+0x932/0xfe0
[   11.485642]  inet_release+0xc1/0x1c0
[   11.486131]  __sock_release+0xc0/0x270
[   11.486697]  sock_close+0xc/0x10
[   11.487145]  __fput+0x277/0x780
[   11.487632]  task_work_run+0xeb/0x180
[   11.488118]  __prepare_exit_to_usermode+0x15a/0x160
[   11.488834]  do_syscall_64+0x4a/0x70
[   11.489326]  entry_SYSCALL_64_after_hwframe+0x44/0xa9

Wei Wang fixed a part of these CDG-malloc issues with commit c1201444
("tcp: memset ca_priv data to 0 properly").

This patch here fixes the listener-scenario: We make sure that listeners
setting the congestion-control through setsockopt won't initialize it
(thus CDG never allocates on listeners). For those who use AF_UNSPEC to
reuse a socket, tcp_disconnect() is changed to cleanup afterwards.

(The issue can be reproduced at least down to v4.4.x.)

Cc: Wei Wang <weiwan@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Fixes: 2b0a8c9e ("tcp: add CDG congestion control")
Signed-off-by: NChristoph Paasch <cpaasch@apple.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This essentially reverts commit 72123032 ("tcp: md5: reject TCP_MD5SIG
or TCP_MD5SIG_EXT on established sockets")

Mathieu reported that many vendors BGP implementations can
actually switch TCP MD5 on established flows.

Quoting Mathieu :
   Here is a list of a few network vendors along with their behavior
   with respect to TCP MD5:

   - Cisco: Allows for password to be changed, but within the hold-down
     timer (~180 seconds).
   - Juniper: When password is initially set on active connection it will
     reset, but after that any subsequent password changes no network
     resets.
   - Nokia: No notes on if they flap the tcp connection or not.
   - Ericsson/RedBack: Allows for 2 password (old/new) to co-exist until
     both sides are ok with new passwords.
   - Meta-Switch: Expects the password to be set before a connection is
     attempted, but no further info on whether they reset the TCP
     connection on a change.
   - Avaya: Disable the neighbor, then set password, then re-enable.
   - Zebos: Would normally allow the change when socket connected.

We can revert my prior change because commit 9424e2e7 ("tcp: md5: fix potential
overestimation of TCP option space") removed the leak of 4 kernel bytes to
the wire that was the main reason for my patch.

While doing my investigations, I found a bug when a MD5 key is changed, leading
to these commits that stable teams want to consider before backporting this revert :

 Commit 6a2febec ("tcp: md5: add missing memory barriers in tcp_md5_do_add()/tcp_md5_hash_key()")
 Commit e6ced831 ("tcp: md5: refine tcp_md5_do_add()/tcp_md5_hash_key() barriers")

Fixes: 72123032 "tcp: md5: reject TCP_MD5SIG or TCP_MD5SIG_EXT on established sockets"
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: NMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

My prior fix went a bit too far, according to Herbert and Mathieu.

Since we accept that concurrent TCP MD5 lookups might see inconsistent
keys, we can use READ_ONCE()/WRITE_ONCE() instead of smp_rmb()/smp_wmb()

Clearing all key->key[] is needed to avoid possible KMSAN reports,
if key->keylen is increased. Since tcp_md5_do_add() is not fast path,
using __GFP_ZERO to clear all struct tcp_md5sig_key is simpler.

data_race() was added in linux-5.8 and will prevent KCSAN reports,
this can safely be removed in stable backports, if data_race() is
not yet backported.

v2: use data_race() both in tcp_md5_hash_key() and tcp_md5_do_add()

Fixes: 6a2febec ("tcp: md5: add missing memory barriers in tcp_md5_do_add()/tcp_md5_hash_key()")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Cc: Herbert Xu <herbert@gondor.apana.org.au>
Cc: Marco Elver <elver@google.com>
Reviewed-by: NMathieu Desnoyers <mathieu.desnoyers@efficios.com>
Acked-by: NHerbert Xu <herbert@gondor.apana.org.au>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

MD5 keys are read with RCU protection, and tcp_md5_do_add()
might update in-place a prior key.

Normally, typical RCU updates would allocate a new piece
of memory. In this case only key->key and key->keylen might
be updated, and we do not care if an incoming packet could
see the old key, the new one, or some intermediate value,
since changing the key on a live flow is known to be problematic
anyway.

