1 files changed, 494 insertions, 0 deletions
diff --git a/net/tls/tls_strp.c b/net/tls/tls_strp.c
new file mode 100644
index 000000000000..9b79e334dbd9
--- /dev/null
+++ b/net/tls/tls_strp.c
@@ -0,0 +1,494 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/* Copyright (c) 2016 Tom Herbert <tom@herbertland.com> */
+
+#include <linux/skbuff.h>
+#include <linux/workqueue.h>
+#include <net/strparser.h>
+#include <net/tcp.h>
+#include <net/sock.h>
+#include <net/tls.h>
+
+#include "tls.h"
+
+static struct workqueue_struct *tls_strp_wq;
+
+static void tls_strp_abort_strp(struct tls_strparser *strp, int err)
+{
+	if (strp->stopped)
+		return;
+
+	strp->stopped = 1;
+
+	/* Report an error on the lower socket */
+	strp->sk->sk_err = -err;
+	sk_error_report(strp->sk);
+}
+
+static void tls_strp_anchor_free(struct tls_strparser *strp)
+{
+	struct skb_shared_info *shinfo = skb_shinfo(strp->anchor);
+
+	DEBUG_NET_WARN_ON_ONCE(atomic_read(&shinfo->dataref) != 1);
+	shinfo->frag_list = NULL;
+	consume_skb(strp->anchor);
+	strp->anchor = NULL;
+}
+
+/* Create a new skb with the contents of input copied to its page frags */
+static struct sk_buff *tls_strp_msg_make_copy(struct tls_strparser *strp)
+{
+	struct strp_msg *rxm;
+	struct sk_buff *skb;
+	int i, err, offset;
+
+	skb = alloc_skb_with_frags(0, strp->stm.full_len, TLS_PAGE_ORDER,
+				   &err, strp->sk->sk_allocation);
+	if (!skb)
+		return NULL;
+
+	offset = strp->stm.offset;
+	for (i = 0; i < skb_shinfo(skb)->nr_frags; i++) {
+		skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
+
+		WARN_ON_ONCE(skb_copy_bits(strp->anchor, offset,
+					   skb_frag_address(frag),
+					   skb_frag_size(frag)));
+		offset += skb_frag_size(frag);
+	}
+
+	skb_copy_header(skb, strp->anchor);
+	rxm = strp_msg(skb);
+	rxm->offset = 0;
+	return skb;
+}
+
+/* Steal the input skb, input msg is invalid after calling this function */
+struct sk_buff *tls_strp_msg_detach(struct tls_sw_context_rx *ctx)
+{
+	struct tls_strparser *strp = &ctx->strp;
+
+#ifdef CONFIG_TLS_DEVICE
+	DEBUG_NET_WARN_ON_ONCE(!strp->anchor->decrypted);
+#else
+	/* This function turns an input into an output,
+	 * that can only happen if we have offload.
+	 */
+	WARN_ON(1);
+#endif
+
+	if (strp->copy_mode) {
+		struct sk_buff *skb;
+
+		/* Replace anchor with an empty skb, this is a little
+		 * dangerous but __tls_cur_msg() warns on empty skbs
+		 * so hopefully we'll catch abuses.
+		 */
+		skb = alloc_skb(0, strp->sk->sk_allocation);
+		if (!skb)
+			return NULL;
+
+		swap(strp->anchor, skb);
+		return skb;
+	}
+
+	return tls_strp_msg_make_copy(strp);
+}
+
+/* Force the input skb to be in copy mode. The data ownership remains
+ * with the input skb itself (meaning unpause will wipe it) but it can
+ * be modified.
+ */
+int tls_strp_msg_cow(struct tls_sw_context_rx *ctx)
+{
+	struct tls_strparser *strp = &ctx->strp;
+	struct sk_buff *skb;
+
+	if (strp->copy_mode)
+		return 0;
+
+	skb = tls_strp_msg_make_copy(strp);
+	if (!skb)
+		return -ENOMEM;
+
+	tls_strp_anchor_free(strp);
+	strp->anchor = skb;
+
+	tcp_read_done(strp->sk, strp->stm.full_len);
+	strp->copy_mode = 1;
+
+	return 0;
+}
+
+/* Make a clone (in the skb sense) of the input msg to keep a reference
+ * to the underlying data. The reference-holding skbs get placed on
+ * @dst.
