RE: linux-next: manual merge of the net-next tree with the net tree

[Vakul Garg]

> -----Original Message-----
> From: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
> Sent: Tuesday, September 18, 2018 2:57 PM
> To: Vakul Garg <vakul.garg@xxxxxxx>; Stephen Rothwell
> <sfr@xxxxxxxxxxxxxxxx>; David Miller <davem@xxxxxxxxxxxxx>;
> Networking <netdev@xxxxxxxxxxxxxxx>
> Cc: Linux-Next Mailing List <linux-next@xxxxxxxxxxxxxxx>; Linux Kernel
> Mailing List <linux-kernel@xxxxxxxxxxxxxxx>
> Subject: Re: linux-next: manual merge of the net-next tree with the net tree
> 
> On 09/18/2018 11:10 AM, Vakul Garg wrote:
> >> -----Original Message-----
> >> From: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
> >> Sent: Tuesday, September 18, 2018 2:14 PM
> >> To: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>; David Miller
> >> <davem@xxxxxxxxxxxxx>; Networking <netdev@xxxxxxxxxxxxxxx>
> >> Cc: Linux-Next Mailing List <linux-next@xxxxxxxxxxxxxxx>; Linux
> >> Kernel Mailing List <linux-kernel@xxxxxxxxxxxxxxx>; Vakul Garg
> >> <vakul.garg@xxxxxxx>
> >> Subject: Re: linux-next: manual merge of the net-next tree with the
> >> net tree
> >>
> >> On 09/18/2018 02:11 AM, Stephen Rothwell wrote:
> >>> Hi all,
> >>>
> >>> Today's linux-next merge of the net-next tree got a conflict in:
> >>>
> >>>   tools/testing/selftests/net/tls.c
> >>>
> >>> between commit:
> >>>
> >>>   50c6b58a814d ("tls: fix currently broken MSG_PEEK behavior")
> >>>
> >>> from the net tree and commit:
> >>>
> >>>   c2ad647c6442 ("selftests/tls: Add test for recv(PEEK) spanning
> >>> across multiple records")
> >>>
> >>> from the net-next tree.
> >>>
> >>> I fixed it up (see below) and can carry the fix as necessary. This
> >>> is now fixed as far as linux-next is concerned, but any non trivial
> >>> conflicts should be mentioned to your upstream maintainer when your
> >>> tree is submitted for merging.  You may also want to consider
> >>> cooperating with the maintainer of the conflicting tree to minimise
> >>> any particularly complex conflicts.
> >>
> >> The test from 50c6b58a814d supersedes the one from c2ad647c6442 so
> >> the recv_peek_large_buf_mult_recs could be removed; latter was also
> >> not working correctly due to this bug.
> >
> > Why remove recv_peek_large_buf_mult_recs if its correct?
> > Why not the newly added one which achieves the same thing?
> 
> Hmm, not quite, on net-next kernel, the recv_peek_large_buf_mult_recs fails
> every time I invoke the tls test suite:
> 
> # ./tls
> [==========] Running 28 tests from 2 test cases.
> [ RUN      ] tls.sendfile
> [       OK ] tls.sendfile
> [ RUN      ] tls.send_then_sendfile
> [       OK ] tls.send_then_sendfile
> [ RUN      ] tls.recv_max
> [       OK ] tls.recv_max
> [ RUN      ] tls.recv_small
> [       OK ] tls.recv_small
> [ RUN      ] tls.msg_more
> [       OK ] tls.msg_more
> [ RUN      ] tls.sendmsg_single
> [       OK ] tls.sendmsg_single
> [ RUN      ] tls.sendmsg_large
> [       OK ] tls.sendmsg_large
> [ RUN      ] tls.sendmsg_multiple
> [       OK ] tls.sendmsg_multiple
> [ RUN      ] tls.sendmsg_multiple_stress
> [       OK ] tls.sendmsg_multiple_stress
> [ RUN      ] tls.splice_from_pipe
> [       OK ] tls.splice_from_pipe
> [ RUN      ] tls.splice_from_pipe2
> [       OK ] tls.splice_from_pipe2
> [ RUN      ] tls.send_and_splice
> [       OK ] tls.send_and_splice
> [ RUN      ] tls.splice_to_pipe
> [       OK ] tls.splice_to_pipe
> [ RUN      ] tls.recvmsg_single
> [       OK ] tls.recvmsg_single
> [ RUN      ] tls.recvmsg_single_max
> [       OK ] tls.recvmsg_single_max
> [ RUN      ] tls.recvmsg_multiple
