sctp: delete the nested flexible array params

This patch deletes the flexible-array params[] from the structure
sctp_inithdr, sctp_addiphdr and sctp_reconf_chunk to avoid some
sparse warnings:

# make C=2 CF="-Wflexible-array-nested" M=./net/sctp/
net/sctp/input.c: note: in included file (through include/net/sctp/structs.h, include/net/sctp/sctp.h):
./include/linux/sctp.h:278:29: warning: nested flexible array
./include/linux/sctp.h:675:30: warning: nested flexible array

This warning is reported if a structure having a flexible array
member is included by other structures.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: fix memory leak in sctp_stream_outq_migrate()

When sctp_stream_outq_migrate() is called to release stream out resources,
the memory pointed to by prio_head in stream out is not released.

The memory leak information is as follows:
unreferenced object 0xffff88801fe79f80 (size 64):
comm "sctp_repo", pid 7957, jiffies 4294951704 (age 36.480s)
hex dump (first 32 bytes):
80 9f e7 1f 80 88 ff ff 80 9f e7 1f 80 88 ff ff ................
90 9f e7 1f 80 88 ff ff 90 9f e7 1f 80 88 ff ff ................
backtrace:
[<ffffffff81b215c6>] kmalloc_trace+0x26/0x60
[<ffffffff88ae517c>] sctp_sched_prio_set+0x4cc/0x770
[<ffffffff88ad64f2>] sctp_stream_init_ext+0xd2/0x1b0
[<ffffffff88aa2604>] sctp_sendmsg_to_asoc+0x1614/0x1a30
[<ffffffff88ab7ff1>] sctp_sendmsg+0xda1/0x1ef0
[<ffffffff87f765ed>] inet_sendmsg+0x9d/0xe0
[<ffffffff8754b5b3>] sock_sendmsg+0xd3/0x120
[<ffffffff8755446a>] __sys_sendto+0x23a/0x340
[<ffffffff87554651>] __x64_sys_sendto+0xe1/0x1b0
[<ffffffff89978b49>] do_syscall_64+0x39/0xb0
[<ffffffff89a0008b>] entry_SYSCALL_64_after_hwframe+0x63/0xcd

Link: https://syzkaller.appspot.com/bug?exrid=29c402e56c4760763cc0
Fixes: 637784ade221 ("sctp: introduce priority based stream scheduler")
Reported-by: syzbot+29c402e56c4760763cc0@syzkaller.appspotmail.com
Signed-off-by: Zhengchao Shao <shaozhengchao@huawei.com>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Link: https://lore.kernel.org/r/20221126031720.378562-1-shaozhengchao@huawei.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

sctp: leave the err path free in sctp_stream_init to sctp_stream_free

A NULL pointer dereference was reported by Wei Chen:

BUG: kernel NULL pointer dereference, address: 0000000000000000
RIP: 0010:__list_del_entry_valid+0x26/0x80
Call Trace:
<TASK>
sctp_sched_dequeue_common+0x1c/0x90
sctp_sched_prio_dequeue+0x67/0x80
__sctp_outq_teardown+0x299/0x380
sctp_outq_free+0x15/0x20
sctp_association_free+0xc3/0x440
sctp_do_sm+0x1ca7/0x2210
sctp_assoc_bh_rcv+0x1f6/0x340

This happens when calling sctp_sendmsg without connecting to server first.
In this case, a data chunk already queues up in send queue of client side
when processing the INIT_ACK from server in sctp_process_init() where it
calls sctp_stream_init() to alloc stream_in. If it fails to alloc stream_in
all stream_out will be freed in sctp_stream_init's err path. Then in the
asoc freeing it will crash when dequeuing this data chunk as stream_out
is missing.

As we can't free stream out before dequeuing all data from send queue, and
this patch is to fix it by moving the err path stream_out/in freeing in
sctp_stream_init() to sctp_stream_free() which is eventually called when
freeing the asoc in sctp_association_free(). This fix also makes the code
in sctp_process_init() more clear.

Note that in sctp_association_init() when it fails in sctp_stream_init(),
sctp_association_free() will not be called, and in that case it should
go to 'stream_free' err path to free stream instead of 'fail_init'.

Fixes: 5bbbbe32a431 ("sctp: introduce stream scheduler foundations")
Reported-by: Wei Chen <harperchen1110@gmail.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Link: https://lore.kernel.org/r/831a3dc100c4908ff76e5bcc363be97f2778bc0b.1658787066.git.lucien.xin@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

net: sctp: Fix negotiation of the number of data streams.