+ */
+int tls_strp_msg_hold(struct tls_strparser *strp, struct sk_buff_head *dst)
+{
+	struct skb_shared_info *shinfo = skb_shinfo(strp->anchor);
+
+	if (strp->copy_mode) {
+		struct sk_buff *skb;
+
+		WARN_ON_ONCE(!shinfo->nr_frags);
+
+		/* We can't skb_clone() the anchor, it gets wiped by unpause */
+		skb = alloc_skb(0, strp->sk->sk_allocation);
+		if (!skb)
+			return -ENOMEM;
+
+		__skb_queue_tail(dst, strp->anchor);
+		strp->anchor = skb;
+	} else {
+		struct sk_buff *iter, *clone;
+		int chunk, len, offset;
+
+		offset = strp->stm.offset;
+		len = strp->stm.full_len;
+		iter = shinfo->frag_list;
+
+		while (len > 0) {
+			if (iter->len <= offset) {
+				offset -= iter->len;
+				goto next;
+			}
+
+			chunk = iter->len - offset;
+			offset = 0;
+
+			clone = skb_clone(iter, strp->sk->sk_allocation);
+			if (!clone)
+				return -ENOMEM;
+			__skb_queue_tail(dst, clone);
+
+			len -= chunk;
+next:
+			iter = iter->next;
+		}
+	}
+
+	return 0;
+}
+
+static void tls_strp_flush_anchor_copy(struct tls_strparser *strp)
+{
+	struct skb_shared_info *shinfo = skb_shinfo(strp->anchor);
+	int i;
+
+	DEBUG_NET_WARN_ON_ONCE(atomic_read(&shinfo->dataref) != 1);
+
+	for (i = 0; i < shinfo->nr_frags; i++)
+		__skb_frag_unref(&shinfo->frags[i], false);
+	shinfo->nr_frags = 0;
+	strp->copy_mode = 0;
+}
+
+static int tls_strp_copyin(read_descriptor_t *desc, struct sk_buff *in_skb,
+			   unsigned int offset, size_t in_len)
+{
+	struct tls_strparser *strp = (struct tls_strparser *)desc->arg.data;
+	struct sk_buff *skb;
+	skb_frag_t *frag;
+	size_t len, chunk;
+	int sz;
+
+	if (strp->msg_ready)
+		return 0;
+
+	skb = strp->anchor;
+	frag = &skb_shinfo(skb)->frags[skb->len / PAGE_SIZE];
+
+	len = in_len;
+	/* First make sure we got the header */
+	if (!strp->stm.full_len) {
+		/* Assume one page is more than enough for headers */
+		chunk =	min_t(size_t, len, PAGE_SIZE - skb_frag_size(frag));
+		WARN_ON_ONCE(skb_copy_bits(in_skb, offset,
+					   skb_frag_address(frag) +
+					   skb_frag_size(frag),
+					   chunk));
+
+		sz = tls_rx_msg_size(strp, strp->anchor);
+		if (sz < 0) {
+			desc->error = sz;
+			return 0;
+		}
+
+		/* We may have over-read, sz == 0 is guaranteed under-read */
+		if (sz > 0)
+			chunk =	min_t(size_t, chunk, sz - skb->len);
+
+		skb->len += chunk;
+		skb->data_len += chunk;
+		skb_frag_size_add(frag, chunk);
+		frag++;
+		len -= chunk;
+		offset += chunk;
+
+		strp->stm.full_len = sz;
+		if (!strp->stm.full_len)
+			goto read_done;
+	}
+
+	/* Load up more data */
+	while (len && strp->stm.full_len > skb->len) {
+		chunk =	min_t(size_t, len, strp->stm.full_len - skb->len);
+		chunk = min_t(size_t, chunk, PAGE_SIZE - skb_frag_size(frag));
+		WARN_ON_ONCE(skb_copy_bits(in_skb, offset,
+					   skb_frag_address(frag) +
+					   skb_frag_size(frag),
+					   chunk));
+
+		skb->len += chunk;
+		skb->data_len += chunk;
+		skb_frag_size_add(frag, chunk);
