From 05e5dafe9a3fb2c07fc9bcb1e5c684ce2d7c4f33 Mon Sep 17 00:00:00 2001
From: Willy Tarreau <w@1wt.eu>
Date: Mon, 11 Dec 2017 15:17:36 +0100
Subject: [PATCH] MINOR: h2: store the demux padding length in the h2c struct

We'll try to process partial frames and for this we need to know the
padding length. The first step requires to extract it during the parsing
and store it in the demux context in the connection. Till now it was only
processed at once.
---
 src/mux_h2.c | 17 ++++++++++-------
 1 file changed, 10 insertions(+), 7 deletions(-)

diff --git a/src/mux_h2.c b/src/mux_h2.c
index a5f420e71..807fbec94 100644
--- a/src/mux_h2.c
+++ b/src/mux_h2.c
@@ -94,7 +94,8 @@ struct h2c {
 	int32_t dfl; /* demux frame length (if dsi >= 0) */
 	int8_t  dft; /* demux frame type   (if dsi >= 0) */
 	int8_t  dff; /* demux frame flags  (if dsi >= 0) */
-	/* 16 bit hole here */
+	uint8_t dpl; /* demux pad length (part of dfl), init to 0 */
+	/* 8 bit hole here */
 	int32_t last_sid; /* last processed stream ID for GOAWAY, <0 before preface */
 
 	/* states for the mux direction */
@@ -1760,6 +1761,7 @@ static void h2_process_demux(struct h2c *h2c)
 			h2c->dsi = hdr.sid;
 			h2c->dft = hdr.ft;
 			h2c->dff = hdr.ff;
+			h2c->dpl = 0;
 			h2c->st0 = H2_CS_FRAME_P;
 		}
 	}
@@ -1787,6 +1789,7 @@ static void h2_process_demux(struct h2c *h2c)
 			h2c->dsi = hdr.sid;
 			h2c->dft = hdr.ft;
 			h2c->dff = hdr.ff;
+			h2c->dpl = 0;
 			h2c->st0 = H2_CS_FRAME_P;
 			h2_skip_frame_hdr(h2c->dbuf);
 		}
@@ -2523,12 +2526,13 @@ static int h2_frt_decode_headers(struct h2s *h2s, struct buffer *buf, int count)
 	 * after data. padlen+data+padding are included in flen.
 	 */
 	if (h2c->dff & H2_F_HEADERS_PADDED) {
-		if (*hdrs >= flen) {
+		h2c->dpl = *hdrs;
+		if (h2c->dpl >= flen) {
 			/* RFC7540#6.2 : pad length = length of frame payload or greater */
 			h2c_error(h2c, H2_ERR_PROTOCOL_ERROR);
 			return 0;
 		}
-		flen -= *hdrs + 1;
+		flen -= h2c->dpl + 1;
 		hdrs += 1; // skip Pad Length
 	}
 
@@ -2638,7 +2642,6 @@ static int h2_frt_transfer_data(struct h2s *h2s, struct buffer *buf, int count)
 	struct h2c *h2c = h2s->h2c;
 	int block1, block2;
 	unsigned int flen = h2c->dfl;
-	unsigned int padlen = 0;
 	int offset = 0;
 
 	h2s->cs->flags &= ~CS_FL_RCV_MORE;
@@ -2650,13 +2653,13 @@ static int h2_frt_transfer_data(struct h2s *h2s, struct buffer *buf, int count)
 	 * after data. padlen+data+padding are included in flen.
 	 */
 	if (h2c->dff & H2_F_DATA_PADDED) {
-		padlen = *(uint8_t *)bi_ptr(h2c->dbuf);
-		if (padlen >= flen) {
+		h2c->dpl = *(uint8_t *)bi_ptr(h2c->dbuf);
+		if (h2c->dpl >= h2c->dfl) {
 			/* RFC7540#6.1 : pad length = length of frame payload or greater */
 			h2c_error(h2c, H2_ERR_PROTOCOL_ERROR);
 			return 0;
 		}
-		flen -= padlen + 1;
+		flen -= h2c->dpl + 1;
 		offset = 1; // skip Pad Length
 	}