The number of output and input streams was never being reduced, eg when
processing received INIT or INIT_ACK chunks.
The effect is that DATA chunks can be sent with invalid stream ids
and then discarded by the remote system.

Fixes: 2075e50caf5ea ("sctp: convert to genradix")
Signed-off-by: David Laight <david.laight@aculab.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: shrink stream outq when fails to do addstream reconf

When adding a stream with stream reconf, the new stream firstly is in
CLOSED state but new out chunks can still be enqueued. Then once gets
the confirmation from the peer, the state will change to OPEN.

However, if the peer denies, it needs to roll back the stream. But when
doing that, it only sets the stream outcnt back, and the chunks already
in the new stream don't get purged. It caused these chunks can still be
dequeued in sctp_outq_dequeue_data().

As its stream is still in CLOSE, the chunk will be enqueued to the head
again by sctp_outq_head_data(). This chunk will never be sent out, and
the chunks after it can never be dequeued. The assoc will be 'hung' in
a dead loop of sending this chunk.

To fix it, this patch is to purge these chunks already in the new
stream by calling sctp_stream_shrink_out() when failing to do the
addstream reconf.

Fixes: 11ae76e67a17 ("sctp: implement receiver-side procedures for the Reconf Response Parameter")
Reported-by: Ying Xu <yinxu@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: shrink stream outq only when new outcnt < old outcnt

It's not necessary to go list_for_each for outq->out_chunk_list
when new outcnt >= old outcnt, as no chunk with higher sid than
new (outcnt - 1) exists in the outqueue.

While at it, also move the list_for_each code in a new function
sctp_stream_shrink_out(), which will be used in the next patch.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: fix err handling of stream initialization

The fix on 951c6db954a1 fixed the issued reported there but introduced
another. When the allocation fails within sctp_stream_init() it is
okay/necessary to free the genradix. But it is also called when adding
new streams, from sctp_send_add_streams() and
sctp_process_strreset_addstrm_in() and in those situations it cannot
just free the genradix because by then it is a fully operational
association.

The fix here then is to only free the genradix in sctp_stream_init()
and on those other call sites move on with what it already had and let
the subsequent error handling to handle it.

Tested with the reproducers from this report and the previous one,
with lksctp-tools and sctp-tests.

Reported-by: syzbot+9a1bc632e78a1a98488b@syzkaller.appspotmail.com
Fixes: 951c6db954a1 ("sctp: fix memleak on err handling of stream initialization")
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: fix memleak on err handling of stream initialization

syzbot reported a memory leak when an allocation fails within
genradix_prealloc() for output streams. That's because
genradix_prealloc() leaves initialized members initialized when the
issue happens and SCTP stack will abort the current initialization but
without cleaning up such members.

The fix here is to always call genradix_free() when genradix_prealloc()
fails, for output and also input streams, as it suffers from the same
issue.

Reported-by: syzbot+772d9e36c490b18d51d1@syzkaller.appspotmail.com
Fixes: 2075e50caf5e ("sctp: convert to genradix")
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Tested-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: get netns from asoc and ep base

Commit 312434617cb1 ("sctp: cache netns in sctp_ep_common") set netns
in asoc and ep base since they're created, and it will never change.
It's a better way to get netns from asoc and ep base, comparing to
calling sock_net().

This patch is to replace them.

v1->v2:
- no change.

Suggested-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: fix memleak in sctp_send_reset_streams

If the stream outq is not empty, need to kfree nstr_list.

Fixes: d570a59c5b5f ("sctp: only allow the out stream reset when the stream outq is empty")
Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: zhengbin <zhengbin13@huawei.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>

sctp: fix error handling on stream scheduler initialization

It allocates the extended area for outbound streams only on sendmsg
calls, if they are not yet allocated. When using the priority
stream scheduler, this initialization may imply into a subsequent
allocation, which may fail. In this case, it was aborting the stream
scheduler initialization but leaving the ->ext pointer (allocated) in
there, thus in a partially initialized state. On a subsequent call to
sendmsg, it would notice the ->ext pointer in there, and trip on
uninitialized stuff when trying to schedule the data chunk.

The fix is undo the ->ext initialization if the stream scheduler
initialization fails and avoid the partially initialized state.

Although syzkaller bisected this to commit 4ff40b86262b ("sctp: set
chunk transport correctly when it's a new asoc"), this bug was actually
introduced on the commit I marked below.