We only want to make sure that in the case key->keylen
is changed, cpus in tcp_md5_hash_key() wont try to use
uninitialized data, or crash because key->keylen was
read twice to feed sg_init_one() and ahash_request_set_crypt()

Fixes: 9ea88a15 ("tcp: md5: check md5 signature without socket lock")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Cc: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

This is preparation for usage in bpf_setsockopt.

v2:
  - remove redundant EXPORT_SYMBOL (Alexei Starovoitov)
Signed-off-by: NDmitry Yakunin <zeil@yandex-team.ru>
Signed-off-by: NAlexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20200620153052.9439-2-zeil@yandex-team.ru

Convert comments that reference old mmap_sem APIs to reference
corresponding new mmap locking APIs instead.
Signed-off-by: NMichel Lespinasse <walken@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NVlastimil Babka <vbabka@suse.cz>
Reviewed-by: NDavidlohr Bueso <dbueso@suse.de>
Reviewed-by: NDaniel Jordan <daniel.m.jordan@oracle.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Laurent Dufour <ldufour@linux.ibm.com>
Cc: Liam Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ying Han <yinghan@google.com>
Link: http://lkml.kernel.org/r/20200520052908.204642-12-walken@google.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This change converts the existing mmap_sem rwsem calls to use the new mmap
locking API instead.

The change is generated using coccinelle with the following rule:

// spatch --sp-file mmap_lock_api.cocci --in-place --include-headers --dir .

@@
expression mm;
@@
(
-init_rwsem
+mmap_init_lock
|
-down_write
+mmap_write_lock
|
-down_write_killable
+mmap_write_lock_killable
|
-down_write_trylock
+mmap_write_trylock
|
-up_write
+mmap_write_unlock
|
-downgrade_write
+mmap_write_downgrade
|
-down_read
+mmap_read_lock
|
-down_read_killable
+mmap_read_lock_killable
|
-down_read_trylock
+mmap_read_trylock
|
-up_read
+mmap_read_unlock
)
-(&mm->mmap_sem)
+(mm)
Signed-off-by: NMichel Lespinasse <walken@google.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NDaniel Jordan <daniel.m.jordan@oracle.com>
Reviewed-by: NLaurent Dufour <ldufour@linux.ibm.com>
Reviewed-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Davidlohr Bueso <dbueso@suse.de>
Cc: David Rientjes <rientjes@google.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Liam Howlett <Liam.Howlett@oracle.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ying Han <yinghan@google.com>
Link: http://lkml.kernel.org/r/20200520052908.204642-5-walken@google.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Use vm_insert_pages() for tcp receive zerocopy.  Spin lock cycles (as
reported by perf) drop from a couple of percentage points to a fraction of
a percent.  This results in a roughly 6% increase in efficiency, measured
roughly as zerocopy receive count divided by CPU utilization.

The intention of this patchset is to reduce atomic ops for tcp zerocopy
receives, which normally hits the same spinlock multiple times
consecutively.

[akpm@linux-foundation.org: suppress gcc-7.2.0 warning]
Link: http://lkml.kernel.org/r/20200128025958.43490-3-arjunroy.kdev@gmail.comSigned-off-by: NArjun Roy <arjunroy@google.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Signed-off-by: NSoheil Hassas Yeganeh <soheil@google.com>
Cc: David Miller <davem@davemloft.net>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add a helper to directly set the TCP_KEEPCNT sockopt from kernel space
without going through a fake uaccess.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add a helper to directly set the TCP_KEEPINTVL sockopt from kernel space
without going through a fake uaccess.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add a helper to directly set the TCP_KEEP_IDLE sockopt from kernel
space without going through a fake uaccess.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add a helper to directly set the TCP_USER_TIMEOUT sockopt from kernel
space without going through a fake uaccess.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add a helper to directly set the TCP_SYNCNT sockopt from kernel space
without going through a fake uaccess.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NSagi Grimberg <sagi@grimberg.me>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add a helper to directly set the TCP_QUICKACK sockopt from kernel space
without going through a fake uaccess.  Cleanup the callers to avoid
pointless wrappers now that this is a simple function call.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add a helper to directly set the TCP_NODELAY sockopt from kernel space
without going through a fake uaccess.  Cleanup the callers to avoid
pointless wrappers now that this is a simple function call.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Acked-by: NSagi Grimberg <sagi@grimberg.me>
Acked-by: NJason Gunthorpe <jgg@mellanox.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Add a helper to directly set the TCP_CORK sockopt from kernel space
without going through a fake uaccess.  Cleanup the callers to avoid
pointless wrappers now that this is a simple function call.
Signed-off-by: NChristoph Hellwig <hch@lst.de>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

If user provides wrong virtual address in TCP_ZEROCOPY_RECEIVE
operation we want to return -EINVAL error.

But depending on zc->recv_skip_hint content, we might return
-EIO error if the socket has SOCK_DONE set.

Make sure to return -EINVAL in this case.

