From b51a7c95144ff5ccc0f79d19f4dd4f57b0b9a317 Mon Sep 17 00:00:00 2001
From: JustAnotherArchivist <JustAnotherArchivist@users.noreply.github.com>
Date: Wed, 3 May 2023 05:04:41 +0000
Subject: [PATCH] Fall back to response length when there is neither
 Content-Length nor Transfer-Encoding in an HTTP/1.1 response

---
 http-response-bodies.c | 58 +++++++++++++++++++++++++-----------------
 1 file changed, 34 insertions(+), 24 deletions(-)

diff --git a/http-response-bodies.c b/http-response-bodies.c
index 9c22ae5..898d040 100644
--- a/http-response-bodies.c
+++ b/http-response-bodies.c
@@ -217,31 +217,41 @@ checkstate:
 				} else {
 					m0 = memcasemem(bufp, eoh - bufp, "\ntransfer-encoding:", 19);
 					if (!m0 || m0 >= eoh) {
-						fprintf(stderr, "Error: Content-Length and Transfer-Encoding missing\n");
-						return 1;
-					}
-					DEBUG_PRINTF("Found Transfer-Encoding header at %p (offset %zu)\n", (void*)(m0 + 1), m0 + 1 - bufp);
-					m1 = memmem(m0 + 1, eoh - (m0 + 1), "\n", 1);
-					if (!m1 || m1 >= eoh - 1) {
-						fprintf(stderr, "Error: CRLF after Transfer-Encoding missing\n");
-						return 1;
-					}
-					m0 += 19;
-					if (*(m1 - 1) == '\r') --m1;
-					while (m0 < bufp + n && (*m0 == ' ' || *m0 == '\t')) ++m0;
-					if (memcmp(m0, "chunked", 7) != 0) {
-						fprintf(stderr, "Error: unsupported Transfer-Encoding\n");
-						return 1;
-					}
-					m0 += 7;
-					while (m0 < bufp + n && (*m0 == ' ' || *m0 == '\t')) ++m0;
-					if (m0 != m1) {
-						fprintf(stderr, "Error: unsupported Transfer-Encoding\n");
-						return 1;
-					}
-					DEBUG_PRINTF("Chunked transfer encoding\n");
+						DEBUG_PRINTF("No Content-Length or Transfer-Encoding, falling back to response length\n");
+						if (!have_response_length) {
+							fprintf(stderr, "Error: Content-Length and Transfer-Encoding missing and no response length from metadata line\n");
+							return 1;
+						}
+						if (bufp + response_length < eoh) {
+							fprintf(stderr, "Error: end of headers occurs after alleged response length\n");
+							return 1;
+						}
+						length = response_length - (eoh - bufp);
+						state = STATE_BODY;
+					} else {
+						DEBUG_PRINTF("Found Transfer-Encoding header at %p (offset %zu)\n", (void*)(m0 + 1), m0 + 1 - bufp);
+						m1 = memmem(m0 + 1, eoh - (m0 + 1), "\n", 1);
+						if (!m1 || m1 >= eoh - 1) {
+							fprintf(stderr, "Error: CRLF after Transfer-Encoding missing\n");
+							return 1;
+						}
+						m0 += 19;
+						if (*(m1 - 1) == '\r') --m1;
+						while (m0 < bufp + n && (*m0 == ' ' || *m0 == '\t')) ++m0;
+						if (memcmp(m0, "chunked", 7) != 0) {
+							fprintf(stderr, "Error: unsupported Transfer-Encoding\n");
+							return 1;
+						}
+						m0 += 7;
+						while (m0 < bufp + n && (*m0 == ' ' || *m0 == '\t')) ++m0;
+						if (m0 != m1) {
+							fprintf(stderr, "Error: unsupported Transfer-Encoding\n");
+							return 1;
+						}
+						DEBUG_PRINTF("Chunked transfer encoding\n");
 
-					state = STATE_CHUNK_LINE;
+						state = STATE_CHUNK_LINE;
+					}
 				}
 
 				if (html_fake_base) {