Reported-by: syzbot+c1a380d42b190ad1e559@syzkaller.appspotmail.com
Fixes: 5bbbbe32a431 ("sctp: introduce stream scheduler foundations")
Tested-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Neil Horman <nhorman@redhat.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 104

Based on 1 normalized pattern(s):

this sctp implementation is free software you can redistribute it
and or modify it under the terms of the gnu general public license
as published by the free software foundation either version 2 or at
your option any later version this sctp implementation is
distributed in the hope that it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details you should have received a copy of the gnu general
public license along with gnu cc see the file copying if not see
http www gnu org licenses

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 42 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Kate Stewart <kstewart@linuxfoundation.org>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190523091649.683323110@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

sctp: convert to genradix

This also makes sctp_stream_alloc_(out|in) saner, in that they no longer
allocate new flex_arrays/genradixes, they just preallocate more
elements.

This code does however have a suspicious lack of locking.

Link: http://lkml.kernel.org/r/20181217131929.11727-7-kent.overstreet@gmail.com
Signed-off-by: Kent Overstreet <kent.overstreet@gmail.com>
Cc: Vlad Yasevich <vyasevich@gmail.com>
Cc: Neil Horman <nhorman@tuxdriver.com>
Cc: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Eric Paris <eparis@parisplace.org>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Paul Moore <paul@paul-moore.com>
Cc: Pravin B Shelar <pshelar@ovn.org>
Cc: Shaohua Li <shli@kernel.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

sctp: remove sched init from sctp_stream_init

syzbot reported a NULL-ptr deref caused by that sched->init() in
sctp_stream_init() set stream->rr_next = NULL.

kasan: GPF could be caused by NULL-ptr deref or user memory access
RIP: 0010:sctp_sched_rr_dequeue+0xd3/0x170 net/sctp/stream_sched_rr.c:141
Call Trace:
sctp_outq_dequeue_data net/sctp/outqueue.c:90 [inline]
sctp_outq_flush_data net/sctp/outqueue.c:1079 [inline]
sctp_outq_flush+0xba2/0x2790 net/sctp/outqueue.c:1205

All sched info is saved in sout->ext now, in sctp_stream_init()
sctp_stream_alloc_out() will not change it, there's no need to
call sched->init() again, since sctp_outq_init() has already
done it.

Fixes: 5bbbbe32a431 ("sctp: introduce stream scheduler foundations")
Reported-by: syzbot+4c9934f20522c0efd657@syzkaller.appspotmail.com
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: set stream ext to NULL after freeing it in sctp_stream_outq_migrate

In sctp_stream_init(), after sctp_stream_outq_migrate() freed the
surplus streams' ext, but sctp_stream_alloc_out() returns -ENOMEM,
stream->outcnt will not be set to 'outcnt'.

With the bigger value on stream->outcnt, when closing the assoc and
freeing its streams, the ext of those surplus streams will be freed
again since those stream exts were not set to NULL after freeing in
sctp_stream_outq_migrate(). Then the invalid-free issue reported by
syzbot would be triggered.

We fix it by simply setting them to NULL after freeing.

Fixes: 5bbbbe32a431 ("sctp: introduce stream scheduler foundations")
Reported-by: syzbot+58e480e7b28f2d890bfd@syzkaller.appspotmail.com
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: check and update stream->out_curr when allocating stream_out

Now when using stream reconfig to add out streams, stream->out
will get re-allocated, and all old streams' information will
be copied to the new ones and the old ones will be freed.

So without stream->out_curr updated, next time when trying to
send from stream->out_curr stream, a panic would be caused.

This patch is to check and update stream->out_curr when
allocating stream_out.

v1->v2:
- define fa_index() to get elem index from stream->out_curr.
v2->v3:
- repost with no change.

Fixes: 5bbbbe32a431 ("sctp: introduce stream scheduler foundations")
Reported-by: Ying Xu <yinxu@redhat.com>
Reported-by: syzbot+e33a3a138267ca119c7d@syzkaller.appspotmail.com
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: improve the events for sctp stream adding

This patch is to improve sctp stream adding events in 2 places:

1. In sctp_process_strreset_addstrm_out(), move up SCTP_MAX_STREAM
and in stream allocation failure checks, as the adding has to
succeed after reconf_timer stops for the in stream adding
request retransmission.

