[PATCH net-next v5 10/10] selftests: tls: Cover the empty-record cap in splice

[Chuck Lever <cel@kernel.org>]

tls_sw_splice_read() stops after TLS_RX_NODATA_LIMIT consecutive
empty data records and reports EAGAIN with the next record still
queued. No zero_len_splice variant reaches the cap: the raw_rec
fixtures carry empty records at sequence numbers 0 to 2 only.

Add a variant that sends sixteen empty records ahead of a payload
record. The empty records differ only in sequence number and AEAD
tag, so a table of tags and a sender that fills in the header and
nonce stand in for sixteen raw_rec fixtures. The first splice
reports EAGAIN at the cap, and the second splices the payload.

Signed-off-by: Chuck Lever <cel@kernel.org>
---
 tools/testing/selftests/net/tls.c | 116 ++++++++++++++++++++++++++++++++------
 1 file changed, 100 insertions(+), 16 deletions(-)

diff --git a/tools/testing/selftests/net/tls.c b/tools/testing/selftests/net/tls.c
index 57edf6e6640f..38443675bc2f 100644
--- a/tools/testing/selftests/net/tls.c
+++ b/tools/testing/selftests/net/tls.c
@@ -2549,6 +2549,61 @@ static const struct raw_rec id2_data_l0 = {
 	},
 };
 
+/* TLS 1.2, AES_CCM, data, seqno:16, plaintext: 'Hello world' */
+static const struct raw_rec id16_data_l11 = {
+	.plain_len = 11,
+	.plain_data = {
+		0x48, 0x65, 0x6c, 0x6c, 0x6f, 0x20, 0x77, 0x6f,
+		0x72, 0x6c, 0x64,
+	},
+	.cipher_len = 40,
+	.cipher_data = {
+		0x17, 0x03, 0x03, 0x00, 0x23, 0x00, 0x00, 0x00,
+		0x00, 0x00, 0x00, 0x00, 0x10, 0xd3, 0x50, 0x90,
+		0xe1, 0x2a, 0x77, 0xc9, 0x38, 0x95, 0xef, 0xa4,
+		0x6f, 0x5e, 0xb6, 0x52, 0x05, 0x4b, 0x01, 0x44,
+		0x06, 0xc2, 0x51, 0x3f, 0x5e, 0xa5, 0x3e, 0x65,
+	},
+};
+
+/* TLS 1.2, AES_CCM, data, seqno:0-15, plaintext: '' -- the AEAD tag
+ * of each; the header and explicit nonce are built at send time
+ */
+static const unsigned char nodata_tags[16][16] = {
+	{ 0xc5, 0x37, 0x90, 0x70, 0x45, 0x89, 0xfb, 0x5c,
+	  0xc7, 0x89, 0x03, 0x68, 0x80, 0xd3, 0xd8, 0xcc, },
+	{ 0xce, 0xfc, 0x86, 0xc8, 0xf0, 0x55, 0xf9, 0x47,
+	  0x3f, 0x74, 0xdc, 0xc9, 0xbf, 0xfe, 0x5b, 0xb1, },
+	{ 0xc3, 0xca, 0x26, 0x22, 0xe4, 0x25, 0xfb, 0x5f,
+	  0x6d, 0xbf, 0x83, 0x30, 0x48, 0x69, 0x1a, 0x47, },
+	{ 0x4d, 0xfc, 0xe2, 0xc3, 0xfe, 0x11, 0x80, 0x85,
+	  0x94, 0x53, 0x79, 0x1d, 0x31, 0x14, 0x39, 0xec, },
+	{ 0x1e, 0x63, 0xa1, 0xfa, 0xef, 0xf1, 0x9e, 0x5c,
+	  0xee, 0x39, 0xcf, 0x41, 0x27, 0x36, 0xf5, 0x69, },
+	{ 0xa3, 0x49, 0x72, 0x01, 0x1a, 0xff, 0x1f, 0x71,
+	  0x51, 0x57, 0x80, 0xd2, 0x81, 0xee, 0xef, 0x75, },
+	{ 0x95, 0x92, 0x72, 0xda, 0x7a, 0x4e, 0x68, 0x91,
+	  0x02, 0x09, 0xfc, 0xe8, 0x2b, 0x3a, 0x54, 0x05, },
+	{ 0x41, 0x00, 0x73, 0xcf, 0xd3, 0xb3, 0xa7, 0x19,
+	  0x7d, 0x0f, 0x6d, 0x9d, 0xf6, 0x57, 0xee, 0xdd, },
+	{ 0xb5, 0x24, 0x17, 0x2d, 0xac, 0xcf, 0x5f, 0xac,
+	  0x2d, 0x24, 0xf2, 0x8c, 0xaf, 0xf3, 0xd7, 0x78, },
+	{ 0xf8, 0x23, 0xde, 0x09, 0x08, 0x7c, 0x75, 0x7c,
+	  0x23, 0x3a, 0xb6, 0x46, 0xc2, 0xfc, 0xac, 0xdb, },
+	{ 0x72, 0x01, 0x24, 0x35, 0x9f, 0x13, 0x92, 0xb2,
+	  0x93, 0xd9, 0xb4, 0x2e, 0xfc, 0xfc, 0x95, 0xa7, },
+	{ 0x2f, 0x0f, 0x94, 0xcf, 0x1a, 0x0f, 0x1a, 0xf1,
+	  0xe2, 0x6a, 0x97, 0x21, 0x12, 0x5f, 0x24, 0x39, },
+	{ 0xb4, 0xb9, 0xe1, 0x0a, 0x9c, 0x28, 0xbb, 0xf6,
+	  0xd9, 0xd7, 0x39, 0xf6, 0xfa, 0xcd, 0x47, 0xd6, },
+	{ 0xe8, 0xb9, 0x01, 0x90, 0x2e, 0x72, 0xa1, 0xd5,
+	  0x13, 0xdc, 0x28, 0xa7, 0x91, 0x04, 0x9b, 0xcb, },
+	{ 0x73, 0x67, 0x17, 0x6e, 0x50, 0xee, 0x28, 0x3b,
+	  0x6e, 0x2b, 0x32, 0xdd, 0xa1, 0x55, 0x97, 0x7a, },
+	{ 0xaf, 0xd4, 0xed, 0x91, 0xc3, 0x91, 0x21, 0x55,
+	  0xd8, 0xef, 0x23, 0xbe, 0xbf, 0x7b, 0xf2, 0x36, },
+};
+
 static void zero_len_sock_pair(struct __test_metadata *_metadata,
 			       int *fd, int *cfd, bool *notls)
 {
@@ -2585,6 +2640,21 @@ zero_len_send_recs(struct __test_metadata *_metadata, int fd,
 	return payload;
 }
 
