Merge branch 'tls-fixes'

Jakub Kicinski says:

====================
net: tls: fix some issues with async encryption

valis was reporting a race on socket close so I sat down to try to fix it.
I used Sabrina's async crypto debug patch to test... and in the process
run into some of the same issues, and created very similar fixes :(
I didn't realize how many of those patches weren't applied. Once I found
Sabrina's code [1] it turned out to be so similar in fact that I added
her S-o-b's and Co-develop'eds in a semi-haphazard way.

With this series in place all expected tests pass with async crypto.
Sabrina had a few more fixes, but I'll leave those to her, things are
not crashing anymore.

[1] https://lore.kernel.org/netdev/cover.1694018970.git.sd@queasysnail.net/
====================

Signed-off-by: David S. Miller <davem@davemloft.net>

include/net/tls.h

@@ -97,9 +97,6 @@ struct tls_sw_context_tx {
 	struct tls_rec *open_rec;
 	struct list_head tx_list;
 	atomic_t encrypt_pending;
-	/* protect crypto_wait with encrypt_pending */
-	spinlock_t encrypt_compl_lock;
-	int async_notify;
 	u8 async_capable:1;
 
 #define BIT_TX_SCHEDULED	0
@@ -136,8 +133,6 @@ struct tls_sw_context_rx {
 	struct tls_strparser strp;
 
 	atomic_t decrypt_pending;
-	/* protect crypto_wait with decrypt_pending*/
-	spinlock_t decrypt_compl_lock;
 	struct sk_buff_head async_hold;
 	struct wait_queue_head wq;
 };

net/tls/tls_sw.c

@@ -63,6 +63,7 @@ struct tls_decrypt_ctx {
 	u8 iv[TLS_MAX_IV_SIZE];
 	u8 aad[TLS_MAX_AAD_SIZE];
 	u8 tail;
+	bool free_sgout;
 	struct scatterlist sg[];
 };
 
@@ -187,7 +188,6 @@ static void tls_decrypt_done(void *data, int err)
 	struct aead_request *aead_req = data;
 	struct crypto_aead *aead = crypto_aead_reqtfm(aead_req);
 	struct scatterlist *sgout = aead_req->dst;
-	struct scatterlist *sgin = aead_req->src;
 	struct tls_sw_context_rx *ctx;
 	struct tls_decrypt_ctx *dctx;
 	struct tls_context *tls_ctx;
@@ -196,6 +196,17 @@ static void tls_decrypt_done(void *data, int err)
 	struct sock *sk;
 	int aead_size;
 
+	/* If requests get too backlogged crypto API returns -EBUSY and calls
+	 * ->complete(-EINPROGRESS) immediately followed by ->complete(0)
+	 * to make waiting for backlog to flush with crypto_wait_req() easier.
+	 * First wait converts -EBUSY -> -EINPROGRESS, and the second one
+	 * -EINPROGRESS -> 0.
+	 * We have a single struct crypto_async_request per direction, this
+	 * scheme doesn't help us, so just ignore the first ->complete().
+	 */
+	if (err == -EINPROGRESS)
+		return;
+
 	aead_size = sizeof(*aead_req) + crypto_aead_reqsize(aead);
 	aead_size = ALIGN(aead_size, __alignof__(*dctx));
 	dctx = (void *)((u8 *)aead_req + aead_size);
@@ -213,7 +224,7 @@ static void tls_decrypt_done(void *data, int err)
 	}
 
 	/* Free the destination pages if skb was not decrypted inplace */
-	if (sgout != sgin) {
+	if (dctx->free_sgout) {
 		/* Skip the first S/G entry as it points to AAD */
 		for_each_sg(sg_next(sgout), sg, UINT_MAX, pages) {
 			if (!sg)
@@ -224,10 +235,17 @@ static void tls_decrypt_done(void *data, int err)
 
 	kfree(aead_req);
 
