Expose core metadata validation functions in public headers

2 files changed, 79 insertions, 4 deletions

diff --git a/src/core/surface/call.c b/src/core/surface/call.c
index a162d99193..2782c1a4dd 100644
--- a/src/core/surface/call.c
+++ b/src/core/surface/call.c
@@ -1,6 +1,6 @@
 /*
  *
- * Copyright 2015, Google Inc.
+ * Copyright 2015-2016, Google Inc.
  * All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
@@ -37,6 +37,7 @@
 #include <string.h>
 
 #include <grpc/compression.h>
+#include <grpc/grpc.h>
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
@@ -562,12 +563,16 @@ static int prepare_application_metadata(grpc_call *call, int count,
     GPR_ASSERT(sizeof(grpc_linked_mdelem) == sizeof(md->internal_data));
     l->md = grpc_mdelem_from_string_and_buffer(
         md->key, (const gpr_uint8 *)md->value, md->value_length);
-    if (!grpc_mdstr_is_legal_header(l->md->key)) {
+    if (!grpc_header_key_is_legal(grpc_mdstr_as_c_string(l->md->key),
+                                  GRPC_MDSTR_LENGTH(l->md->key))) {
       gpr_log(GPR_ERROR, "attempt to send invalid metadata key: %s",
               grpc_mdstr_as_c_string(l->md->key));
       return 0;
-    } else if (!grpc_mdstr_is_bin_suffixed(l->md->key) &&
-               !grpc_mdstr_is_legal_nonbin_header(l->md->value)) {
+    } else if (!grpc_is_binary_header(grpc_mdstr_as_c_string(l->md->key),
+                                      GRPC_MDSTR_LENGTH(l->md->key)) &&
+               !grpc_header_nonbin_value_is_legal(
+                   grpc_mdstr_as_c_string(l->md->value),
+                   GRPC_MDSTR_LENGTH(l->md->value))) {
       gpr_log(GPR_ERROR, "attempt to send invalid metadata value");
       return 0;
     }
diff --git a/src/core/surface/validate_metadata.c b/src/core/surface/validate_metadata.c
new file mode 100644
index 0000000000..21d29a6295
--- /dev/null
+++ b/src/core/surface/validate_metadata.c
@@ -0,0 +1,70 @@
+/*
+ *
+ * Copyright 2016, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ *
+ */
+
+#include <stdlib.h>
+#include <string.h>
+
+#include "grpc/support/port_platform.h"
+
+static int conforms_to(const char *s, size_t len, const gpr_uint8 *legal_bits) {
+  const char *p = s;
+  const char *e = s + len;
+  for (; p != e; p++) {
+    int idx = *p;
+    int byte = idx / 8;
+    int bit = idx % 8;
+    if ((legal_bits[byte] & (1 << bit)) == 0) return 0;
+  }
+  return 1;
+}
+
+int grpc_header_key_is_legal(const char *key, size_t length) {
+  static const gpr_uint8 legal_header_bits[256 / 8] = {
+      0x00, 0x00, 0x00, 0x00, 0x00, 0x20, 0xff, 0x03, 0x00, 0x00, 0x00,
+      0x80, 0xfe, 0xff, 0xff, 0x07, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+      0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+  return conforms_to(key, length, legal_header_bits);
+}
+
+int grpc_header_nonbin_value_is_legal(const char *value, size_t length) {
+  static const gpr_uint8 legal_header_bits[256 / 8] = {
+      0x00, 0x00, 0x00, 0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff,
+      0xff, 0xff, 0xff, 0xff, 0x7f, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
+      0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00};
+  return conforms_to(value, length, legal_header_bits);
+}
+
+int grpc_is_binary_header(const char *key, size_t length) {
+  if (length < 5) return 0;
+  return 0 == memcmp(key + length - 4, "-bin", 4);
+}