x86/kprobes: Fix crash when probing CS CALL instructionsgrafted

When using eBPF to probe CS CALL instructions within a function,
a crash can be triggered.

The eBPF tool probes offset 257 of the __hrtimer_run_queues()
function:

<__hrtimer_run_queues+249>:  nopl   0x0(%rax,%rax,1)
<__hrtimer_run_queues+254>:  mov    %r14,%rdi
<__hrtimer_run_queues+257>:  cs call <__x86_indirect_thunk_r12>
<__hrtimer_run_queues+263>:  mov    %eax,%r12d
<__hrtimer_run_queues+266>:  xchg   %ax,%ax
<__hrtimer_run_queues+268>:  mov    %r13,%rdi

Which triggers this crash:

  BUG: unable to handle page fault for address: 00000000000f41c9
  #PF: supervisor write access in kernel mode
  #PF: error_code(0x0002) - not-present page
  PGD 0 P4D 0
  Oops: 0002 [#1] SMP NOPTI
  CPU: 1 PID: 0 Comm: swapper/1 Kdump: loaded Tainted: P
  RIP: 0010:__hrtimer_run_queues+0x106/0x230

Note that __hrtimer_run_queues+0x106 is __hrtimer_run_queues+262, which is
at the 6th byte of the above CS CALL instruction. Since the CS CALL
instruction occupies 6 bytes, the exception occurred in the middle of that
call instruction.

The root cause is that when using eBPF tools to probe in the middle of a
function, a kprobe with INT3 is used as the underlying implementation.

During single-step emulation of the original CALL instruction,
int3_emulate_call() assumes that the probed CALL instruction is 5 bytes
long. However, the actual CS-prefixed CALL instruction occupies 6 bytes,
so it constructs an incorrect exception return address. When the CPU
returns from the kprobe handler, the next instruction to be executed is at
the address of the last byte of that CS CALL instruction. Coincidentally,
starting from that address, the CPU fetches and decodes a completely
different instruction, which ultimately triggers a kernel crash.

Fix the issue by using the actual instruction length obtained from
the instruction decoder when constructing the exception return
address, rather than relying on the hardcoded CALL_INSN_SIZE macro.

[ mingo: Refined the changelog ]

Fixes: 6256e668b7af ("x86/kprobes: Use int3 instead of debug trap for single-step")
Suggested-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Signed-off-by: Jinke Han <jinkehan@didiglobal.com>
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Acked-by: Yafang Shao <laoar.shao@gmail.com>
Acked-by: Borislav Petkov <bp@alien8.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: https://patch.msgid.link/20260908073742.GA10517@didi-ThinkCentre-M920t-N000

1 files changed, 1113 insertions, 0 deletions

diff --git a/net/sctp/stream.c b/net/sctp/stream.c
new file mode 100644
index 000000000..e4354d58f
--- /dev/null
+++ b/net/sctp/stream.c
@@ -0,0 +1,1113 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/* SCTP kernel implementation
+ * (C) Copyright IBM Corp. 2001, 2004
+ * Copyright (c) 1999-2000 Cisco, Inc.
+ * Copyright (c) 1999-2001 Motorola, Inc.
+ * Copyright (c) 2001 Intel Corp.
+ *
+ * This file is part of the SCTP kernel implementation
+ *
+ * This file contains sctp stream maniuplation primitives and helpers.
+ *
+ * Please send any bug reports or fixes you make to the
+ * email address(es):
+ *    lksctp developers <linux-sctp@vger.kernel.org>
+ *
+ * Written or modified by:
+ *    Xin Long <lucien.xin@gmail.com>
+ */
+
+#include <linux/list.h>
+#include <net/sctp/sctp.h>
+#include <net/sctp/sm.h>
+#include <net/sctp/stream_sched.h>
+
+#define SCTP_STRRESET_MASK(type) \
+	BIT(ntohs(type) - ntohs(SCTP_PARAM_RESET_OUT_REQUEST))
+#define SCTP_STRRESET_TEST(asoc, type) \
+	((asoc)->strreset_outstanding & SCTP_STRRESET_MASK(type))
+#define SCTP_STRRESET_SET(asoc, type) \
+	((asoc)->strreset_outstanding |= SCTP_STRRESET_MASK(type))
+#define SCTP_STRRESET_CLEAR(asoc, type) \
+	((asoc)->strreset_outstanding &= ~SCTP_STRRESET_MASK(type))
+
+static void sctp_stream_shrink_out(struct sctp_stream *stream, __u16 outcnt)
+{
+	struct sctp_association *asoc;
+	struct sctp_chunk *ch, *temp;
+	struct sctp_outq *outq;
+
+	asoc = container_of(stream, struct sctp_association, stream);
+	outq = &asoc->outqueue;
+
+	list_for_each_entry_safe(ch, temp, &outq->out_chunk_list, list) {
+		__u16 sid = sctp_chunk_stream_no(ch);
+
+		if (sid < outcnt)
+			continue;
+
+		sctp_sched_dequeue_common(outq, ch);
+		/* No need to call dequeue_done here because
+		 * the chunks are not scheduled by now.
+		 */
+
+		/* Mark as failed send. */
+		sctp_chunk_fail(ch, (__force __u32)SCTP_ERROR_INV_STRM);
+		if (asoc->peer.prsctp_capable &&
+		    SCTP_PR_PRIO_ENABLED(ch->sinfo.sinfo_flags))
+			asoc->sent_cnt_removable--;
+
+		sctp_chunk_free(ch);
+	}
+}
+
+static void sctp_stream_free_ext(struct sctp_stream *stream, __u16 sid)
+{
+	const struct sctp_sched_ops *sched;
+
+	if (!SCTP_SO(stream, sid)->ext)
+		return;
+
+	sched = sctp_sched_ops_from_stream(stream);
+	sched->free_sid(stream, sid);
+	kfree(SCTP_SO(stream, sid)->ext);
+	SCTP_SO(stream, sid)->ext = NULL;
+}
+
+/* Migrates chunks from stream queues to new stream queues if needed,
+ * but not across associations. Also, removes those chunks to streams
+ * higher than the new max.