+/* Send @count empty data records with sequence numbers 0 to @count - 1 */
+static void
+zero_len_send_nodata(struct __test_metadata *_metadata, int fd,
+		     unsigned int count)
+{
+	unsigned char rec[29] = { 0x17, 0x03, 0x03, 0x00, 0x18, };
+	unsigned int seq;
+
+	for (seq = 0; seq < count; seq++) {
+		rec[12] = seq;
+		memcpy(rec + 13, nodata_tags[seq], 16);
+		EXPECT_EQ(send(fd, rec, sizeof(rec), 0), sizeof(rec));
+	}
+}
+
 FIXTURE(zero_len)
 {
 	int fd, cfd;
@@ -2785,6 +2855,7 @@ FIXTURE(zero_len_splice)
 
 FIXTURE_VARIANT(zero_len_splice)
 {
+	unsigned int nodata;
 	const struct raw_rec *recs[4];
 	ssize_t splice_ret;
 };
@@ -2813,6 +2884,14 @@ FIXTURE_VARIANT_ADD(zero_len_splice, 0data_0ctrl)
 	.splice_ret = -EINVAL,
 };
 
+/* TLS_RX_NODATA_LIMIT empty records ahead of the payload */
+FIXTURE_VARIANT_ADD(zero_len_splice, 0data_x16_data)
+{
+	.nodata = 16,
+	.recs = { &id16_data_l11, },
+	.splice_ret = -EAGAIN,
+};
+
 FIXTURE_SETUP(zero_len_splice)
 {
 	zero_len_sock_pair(_metadata, &self->fd, &self->cfd, &self->notls);
@@ -2827,7 +2906,8 @@ FIXTURE_TEARDOWN(zero_len_splice)
 /* Splicing must skip a run of empty data records to reach the payload
  * behind it, since a zero-byte splice reads as EOF. Splice reports
  * EAGAIN for a run with no payload behind it, and EINVAL for a control
- * record behind the run.
+ * record behind the run. A run at the cap reports EAGAIN with the
+ * payload left for the next splice.
  */
 static void
 zero_len_do_splice(struct __test_metadata *_metadata,
@@ -2843,29 +2923,33 @@ zero_len_do_splice(struct __test_metadata *_metadata,
 
 	ASSERT_GE(pipe(p), 0);
 
+	zero_len_send_nodata(_metadata, self->fd, variant->nodata);
 	payload = zero_len_send_recs(_metadata, self->fd, variant->recs);
 
+	ret = splice(self->cfd, NULL, p[1], NULL, sizeof(buf), splice_flags);
 	if (variant->splice_ret < 0) {
-		ret = splice(self->cfd, NULL, p[1], NULL, sizeof(buf),
-			     splice_flags);
 		EXPECT_EQ(ret, -1);
 		EXPECT_EQ(errno, -variant->splice_ret);
-	} else {
-		/* ASSERT so a zero return stops the test here; the read
-		 * below would block until the harness timeout.
-		 */
-		ASSERT_EQ(splice(self->cfd, NULL, p[1], NULL, sizeof(buf),
-				 splice_flags), variant->splice_ret);
-		ret = read(p[0], buf, sizeof(buf));
-		EXPECT_EQ(ret, variant->splice_ret);
-		if (ret == variant->splice_ret)
-			EXPECT_EQ(memcmp(buf, payload->plain_data,
-					 variant->splice_ret), 0);
+		if (!payload)
+			goto out;
 
-		/* The empty records were consumed, not left queued */
-		EXPECT_EQ(poll(&pfd, 1, 0), 0);
+		ret = splice(self->cfd, NULL, p[1], NULL, sizeof(buf),
+			     splice_flags);
 	}
 
+	/* ASSERT so a zero return stops the test here; the read
+	 * below would block until the harness timeout.
+	 */
+	ASSERT_EQ(ret, payload->plain_len);
+	ret = read(p[0], buf, sizeof(buf));
+	EXPECT_EQ(ret, payload->plain_len);
+	if (ret == payload->plain_len)
+		EXPECT_EQ(memcmp(buf, payload->plain_data, ret), 0);
+
+	/* The empty records were consumed, not left queued */
+	EXPECT_EQ(poll(&pfd, 1, 0), 0);
+
+out:
 	close(p[0]);
 	close(p[1]);
 }

-- 
2.55.0