+		frag++;
+		len -= chunk;
+		offset += chunk;
+	}
+
+	if (strp->stm.full_len == skb->len) {
+		desc->count = 0;
+
+		strp->msg_ready = 1;
+		tls_rx_msg_ready(strp);
+	}
+
+read_done:
+	return in_len - len;
+}
+
+static int tls_strp_read_copyin(struct tls_strparser *strp)
+{
+	struct socket *sock = strp->sk->sk_socket;
+	read_descriptor_t desc;
+
+	desc.arg.data = strp;
+	desc.error = 0;
+	desc.count = 1; /* give more than one skb per call */
+
+	/* sk should be locked here, so okay to do read_sock */
+	sock->ops->read_sock(strp->sk, &desc, tls_strp_copyin);
+
+	return desc.error;
+}
+
+static int tls_strp_read_short(struct tls_strparser *strp)
+{
+	struct skb_shared_info *shinfo;
+	struct page *page;
+	int need_spc, len;
+
+	/* If the rbuf is small or rcv window has collapsed to 0 we need
+	 * to read the data out. Otherwise the connection will stall.
+	 * Without pressure threshold of INT_MAX will never be ready.
+	 */
+	if (likely(!tcp_epollin_ready(strp->sk, INT_MAX)))
+		return 0;
+
+	shinfo = skb_shinfo(strp->anchor);
+	shinfo->frag_list = NULL;
+
+	/* If we don't know the length go max plus page for cipher overhead */
+	need_spc = strp->stm.full_len ?: TLS_MAX_PAYLOAD_SIZE + PAGE_SIZE;
+
+	for (len = need_spc; len > 0; len -= PAGE_SIZE) {
+		page = alloc_page(strp->sk->sk_allocation);
+		if (!page) {
+			tls_strp_flush_anchor_copy(strp);
+			return -ENOMEM;
+		}
+
+		skb_fill_page_desc(strp->anchor, shinfo->nr_frags++,
+				   page, 0, 0);
+	}
+
+	strp->copy_mode = 1;
+	strp->stm.offset = 0;
+
+	strp->anchor->len = 0;
+	strp->anchor->data_len = 0;
+	strp->anchor->truesize = round_up(need_spc, PAGE_SIZE);
+
+	tls_strp_read_copyin(strp);
+
+	return 0;
+}
+
+static void tls_strp_load_anchor_with_queue(struct tls_strparser *strp, int len)
+{
+	struct tcp_sock *tp = tcp_sk(strp->sk);
+	struct sk_buff *first;
+	u32 offset;
+
+	first = tcp_recv_skb(strp->sk, tp->copied_seq, &offset);
+	if (WARN_ON_ONCE(!first))
+		return;
+
+	/* Bestow the state onto the anchor */
+	strp->anchor->len = offset + len;
+	strp->anchor->data_len = offset + len;
+	strp->anchor->truesize = offset + len;
+
+	skb_shinfo(strp->anchor)->frag_list = first;
+
+	skb_copy_header(strp->anchor, first);
+	strp->anchor->destructor = NULL;
+
+	strp->stm.offset = offset;
+}
+
+void tls_strp_msg_load(struct tls_strparser *strp, bool force_refresh)
+{
+	struct strp_msg *rxm;
+	struct tls_msg *tlm;
+
+	DEBUG_NET_WARN_ON_ONCE(!strp->msg_ready);
+	DEBUG_NET_WARN_ON_ONCE(!strp->stm.full_len);
+
+	if (!strp->copy_mode && force_refresh) {
+		if (WARN_ON(tcp_inq(strp->sk) < strp->stm.full_len))
+			return;
+
+		tls_strp_load_anchor_with_queue(strp, strp->stm.full_len);
+	}
+
+	rxm = strp_msg(strp->anchor);
+	rxm->full_len	= strp->stm.full_len;
+	rxm->offset	= strp->stm.offset;
+	tlm = tls_msg(strp->anchor);
+	tlm->control	= strp->mark;
+}
+
+/* Called with lock held on lower socket */
