commit e814d33900992e034a8c3ddec2c65463c5206090
author Michael Brown <mcb30@ipxe.org> Thu Jan 13 14:53:36 2022 +0000
committer Michael Brown <mcb30@ipxe.org> Thu Jan 13 15:03:22 2022 +0000
tree dae1062d5eb6642c724d3204d442e67c9b20efa4
parent f4f9adf618cd85d330a896e1f721f3aa78d2409d

[uri] Allow for relative URIs that include colons within the path

RFC3986 allows for colons to appear within the path component of a
relative URI, but iPXE will currently parse such URIs incorrectly by
interpreting the text before the colon as the URI scheme.

Fix by checking for valid characters when identifying the URI scheme.
Deliberately deviate from the RFC3986 definition of valid characters
by accepting "_" (which was incorrectly used in the iPXE-specific
"ib_srp" URI scheme and so must be accepted for compatibility with
existing deployments), and by omitting the code to check for
characters that are not used in any URI scheme supported by iPXE.

Reported-by: Ignat Korchagin <ignat@cloudflare.com>
Signed-off-by: Michael Brown <mcb30@ipxe.org>

src/core/uri.c

diff --git a/src/core/uri.c b/src/core/uri.c
index a0f79e9..b82472e 100644
--- a/src/core/uri.c
+++ b/src/core/uri.c
@@ -334,8 +334,15 @@
 		uri->efragment = tmp;
 	}
 
-	/* Identify absolute/relative URI */
-	if ( ( tmp = strchr ( raw, ':' ) ) ) {
+	/* Identify absolute URIs */
+	epath = raw;
+	for ( tmp = raw ; ; tmp++ ) {
+		/* Possible scheme character (for our URI schemes) */
+		if ( isalpha ( *tmp ) || ( *tmp == '-' ) || ( *tmp == '_' ) )
+			continue;
+		/* Invalid scheme character or NUL: is a relative URI */
+		if ( *tmp != ':' )
+			break;
 		/* Absolute URI: identify hierarchical/opaque */
 		uri->scheme = raw;
 		*(tmp++) = '\0';
@@ -347,9 +354,7 @@
 			uri->opaque = tmp;
 			epath = NULL;
 		}
-	} else {
-		/* Relative URI */
-		epath = raw;
+		break;
 	}
 
 	/* If we don't have a path (i.e. we have an absolute URI with

src/tests/uri_test.c

diff --git a/src/tests/uri_test.c b/src/tests/uri_test.c
index 929ab36..338f479 100644
--- a/src/tests/uri_test.c
+++ b/src/tests/uri_test.c
@@ -657,6 +657,15 @@
 	},
 };
 
+/** Relative URI with colons in path */
+static struct uri_test uri_colons = {
+	"/boot/52:54:00:12:34:56/boot.ipxe",
+	{
+		.path = "/boot/52:54:00:12:34:56/boot.ipxe",
+		.epath = "/boot/52:54:00:12:34:56/boot.ipxe",
+	},
+};
+
 /** URI with port number */
 static struct uri_port_test uri_explicit_port = {
 	"http://192.168.0.1:8080/boot.php",
@@ -957,6 +966,7 @@
 	uri_parse_format_dup_ok ( &uri_file_relative );
 	uri_parse_format_dup_ok ( &uri_file_absolute );
 	uri_parse_format_dup_ok ( &uri_file_volume );
+	uri_parse_format_dup_ok ( &uri_colons );
 
 	/** URI port number tests */
 	uri_port_ok ( &uri_explicit_port );