diff options
author | Dmitry Belyavskiy <beldmit@gmail.com> | 2019-08-21 18:31:43 +0300 |
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committer | Dmitry Belyavskiy <beldmit@gmail.com> | 2020-08-26 14:04:11 +0300 |
commit | 4650f2b5908947a318ff28b0970b7d451fac32ae (patch) | |
tree | db62450878357a1f8bca13e6ac73c856cd5ab8ea | |
parent | eb800ef5533947b8583d42a8f767f6ff385d2c17 (diff) |
Punycode decoding implementation
Reviewed-by: Richard Levitte <levitte@openssl.org>
(Merged from https://github.com/openssl/openssl/pull/9654)
-rw-r--r-- | crypto/build.info | 1 | ||||
-rw-r--r-- | crypto/punycode.c | 338 | ||||
-rw-r--r-- | include/crypto/punycode.h | 24 |
3 files changed, 363 insertions, 0 deletions
diff --git a/crypto/build.info b/crypto/build.info index 9e10145d3c..814d8dcab7 100644 --- a/crypto/build.info +++ b/crypto/build.info @@ -78,6 +78,7 @@ SOURCE[../libcrypto]=$UTIL_COMMON \ mem.c mem_sec.c \ cversion.c info.c cpt_err.c ebcdic.c uid.c o_time.c o_dir.c \ o_fopen.c getenv.c o_init.c init.c trace.c provider.c \ + punycode.c \ $UPLINKSRC SOURCE[../providers/libfips.a]=$UTIL_COMMON SOURCE[../providers/liblegacy.a]=$UTIL_COMMON diff --git a/crypto/punycode.c b/crypto/punycode.c new file mode 100644 index 0000000000..2607d6157a --- /dev/null +++ b/crypto/punycode.c @@ -0,0 +1,338 @@ +/* + * Copyright 2019 The OpenSSL Project Authors. All Rights Reserved. + * + * Licensed under the Apache License 2.0 (the "License"). You may not use + * this file except in compliance with the License. You can obtain a copy + * in the file LICENSE in the source distribution or at + * https://www.openssl.org/source/license.html + */ + +#include <stddef.h> +#include <string.h> +#include <stdio.h> +#include <openssl/e_os2.h> +#include "crypto/punycode.h" + +static const unsigned int base = 36; +static const unsigned int tmin = 1; +static const unsigned int tmax = 26; +static const unsigned int skew = 38; +static const unsigned int damp = 700; +static const unsigned int initial_bias = 72; +static const unsigned int initial_n = 0x80; +static const unsigned int maxint = 0xFFFFFFFF; +static const char delimiter = '-'; + +#define LABEL_BUF_SIZE 512 + +/*- + * Pseudocode: + * + * function adapt(delta,numpoints,firsttime): + * if firsttime then let delta = delta div damp + * else let delta = delta div 2 + * let delta = delta + (delta div numpoints) + * let k = 0 + * while delta > ((base - tmin) * tmax) div 2 do begin + * let delta = delta div (base - tmin) + * let k = k + base + * end + * return k + (((base - tmin + 1) * delta) div (delta + skew)) + */ + +static int adapt(unsigned int delta, unsigned int numpoints, + unsigned int firsttime) +{ + unsigned int k = 0; + + delta = (firsttime) ? delta / damp : delta / 2; + delta = delta + delta / numpoints; + + while (delta > ((base - tmin) * tmax) / 2) { + delta = delta / (base - tmin); + k = k + base; + } + + return k + (((base - tmin + 1) * delta) / (delta + skew)); +} + +static ossl_inline int is_basic(unsigned int a) +{ + return (a < 0x80) ? 