+ */
+static void sctp_stream_outq_migrate(struct sctp_stream *stream,
+				     struct sctp_stream *new, __u16 outcnt)
+{
+	int i;
+
+	if (stream->outcnt > outcnt)
+		sctp_stream_shrink_out(stream, outcnt);
+
+	if (new) {
+		/* Here we actually move the old ext stuff into the new
+		 * buffer, because we want to keep it. Then
+		 * sctp_stream_update will swap ->out pointers.
+		 */
+		for (i = 0; i < outcnt; i++) {
+			sctp_stream_free_ext(new, i);
+			SCTP_SO(new, i)->ext = SCTP_SO(stream, i)->ext;
+			SCTP_SO(stream, i)->ext = NULL;
+		}
+	}
+
+	for (i = outcnt; i < stream->outcnt; i++)
+		sctp_stream_free_ext(stream, i);
+}
+
+static int sctp_stream_alloc_out(struct sctp_stream *stream, __u16 outcnt,
+				 gfp_t gfp)
+{
+	int ret;
+
+	if (outcnt <= stream->outcnt)
+		goto out;
+
+	ret = genradix_prealloc(&stream->out, outcnt, gfp);
+	if (ret)
+		return ret;
+
+out:
+	stream->outcnt = outcnt;
+	return 0;
+}
+
+static int sctp_stream_alloc_in(struct sctp_stream *stream, __u16 incnt,
+				gfp_t gfp)
+{
+	int ret;
+
+	if (incnt <= stream->incnt)
+		goto out;
+
+	ret = genradix_prealloc(&stream->in, incnt, gfp);
+	if (ret)
+		return ret;
+
+out:
+	stream->incnt = incnt;
+	return 0;
+}
+
+int sctp_stream_init(struct sctp_stream *stream, __u16 outcnt, __u16 incnt,
+		     gfp_t gfp)
+{
+	const struct sctp_sched_ops *sched = sctp_sched_ops_from_stream(stream);
+	int i, ret = 0;
+
+	gfp |= __GFP_NOWARN;
+
+	/* Initial stream->out size may be very big, so free it and alloc
+	 * a new one with new outcnt to save memory if needed.
+	 */
+	if (outcnt == stream->outcnt)
+		goto handle_in;
+
+	/* Filter out chunks queued on streams that won't exist anymore */
+	sched->unsched_all(stream);
+	sctp_stream_outq_migrate(stream, NULL, outcnt);
+	sched->sched_all(stream);
+
+	ret = sctp_stream_alloc_out(stream, outcnt, gfp);
+	if (ret)
+		return ret;
+
+	for (i = 0; i < stream->outcnt; i++)
+		SCTP_SO(stream, i)->state = SCTP_STREAM_OPEN;
+
+handle_in:
+	sctp_stream_interleave_init(stream);
+	if (!incnt)
+		return 0;
+
+	return sctp_stream_alloc_in(stream, incnt, gfp);
+}
+
+int sctp_stream_init_ext(struct sctp_stream *stream, __u16 sid)
+{
+	struct sctp_stream_out_ext *soute;
+	int ret;
+
+	soute = kzalloc_obj(*soute);
+	if (!soute)
+		return -ENOMEM;
+	SCTP_SO(stream, sid)->ext = soute;
+
+	ret = sctp_sched_init_sid(stream, sid, GFP_KERNEL);
+	if (ret) {
+		kfree(SCTP_SO(stream, sid)->ext);
+		SCTP_SO(stream, sid)->ext = NULL;
+	}
+
+	return ret;
+}
+
+void sctp_stream_free(struct sctp_stream *stream)
+{
+	const struct sctp_sched_ops *sched = sctp_sched_ops_from_stream(stream);
+	int i;
+
+	sched->unsched_all(stream);
+	for (i = 0; i < stream->outcnt; i++)
+		sctp_stream_free_ext(stream, i);
+	genradix_free(&stream->out);
+	genradix_free(&stream->in);
+}
+
+void sctp_stream_clear(struct sctp_stream *stream)
+{
+	int i;
+
+	for (i = 0; i < stream->outcnt; i++) {
+		SCTP_SO(stream, i)->mid = 0;
+		SCTP_SO(stream, i)->mid_uo = 0;
+	}
+
+	for (i = 0; i < stream->incnt; i++)
+		SCTP_SI(stream, i)->mid = 0;
+}
+
+void sctp_stream_update(struct sctp_stream *stream, struct sctp_stream *new)
+{
+	const struct sctp_sched_ops *sched = sctp_sched_ops_from_stream(stream);
+
+	sched->unsched_all(stream);
+	sctp_stream_outq_migrate(stream, new, new->outcnt);
+	sctp_stream_free(stream);
+
+	stream->out = new->out;
+	stream->in  = new->in;
+	stream->outcnt = new->outcnt;
+	stream->incnt  = new->incnt;
+
+	sched->sched_all(stream);
+
+	new->out.tree.root = NULL;
+	new->in.tree.root  = NULL;
+	new->outcnt = 0;
+	new->incnt  = 0;
+}
+
+static int sctp_send_reconf(struct sctp_association *asoc,
+			    struct sctp_chunk *chunk)
+{
+	int retval = 0;
+
+	retval = sctp_primitive_RECONF(asoc->base.net, asoc, chunk);
+	if (retval)
+		sctp_chunk_free(chunk);
+
+	return retval;
+}
+