-	spin_lock_bh(&ctx->decrypt_compl_lock);
-	if (!atomic_dec_return(&ctx->decrypt_pending))
+	if (atomic_dec_and_test(&ctx->decrypt_pending))
 		complete(&ctx->async_wait.completion);
-	spin_unlock_bh(&ctx->decrypt_compl_lock);
+}
+
+static int tls_decrypt_async_wait(struct tls_sw_context_rx *ctx)
+{
+	if (!atomic_dec_and_test(&ctx->decrypt_pending))
+		crypto_wait_req(-EINPROGRESS, &ctx->async_wait);
+	atomic_inc(&ctx->decrypt_pending);
+
+	return ctx->async_wait.err;
 }
 
 static int tls_do_decryption(struct sock *sk,
@@ -253,6 +271,7 @@ static int tls_do_decryption(struct sock *sk,
 		aead_request_set_callback(aead_req,
 					  CRYPTO_TFM_REQ_MAY_BACKLOG,
 					  tls_decrypt_done, aead_req);
+		DEBUG_NET_WARN_ON_ONCE(atomic_read(&ctx->decrypt_pending) < 1);
 		atomic_inc(&ctx->decrypt_pending);
 	} else {
 		aead_request_set_callback(aead_req,
@@ -261,6 +280,10 @@ static int tls_do_decryption(struct sock *sk,
 	}
 
 	ret = crypto_aead_decrypt(aead_req);
+	if (ret == -EBUSY) {
+		ret = tls_decrypt_async_wait(ctx);
+		ret = ret ?: -EINPROGRESS;
+	}
 	if (ret == -EINPROGRESS) {
 		if (darg->async)
 			return 0;
@@ -439,9 +462,10 @@ static void tls_encrypt_done(void *data, int err)
 	struct tls_rec *rec = data;
 	struct scatterlist *sge;
 	struct sk_msg *msg_en;
-	bool ready = false;
 	struct sock *sk;
-	int pending;
+
+	if (err == -EINPROGRESS) /* see the comment in tls_decrypt_done() */
+		return;
 
 	msg_en = &rec->msg_encrypted;
 
@@ -476,23 +500,25 @@ static void tls_encrypt_done(void *data, int err)
 		/* If received record is at head of tx_list, schedule tx */
 		first_rec = list_first_entry(&ctx->tx_list,
 					     struct tls_rec, list);
-		if (rec == first_rec)
-			ready = true;
+		if (rec == first_rec) {
+			/* Schedule the transmission */
+			if (!test_and_set_bit(BIT_TX_SCHEDULED,
+					      &ctx->tx_bitmask))
+				schedule_delayed_work(&ctx->tx_work.work, 1);
+		}
 	}
 
-	spin_lock_bh(&ctx->encrypt_compl_lock);
-	pending = atomic_dec_return(&ctx->encrypt_pending);
-
-	if (!pending && ctx->async_notify)
+	if (atomic_dec_and_test(&ctx->encrypt_pending))
 		complete(&ctx->async_wait.completion);
-	spin_unlock_bh(&ctx->encrypt_compl_lock);
+}
 
-	if (!ready)
-		return;
+static int tls_encrypt_async_wait(struct tls_sw_context_tx *ctx)
+{
+	if (!atomic_dec_and_test(&ctx->encrypt_pending))
+		crypto_wait_req(-EINPROGRESS, &ctx->async_wait);
+	atomic_inc(&ctx->encrypt_pending);
 
-	/* Schedule the transmission */
-	if (!test_and_set_bit(BIT_TX_SCHEDULED, &ctx->tx_bitmask))
-		schedule_delayed_work(&ctx->tx_work.work, 1);
+	return ctx->async_wait.err;
 }
 
 static int tls_do_encryption(struct sock *sk,
@@ -541,9 +567,14 @@ static int tls_do_encryption(struct sock *sk,
 
