From: Patrick Griffis <pgriffis@igalia.com>
Date: Mon, 8 Jul 2024 12:33:15 -0500
Subject: headers: Strictly don't allow NUL bytes

In the past (2015) this was allowed for some problematic sites. However
Chromium also does not allow NUL bytes in either header names or values
these days. So this should no longer be a problem.

Bug: https://gitlab.gnome.org/GNOME/libsoup/-/issues/377
Bug-CVE: https://security-tracker.debian.org/tracker/CVE-2024-52530
Bug-Debian: libsoup3 equivalent of https://bugs.debian.org/1088812
---
 libsoup/soup-headers.c      | 15 +++--------
 tests/header-parsing-test.c | 62 ++++++++++++++++++++-------------------------
 2 files changed, 32 insertions(+), 45 deletions(-)

diff --git a/libsoup/soup-headers.c b/libsoup/soup-headers.c
index 2edeece..a1de8c4 100644
--- a/libsoup/soup-headers.c
+++ b/libsoup/soup-headers.c
@@ -51,13 +51,14 @@ soup_headers_parse (const char *str, int len, SoupMessageHeaders *dest)
 	 * ignorable trailing whitespace.
 	 */
 
+	/* No '\0's are allowed */
+	if (memchr (str, '\0', len))
+		return FALSE;
+
 	/* Skip over the Request-Line / Status-Line */
 	headers_start = memchr (str, '\n', len);
 	if (!headers_start)
 		return FALSE;
-	/* No '\0's in the Request-Line / Status-Line */
-	if (memchr (str, '\0', headers_start - str))
-		return FALSE;
 
 	/* We work on a copy of the headers, which we can write '\0's
 	 * into, so that we don't have to individually g_strndup and
@@ -69,14 +70,6 @@ soup_headers_parse (const char *str, int len, SoupMessageHeaders *dest)
 	headers_copy[copy_len] = '\0';
 	value_end = headers_copy;
 
-	/* There shouldn't be any '\0's in the headers already, but
-	 * this is the web we're talking about.
-	 */
-	while ((p = memchr (headers_copy, '\0', copy_len))) {
-		memmove (p, p + 1, copy_len - (p - headers_copy));
-		copy_len--;
-	}
-
 	while (*(value_end + 1)) {
 		name = value_end + 1;
 		name_end = strchr (name, ':');
diff --git a/tests/header-parsing-test.c b/tests/header-parsing-test.c
index 7f324b7..4bf981e 100644
--- a/tests/header-parsing-test.c
+++ b/tests/header-parsing-test.c
@@ -358,24 +358,6 @@ static struct RequestTest {
 	  }
 	},
 
-	{ "NUL in header name", "760832",
-	  "GET / HTTP/1.1\r\nHost\x00: example.com\r\n", 36,
-	  SOUP_STATUS_OK,
-	  "GET", "/", SOUP_HTTP_1_1,
-	  { { "Host", "example.com" },
-	    { NULL }
-	  }
-	},
-
-	{ "NUL in header value", "760832",
-	  "GET / HTTP/1.1\r\nHost: example\x00" "com\r\n", 35,
-	  SOUP_STATUS_OK,
-	  "GET", "/", SOUP_HTTP_1_1,
-	  { { "Host", "examplecom" },
-	    { NULL }
-	  }
-	},
-
 	/************************/
 	/*** INVALID REQUESTS ***/
 	/************************/
@@ -448,6 +430,21 @@ static struct RequestTest {
 	  SOUP_STATUS_EXPECTATION_FAILED,
 	  NULL, NULL, -1,
 	  { { NULL } }
+	},
+
+	// https://gitlab.gnome.org/GNOME/libsoup/-/issues/377
+	{ "NUL in header name", NULL,
+	  "GET / HTTP/1.1\r\nHost\x00: example.com\r\n", 36,
+	  SOUP_STATUS_BAD_REQUEST,
+	  NULL, NULL, -1,
+	  { { NULL } }
+	},
+
+	{ "NUL in header value", NULL,
+	  "HTTP/1.1 200 OK\r\nFoo: b\x00" "ar\r\n", 28,
+	  SOUP_STATUS_BAD_REQUEST,
+           NULL, NULL, -1,
+	  { { NULL } }
 	}
 };
 static const int num_reqtests = G_N_ELEMENTS (reqtests);
@@ -620,22 +617,6 @@ static struct ResponseTest {
 	    { NULL } }
 	},
 
-	{ "NUL in header name", "760832",
-	  "HTTP/1.1 200 OK\r\nF\x00oo: bar\r\n", 28,
-	  SOUP_HTTP_1_1, SOUP_STATUS_OK, "OK",
-	  { { "Foo", "bar" },
-	    { NULL }
-	  }
-	},
-
-	{ "NUL in header value", "760832",
-	  "HTTP/1.1 200 OK\r\nFoo: b\x00" "ar\r\n", 28,
-	  SOUP_HTTP_1_1, SOUP_STATUS_OK, "OK",
-	  { { "Foo", "bar" },
-	    { NULL }
-	  }
-	},
-
 	/********************************/
 	/*** VALID CONTINUE RESPONSES ***/
 	/********************************/
@@ -768,6 +749,19 @@ static struct ResponseTest {
 	  { { NULL }
 	  }
 	},
+
+	// https://gitlab.gnome.org/GNOME/libsoup/-/issues/377
+	{ "NUL in header name", NULL,
+	  "HTTP/1.1 200 OK\r\nF\x00oo: bar\r\n", 28,
+	  -1, 0, NULL,
+	  { { NULL } }
+	},
+
+	{ "NUL in header value", "760832",
+	  "HTTP/1.1 200 OK\r\nFoo: b\x00" "ar\r\n", 28,
+	  -1, 0, NULL,
+	  { { NULL } }
+	},
 };
 static const int num_resptests = G_N_ELEMENTS (resptests);