BUG: KMSAN: uninit-value in tcp_zerocopy_receive net/ipv4/tcp.c:1833 [inline]
BUG: KMSAN: uninit-value in do_tcp_getsockopt+0x4494/0x6320 net/ipv4/tcp.c:3685
CPU: 1 PID: 625 Comm: syz-executor.0 Not tainted 5.7.0-rc4-syzkaller #0
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 01/01/2011
Call Trace:
 __dump_stack lib/dump_stack.c:77 [inline]
 dump_stack+0x1c9/0x220 lib/dump_stack.c:118
 kmsan_report+0xf7/0x1e0 mm/kmsan/kmsan_report.c:121
 __msan_warning+0x58/0xa0 mm/kmsan/kmsan_instr.c:215
 tcp_zerocopy_receive net/ipv4/tcp.c:1833 [inline]
 do_tcp_getsockopt+0x4494/0x6320 net/ipv4/tcp.c:3685
 tcp_getsockopt+0xf8/0x1f0 net/ipv4/tcp.c:3728
 sock_common_getsockopt+0x13f/0x180 net/core/sock.c:3131
 __sys_getsockopt+0x533/0x7b0 net/socket.c:2177
 __do_sys_getsockopt net/socket.c:2192 [inline]
 __se_sys_getsockopt+0xe1/0x100 net/socket.c:2189
 __x64_sys_getsockopt+0x62/0x80 net/socket.c:2189
 do_syscall_64+0xb8/0x160 arch/x86/entry/common.c:297
 entry_SYSCALL_64_after_hwframe+0x44/0xa9
RIP: 0033:0x45c829
Code: 0d b7 fb ff c3 66 2e 0f 1f 84 00 00 00 00 00 66 90 48 89 f8 48 89 f7 48 89 d6 48 89 ca 4d 89 c2 4d 89 c8 4c 8b 4c 24 08 0f 05 <48> 3d 01 f0 ff ff 0f 83 db b6 fb ff c3 66 2e 0f 1f 84 00 00 00 00
RSP: 002b:00007f1deeb72c78 EFLAGS: 00000246 ORIG_RAX: 0000000000000037
RAX: ffffffffffffffda RBX: 00000000004e01e0 RCX: 000000000045c829
RDX: 0000000000000023 RSI: 0000000000000006 RDI: 0000000000000009
RBP: 000000000078bf00 R08: 0000000020000200 R09: 0000000000000000
R10: 00000000200001c0 R11: 0000000000000246 R12: 00000000ffffffff
R13: 00000000000001d8 R14: 00000000004d3038 R15: 00007f1deeb736d4

Local variable ----zc@do_tcp_getsockopt created at:
 do_tcp_getsockopt+0x1a74/0x6320 net/ipv4/tcp.c:3670
 do_tcp_getsockopt+0x1a74/0x6320 net/ipv4/tcp.c:3670

Fixes: 05255b82 ("tcp: add TCP_ZEROCOPY_RECEIVE support for zerocopy receive")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Reported-by: Nsyzbot <syzkaller@googlegroups.com>
Acked-by: NSoheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We autotune rcvbuf whenever SO_RCVLOWAT is set to account for 100%
overhead in tcp_set_rcvlowat()

This works well when skb->len/skb->truesize ratio is bigger than 0.5

But if we receive packets with small MSS, we can end up in a situation
where not enough bytes are available in the receive queue to satisfy
RCVLOWAT setting.
As our sk_rcvbuf limit is hit, we send zero windows in ACK packets,
preventing remote peer from sending more data.

Even autotuning does not help, because it only triggers at the time
user process drains the queue. If no EPOLLIN is generated, this
can not happen.

Note poll() has a similar issue, after commit
c7004482 ("tcp: Respect SO_RCVLOWAT in tcp_poll().")

Fixes: 03f45c88 ("tcp: avoid extra wakeups for SO_RCVLOWAT users")
Signed-off-by: NEric Dumazet <edumazet@google.com>
Acked-by: NSoheil Hassas Yeganeh <soheil@google.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

The stated intent of the original commit is to is to "return the timestamp
corresponding to the highest sequence number data returned." The current
implementation returns the timestamp for the last byte of the last fully
read skb, which is not necessarily the last byte in the recv buffer. This
patch converts behavior to the original definition, and to the behavior of
the previous draft versions of commit 98aaa913 ("tcp: Extend
SOF_TIMESTAMPING_RX_SOFTWARE to TCP recvmsg") which also match this
behavior.

Fixes: 98aaa913 ("tcp: Extend SOF_TIMESTAMPING_RX_SOFTWARE to TCP recvmsg")
Co-developed-by: NIris Liu <iris@onechronos.com>
Signed-off-by: NIris Liu <iris@onechronos.com>
Signed-off-by: NKelly Littlepage <kelly@onechronos.com>
Signed-off-by: NEric Dumazet <edumazet@google.com>
Acked-by: NSoheil Hassas Yeganeh <soheil@google.com>
Acked-by: NWillem de Bruijn <willemb@google.com>
Signed-off-by: NJakub Kicinski <kuba@kernel.org>