+static int tls_strp_read_sock(struct tls_strparser *strp)
+{
+	int sz, inq;
+
+	inq = tcp_inq(strp->sk);
+	if (inq < 1)
+		return 0;
+
+	if (unlikely(strp->copy_mode))
+		return tls_strp_read_copyin(strp);
+
+	if (inq < strp->stm.full_len)
+		return tls_strp_read_short(strp);
+
+	if (!strp->stm.full_len) {
+		tls_strp_load_anchor_with_queue(strp, inq);
+
+		sz = tls_rx_msg_size(strp, strp->anchor);
+		if (sz < 0) {
+			tls_strp_abort_strp(strp, sz);
+			return sz;
+		}
+
+		strp->stm.full_len = sz;
+
+		if (!strp->stm.full_len || inq < strp->stm.full_len)
+			return tls_strp_read_short(strp);
+	}
+
+	strp->msg_ready = 1;
+	tls_rx_msg_ready(strp);
+
+	return 0;
+}
+
+void tls_strp_check_rcv(struct tls_strparser *strp)
+{
+	if (unlikely(strp->stopped) || strp->msg_ready)
+		return;
+
+	if (tls_strp_read_sock(strp) == -ENOMEM)
+		queue_work(tls_strp_wq, &strp->work);
+}
+
+/* Lower sock lock held */
+void tls_strp_data_ready(struct tls_strparser *strp)
+{
+	/* This check is needed to synchronize with do_tls_strp_work.
+	 * do_tls_strp_work acquires a process lock (lock_sock) whereas
+	 * the lock held here is bh_lock_sock. The two locks can be
+	 * held by different threads at the same time, but bh_lock_sock
+	 * allows a thread in BH context to safely check if the process
+	 * lock is held. In this case, if the lock is held, queue work.
+	 */
+	if (sock_owned_by_user_nocheck(strp->sk)) {
+		queue_work(tls_strp_wq, &strp->work);
+		return;
+	}
+
+	tls_strp_check_rcv(strp);
+}
+
+static void tls_strp_work(struct work_struct *w)
+{
+	struct tls_strparser *strp =
+		container_of(w, struct tls_strparser, work);
+
+	lock_sock(strp->sk);
+	tls_strp_check_rcv(strp);
+	release_sock(strp->sk);
+}
+
+void tls_strp_msg_done(struct tls_strparser *strp)
+{
+	WARN_ON(!strp->stm.full_len);
+
+	if (likely(!strp->copy_mode))
+		tcp_read_done(strp->sk, strp->stm.full_len);
+	else
+		tls_strp_flush_anchor_copy(strp);
+
+	strp->msg_ready = 0;
+	memset(&strp->stm, 0, sizeof(strp->stm));
+
+	tls_strp_check_rcv(strp);
+}
+
+void tls_strp_stop(struct tls_strparser *strp)
+{
+	strp->stopped = 1;
+}
+
+int tls_strp_init(struct tls_strparser *strp, struct sock *sk)
+{
+	memset(strp, 0, sizeof(*strp));
+
+	strp->sk = sk;
+
+	strp->anchor = alloc_skb(0, GFP_KERNEL);
+	if (!strp->anchor)
+		return -ENOMEM;
+
+	INIT_WORK(&strp->work, tls_strp_work);
+
+	return 0;
+}
+
+/* strp must already be stopped so that tls_strp_recv will no longer be called.
+ * Note that tls_strp_done is not called with the lower socket held.
+ */
+void tls_strp_done(struct tls_strparser *strp)
+{
+	WARN_ON(!strp->stopped);
+
+	cancel_work_sync(&strp->work);
+	tls_strp_anchor_free(strp);
+}
+
+int __init tls_strp_dev_init(void)
+{
+	tls_strp_wq = create_workqueue("tls-strp");
+	if (unlikely(!tls_strp_wq))
+		return -ENOMEM;
+
+	return 0;
+}
+
+void tls_strp_dev_exit(void)
+{
+	destroy_workqueue(tls_strp_wq);
+}