 	/* Add the record in tx_list */
 	list_add_tail((struct list_head *)&rec->list, &ctx->tx_list);
+	DEBUG_NET_WARN_ON_ONCE(atomic_read(&ctx->encrypt_pending) < 1);
 	atomic_inc(&ctx->encrypt_pending);
 
 	rc = crypto_aead_encrypt(aead_req);
+	if (rc == -EBUSY) {
+		rc = tls_encrypt_async_wait(ctx);
+		rc = rc ?: -EINPROGRESS;
+	}
 	if (!rc || rc != -EINPROGRESS) {
 		atomic_dec(&ctx->encrypt_pending);
 		sge->offset -= prot->prepend_size;
@@ -984,7 +1015,6 @@ static int tls_sw_sendmsg_locked(struct sock *sk, struct msghdr *msg,
 	int num_zc = 0;
 	int orig_size;
 	int ret = 0;
-	int pending;
 
 	if (!eor && (msg->msg_flags & MSG_EOR))
 		return -EINVAL;
@@ -1163,24 +1193,12 @@ static int tls_sw_sendmsg_locked(struct sock *sk, struct msghdr *msg,
 	if (!num_async) {
 		goto send_end;
 	} else if (num_zc) {
-		/* Wait for pending encryptions to get completed */
-		spin_lock_bh(&ctx->encrypt_compl_lock);
-		ctx->async_notify = true;
-
-		pending = atomic_read(&ctx->encrypt_pending);
-		spin_unlock_bh(&ctx->encrypt_compl_lock);
-		if (pending)
-			crypto_wait_req(-EINPROGRESS, &ctx->async_wait);
-		else
-			reinit_completion(&ctx->async_wait.completion);
-
-		/* There can be no concurrent accesses, since we have no
-		 * pending encrypt operations
-		 */
-		WRITE_ONCE(ctx->async_notify, false);
+		int err;
 
-		if (ctx->async_wait.err) {
-			ret = ctx->async_wait.err;
+		/* Wait for pending encryptions to get completed */
+		err = tls_encrypt_async_wait(ctx);
+		if (err) {
+			ret = err;
 			copied = 0;
 		}
 	}
@@ -1229,7 +1247,6 @@ void tls_sw_splice_eof(struct socket *sock)
 	ssize_t copied = 0;
 	bool retrying = false;
 	int ret = 0;
-	int pending;
 
 	if (!ctx->open_rec)
 		return;
@@ -1264,22 +1281,7 @@ void tls_sw_splice_eof(struct socket *sock)
 	}
 
 	/* Wait for pending encryptions to get completed */
-	spin_lock_bh(&ctx->encrypt_compl_lock);
-	ctx->async_notify = true;
-
-	pending = atomic_read(&ctx->encrypt_pending);
-	spin_unlock_bh(&ctx->encrypt_compl_lock);
-	if (pending)
-		crypto_wait_req(-EINPROGRESS, &ctx->async_wait);
-	else
-		reinit_completion(&ctx->async_wait.completion);
-
-	/* There can be no concurrent accesses, since we have no pending
-	 * encrypt operations
-	 */
-	WRITE_ONCE(ctx->async_notify, false);
-
-	if (ctx->async_wait.err)
+	if (tls_encrypt_async_wait(ctx))
 		goto unlock;
 
 	/* Transmit if any encryptions have completed */
@@ -1581,6 +1583,7 @@ static int tls_decrypt_sg(struct sock *sk, struct iov_iter *out_iov,
 	} else if (out_sg) {
 		memcpy(sgout, out_sg, n_sgout * sizeof(*sgout));
 	}
+	dctx->free_sgout = !!pages;
 
 	/* Prepare and submit AEAD request */
 	err = tls_do_decryption(sk, sgin, sgout, dctx->iv,
@@ -2109,16 +2112,10 @@ int tls_sw_recvmsg(struct sock *sk,
 
 recv_end:
 	if (async) {
-		int ret, pending;
+		int ret;
 
