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-rw-r--r--security/nss/lib/ssl/tls13echv.c167
1 files changed, 167 insertions, 0 deletions
diff --git a/security/nss/lib/ssl/tls13echv.c b/security/nss/lib/ssl/tls13echv.c
new file mode 100644
index 0000000000..ae9792a910
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+++ b/security/nss/lib/ssl/tls13echv.c
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+/* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+/* Validation functions for ECH public names. */
+
+#include "seccomon.h"
+
+/* Convert a single character `c` into a number `*d` with the given radix.
+ * Fails if the character isn't valid for the radix.
+ */
+static SECStatus
+tls13_IpDigit(PRUint8 c, PRUint8 radix, PRUint8 *d)
+{
+ PRUint8 v = 0xff;
+ if (c >= '0' && c <= '9') {
+ v = c - '0';
+ } else if (radix > 10) {
+ if (c >= 'a' && c <= 'f') {
+ v = c - 'a';
+ } else if (c >= 'A' && c <= 'F') {
+ v = c - 'A';
+ }
+ }
+ if (v >= radix) {
+ return SECFailure;
+ }
+ *d = v;
+ return SECSuccess;
+}
+
+/* This function takes the first couple of characters from `str`, starting at offset
+ * `*i` and calculates a radix. If it starts with "0x" or "0X", then `*i` is moved up
+ * by two and `*radix` is set to 16 (hexadecimal). If it starts with "0", then `*i` is
+ * moved up by one and `*radix` is set to 8 (octal). Otherwise, `*i` is left alone and
+ * `*radix` is set to 10 (decimal).
+ * Fails if there are no characters remaining or the next character is '.', either at
+ * the start or after "0x".
+ */
+static SECStatus
+tls13_IpRadix(const PRUint8 *str, unsigned int len, unsigned int *i, PRUint8 *radix)
+{
+ if (*i == len || str[*i] == '.') {
+ return SECFailure;
+ }
+ if (str[*i] == '0') {
+ (*i)++;
+ if (*i < len && (str[*i] == 'x' || str[*i] == 'X')) {
+ (*i)++;
+ if (*i == len || str[*i] == '.') {
+ return SECFailure;
+ }
+ *radix = 16;
+ } else {
+ *radix = 8;
+ }
+ } else {
+ *radix = 10;
+ }
+ return SECSuccess;
+}
+
+/* Take a number from `str` from offset `*i` and put the value in `*v`.
+ * This calculates the radix and returns a value between 0 and 2^32-1, using all
+ * of the digits up to the end of the string (determined by `len`) or a period ('.').
+ * Fails if there is no value, if there a non-digit characters, or if the value is
+ * too large.
+ */
+static SECStatus
+tls13_IpValue(const PRUint8 *str, unsigned int len, unsigned int *i, PRUint32 *v)
+{
+ PRUint8 radix;
+ SECStatus rv = tls13_IpRadix(str, len, i, &radix);
+ if (rv != SECSuccess) {
+ return SECFailure;
+ }
+ PRUint64 part = 0;
+ while (*i < len) {
+ PRUint8 d;
+ rv = tls13_IpDigit(str[*i], radix, &d);
+ if (rv != SECSuccess) {
+ if (str[*i] != '.') {
+ return SECFailure;
+ }
+ break;
+ }
+ part = part * radix + d;
+ if (part > PR_UINT32_MAX) {
+ return SECFailure;
+ }
+ (*i)++;
+ }
+ *v = part;
+ return SECSuccess;
+}
+
+/* Returns true if `end` is true and `v` is within the `limit`. Used to validate the
+ * last part of an IPv4 address, which can hold larger numbers if there are fewer then
+ * four parts. */
+static PRBool
+tls13_IpLastPart(PRBool end, PRUint32 v, PRUint32 limit)
+{
+ if (!end) {
+ return PR_FALSE;
+ }
+ return v <= limit;
+}
+
+/* Returns true if `str` contains an IPv4 address. */
+PRBool
+tls13_IsIp(const PRUint8 *str, unsigned int len)
+{
+ PRUint32 part;
+ PRUint32 v;
+ unsigned int i = 0;
+ for (part = 0; part < 4; part++) {
+ SECStatus rv = tls13_IpValue(str, len, &i, &v);
+ if (rv != SECSuccess) {
+ return PR_FALSE;
+ }
+ if (v > 0xff || i == len) {
+ return tls13_IpLastPart(i == len, v, PR_UINT32_MAX >> (part * 8));
+ }
+ PORT_Assert(str[i] == '.');
+ i++;
+ }
+
+ return tls13_IpLastPart(i == len, v, 0xff);
+}
+
+static PRBool
+tls13_IsLD(PRUint8 c)
+{
+ return (c >= 'a' && c <= 'z') ||
+ (c >= 'A' && c <= 'Z') ||
+ (c >= '0' && c <= '9') ||
+ c == '_'; /* not in spec, but in the world; bug 1136616 */
+}
+
+/* Is this a valid dotted LDH string (that is, an A-Label domain name)?
+ * This does not tolerate a trailing '.', where the DNS generally does.
+ */
+PRBool
+tls13_IsLDH(const PRUint8 *str, unsigned int len)
+{
+ unsigned int i = 0;
+ while (i < len && tls13_IsLD(str[i])) {
+ unsigned int labelEnd = PR_MIN(len, i + 63);
+ i++;
+ while (i < labelEnd && (tls13_IsLD(str[i]) || str[i] == '-')) {
+ i++;
+ }
+ if (str[i - 1] == '-') {
+ /* labels cannot end in a hyphen */
+ return PR_FALSE;
+ }
+ if (i == len) {
+ return PR_TRUE;
+ }
+ if (str[i] != '.') {
+ return PR_FALSE;
+ }
+ i++;
+ }
+ return PR_FALSE;
+}