/src/nss/lib/ssl/tls13echv.c
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1 | | /* -*- Mode: C; tab-width: 8; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ |
2 | | /* This Source Code Form is subject to the terms of the Mozilla Public |
3 | | * License, v. 2.0. If a copy of the MPL was not distributed with this |
4 | | * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ |
5 | | |
6 | | /* Validation functions for ECH public names. */ |
7 | | |
8 | | #include "seccomon.h" |
9 | | |
10 | | /* Convert a single character `c` into a number `*d` with the given radix. |
11 | | * Fails if the character isn't valid for the radix. |
12 | | */ |
13 | | static SECStatus |
14 | | tls13_IpDigit(PRUint8 c, PRUint8 radix, PRUint8 *d) |
15 | 0 | { |
16 | 0 | PRUint8 v = 0xff; |
17 | 0 | if (c >= '0' && c <= '9') { |
18 | 0 | v = c - '0'; |
19 | 0 | } else if (radix > 10) { |
20 | 0 | if (c >= 'a' && c <= 'f') { |
21 | 0 | v = c - 'a'; |
22 | 0 | } else if (c >= 'A' && c <= 'F') { |
23 | 0 | v = c - 'A'; |
24 | 0 | } |
25 | 0 | } |
26 | 0 | if (v >= radix) { |
27 | 0 | return SECFailure; |
28 | 0 | } |
29 | 0 | *d = v; |
30 | 0 | return SECSuccess; |
31 | 0 | } |
32 | | |
33 | | /* This function takes the first couple of characters from `str`, starting at offset |
34 | | * `*i` and calculates a radix. If it starts with "0x" or "0X", then `*i` is moved up |
35 | | * by two and `*radix` is set to 16 (hexadecimal). If it starts with "0", then `*i` is |
36 | | * moved up by one and `*radix` is set to 8 (octal). Otherwise, `*i` is left alone and |
37 | | * `*radix` is set to 10 (decimal). |
38 | | * Fails if there are no characters remaining or the next character is '.', either at |
39 | | * the start or after "0x". |
40 | | */ |
41 | | static SECStatus |
42 | | tls13_IpRadix(const PRUint8 *str, unsigned int len, unsigned int *i, PRUint8 *radix) |
43 | 0 | { |
44 | 0 | if (*i == len || str[*i] == '.') { |
45 | 0 | return SECFailure; |
46 | 0 | } |
47 | 0 | if (str[*i] == '0') { |
48 | 0 | (*i)++; |
49 | 0 | if (*i < len && (str[*i] == 'x' || str[*i] == 'X')) { |
50 | 0 | (*i)++; |
51 | 0 | if (*i == len || str[*i] == '.') { |
52 | 0 | return SECFailure; |
53 | 0 | } |
54 | 0 | *radix = 16; |
55 | 0 | } else { |
56 | 0 | *radix = 8; |
57 | 0 | } |
58 | 0 | } else { |
59 | 0 | *radix = 10; |
60 | 0 | } |
61 | 0 | return SECSuccess; |
62 | 0 | } |
63 | | |
64 | | /* Take a number from `str` from offset `*i` and put the value in `*v`. |
65 | | * This calculates the radix and returns a value between 0 and 2^32-1, using all |
66 | | * of the digits up to the end of the string (determined by `len`) or a period ('.'). |
67 | | * Fails if there is no value, if there a non-digit characters, or if the value is |
68 | | * too large. |
69 | | */ |
70 | | static SECStatus |
71 | | tls13_IpValue(const PRUint8 *str, unsigned int len, unsigned int *i, PRUint32 *v) |
72 | 0 | { |
73 | 0 | PRUint8 radix; |