+static bool sctp_stream_outq_is_empty(struct sctp_stream *stream,
+				      __u16 str_nums, __be16 *str_list)
+{
+	struct sctp_association *asoc;
+	__u16 i;
+
+	asoc = container_of(stream, struct sctp_association, stream);
+	if (!asoc->outqueue.out_qlen)
+		return true;
+
+	if (!str_nums)
+		return false;
+
+	for (i = 0; i < str_nums; i++) {
+		__u16 sid = ntohs(str_list[i]);
+
+		if (SCTP_SO(stream, sid)->ext &&
+		    !list_empty(&SCTP_SO(stream, sid)->ext->outq))
+			return false;
+	}
+
+	return true;
+}
+
+int sctp_send_reset_streams(struct sctp_association *asoc,
+			    struct sctp_reset_streams *params)
+{
+	struct sctp_stream *stream = &asoc->stream;
+	__u16 i, str_nums, *str_list;
+	struct sctp_chunk *chunk;
+	int retval = -EINVAL;
+	__be16 *nstr_list;
+	bool out, in;
+
+	if (!asoc->peer.reconf_capable ||
+	    !(asoc->strreset_enable & SCTP_ENABLE_RESET_STREAM_REQ)) {
+		retval = -ENOPROTOOPT;
+		goto out;
+	}
+
+	if (asoc->strreset_outstanding) {
+		retval = -EINPROGRESS;
+		goto out;
+	}
+
+	out = params->srs_flags & SCTP_STREAM_RESET_OUTGOING;
+	in  = params->srs_flags & SCTP_STREAM_RESET_INCOMING;
+	if (!out && !in)
+		goto out;
+
+	str_nums = params->srs_number_streams;
+	str_list = params->srs_stream_list;
+	if (str_nums) {
+		int param_len = 0;
+
+		if (out) {
+			for (i = 0; i < str_nums; i++)
+				if (str_list[i] >= stream->outcnt)
+					goto out;
+
+			param_len = str_nums * sizeof(__u16) +
+				    sizeof(struct sctp_strreset_outreq);
+		}
+
+		if (in) {
+			for (i = 0; i < str_nums; i++)
+				if (str_list[i] >= stream->incnt)
+					goto out;
+
+			param_len += str_nums * sizeof(__u16) +
+				     (out ? sizeof(struct sctp_strreset_inreq)
+					  : sizeof(struct sctp_strreset_outreq));
+		}
+
+		if (param_len > SCTP_MAX_CHUNK_LEN -
+				sizeof(struct sctp_reconf_chunk))
+			goto out;
+	}
+
+	nstr_list = kcalloc(str_nums, sizeof(__be16), GFP_KERNEL);
+	if (!nstr_list) {
+		retval = -ENOMEM;
+		goto out;
+	}
+
+	for (i = 0; i < str_nums; i++)
+		nstr_list[i] = htons(str_list[i]);
+
+	if (out && !sctp_stream_outq_is_empty(stream, str_nums, nstr_list)) {
+		kfree(nstr_list);
+		retval = -EAGAIN;
+		goto out;
+	}
+
+	chunk = sctp_make_strreset_req(asoc, str_nums, nstr_list, out, in);
+
+	kfree(nstr_list);
+
+	if (!chunk) {
+		retval = -ENOMEM;
+		goto out;
+	}
+
+	if (out) {
+		if (str_nums)
+			for (i = 0; i < str_nums; i++)
+				SCTP_SO(stream, str_list[i])->state =
+						       SCTP_STREAM_CLOSED;
+		else
+			for (i = 0; i < stream->outcnt; i++)
+				SCTP_SO(stream, i)->state = SCTP_STREAM_CLOSED;
+	}
+
+	asoc->strreset_chunk = chunk;
+	sctp_chunk_hold(asoc->strreset_chunk);
+
+	retval = sctp_send_reconf(asoc, chunk);
+	if (retval) {
+		sctp_chunk_put(asoc->strreset_chunk);
+		asoc->strreset_chunk = NULL;
+		if (!out)
+			goto out;
+
+		if (str_nums)
+			for (i = 0; i < str_nums; i++)
+				SCTP_SO(stream, str_list[i])->state =
+						       SCTP_STREAM_OPEN;
+		else
+			for (i = 0; i < stream->outcnt; i++)
+				SCTP_SO(stream, i)->state = SCTP_STREAM_OPEN;
+
+		goto out;
+	}
+
+	if (out)
+		SCTP_STRRESET_SET(asoc, SCTP_PARAM_RESET_OUT_REQUEST);
+	if (in)
+		SCTP_STRRESET_SET(asoc, SCTP_PARAM_RESET_IN_REQUEST);
+
+out:
+	return retval;
+}
+
+int sctp_send_reset_assoc(struct sctp_association *asoc)
+{
+	struct sctp_stream *stream = &asoc->stream;
+	struct sctp_chunk *chunk = NULL;
+	int retval;
+	__u16 i;
+
+	if (!asoc->peer.reconf_capable ||
+	    !(asoc->strreset_enable & SCTP_ENABLE_RESET_ASSOC_REQ))
+		return -ENOPROTOOPT;
+
+	if (asoc->strreset_outstanding)
+		return -EINPROGRESS;
+
+	if (!sctp_outq_is_empty(&asoc->outqueue))
+		return -EAGAIN;
+
+	chunk = sctp_make_strreset_tsnreq(asoc);
+	if (!chunk)
+		return -ENOMEM;
+
+	/* Block further xmit of data until this request is completed */
+	for (i = 0; i < stream->outcnt; i++)