3. In sctp_process_strreset_addstrm_in(), no event should be sent,
as no in or out stream is added here.

Fixes: 50a41591f110 ("sctp: implement receiver-side procedures for the Add Outgoing Streams Request Parameter")
Fixes: c5c4ebb3ab87 ("sctp: implement receiver-side procedures for the Add Incoming Streams Request Parameter")
Reported-by: Ying Xu <yinxu@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: improve the events for sctp stream reset

This patch is to improve sctp stream reset events in 4 places:

1. In sctp_process_strreset_outreq(), the flag should always be set with
SCTP_STREAM_RESET_INCOMING_SSN instead of OUTGOING, as receiver's in
stream is reset here.
2. In sctp_process_strreset_outreq(), move up SCTP_STRRESET_ERR_WRONG_SSN
check, as the reset has to succeed after reconf_timer stops for the
in stream reset request retransmission.
3. In sctp_process_strreset_inreq(), no event should be sent, as no in
or out stream is reset here.
4. In sctp_process_strreset_resp(), SCTP_STREAM_RESET_INCOMING_SSN or
OUTGOING event should always be sent for stream reset requests, no
matter it fails or succeeds to process the request.

Fixes: 810544764536 ("sctp: implement receiver-side procedures for the Outgoing SSN Reset Request Parameter")
Fixes: 16e1a91965b0 ("sctp: implement receiver-side procedures for the Incoming SSN Reset Request Parameter")
Fixes: 11ae76e67a17 ("sctp: implement receiver-side procedures for the Reconf Response Parameter")
Reported-by: Ying Xu <yinxu@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: not increase stream's incnt before sending addstrm_in request

Different from processing the addstrm_out request, The receiver handles
an addstrm_in request by sending back an addstrm_out request to the
sender who will increase its stream's in and incnt later.

Now stream->incnt has been increased since it sent out the addstrm_in
request in sctp_send_add_streams(), with the wrong stream->incnt will
even cause crash when copying stream info from the old stream's in to
the new one's in sctp_process_strreset_addstrm_out().

This patch is to fix it by simply removing the stream->incnt change
from sctp_send_add_streams().

Fixes: 242bd2d519d7 ("sctp: implement sender-side procedures for Add Incoming/Outgoing Streams Request Parameter")
Reported-by: Jianwen Ji <jiji@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sctp: Replace in/out stream arrays with flex_array

This path replaces physically contiguous memory arrays
allocated using kmalloc_array() with flexible arrays.
This enables to avoid memory allocation failures on the
systems under a memory stress.

Signed-off-by: Oleg Babin <obabin@virtuozzo.com>
Signed-off-by: Konstantin Khorenko <khorenko@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

net/sctp: Make wrappers for accessing in/out streams

This patch introduces wrappers for accessing in/out streams indirectly.
This will enable to replace physically contiguous memory arrays
of streams with flexible arrays (or maybe any other appropriate
mechanism) which do memory allocation on a per-page basis.

Signed-off-by: Oleg Babin <obabin@virtuozzo.com>
Signed-off-by: Konstantin Khorenko <khorenko@virtuozzo.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: clear the new asoc's stream outcnt in sctp_stream_update

When processing a duplicate cookie-echo chunk, sctp moves the new
temp asoc's stream out/in into the old asoc, and later frees this
new temp asoc.

But now after this move, the new temp asoc's stream->outcnt is not
cleared while stream->out is set to NULL, which would cause a same
crash as the one fixed in Commit 79d0895140e9 ("sctp: fix error
path in sctp_stream_init") when freeing this asoc later.

This fix is to clear this outcnt in sctp_stream_update.

Fixes: f952be79cebd ("sctp: introduce struct sctp_stream_out_ext")
Reported-by: Jianwen Ji <jiji@redhat.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: fix some copy-paste errors for file comments

This patch is to fix the file comments in stream.c and
stream_interleave.c

v1->v2:
rephrase the comment for stream.c according to Neil's suggestion.

Fixes: a83863174a61 ("sctp: prepare asoc stream for stream reconf")
Fixes: 0c3f6f655487 ("sctp: implement make_datafrag for sctp_stream_interleave")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: fix error path in sctp_stream_init

syzbot noticed a NULL pointer dereference panic in sctp_stream_free()
which was caused by an incomplete error handling in sctp_stream_init().
By not clearing stream->outcnt, it made a for() in sctp_stream_free()
think that it had elements to free, but not, leading to the panic.

As suggested by Xin Long, this patch also simplifies the error path by
moving it to the only if() that uses it.

See-also: https://www.spinics.net/lists/netdev/msg473756.html
See-also: https://www.spinics.net/lists/netdev/msg465024.html
Reported-by: syzbot <syzkaller@googlegroups.com>
Fixes: f952be79cebd ("sctp: introduce struct sctp_stream_out_ext")
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Reviewed-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: update mid instead of ssn when doing stream and asoc reset

When using idata and doing stream and asoc reset, setting ssn with
0 could only clear the 1st 16 bits of mid.