> [       OK ] tls.recvmsg_multiple
> [ RUN      ] tls.single_send_multiple_recv
> [       OK ] tls.single_send_multiple_recv
> [ RUN      ] tls.multiple_send_single_recv
> [       OK ] tls.multiple_send_single_recv
> [ RUN      ] tls.recv_partial
> [       OK ] tls.recv_partial
> [ RUN      ] tls.recv_nonblock
> [       OK ] tls.recv_nonblock
> [ RUN      ] tls.recv_peek
> [       OK ] tls.recv_peek
> [ RUN      ] tls.recv_peek_multiple
> [       OK ] tls.recv_peek_multiple
> [ RUN      ] tls.recv_peek_large_buf_mult_recs
> tls.c:524:tls.recv_peek_large_buf_mult_recs:Expected memcmp(test_str,
> buf, len) (18446744073709551595) == 0 (0)
> tls.recv_peek_large_buf_mult_recs: Test failed at step #8
> [     FAIL ] tls.recv_peek_large_buf_mult_recs
> [ RUN      ] tls.pollin
> [       OK ] tls.pollin
> [ RUN      ] tls.poll_wait
> [       OK ] tls.poll_wait
> [ RUN      ] tls.blocking
> [       OK ] tls.blocking
> [ RUN      ] tls.nonblocking
> [       OK ] tls.nonblocking
> [ RUN      ] tls.control_msg
> [       OK ] tls.control_msg
> [==========] 27 / 28 tests passed.
> [  FAILED  ]
> 
> Here's what the recvfrom() with MSG_PEEK sees:
> 
> [pid  2602] socket(AF_INET, SOCK_STREAM, IPPROTO_IP) = 3 [pid  2602]
> socket(AF_INET, SOCK_STREAM, IPPROTO_IP) = 4 [pid  2602] bind(4,
> {sa_family=AF_INET, sin_port=htons(0), sin_addr=inet_addr("0.0.0.0")}, 16) =
> 0
> [pid  2602] listen(4, 10)               = 0
> [pid  2602] getsockname(4, {sa_family=AF_INET, sin_port=htons(41483),
> sin_addr=inet_addr("0.0.0.0")}, [16]) = 0 [pid  2602] connect(3,
> {sa_family=AF_INET, sin_port=htons(41483), sin_addr=inet_addr("0.0.0.0")},
> 16) = 0 [pid  2602] setsockopt(3, SOL_TCP, 0x1f /* TCP_??? */, [7564404], 4)
> = 0 [pid  2602] setsockopt(3, 0x11a /* SOL_?? */, 1,
> "\3\0033\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> 40) = 0 [pid  2602] accept(4, {sa_family=AF_INET, sin_port=htons(46290),
> sin_addr=inet_addr("127.0.0.1")}, [16]) = 5 [pid  2602] setsockopt(5,
> SOL_TCP, 0x1f /* TCP_??? */, [7564404], 4) = 0 [pid  2602] setsockopt(5,
> 0x11a /* SOL_?? */, 2,
> "\3\0033\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0\0"...,
> 40) = 0
> [pid  2602] close(4)                    = 0
> [pid  2602] sendto(3, "test_read_peek", 14, 0, NULL, 0) = 14 [pid  2602]
> sendto(3, "_mult_recs\0", 11, 0, NULL, 0) = 11 [pid  2602] recvfrom(5,
> "test_read_peektest_read_peektest"..., 64, MSG_PEEK, NULL, NULL) = 64
> [pid  2602] write(2, "tls.c:526:tls.recv_peek_large_bu"...,
> 112tls.c:526:tls.recv_peek_large_buf_mult_recs:Expected memcmp(test_str,
> buf, len) (18446744073709551595) == 0 (0)
> ) = 112
> [pid  2602] close(3)                    = 0
> [pid  2602] close(5)                    = 0
> [pid  2602] exit_group(8)               = ?
> 
> Reason for the "test_read_peektest_read_peektest[...]" is because
> MSG_PEEK cannot call tls_sw_advance_skb(), since the skb is sitting there
> that needs to be consumed for non-MSG_PEEK case, and only then we can
> advance it.
> 

I general, my plan was to modify the tls_sw_recvmsg() to trigger as many 
decryption as possible as required by requested user space PEEK size.
This would have required creating a pending list of decrypted records in tls_tx context.

> Could you elaborate on where you ever had this test succeeding? With nxp
> accelerator?
 
I never had this test succeeding. I pointed the problem to Dave Watson sometime
back (found during code reading). 

To make sure that this bug does not slip out, I simply submitted a test case to keep
reminding ourselves that we need to fix it sometime.

> 
> Thanks,
> Daniel