+		SCTP_SO(stream, i)->state = SCTP_STREAM_CLOSED;
+
+	asoc->strreset_chunk = chunk;
+	sctp_chunk_hold(asoc->strreset_chunk);
+
+	retval = sctp_send_reconf(asoc, chunk);
+	if (retval) {
+		sctp_chunk_put(asoc->strreset_chunk);
+		asoc->strreset_chunk = NULL;
+
+		for (i = 0; i < stream->outcnt; i++)
+			SCTP_SO(stream, i)->state = SCTP_STREAM_OPEN;
+
+		return retval;
+	}
+
+	SCTP_STRRESET_SET(asoc, SCTP_PARAM_RESET_TSN_REQUEST);
+
+	return 0;
+}
+
+int sctp_send_add_streams(struct sctp_association *asoc,
+			  struct sctp_add_streams *params)
+{
+	struct sctp_stream *stream = &asoc->stream;
+	struct sctp_chunk *chunk = NULL;
+	int retval;
+	__u32 outcnt, incnt;
+	__u16 out, in;
+
+	if (!asoc->peer.reconf_capable ||
+	    !(asoc->strreset_enable & SCTP_ENABLE_CHANGE_ASSOC_REQ)) {
+		retval = -ENOPROTOOPT;
+		goto out;
+	}
+
+	if (asoc->strreset_outstanding) {
+		retval = -EINPROGRESS;
+		goto out;
+	}
+
+	out = params->sas_outstrms;
+	in  = params->sas_instrms;
+	outcnt = stream->outcnt + out;
+	incnt = stream->incnt + in;
+	if (outcnt > SCTP_MAX_STREAM || incnt > SCTP_MAX_STREAM ||
+	    (!out && !in)) {
+		retval = -EINVAL;
+		goto out;
+	}
+
+	if (out) {
+		retval = sctp_stream_alloc_out(stream, outcnt, GFP_KERNEL);
+		if (retval)
+			goto out;
+	}
+
+	chunk = sctp_make_strreset_addstrm(asoc, out, in);
+	if (!chunk) {
+		retval = -ENOMEM;
+		goto out;
+	}
+
+	asoc->strreset_chunk = chunk;
+	sctp_chunk_hold(asoc->strreset_chunk);
+
+	retval = sctp_send_reconf(asoc, chunk);
+	if (retval) {
+		sctp_chunk_put(asoc->strreset_chunk);
+		asoc->strreset_chunk = NULL;
+		goto out;
+	}
+
+	if (out)
+		SCTP_STRRESET_SET(asoc, SCTP_PARAM_RESET_ADD_OUT_STREAMS);
+	if (in)
+		SCTP_STRRESET_SET(asoc, SCTP_PARAM_RESET_ADD_IN_STREAMS);
+
+out:
+	return retval;
+}
+
+static struct sctp_paramhdr *sctp_chunk_lookup_strreset_param(
+			struct sctp_association *asoc, __be32 resp_seq,
+			__be16 type, bool match_seq)
+{
+	struct sctp_chunk *chunk = asoc->strreset_chunk;
+	struct sctp_reconf_chunk *hdr;
+	union sctp_params param;
+
+	if (!chunk || !chunk->transport)
+		return NULL;
+
+	hdr = (struct sctp_reconf_chunk *)chunk->chunk_hdr;
+	sctp_walk_params(param, hdr) {
+		/* sctp_strreset_tsnreq is actually the basic structure
+		 * of all stream reconf params, so it's safe to use it
+		 * to access request_seq.
+		 */
+		struct sctp_strreset_tsnreq *req = param.v;
+
+		if ((!match_seq || req->request_seq == resp_seq) &&
+		    (!type || type == req->param_hdr.type))
+			return param.v;
+	}
+
+	return NULL;
+}
+
+static void sctp_update_strreset_result(struct sctp_association *asoc,
+					__u32 result)
+{
+	asoc->strreset_result[1] = asoc->strreset_result[0];
+	asoc->strreset_result[0] = result;
+}
+
+struct sctp_chunk *sctp_process_strreset_outreq(
+				struct sctp_association *asoc,
+				union sctp_params param,
+				struct sctp_ulpevent **evp)
+{
+	struct sctp_strreset_outreq *outreq = param.v;
+	struct sctp_stream *stream = &asoc->stream;
+	__u32 result = SCTP_STRRESET_DENIED;
+	__be16 *str_p = NULL;
+	__u32 request_seq;
+	__u16 i, nums;
+
+	request_seq = ntohl(outreq->request_seq);
+
+	if (ntohl(outreq->send_reset_at_tsn) >
+	    sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map)) {
+		result = SCTP_STRRESET_IN_PROGRESS;
+		goto err;
+	}
+
+	if (TSN_lt(asoc->strreset_inseq, request_seq) ||
+	    TSN_lt(request_seq, asoc->strreset_inseq - 2)) {
+		result = SCTP_STRRESET_ERR_BAD_SEQNO;
+		goto err;
+	} else if (TSN_lt(request_seq, asoc->strreset_inseq)) {
+		i = asoc->strreset_inseq - request_seq - 1;
+		result = asoc->strreset_result[i];
+		goto err;
+	}
+	asoc->strreset_inseq++;
+
+	/* Check strreset_enable after inseq inc, as sender cannot tell
+	 * the peer doesn't enable strreset after receiving response with
+	 * result denied, as well as to keep consistent with bsd.