So to make this work for both data and idata, it sets mid with 0
instead of ssn, and also mid_uo for unordered idata also need to
be cleared, as said in section 2.3.2 of RFC8260.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo R. Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: implement report_ftsn for sctp_stream_interleave

report_ftsn is added as a member of sctp_stream_interleave, used to
skip tsn from tsnmap, remove old events from reasm or lobby queue,
and abort pd for data or idata, called for SCTP_CMD_REPORT_FWDTSN
cmd and asoc reset.

sctp_report_iftsn works for ifwdtsn, and sctp_report_fwdtsn works
for fwdtsn. Note that sctp_report_iftsn doesn't do asoc abort_pd,
as stream abort_pd will be done when handling ifwdtsn. But when
ftsn is equal with ftsn, which means asoc reset, asoc abort_pd has
to be done.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo R. Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: implement make_datafrag for sctp_stream_interleave

To avoid hundreds of checks for the different process on I-DATA chunk,
struct sctp_stream_interleave is defined as a group of functions used
to replace the codes in some place where it needs to do different job
according to if the asoc intl_enabled is set.

With these ops, it only needs to initialize asoc->stream.si with
sctp_stream_interleave_0 for normal data if asoc intl_enable is 0,
or sctp_stream_interleave_1 for idata if asoc intl_enable is set in
sctp_stream_init.

After that, the members in asoc->stream.si can be used directly in
some special places without checking asoc intl_enable.

make_datafrag is the first member for sctp_stream_interleave, it's
used to make data or idata frags, called in sctp_datamsg_from_user.
The old function sctp_make_datafrag_empty needs to be adjust some
to fit in this ops.

Note that as idata and data chunks have different length, it also
defines data_chunk_len for sctp_stream_interleave to describe the
chunk size.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: force SCTP_ERROR_INV_STRM with __u32 when calling sctp_chunk_fail

This patch is to force SCTP_ERROR_INV_STRM with right type to
fit in sctp_chunk_fail to avoid the sparse error.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: set sender next_tsn for the old result with ctsn_ack_point plus 1

When doing asoc reset, if the sender of the response has already sent some
chunk and increased asoc->next_tsn before the duplicate request comes, the
response will use the old result with an incorrect sender next_tsn.

Better than asoc->next_tsn, asoc->ctsn_ack_point can't be changed after
the sender of the response has performed the asoc reset and before the
peer has confirmed it, and it's value is still asoc->next_tsn original
value minus 1.

This patch sets sender next_tsn for the old result with ctsn_ack_point
plus 1 when processing the duplicate request, to make sure the sender
next_tsn value peer gets will be always right.

Fixes: 692787cef651 ("sctp: implement receiver-side procedures for the SSN/TSN Reset Request Parameter")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: avoid flushing unsent queue when doing asoc reset

Now when doing asoc reset, it cleans up sacked and abandoned queues
by calling sctp_outq_free where it also cleans up unsent, retransmit
and transmitted queues.

It's safe for the sender of response, as these 3 queues are empty at
that time. But when the receiver of response is doing the reset, the
users may already enqueue some chunks into unsent during the time
waiting the response, and these chunks should not be flushed.

To void the chunks in it would be removed, it moves the queue into a
temp list, then gets it back after sctp_outq_free is done.

The patch also fixes some incorrect comments in
sctp_process_strreset_tsnreq.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: only allow the asoc reset when the asoc outq is empty

As it says in rfc6525#section5.1.4, before sending the request,

C2: The sender has either no outstanding TSNs or considers all
outstanding TSNs abandoned.

Prior to this patch, it tried to consider all outstanding TSNs abandoned
by dropping all chunks in all outqs with sctp_outq_free (even including
sacked, retransmit and transmitted queues) when doing this reset, which
is too aggressive.

To make it work gently, this patch will only allow the asoc reset when
the sender has no outstanding TSNs by checking if unsent, transmitted
and retransmit are all empty with sctp_outq_is_empty before sending
and processing the request.

Fixes: 692787cef651 ("sctp: implement receiver-side procedures for the SSN/TSN Reset Request Parameter")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: only allow the out stream reset when the stream outq is empty

Now the out stream reset in sctp stream reconf could be done even if
the stream outq is not empty. It means that users can not be sure
since which msg the new ssn will be used.

To make this more synchronous, it shouldn't allow to do out stream
reset until these chunks in unsent outq all are sent out.

This patch checks the corresponding stream outqs when sending and
processing the request . If any of them has unsent chunks in outq,
it will return -EAGAIN instead or send SCTP_STRRESET_IN_PROGRESS
back to the sender.

