From: Eduard Bagdasaryan <eduard.bagdasaryan@measurement-factory.com>
Date: Sun, 23 Jun 2019 14:14:47 +0000 (+0000)
Subject: Fix handling of tiny invalid responses (#422)
X-Git-Tag: SQUID_5_0_1~78
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=26e3e64019d5d8adc3f16ed2a0547e828b4007f5;p=thirdparty%2Fsquid.git

Fix handling of tiny invalid responses (#422)

Squid converted any invalid response shorter than 4 bytes into an
invalid "HTTP/1.1 0 Init" response (with those received characters and a
CRLFCRLF suffix as a body). In some cases (e.g., with ICAP RESPMOD), the
resulting body was not sent to the client at all.

Now Squid handles such responses the same way it handles any non-HTTP/1
(and non-ICY) response, converting it into a valid HTTP/200 response
with an X-Transformed-From:HTTP/0.9 header and received bytes as
a message body.
---

diff --git a/src/HttpReply.cc b/src/HttpReply.cc
index e5e1c8f1bf..c63fccdf30 100644
--- a/src/HttpReply.cc
+++ b/src/HttpReply.cc
@@ -491,6 +491,7 @@ HttpReply::expectingBody(const HttpRequestMethod& req_method, int64_t& theSize)
         expectBody = false;
     else if (sline.status() == Http::scNotModified)
         expectBody = false;
+    // TODO: Consider assuming that gray-area 0xx responses have bodies, like 9xx responses.
     else if (sline.status() < Http::scOkay)
         expectBody = false;
     else
diff --git a/src/http/one/ResponseParser.cc b/src/http/one/ResponseParser.cc
index 4d09a03cc1..24f0248d5e 100644
--- a/src/http/one/ResponseParser.cc
+++ b/src/http/one/ResponseParser.cc
@@ -158,8 +158,13 @@ Http::One::ResponseParser::parseResponseFirstLine()
         debugs(74, DBG_DATA, "parse remaining buf={length=" << tok.remaining().length() << ", data='" << tok.remaining() << "'}");
         buf_ = tok.remaining(); // resume checkpoint
         return parseResponseStatusAndReason(tok, WspDelim);
-
-    } else if (buf_.length() > Http1magic.length() && buf_.length() > IcyMagic.length()) {
+    } else if (buf_.length() < Http1magic.length() && Http1magic.startsWith(buf_)) {
+        debugs(74, 7, Raw("valid HTTP/1 prefix", buf_.rawContent(), buf_.length()));
+        return 0;
+    } else if (buf_.length() < IcyMagic.length() && IcyMagic.startsWith(buf_)) {
+        debugs(74, 7, Raw("valid ICY prefix", buf_.rawContent(), buf_.length()));
+        return 0;
+    } else {
         debugs(74, 2, "unknown/missing prefix magic. Interpreting as HTTP/0.9");
         // found something that looks like an HTTP/0.9 response
         // Gateway/Transform it into HTTP/1.1
@@ -179,7 +184,9 @@ Http::One::ResponseParser::parseResponseFirstLine()
         return 1; // no more parsing
     }
 
-    return 0; // need more to parse anything.
+    // unreachable
+    assert(false);
+    return -1;
 }
 
 bool