1 : 0; +} + +/*- + * code points digit-values + * ------------ ---------------------- + * 41..5A (A-Z) = 0 to 25, respectively + * 61..7A (a-z) = 0 to 25, respectively + * 30..39 (0-9) = 26 to 35, respectively + */ +static ossl_inline int digit_decoded(const unsigned char a) +{ + if (a >= 0x41 && a <= 0x5A) + return a - 0x41; + + if (a >= 0x61 && a <= 0x7A) + return a - 0x61; + + if (a >= 0x30 && a <= 0x39) + return a - 0x30 + 26; + + return -1; +} + +/*- + * Pseudocode: + * + * function ossl_punycode_decode + * let n = initial_n + * let i = 0 + * let bias = initial_bias + * let output = an empty string indexed from 0 + * consume all code points before the last delimiter (if there is one) + * and copy them to output, fail on any non-basic code point + * if more than zero code points were consumed then consume one more + * (which will be the last delimiter) + * while the input is not exhausted do begin + * let oldi = i + * let w = 1 + * for k = base to infinity in steps of base do begin + * consume a code point, or fail if there was none to consume + * let digit = the code point's digit-value, fail if it has none + * let i = i + digit * w, fail on overflow + * let t = tmin if k <= bias {+ tmin}, or + * tmax if k >= bias + tmax, or k - bias otherwise + * if digit < t then break + * let w = w * (base - t), fail on overflow + * end + * let bias = adapt(i - oldi, length(output) + 1, test oldi is 0?) + * let n = n + i div (length(output) + 1), fail on overflow + * let i = i mod (length(output) + 1) + * {if n is a basic code point then fail} + * insert n into output at position i + * increment i + * end + */ + +int ossl_punycode_decode(const char *pEncoded, const size_t enc_len, + unsigned int *pDecoded, unsigned int *pout_length) +{ + unsigned int n = initial_n; + unsigned int i = 0; + unsigned int bias = initial_bias; + size_t processed_in = 0, written_out = 0; + unsigned int max_out = *pout_length; + + unsigned int basic_count = 0; + unsigned int loop; + + for (loop = 0; loop < enc_len; loop++) { + if (pEncoded[loop] == delimiter) + basic_count = loop; + } + + if (basic_count > 0) { + if (basic_count > max_out) + return 0; + + for (loop = 0; loop < basic_count; loop++) { + if (is_basic(pEncoded[loop]) == 0) + return 0; + + pDecoded[loop] = pEncoded[loop]; + written_out++; + } + processed_in = basic_count + 1; + } + + for (loop = processed_in; loop < enc_len;) { + unsigned int oldi = i; + unsigned int w = 1; + unsigned int k, t; + int digit; + + for (k = base;; k += base) { + if (loop >= enc_len) + return 0; + + digit = digit_decoded(pEncoded[loop]); + loop++; + + if (digit < 0) + return 0; + if ((unsigned int)digit > (maxint - i) / w) + return 0; + + i = i + digit * w; + t = (k <= bias) ? tmin : (k >= bias + tmax) ? tmax : k - bias; + + if ((unsigned int)digit < t) + break; + + if (w > maxint / (base - t)) + return 0; + w = w * (base - t); + } + + bias = adapt(i - oldi, written_out + 1, (oldi == 0)); + if (i / (written_out + 1) > maxint - n) + return 0; + n = n + i / (written_out + 1); + i %= (written_out + 1); + + if (written_out > max_out) + return 0; + + memmove(pDecoded + i + 1, pDecoded + i, + (written_out - i) * sizeof *pDecoded); + pDecoded[i] = n; + i++; + written_out++; + } + + *pout_length = written_out; + return 1; +} + +/* + * Encode a code point using UTF-8 + * return number of bytes on success, 0 on failure + * (also produces U+FFFD, which uses 3 bytes on failure) + */ +static int codepoint2utf8(unsigned char *out, unsigned long utf) +{ + if (utf <= 0x7F) { + /* Plain ASCII */ + out[0] = (unsigned char)utf; + out[1] = 0; + return 1; + } else if (utf <= 0x07FF) { + /* 2-byte unicode */ + out[0] = (unsigned char)(((utf >> 6) & 0x1F) | 0xC0); + out[1] = (unsigned char)(((utf >> 0) & 0x3F) | 0x80); + out[2] = 0; + return 2; + } else if (utf <= 0xFFFF) { + /* 3-byte unicode */ + out[0] = (unsigned char)(((utf >> 12) & 0x0F) | 