+	 */
+	if (!(asoc->strreset_enable & SCTP_ENABLE_RESET_STREAM_REQ))
+		goto out;
+
+	nums = (ntohs(param.p->length) - sizeof(*outreq)) / sizeof(__u16);
+	str_p = outreq->list_of_streams;
+	for (i = 0; i < nums; i++) {
+		if (ntohs(str_p[i]) >= stream->incnt) {
+			result = SCTP_STRRESET_ERR_WRONG_SSN;
+			goto out;
+		}
+	}
+
+	if (asoc->strreset_chunk) {
+		if (!sctp_chunk_lookup_strreset_param(
+				asoc, outreq->response_seq,
+				SCTP_PARAM_RESET_IN_REQUEST, true) ||
+		    !SCTP_STRRESET_TEST(asoc, SCTP_PARAM_RESET_IN_REQUEST)) {
+			/* same process with outstanding isn't 0 */
+			result = SCTP_STRRESET_ERR_IN_PROGRESS;
+			goto out;
+		}
+
+		SCTP_STRRESET_CLEAR(asoc, SCTP_PARAM_RESET_IN_REQUEST);
+		asoc->strreset_outseq++;
+
+		if (!asoc->strreset_outstanding) {
+			struct sctp_transport *t;
+
+			t = asoc->strreset_chunk->transport;
+			if (timer_delete(&t->reconf_timer))
+				sctp_transport_put(t);
+
+			sctp_chunk_put(asoc->strreset_chunk);
+			asoc->strreset_chunk = NULL;
+		}
+	}
+
+	if (nums)
+		for (i = 0; i < nums; i++)
+			SCTP_SI(stream, ntohs(str_p[i]))->mid = 0;
+	else
+		for (i = 0; i < stream->incnt; i++)
+			SCTP_SI(stream, i)->mid = 0;
+
+	result = SCTP_STRRESET_PERFORMED;
+
+	*evp = sctp_ulpevent_make_stream_reset_event(asoc,
+		SCTP_STREAM_RESET_INCOMING_SSN, nums, str_p, GFP_ATOMIC);
+
+out:
+	sctp_update_strreset_result(asoc, result);
+err:
+	return sctp_make_strreset_resp(asoc, result, request_seq);
+}
+
+struct sctp_chunk *sctp_process_strreset_inreq(
+				struct sctp_association *asoc,
+				union sctp_params param,
+				struct sctp_ulpevent **evp)
+{
+	struct sctp_strreset_inreq *inreq = param.v;
+	struct sctp_stream *stream = &asoc->stream;
+	__u32 result = SCTP_STRRESET_DENIED;
+	struct sctp_chunk *chunk = NULL;
+	__u32 request_seq;
+	__u16 i, nums;
+	__be16 *str_p;
+
+	request_seq = ntohl(inreq->request_seq);
+	if (TSN_lt(asoc->strreset_inseq, request_seq) ||
+	    TSN_lt(request_seq, asoc->strreset_inseq - 2)) {
+		result = SCTP_STRRESET_ERR_BAD_SEQNO;
+		goto err;
+	} else if (TSN_lt(request_seq, asoc->strreset_inseq)) {
+		i = asoc->strreset_inseq - request_seq - 1;
+		result = asoc->strreset_result[i];
+		if (result == SCTP_STRRESET_PERFORMED)
+			return NULL;
+		goto err;
+	}
+	asoc->strreset_inseq++;
+
+	if (!(asoc->strreset_enable & SCTP_ENABLE_RESET_STREAM_REQ))
+		goto out;
+
+	if (asoc->strreset_outstanding) {
+		result = SCTP_STRRESET_ERR_IN_PROGRESS;
+		goto out;
+	}
+
+	nums = (ntohs(param.p->length) - sizeof(*inreq)) / sizeof(__u16);
+	str_p = inreq->list_of_streams;
+	if (nums * sizeof(__u16) + sizeof(struct sctp_strreset_outreq) >
+	    SCTP_MAX_CHUNK_LEN - sizeof(struct sctp_reconf_chunk))
+		goto out;
+	for (i = 0; i < nums; i++) {
+		if (ntohs(str_p[i]) >= stream->outcnt) {
+			result = SCTP_STRRESET_ERR_WRONG_SSN;
+			goto out;
+		}
+	}
+
+	if (!sctp_stream_outq_is_empty(stream, nums, str_p)) {
+		result = SCTP_STRRESET_IN_PROGRESS;
+		asoc->strreset_inseq--;
+		goto err;
+	}
+
+	chunk = sctp_make_strreset_req(asoc, nums, str_p, 1, 0);
+	if (!chunk)
+		goto out;
+
+	if (nums)
+		for (i = 0; i < nums; i++)
+			SCTP_SO(stream, ntohs(str_p[i]))->state =
+					       SCTP_STREAM_CLOSED;
+	else
+		for (i = 0; i < stream->outcnt; i++)
+			SCTP_SO(stream, i)->state = SCTP_STREAM_CLOSED;
+
+	asoc->strreset_chunk = chunk;
+	SCTP_STRRESET_SET(asoc, SCTP_PARAM_RESET_OUT_REQUEST);
+	sctp_chunk_hold(asoc->strreset_chunk);
+
+	result = SCTP_STRRESET_PERFORMED;
+
+out:
+	sctp_update_strreset_result(asoc, result);
+err:
+	if (!chunk)
+		chunk =  sctp_make_strreset_resp(asoc, result, request_seq);
+
+	return chunk;
+}
+
+struct sctp_chunk *sctp_process_strreset_tsnreq(
+				struct sctp_association *asoc,
+				union sctp_params param,
+				struct sctp_ulpevent **evp)
+{
+	__u32 init_tsn = 0, next_tsn = 0, max_tsn_seen;
+	struct sctp_strreset_tsnreq *tsnreq = param.v;
+	struct sctp_stream *stream = &asoc->stream;
+	__u32 result = SCTP_STRRESET_DENIED;
+	__u32 request_seq;
+	__u16 i;
+
+	request_seq = ntohl(tsnreq->request_seq);
+	if (TSN_lt(asoc->strreset_inseq, request_seq) ||
+	    TSN_lt(request_seq, asoc->strreset_inseq - 2)) {
+		result = SCTP_STRRESET_ERR_BAD_SEQNO;
+		goto err;
+	} else if (TSN_lt(request_seq, asoc->strreset_inseq)) {
+		i = asoc->strreset_inseq - request_seq - 1;
+		result = asoc->strreset_result[i];
+		if (result == SCTP_STRRESET_PERFORMED) {
+			next_tsn = asoc->ctsn_ack_point + 1;
+			init_tsn =
+				sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map) + 1;
+		}
+		goto err;
+	}
+
+	if (!sctp_outq_is_empty(&asoc->outqueue)) {
+		result = SCTP_STRRESET_IN_PROGRESS;
+		goto err;
+	}
+
+	asoc->strreset_inseq++;
+
+	if (!(asoc->strreset_enable & SCTP_ENABLE_RESET_ASSOC_REQ))
+		goto out;
+
+	if (asoc->strreset_outstanding) {
+		result = SCTP_STRRESET_ERR_IN_PROGRESS;
+		goto out;
+	}
+
+	/* G4: The same processing as though a FWD-TSN chunk (as defined in
+	 *     [RFC3758]) with all streams affected and a new cumulative TSN
+	 *     ACK of the Receiver's Next TSN minus 1 were received MUST be
+	 *     performed.