Fixes: 7f9d68ac944e ("sctp: implement sender-side procedures for SSN Reset Request Parameter")
Suggested-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: use sizeof(__u16) for each stream number length instead of magic number

Now in stream reconf part there are still some places using magic
number 2 for each stream number length. To make it more readable,
this patch is to replace them with sizeof(__u16).

Reported-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: check stream reset info len before making reconf chunk

Now when resetting stream, if both in and out flags are set, the info
len can reach:
sizeof(struct sctp_strreset_outreq) + SCTP_MAX_STREAM(65535) +
sizeof(struct sctp_strreset_inreq) + SCTP_MAX_STREAM(65535)
even without duplicated stream no, this value is far greater than the
chunk's max size.

_sctp_make_chunk doesn't do any check for this, which would cause the
skb it allocs is huge, syzbot even reported a crash due to this.

This patch is to check stream reset info len before making reconf
chunk and return EINVAL if the len exceeds chunk's capacity.

Thanks Marcelo and Neil for making this clear.

v1->v2:
- move the check into sctp_send_reset_streams instead.

Fixes: cc16f00f6529 ("sctp: add support for generating stream reconf ssn reset request chunk")
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: fix error return code in sctp_send_add_streams()

Fix to returnerror code -ENOMEM from the sctp_make_strreset_addstrm()
error handling case instead of 0. 'retval' can be overwritten to 0 after
call sctp_stream_alloc_out().

Fixes: e090abd0d81c ("sctp: factor out stream->out allocation")
Signed-off-by: Wei Yongjun <weiyongjun1@huawei.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Acked-by: Neil Horman <nhorman@tuxdriver.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: fix some type cast warnings introduced by stream reconf

These warnings were found by running 'make C=2 M=net/sctp/'.

They are introduced by not aware of Endian when coding stream
reconf patches.

Since commit c0d8bab6ae51 ("sctp: add get and set sockopt for
reconf_enable") enabled stream reconf feature for users, the
Fixes tag below would use it.

Fixes: c0d8bab6ae51 ("sctp: add get and set sockopt for reconf_enable")
Reported-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: introduce stream scheduler foundations

This patch introduces the hooks necessary to do stream scheduling, as
per RFC Draft ndata. It also introduces the first scheduler, which is
what we do today but now factored out: first come first served (FCFS).

With stream scheduling now we have to track which chunk was enqueued on
which stream and be able to select another other than the in front of
the main outqueue. So we introduce a list on sctp_stream_out_ext
structure for this purpose.

We reuse sctp_chunk->transmitted_list space for the list above, as the
chunk cannot belong to the two lists at the same time. By using the
union in there, we can have distinct names for these moments.

sctp_sched_ops are the operations expected to be implemented by each
scheduler. The dequeueing is a bit particular to this implementation but
it is to match how we dequeue packets today. We first dequeue and then
check if it fits the packet and if not, we requeue it at head. Thus why
we don't have a peek operation but have dequeue_done instead, which is
called once the chunk can be safely considered as transmitted.

The check removed from sctp_outq_flush is now performed by
sctp_stream_outq_migrate, which is only called during assoc setup.
(sctp_sendmsg() also checks for it)

The only operation that is foreseen but not yet added here is a way to
signalize that a new packet is starting or that the packet is done, for
round robin scheduler per packet, but is intentionally left to the
patch that actually implements it.

Support for I-DATA chunks, also described in this RFC, with user message
interleaving is straightforward as it just requires the schedulers to
probe for the feature and ignore datamsg boundaries when dequeueing.

See-also: https://tools.ietf.org/html/draft-ietf-tsvwg-sctp-ndata-13
Tested-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: introduce struct sctp_stream_out_ext

With the stream schedulers, sctp_stream_out will become too big to be
allocated by kmalloc and as we need to allocate with BH disabled, we
cannot use __vmalloc in sctp_stream_init().

This patch moves out the stats from sctp_stream_out to
sctp_stream_out_ext, which will be allocated only when the application
tries to sendmsg something on it.

Just the introduction of sctp_stream_out_ext would already fix the issue
described above by splitting the allocation in two. Moving the stats
to it also reduces the pressure on the allocator as we will ask for less
memory atomically when creating the socket and we will use GFP_KERNEL
later.

Then, for stream schedulers, we will just use sctp_stream_out_ext.

Tested-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: factor out stream->in allocation

There is 1 place allocating it and another reallocating. Move such
procedures to a common function.

v2: updated changelog

Tested-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: factor out stream->out allocation

There is 1 place allocating it and 2 other reallocating. Move such
procedures to a common function.