 		/* Wait for all previously submitted records to be decrypted */
-		spin_lock_bh(&ctx->decrypt_compl_lock);
-		reinit_completion(&ctx->async_wait.completion);
-		pending = atomic_read(&ctx->decrypt_pending);
-		spin_unlock_bh(&ctx->decrypt_compl_lock);
-		ret = 0;
-		if (pending)
-			ret = crypto_wait_req(-EINPROGRESS, &ctx->async_wait);
+		ret = tls_decrypt_async_wait(ctx);
 		__skb_queue_purge(&ctx->async_hold);
 
 		if (ret) {
@@ -2135,7 +2132,6 @@ int tls_sw_recvmsg(struct sock *sk,
 		else
 			err = process_rx_list(ctx, msg, &control, 0,
 					      async_copy_bytes, is_peek);
-		decrypted += max(err, 0);
 	}
 
 	copied += decrypted;
@@ -2435,16 +2431,9 @@ void tls_sw_release_resources_tx(struct sock *sk)
 	struct tls_context *tls_ctx = tls_get_ctx(sk);
 	struct tls_sw_context_tx *ctx = tls_sw_ctx_tx(tls_ctx);
 	struct tls_rec *rec, *tmp;
-	int pending;
 
 	/* Wait for any pending async encryptions to complete */
-	spin_lock_bh(&ctx->encrypt_compl_lock);
-	ctx->async_notify = true;
-	pending = atomic_read(&ctx->encrypt_pending);
-	spin_unlock_bh(&ctx->encrypt_compl_lock);
-
-	if (pending)
-		crypto_wait_req(-EINPROGRESS, &ctx->async_wait);
+	tls_encrypt_async_wait(ctx);
 
 	tls_tx_records(sk, -1);
 
@@ -2607,7 +2596,7 @@ static struct tls_sw_context_tx *init_ctx_tx(struct tls_context *ctx, struct soc
 	}
 
 	crypto_init_wait(&sw_ctx_tx->async_wait);
-	spin_lock_init(&sw_ctx_tx->encrypt_compl_lock);
+	atomic_set(&sw_ctx_tx->encrypt_pending, 1);
 	INIT_LIST_HEAD(&sw_ctx_tx->tx_list);
 	INIT_DELAYED_WORK(&sw_ctx_tx->tx_work.work, tx_work_handler);
 	sw_ctx_tx->tx_work.sk = sk;
@@ -2628,7 +2617,7 @@ static struct tls_sw_context_rx *init_ctx_rx(struct tls_context *ctx)
 	}
 
 	crypto_init_wait(&sw_ctx_rx->async_wait);
-	spin_lock_init(&sw_ctx_rx->decrypt_compl_lock);
+	atomic_set(&sw_ctx_rx->decrypt_pending, 1);
 	init_waitqueue_head(&sw_ctx_rx->wq);
 	skb_queue_head_init(&sw_ctx_rx->rx_list);
 	skb_queue_head_init(&sw_ctx_rx->async_hold);

tools/testing/selftests/net/tls.c

@@ -1002,12 +1002,12 @@ TEST_F(tls, recv_partial)
 
 	memset(recv_mem, 0, sizeof(recv_mem));
 	EXPECT_EQ(send(self->fd, test_str, send_len, 0), send_len);
-	EXPECT_NE(recv(self->cfd, recv_mem, strlen(test_str_first),
-		       MSG_WAITALL), -1);
+	EXPECT_EQ(recv(self->cfd, recv_mem, strlen(test_str_first),
+		       MSG_WAITALL), strlen(test_str_first));
 	EXPECT_EQ(memcmp(test_str_first, recv_mem, strlen(test_str_first)), 0);
 	memset(recv_mem, 0, sizeof(recv_mem));
-	EXPECT_NE(recv(self->cfd, recv_mem, strlen(test_str_second),
-		       MSG_WAITALL), -1);
+	EXPECT_EQ(recv(self->cfd, recv_mem, strlen(test_str_second),
+		       MSG_WAITALL), strlen(test_str_second));
 	EXPECT_EQ(memcmp(test_str_second, recv_mem, strlen(test_str_second)),
 		  0);
 }