+	 */
+	max_tsn_seen = sctp_tsnmap_get_max_tsn_seen(&asoc->peer.tsn_map);
+	asoc->stream.si->report_ftsn(&asoc->ulpq, max_tsn_seen);
+
+	/* G1: Compute an appropriate value for the Receiver's Next TSN -- the
+	 *     TSN that the peer should use to send the next DATA chunk.  The
+	 *     value SHOULD be the smallest TSN not acknowledged by the
+	 *     receiver of the request plus 2^31.
+	 */
+	init_tsn = sctp_tsnmap_get_ctsn(&asoc->peer.tsn_map) + (1U << 31);
+	sctp_tsnmap_init(&asoc->peer.tsn_map, SCTP_TSN_MAP_INITIAL,
+			 init_tsn, GFP_ATOMIC);
+
+	/* G3: The same processing as though a SACK chunk with no gap report
+	 *     and a cumulative TSN ACK of the Sender's Next TSN minus 1 were
+	 *     received MUST be performed.
+	 */
+	sctp_outq_free(&asoc->outqueue);
+
+	/* G2: Compute an appropriate value for the local endpoint's next TSN,
+	 *     i.e., the next TSN assigned by the receiver of the SSN/TSN reset
+	 *     chunk.  The value SHOULD be the highest TSN sent by the receiver
+	 *     of the request plus 1.
+	 */
+	next_tsn = asoc->next_tsn;
+	asoc->ctsn_ack_point = next_tsn - 1;
+	asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
+
+	/* G5:  The next expected and outgoing SSNs MUST be reset to 0 for all
+	 *      incoming and outgoing streams.
+	 */
+	for (i = 0; i < stream->outcnt; i++) {
+		SCTP_SO(stream, i)->mid = 0;
+		SCTP_SO(stream, i)->mid_uo = 0;
+	}
+	for (i = 0; i < stream->incnt; i++)
+		SCTP_SI(stream, i)->mid = 0;
+
+	result = SCTP_STRRESET_PERFORMED;
+
+	*evp = sctp_ulpevent_make_assoc_reset_event(asoc, 0, init_tsn,
+						    next_tsn, GFP_ATOMIC);
+
+out:
+	sctp_update_strreset_result(asoc, result);
+err:
+	return sctp_make_strreset_tsnresp(asoc, result, request_seq,
+					  next_tsn, init_tsn);
+}
+
+struct sctp_chunk *sctp_process_strreset_addstrm_out(
+				struct sctp_association *asoc,
+				union sctp_params param,
+				struct sctp_ulpevent **evp)
+{
+	struct sctp_strreset_addstrm *addstrm = param.v;
+	struct sctp_stream *stream = &asoc->stream;
+	__u32 result = SCTP_STRRESET_DENIED;
+	__u32 request_seq, incnt;
+	__u16 in, i;
+
+	request_seq = ntohl(addstrm->request_seq);
+	if (TSN_lt(asoc->strreset_inseq, request_seq) ||
+	    TSN_lt(request_seq, asoc->strreset_inseq - 2)) {
+		result = SCTP_STRRESET_ERR_BAD_SEQNO;
+		goto err;
+	} else if (TSN_lt(request_seq, asoc->strreset_inseq)) {
+		i = asoc->strreset_inseq - request_seq - 1;
+		result = asoc->strreset_result[i];
+		goto err;
+	}
+	asoc->strreset_inseq++;
+
+	if (!(asoc->strreset_enable & SCTP_ENABLE_CHANGE_ASSOC_REQ))
+		goto out;
+
+	in = ntohs(addstrm->number_of_streams);
+	incnt = stream->incnt + in;
+	if (!in || incnt > SCTP_MAX_STREAM)
+		goto out;
+
+	if (sctp_stream_alloc_in(stream, incnt, GFP_ATOMIC))
+		goto out;
+
+	if (asoc->strreset_chunk) {
+		if (!sctp_chunk_lookup_strreset_param(
+			asoc, 0, SCTP_PARAM_RESET_ADD_IN_STREAMS, false) ||
+		    !SCTP_STRRESET_TEST(asoc, SCTP_PARAM_RESET_ADD_IN_STREAMS)) {
+			/* same process with outstanding isn't 0 */
+			result = SCTP_STRRESET_ERR_IN_PROGRESS;
+			goto out;
+		}
+
+		SCTP_STRRESET_CLEAR(asoc, SCTP_PARAM_RESET_ADD_IN_STREAMS);
+		asoc->strreset_outseq++;
+
+		if (!asoc->strreset_outstanding) {
+			struct sctp_transport *t;
+
+			t = asoc->strreset_chunk->transport;
+			if (timer_delete(&t->reconf_timer))
+				sctp_transport_put(t);
+
+			sctp_chunk_put(asoc->strreset_chunk);
+			asoc->strreset_chunk = NULL;
+		}
+	}
+
+	stream->incnt = incnt;
+
+	result = SCTP_STRRESET_PERFORMED;
+
+	*evp = sctp_ulpevent_make_stream_change_event(asoc,
+		0, ntohs(addstrm->number_of_streams), 0, GFP_ATOMIC);
