Building with some experimental patches, I came across a warning
in the tls code:
include/linux/compiler.h:215:30: warning: assignment discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
215 | *(volatile typeof(x) *)&(x) = (val); \
| ^
net/tls/tls_main.c:650:4: note: in expansion of macro 'smp_store_release'
650 | smp_store_release(&saved_tcpv4_prot, prot);
This appears to be a legitimate warning about assigning a const pointer
into the non-const 'saved_tcpv4_prot' global. Annotate both the ipv4 and
ipv6 pointers 'const' to make the code internally consistent.
Fixes: 5bb4c45d466c ("net/tls: Read sk_prot once when building tls proto ops")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
sockmap performs lockless writes to sk->sk_prot on the following paths:
tcp_bpf_{recvmsg|sendmsg} / sock_map_unref
sk_psock_put
sk_psock_drop
sk_psock_restore_proto
WRITE_ONCE(sk->sk_prot, proto)
To prevent load/store tearing [1], and to make tooling aware of intentional
shared access [2], we need to annotate other sites that access sk_prot with
READ_ONCE/WRITE_ONCE macros.
Change done with Coccinelle with following semantic patch:
@@
expression E;
identifier I;
struct sock *sk;
identifier sk_prot =~ "^sk_prot$";
@@
(
E =
-sk->sk_prot
+READ_ONCE(sk->sk_prot)
|
-sk->sk_prot = E
+WRITE_ONCE(sk->sk_prot, E)
|
-sk->sk_prot
+READ_ONCE(sk->sk_prot)
->I
)
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Apart from being a "tremendous" win when it comes to generated machine code (see bloat-o-meter output for x86-64 below) this mainly prepares ground for annotating access to sk_prot with READ_ONCE, so that we don't pepper the code with access annotations and needlessly repeat loads. add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-46 (-46) Function old new delta tls_init 851 805 -46 Total: Before=21063, After=21017, chg -0.22% Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
The helper that builds kTLS proto ops doesn't need to and should not modify the base proto ops. Annotate the parameter as read-only. Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Daniel Borkmann says: ==================== pull-request: bpf-next 2020-02-21 The following pull-request contains BPF updates for your *net-next* tree. We've added 25 non-merge commits during the last 4 day(s) which contain a total of 33 files changed, 2433 insertions(+), 161 deletions(-). The main changes are: 1) Allow for adding TCP listen sockets into sock_map/hash so they can be used with reuseport BPF programs, from Jakub Sitnicki. 2) Add a new bpf_program__set_attach_target() helper for adding libbpf support to specify the tracepoint/function dynamically, from Eelco Chaudron. 3) Add bpf_read_branch_records() BPF helper which helps use cases like profile guided optimizations, from Daniel Xu. 4) Enable bpf_perf_event_read_value() in all tracing programs, from Song Liu. 5) Relax BTF mandatory check if only used for libbpf itself e.g. to process BTF defined maps, from Andrii Nakryiko. 6) Move BPF selftests -mcpu compilation attribute from 'probe' to 'v3' as it has been observed that former fails in envs with low memlock, from Yonghong Song. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
sk_msg and ULP frameworks override protocol callbacks pointer in
sk->sk_prot, while tcp accesses it locklessly when cloning the listening
socket, that is with neither sk_lock nor sk_callback_lock held.
Once we enable use of listening sockets with sockmap (and hence sk_msg),
there will be shared access to sk->sk_prot if socket is getting cloned
while being inserted/deleted to/from the sockmap from another CPU:
Read side:
tcp_v4_rcv
sk = __inet_lookup_skb(...)
tcp_check_req(sk)
inet_csk(sk)->icsk_af_ops->syn_recv_sock
tcp_v4_syn_recv_sock
tcp_create_openreq_child
inet_csk_clone_lock
sk_clone_lock
READ_ONCE(sk->sk_prot)
Write side:
sock_map_ops->map_update_elem
sock_map_update_elem
sock_map_update_common
sock_map_link_no_progs
tcp_bpf_init
tcp_bpf_update_sk_prot
sk_psock_update_proto
WRITE_ONCE(sk->sk_prot, ops)
sock_map_ops->map_delete_elem
sock_map_delete_elem
__sock_map_delete
sock_map_unref
sk_psock_put
sk_psock_drop
sk_psock_restore_proto
tcp_update_ulp
WRITE_ONCE(sk->sk_prot, proto)
Mark the shared access with READ_ONCE/WRITE_ONCE annotations.
Signed-off-by: Jakub Sitnicki <jakub@cloudflare.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Link: https://lore.kernel.org/bpf/20200218171023.844439-2-jakub@cloudflare.com
Current code doesn't check if tcp sequence number is starting from (/after)
1st record's start sequnce number. It only checks if seq number is before
1st record's end sequnce number. This problem will always be a possibility
in re-transmit case. If a record which belongs to a requested seq number is
already deleted, tls_get_record will start looking into list and as per the
check it will look if seq number is before the end seq of 1st record, which
will always be true and will return 1st record always, it should in fact
return NULL.
As part of the fix, start looking each record only if the sequence number
lies in the list else return NULL.
There is one more check added, driver look for the start marker record to
handle tcp packets which are before the tls offload start sequence number,
hence return 1st record if the record is tls start marker and seq number is
before the 1st record's starting sequence number.
Fixes: e8f69799810c ("net/tls: Add generic NIC offload infrastructure")
Signed-off-by: Rohit Maheshwari <rohitm@chelsio.com>
Reviewed-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
Daniel Borkmann says: ==================== pull-request: bpf 2020-01-15 The following pull-request contains BPF updates for your *net* tree. We've added 12 non-merge commits during the last 9 day(s) which contain a total of 13 files changed, 95 insertions(+), 43 deletions(-). The main changes are: 1) Fix refcount leak for TCP time wait and request sockets for socket lookup related BPF helpers, from Lorenz Bauer. 2) Fix wrong verification of ARSH instruction under ALU32, from Daniel Borkmann. 3) Batch of several sockmap and related TLS fixes found while operating more complex BPF programs with Cilium and OpenSSL, from John Fastabend. 4) Fix sockmap to read psock's ingress_msg queue before regular sk_receive_queue() to avoid purging data upon teardown, from Lingpeng Chen. 5) Fix printing incorrect pointer in bpftool's btf_dump_ptr() in order to properly dump a BPF map's value with BTF, from Martin KaFai Lau. ==================== Signed-off-by: David S. Miller <davem@davemloft.net>
When user returns SK_DROP we need to reset the number of copied bytes
to indicate to the user the bytes were dropped and not sent. If we
don't reset the copied arg sendmsg will return as if those bytes were
copied giving the user a positive return value.
This works as expected today except in the case where the user also
pops bytes. In the pop case the sg.size is reduced but we don't correctly
account for this when copied bytes is reset. The popped bytes are not
accounted for and we return a small positive value potentially confusing
the user.
The reason this happens is due to a typo where we do the wrong comparison
when accounting for pop bytes. In this fix notice the if/else is not
needed and that we have a similar problem if we push data except its not
visible to the user because if delta is larger the sg.size we return a
negative value so it appears as an error regardless.
Fixes: 7246d8ed4dcce ("bpf: helper to pop data from messages")
Signed-off-by: John Fastabend <john.fastabend@gmail.com>
Signed-off-by: Daniel Borkmann <daniel@iogearbox.net>
Acked-by: Jonathan Lemon <jonathan.lemon@gmail.com>
Cc: stable@vger.kernel.org
Link: https://lore.kernel.org/bpf/20200111061206.8028-9-john.fastabend@gmail.com