Tested-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: silence warns on sctp_stream_init allocations

As SCTP supports up to 65535 streams, that can lead to very large
allocations in sctp_stream_init(). As Xin Long noticed, systems with
small amounts of memory are more prone to not have enough memory and
dump warnings on dmesg initiated by user actions. Thus, silence them.

Also, if the reallocation of stream->out is not necessary, skip it and
keep the memory we already have.

Reported-by: Xin Long <lucien.xin@gmail.com>
Tested-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: remove the typedef sctp_paramhdr_t

This patch is to remove the typedef sctp_paramhdr_t, and replace
with struct sctp_paramhdr in the places where it's using this
typedef.

It is also to fix some indents and use sizeof(variable) instead
of sizeof(type).

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: merge sctp_stream_new and sctp_stream_init

Since last patch, sctp doesn't need to alloc memory for asoc->stream any
more. sctp_stream_new and sctp_stream_init both are used to alloc memory
for stream.in or stream.out, and their names are also confusing.

This patch is to merge them into sctp_stream_init, and only pass stream
and streamcnt parameters into it, instead of the whole asoc.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: define the member stream as an object instead of pointer in asoc

As Marcelo's suggestion, stream is a fixed size member of asoc and would
not grow with more streams. To avoid an allocation for it, this patch is
to define it as an object instead of pointer and update the places using
it, also create sctp_stream_update() called in sctp_assoc_update() to
migrate the stream info from one stream to another.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: process duplicated strreset asoc request correctly

This patch is to fix the replay attack issue for strreset asoc requests.

When a duplicated strreset asoc request is received, reply it with bad
seqno if it's seqno < asoc->strreset_inseq - 2, and reply it with the
result saved in asoc if it's seqno >= asoc->strreset_inseq - 2.

But note that if the result saved in asoc is performed, the sender's next
tsn and receiver's next tsn for the response chunk should be set. It's
safe to get them from asoc. Because if it's changed, which means the peer
has received the response already, the new response with wrong tsn won't
be accepted by peer.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: process duplicated strreset in and addstrm in requests correctly

This patch is to fix the replay attack issue for strreset and addstrm in
requests.

When a duplicated strreset in or addstrm in request is received, reply it
with bad seqno if it's seqno < asoc->strreset_inseq - 2, and reply it with
the result saved in asoc if it's seqno >= asoc->strreset_inseq - 2.

For strreset in or addstrm in request, if the receiver side processes it
successfully, a strreset out or addstrm out request(as a response for that
request) will be sent back to peer. reconf_time will retransmit the out
request even if it's lost.

So when receiving a duplicated strreset in or addstrm in request and it's
result was performed, it shouldn't reply this request, but drop it instead.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: process duplicated strreset out and addstrm out requests correctly

Now sctp stream reconf will process a request again even if it's seqno is
less than asoc->strreset_inseq.

If one request has been done successfully and some data chunks have been
accepted and then a duplicated strreset out request comes, the streamin's
ssn will be cleared. It will cause that stream will never receive chunks
any more because of unsynchronized ssn. It allows a replay attack.

A similar issue also exists when processing addstrm out requests. It will
cause more extra streams being added.

This patch is to fix it by saving the last 2 results into asoc. When a
duplicated strreset out or addstrm out request is received, reply it with
bad seqno if it's seqno < asoc->strreset_inseq - 2, and reply it with the
result saved in asoc if it's seqno >= asoc->strreset_inseq - 2.

Note that it saves last 2 results instead of only last 1 result, because
two requests can be sent together in one chunk.

And note that when receiving a duplicated request, the receiver side will
still reply it even if the peer has received the response. It's safe, As
the response will be dropped by the peer.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: get list_of_streams of strreset outreq earlier

Now when processing strreset out responses, it gets outreq->list_of_streams
only when result is performed. But if result is not performed, str_p will
be NULL. It will cause panic in sctp_ulpevent_make_stream_reset_event if
nums is not 0.

This patch is to fix it by getting outreq->list_of_streams earlier, and
also to improve some codes for the strreset inreq process.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: alloc stream info when initializing asoc

When sending a msg without asoc established, sctp will send INIT packet
first and then enqueue chunks.

Before receiving INIT_ACK, stream info is not yet alloced. But enqueuing
chunks needs to access stream info, like out stream state and out stream
cnt.