+
+out:
+	sctp_update_strreset_result(asoc, result);
+err:
+	return sctp_make_strreset_resp(asoc, result, request_seq);
+}
+
+struct sctp_chunk *sctp_process_strreset_addstrm_in(
+				struct sctp_association *asoc,
+				union sctp_params param,
+				struct sctp_ulpevent **evp)
+{
+	struct sctp_strreset_addstrm *addstrm = param.v;
+	struct sctp_stream *stream = &asoc->stream;
+	__u32 result = SCTP_STRRESET_DENIED;
+	struct sctp_chunk *chunk = NULL;
+	__u32 request_seq, outcnt;
+	__u16 out, i;
+	int ret;
+
+	request_seq = ntohl(addstrm->request_seq);
+	if (TSN_lt(asoc->strreset_inseq, request_seq) ||
+	    TSN_lt(request_seq, asoc->strreset_inseq - 2)) {
+		result = SCTP_STRRESET_ERR_BAD_SEQNO;
+		goto err;
+	} else if (TSN_lt(request_seq, asoc->strreset_inseq)) {
+		i = asoc->strreset_inseq - request_seq - 1;
+		result = asoc->strreset_result[i];
+		if (result == SCTP_STRRESET_PERFORMED)
+			return NULL;
+		goto err;
+	}
+	asoc->strreset_inseq++;
+
+	if (!(asoc->strreset_enable & SCTP_ENABLE_CHANGE_ASSOC_REQ))
+		goto out;
+
+	if (asoc->strreset_outstanding) {
+		result = SCTP_STRRESET_ERR_IN_PROGRESS;
+		goto out;
+	}
+
+	out = ntohs(addstrm->number_of_streams);
+	outcnt = stream->outcnt + out;
+	if (!out || outcnt > SCTP_MAX_STREAM)
+		goto out;
+
+	ret = sctp_stream_alloc_out(stream, outcnt, GFP_ATOMIC);
+	if (ret)
+		goto out;
+
+	chunk = sctp_make_strreset_addstrm(asoc, out, 0);
+	if (!chunk)
+		goto out;
+
+	asoc->strreset_chunk = chunk;
+	SCTP_STRRESET_SET(asoc, SCTP_PARAM_RESET_ADD_OUT_STREAMS);
+	sctp_chunk_hold(asoc->strreset_chunk);
+
+	stream->outcnt = outcnt;
+
+	result = SCTP_STRRESET_PERFORMED;
+
+out:
+	sctp_update_strreset_result(asoc, result);
+err:
+	if (!chunk)
+		chunk = sctp_make_strreset_resp(asoc, result, request_seq);
+
+	return chunk;
+}
+
+struct sctp_chunk *sctp_process_strreset_resp(
+				struct sctp_association *asoc,
+				union sctp_params param,
+				struct sctp_ulpevent **evp)
+{
+	struct sctp_stream *stream = &asoc->stream;
+	struct sctp_strreset_resp *resp = param.v;
+	struct sctp_transport *t;
+	__u16 i, nums, flags = 0;
+	struct sctp_paramhdr *req;
+	__u32 result;
+
+	req = sctp_chunk_lookup_strreset_param(asoc, resp->response_seq, 0,
+					       true);
+	if (!req || !SCTP_STRRESET_TEST(asoc, req->type))
+		return NULL;
+
+	result = ntohl(resp->result);
+	if (result != SCTP_STRRESET_PERFORMED) {
+		/* if in progress, do nothing but retransmit */
+		if (result == SCTP_STRRESET_IN_PROGRESS)
+			return NULL;
+		else if (result == SCTP_STRRESET_DENIED)
+			flags = SCTP_STREAM_RESET_DENIED;
+		else
+			flags = SCTP_STREAM_RESET_FAILED;
+	}
+
+	if (req->type == SCTP_PARAM_RESET_OUT_REQUEST) {
+		struct sctp_strreset_outreq *outreq;
+		__be16 *str_p;
+
+		outreq = (struct sctp_strreset_outreq *)req;
+		str_p = outreq->list_of_streams;
+		nums = (ntohs(outreq->param_hdr.length) - sizeof(*outreq)) /
+		       sizeof(__u16);
+
+		if (result == SCTP_STRRESET_PERFORMED) {
+			struct sctp_stream_out *sout;
+			if (nums) {
+				for (i = 0; i < nums; i++) {
+					sout = SCTP_SO(stream, ntohs(str_p[i]));
+					sout->mid = 0;
+					sout->mid_uo = 0;
+				}
+			} else {
+				for (i = 0; i < stream->outcnt; i++) {
+					sout = SCTP_SO(stream, i);
+					sout->mid = 0;
+					sout->mid_uo = 0;
+				}
+			}
+		}
+
+		flags |= SCTP_STREAM_RESET_OUTGOING_SSN;
+
+		for (i = 0; i < stream->outcnt; i++)
+			SCTP_SO(stream, i)->state = SCTP_STREAM_OPEN;
+
+		*evp = sctp_ulpevent_make_stream_reset_event(asoc, flags,
+			nums, str_p, GFP_ATOMIC);
+	} else if (req->type == SCTP_PARAM_RESET_IN_REQUEST) {