0xE0); + out[1] = (unsigned char)(((utf >> 6) & 0x3F) | 0x80); + out[2] = (unsigned char)(((utf >> 0) & 0x3F) | 0x80); + out[3] = 0; + return 3; + } else if (utf <= 0x10FFFF) { + /* 4-byte unicode */ + out[0] = (unsigned char)(((utf >> 18) & 0x07) | 0xF0); + out[1] = (unsigned char)(((utf >> 12) & 0x3F) | 0x80); + out[2] = (unsigned char)(((utf >> 6) & 0x3F) | 0x80); + out[3] = (unsigned char)(((utf >> 0) & 0x3F) | 0x80); + out[4] = 0; + return 4; + } else { + /* error - use replacement character */ + out[0] = (unsigned char)0xEF; + out[1] = (unsigned char)0xBF; + out[2] = (unsigned char)0xBD; + out[3] = 0; + return 0; + } +} + +/*- + * Return values: + * 1 - ok, *outlen contains valid buf length + * 0 - ok but buf was too short, *outlen contains valid buf length + * -1 - bad string passed + */ + +int ossl_a2ulabel(const char *in, char *out, size_t *outlen) +{ + /*- + * Domain name has some parts consisting of ASCII chars joined with dot. + * If a part is shorter than 5 chars, it becomes U-label as is. + * If it does not start with xn--, it becomes U-label as is. + * Otherwise we try to decode it. + */ + char *outptr = out; + const char *inptr = in; + size_t size = 0; + int result = 1; + + unsigned int buf[LABEL_BUF_SIZE]; /* It's a hostname */ + if (out == NULL) + result = 0; + + while (1) { + char *tmpptr = strchr(inptr, '.'); + size_t delta = (tmpptr) ? (size_t)(tmpptr - inptr) : strlen(inptr); + + if (strncmp(inptr, "xn--", 4) != 0) { + size += delta + 1; + + if (size >= *outlen - 1) + result = 0; + + if (result > 0) { + memcpy(outptr, inptr, delta + 1); + outptr += delta + 1; + } + } else { + unsigned int bufsize = LABEL_BUF_SIZE; + unsigned int i; + + if (ossl_punycode_decode(inptr + 4, delta - 4, buf, &bufsize) <= 0) + return -1; + + for (i = 0; i < bufsize; i++) { + unsigned char seed[6]; + size_t utfsize = codepoint2utf8(seed, buf[i]); + if (utfsize == 0) + return -1; + + size += utfsize; + if (size >= *outlen - 1) + result = 0; + + if (result > 0) { + memcpy(outptr, seed, utfsize); + outptr += utfsize; + } + } + + if (tmpptr != NULL) { + *outptr = '.'; + outptr++; + size++; + if (size >= *outlen - 1) + result = 0; + } + } + + if (tmpptr == NULL) + break; + + inptr = tmpptr + 1; + } + + return result; +} + +/*- + * a MUST be A-label + * u MUST be U-label + * Returns 0 if compared values are equal + * 1 if not + * -1 in case of errors + */ + +int ossl_a2ucompare(const char *a, const char *u) +{ + char a_ulabel[LABEL_BUF_SIZE]; + size_t a_size = sizeof(a_ulabel); + + if (ossl_a2ulabel(a, a_ulabel, &a_size) <= 0) { + return -1; + } + + return (strcmp(a_ulabel, u) == 0) ? 0 : 1; +} diff --git a/include/crypto/punycode.h b/include/crypto/punycode.h new file mode 100644 index 0000000000..ec97c17cab --- /dev/null +++ b/include/crypto/punycode.h @@ -0,0 +1,24 @@ +/* + * Copyright 2019 The OpenSSL Project Authors. All Rights Reserved. + * + * Licensed under the Apache License 2.0 (the "License"). You may not use + * this file except in compliance with the License. You can obtain a copy + * in the file LICENSE in the source distribution or at + * https://www.openssl.org/source/license.html + */ + +#ifndef OSSL_CRYPTO_PUNYCODE_H +# define OSSL_CRYPTO_PUNYCODE_H + + +int ossl_punycode_decode ( + const char *pEncoded, + const size_t enc_len, + unsigned int *pDecoded, + unsigned int *pout_length +); + +int ossl_a2ulabel(const char *in, char *out, size_t *outlen); + +int ossl_a2ucompare(const char *a, const char *u); +#endif |