diff options
Diffstat (limited to '')
-rw-r--r-- | security/nss/lib/ssl/tls13echv.c | 167 |
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 --- /dev/null +++ b/security/nss/lib/ssl/tls13echv.c @@ -0,0 +1,167 @@ +/* -*- 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; +} |