74 | 0 | SECStatus rv = tls13_IpRadix(str, len, i, &radix); |
75 | 0 | if (rv != SECSuccess) { |
76 | 0 | return SECFailure; |
77 | 0 | } |
78 | 0 | PRUint64 part = 0; |
79 | 0 | while (*i < len) { |
80 | 0 | PRUint8 d; |
81 | 0 | rv = tls13_IpDigit(str[*i], radix, &d); |
82 | 0 | if (rv != SECSuccess) { |
83 | 0 | if (str[*i] != '.') { |
84 | 0 | return SECFailure; |
85 | 0 | } |
86 | 0 | break; |
87 | 0 | } |
88 | 0 | part = part * radix + d; |
89 | 0 | if (part > PR_UINT32_MAX) { |
90 | 0 | return SECFailure; |
91 | 0 | } |
92 | 0 | (*i)++; |
93 | 0 | } |
94 | 0 | *v = part; |
95 | 0 | return SECSuccess; |
96 | 0 | } |
97 | | |
98 | | /* Returns true if `end` is true and `v` is within the `limit`. Used to validate the |
99 | | * last part of an IPv4 address, which can hold larger numbers if there are fewer then |
100 | | * four parts. */ |
101 | | static PRBool |
102 | | tls13_IpLastPart(PRBool end, PRUint32 v, PRUint32 limit) |
103 | 0 | { |
104 | 0 | if (!end) { |
105 | 0 | return PR_FALSE; |
106 | 0 | } |
107 | 0 | return v <= limit; |
108 | 0 | } |
109 | | |
110 | | /* Returns true if `str` contains an IPv4 address. */ |
111 | | PRBool |
112 | | tls13_IsIp(const PRUint8 *str, unsigned int len) |
113 | 0 | { |
114 | 0 | PRUint32 part; |
115 | 0 | PRUint32 v; |
116 | 0 | unsigned int i = 0; |
117 | 0 | for (part = 0; part < 4; part++) { |
118 | 0 | SECStatus rv = tls13_IpValue(str, len, &i, &v); |
119 | 0 | if (rv != SECSuccess) { |
120 | 0 | return PR_FALSE; |
121 | 0 | } |
122 | 0 | if (v > 0xff || i == len) { |
123 | 0 | return tls13_IpLastPart(i == len, v, PR_UINT32_MAX >> (part * 8)); |
124 | 0 | } |
125 | 0 | PORT_Assert(str[i] == '.'); |
126 | 0 | i++; |
127 | 0 | } |
128 | | |
129 | 0 | return tls13_IpLastPart(i == len, v, 0xff); |
130 | 0 | } |
131 | | |
132 | | static PRBool |
133 | | tls13_IsLD(PRUint8 c) |
134 | 0 | { |
135 | 0 | return (c >= 'a' && c <= 'z') || |
136 | 0 | (c >= 'A' && c <= 'Z') || |
137 | 0 | (c >= '0' && c <= '9') || |
138 | 0 | c == '_'; /* not in spec, but in the world; bug 1136616 */ |
139 | 0 | } |
140 | | |
141 | | /* Is this a valid dotted LDH string (that is, an A-Label domain name)? |
142 | | * This does not tolerate a trailing '.', where the DNS generally does. |
143 | | */ |
144 | | PRBool |
145 | | tls13_IsLDH(const PRUint8 *str, unsigned int len) |
146 | 0 | { |
147 | 0 | unsigned int i = 0; |
148 | 0 | while (i < len && tls13_IsLD(str[i])) { |
149 | 0 | unsigned int labelEnd = PR_MIN(len, i + 63); |
150 | 0 | i++; |
151 | 0 | while (i < labelEnd && (tls13_IsLD(str[i]) || str[i] == '-')) { |
152 | 0 | i++; |
153 | 0 | } |
154 | 0 | if (str[i - 1] == '-') { |
155 | | /* labels cannot end in a hyphen */ |
156 | 0 | return PR_FALSE; |
157 | 0 | } |
158 | 0 | if (i == len) { |
159 | 0 | return PR_TRUE; |
160 | 0 | } |
161 | 0 | if (str[i] != '.') { |
162 | 0 | return PR_FALSE; |
163 | 0 | } |
164 | 0 | i++; |
165 | 0 | } |
166 | 0 | return PR_FALSE; |
167 | 0 | } |