+		struct sctp_strreset_inreq *inreq;
+		__be16 *str_p;
+
+		/* if the result is performed, it's impossible for inreq */
+		if (result == SCTP_STRRESET_PERFORMED)
+			return NULL;
+
+		inreq = (struct sctp_strreset_inreq *)req;
+		str_p = inreq->list_of_streams;
+		nums = (ntohs(inreq->param_hdr.length) - sizeof(*inreq)) /
+		       sizeof(__u16);
+
+		flags |= SCTP_STREAM_RESET_INCOMING_SSN;
+
+		*evp = sctp_ulpevent_make_stream_reset_event(asoc, flags,
+			nums, str_p, GFP_ATOMIC);
+	} else if (req->type == SCTP_PARAM_RESET_TSN_REQUEST) {
+		struct sctp_strreset_resptsn *resptsn;
+		__u32 stsn, rtsn;
+
+		/* check for resptsn, as sctp_verify_reconf didn't do it*/
+		if (ntohs(param.p->length) != sizeof(*resptsn))
+			return NULL;
+
+		resptsn = (struct sctp_strreset_resptsn *)resp;
+		stsn = ntohl(resptsn->senders_next_tsn);
+		rtsn = ntohl(resptsn->receivers_next_tsn);
+
+		if (result == SCTP_STRRESET_PERFORMED) {
+			__u32 mtsn = sctp_tsnmap_get_max_tsn_seen(
+						&asoc->peer.tsn_map);
+			LIST_HEAD(temp);
+
+			asoc->stream.si->report_ftsn(&asoc->ulpq, mtsn);
+
+			sctp_tsnmap_init(&asoc->peer.tsn_map,
+					 SCTP_TSN_MAP_INITIAL,
+					 stsn, GFP_ATOMIC);
+
+			/* Clean up sacked and abandoned queues only. As the
+			 * out_chunk_list may not be empty, splice it to temp,
+			 * then get it back after sctp_outq_free is done.
+			 */
+			list_splice_init(&asoc->outqueue.out_chunk_list, &temp);
+			sctp_outq_free(&asoc->outqueue);
+			list_splice_init(&temp, &asoc->outqueue.out_chunk_list);
+
+			asoc->next_tsn = rtsn;
+			asoc->ctsn_ack_point = asoc->next_tsn - 1;
+			asoc->adv_peer_ack_point = asoc->ctsn_ack_point;
+
+			for (i = 0; i < stream->outcnt; i++) {
+				SCTP_SO(stream, i)->mid = 0;
+				SCTP_SO(stream, i)->mid_uo = 0;
+			}
+			for (i = 0; i < stream->incnt; i++)
+				SCTP_SI(stream, i)->mid = 0;
+		}
+
+		for (i = 0; i < stream->outcnt; i++)
+			SCTP_SO(stream, i)->state = SCTP_STREAM_OPEN;
+
+		*evp = sctp_ulpevent_make_assoc_reset_event(asoc, flags,
+			stsn, rtsn, GFP_ATOMIC);
+	} else if (req->type == SCTP_PARAM_RESET_ADD_OUT_STREAMS) {
+		struct sctp_strreset_addstrm *addstrm;
+		const struct sctp_sched_ops *sched;
+		__u16 number;
+
+		addstrm = (struct sctp_strreset_addstrm *)req;
+		nums = ntohs(addstrm->number_of_streams);
+		number = stream->outcnt - nums;
+
+		if (result == SCTP_STRRESET_PERFORMED) {
+			for (i = number; i < stream->outcnt; i++)
+				SCTP_SO(stream, i)->state = SCTP_STREAM_OPEN;
+		} else {
+			sched = sctp_sched_ops_from_stream(stream);
+			sched->unsched_all(stream);
+			sctp_stream_outq_migrate(stream, NULL, number);
+			sched->sched_all(stream);
+			stream->outcnt = number;
+		}
+
+		*evp = sctp_ulpevent_make_stream_change_event(asoc, flags,
+			0, nums, GFP_ATOMIC);
+	} else if (req->type == SCTP_PARAM_RESET_ADD_IN_STREAMS) {
+		struct sctp_strreset_addstrm *addstrm;
+
+		/* if the result is performed, it's impossible for addstrm in
+		 * request.
+		 */
+		if (result == SCTP_STRRESET_PERFORMED)
+			return NULL;
+
+		addstrm = (struct sctp_strreset_addstrm *)req;
+		nums = ntohs(addstrm->number_of_streams);
+
+		*evp = sctp_ulpevent_make_stream_change_event(asoc, flags,
+			nums, 0, GFP_ATOMIC);
+	}
+
+	SCTP_STRRESET_CLEAR(asoc, req->type);
+	asoc->strreset_outseq++;
+
+	/* remove everything for this reconf request */
+	if (!asoc->strreset_outstanding) {
+		t = asoc->strreset_chunk->transport;
+		if (timer_delete(&t->reconf_timer))
+			sctp_transport_put(t);
+
+		sctp_chunk_put(asoc->strreset_chunk);
+		asoc->strreset_chunk = NULL;
+	}
+
+	return NULL;
+}