This patch is to fix it by allocing out stream info when initializing an
asoc, allocing in stream and re-allocing out stream when processing init.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: implement receiver-side procedures for the Reconf Response Parameter

This patch is to implement Receiver-Side Procedures for the
Re-configuration Response Parameter in rfc6525 section 5.2.7.

sctp_process_strreset_resp would process the response for any
kind of reconf request, and the stream reconf is applied only
when the response result is success.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: implement receiver-side procedures for the Add Incoming Streams Request Parameter

This patch is to implement Receiver-Side Procedures for the Add Incoming
Streams Request Parameter described in rfc6525 section 5.2.6.

It is also to fix that it shouldn't have add streams when sending addstrm
in request, as the process in peer will handle it by sending a addstrm out
request back.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: implement receiver-side procedures for the Add Outgoing Streams Request Parameter

This patch is to add Receiver-Side Procedures for the Add Outgoing
Streams Request Parameter described in section 5.2.5.

It is also to improve sctp_chunk_lookup_strreset_param, so that it
can be used for processing addstrm_out request.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: implement receiver-side procedures for the SSN/TSN Reset Request Parameter

This patch is to implement Receiver-Side Procedures for the SSN/TSN
Reset Request Parameter described in rfc6525 section 6.2.4.

The process is kind of complicate, it's wonth having some comments
from section 6.2.4 in the codes.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: implement receiver-side procedures for the Incoming SSN Reset Request Parameter

This patch is to implement Receiver-Side Procedures for the Incoming
SSN Reset Request Parameter described in rfc6525 section 5.2.3.

It's also to move str_list endian conversion out of sctp_make_strreset_req,
so that sctp_make_strreset_req can be used more conveniently to process
inreq.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: implement receiver-side procedures for the Outgoing SSN Reset Request Parameter

This patch is to implement Receiver-Side Procedures for the Outgoing
SSN Reset Request Parameter described in rfc6525 section 5.2.2.

Note that some checks must be after request_seq check, as even those
checks fail, strreset_inseq still has to be increase by 1.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: implement sender-side procedures for Add Incoming/Outgoing Streams Request Parameter

This patch is to implement Sender-Side Procedures for the Add
Outgoing and Incoming Streams Request Parameter described in
rfc6525 section 5.1.5-5.1.6.

It is also to add sockopt SCTP_ADD_STREAMS in rfc6525 section
6.3.4 for users.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: implement sender-side procedures for SSN/TSN Reset Request Parameter

This patch is to implement Sender-Side Procedures for the SSN/TSN
Reset Request Parameter descibed in rfc6525 section 5.1.4.

It is also to add sockopt SCTP_RESET_ASSOC in rfc6525 section 6.3.3
for users.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: streams should be recovered when it fails to send request.

Now when sending stream reset request, it closes the streams to
block further xmit of data until this request is completed, then
calls sctp_send_reconf to send the chunk.

But if sctp_send_reconf returns err, and it doesn't recover the
streams' states back, which means the request chunk would not be
queued and sent, so the asoc will get stuck, streams are closed
and no packet is even queued.

This patch is to fix it by recovering the streams' states when
it fails to send the request, it is also to fix a return value.

Fixes: 7f9d68ac944e ("sctp: implement sender-side procedures for SSN Reset Request Parameter")
Signed-off-by: Xin Long <lucien.xin@gmail.com>
Acked-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: implement sender-side procedures for SSN Reset Request Parameter

This patch is to implement sender-side procedures for the Outgoing
and Incoming SSN Reset Request Parameter described in rfc6525 section
5.1.2 and 5.1.3.

It is also add sockopt SCTP_RESET_STREAMS in rfc6525 section 6.3.2
for users.

Note that the new asoc member strreset_outstanding is to make sure
only one reconf request chunk on the fly as rfc6525 section 5.1.1
demands.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

sctp: prepare asoc stream for stream reconf

sctp stream reconf, described in RFC 6525, needs a structure to
save per stream information in assoc, like stream state.

In the future, sctp stream scheduler also needs it to save some
stream scheduler params and queues.

This patchset is to prepare the stream array in assoc for stream
reconf. It defines sctp_stream that includes stream arrays inside
to replace ssnmap.

Note that we use different structures for IN and OUT streams, as
the members in per OUT stream will get more and more different
from per IN stream.

v1->v2:
- put these patches into a smaller group.
v2->v3:
- define sctp_stream to contain stream arrays, and create stream.c
to put stream-related functions.
- merge 3 patches into 1, as new sctp_stream has the same name
with before.

Signed-off-by: Xin Long <lucien.xin@gmail.com>
Reviewed-by: Marcelo Ricardo Leitner <marcelo.leitner@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>