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author | Christian Grothoff <christian@grothoff.org> | 2023-05-02 17:29:41 +0200 |
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committer | Christian Grothoff <christian@grothoff.org> | 2023-05-02 17:29:41 +0200 |
commit | ffd4057c61a1c507e348b76d1df10641c7ed64b1 (patch) | |
tree | 96754a5de2d3468f2ad361771d4127e9979b3f5c /src/util | |
parent | 41cb79c685b25bcf2c3e566f25c386c89442cbeb (diff) | |
download | exchange-ffd4057c61a1c507e348b76d1df10641c7ed64b1.tar.xz |
use same canonicalization of JSON as for contract hashes when doing normal JSON hashing
Diffstat (limited to 'src/util')
-rw-r--r-- | src/util/util.c | 169 |
1 files changed, 167 insertions, 2 deletions
diff --git a/src/util/util.c b/src/util/util.c index 96d791912..7cd4b0c35 100644 --- a/src/util/util.c +++ b/src/util/util.c @@ -25,6 +25,7 @@ #include "taler_util.h" #include "taler_attributes.h" #include <gnunet/gnunet_json_lib.h> +#include <unistr.h> const char * @@ -205,6 +206,170 @@ TALER_denom_fee_check_currency ( /** + * Dump character in the low range into @a buf + * following RFC 8785. + * + * @param[in,out] buf buffer to modify + * @param val value to dump + */ +static void +lowdump (struct GNUNET_Buffer *buf, + unsigned char val) +{ + char scratch[7]; + + switch (val) + { + case 0x8: + GNUNET_buffer_write (buf, + "\\b", + 2); + break; + case 0x9: + GNUNET_buffer_write (buf, + "\\t", + 2); + break; + case 0xA: + GNUNET_buffer_write (buf, + "\\n", + 2); + break; + case 0xC: + GNUNET_buffer_write (buf, + "\\f", + 2); + break; + case 0xD: + GNUNET_buffer_write (buf, + "\\r", + 2); + break; + default: + GNUNET_snprintf (scratch, + sizeof (scratch), + "\\u%04x", + (unsigned int) val); + GNUNET_buffer_write (buf, + scratch, + 6); + break; + } +} + + +/** + * Re-encode string at @a inp to match RFC 8785 (section 3.2.2.2). + * + * @param[in,out] inp pointer to string to re-encode + * @return number of bytes in resulting @a inp + */ +size_t +TALER_rfc8785encode (char **inp) +{ + struct GNUNET_Buffer buf = { 0 }; + size_t left = strlen (*inp) + 1; + size_t olen; + char *in = *inp; + const char *pos = in; + + GNUNET_buffer_prealloc (&buf, + left + 40); + buf.warn_grow = 0; /* disable, + 40 is just a wild guess */ + while (1) + { + int mbl = u8_mblen ((unsigned char *) pos, + left); + unsigned char val; + + if (0 == mbl) + break; + val = (unsigned char) *pos; + if ( (1 == mbl) && + (val <= 0x1F) ) + { + /* Should not happen, as input is produced by + * JSON stringification */ + GNUNET_break (0); + lowdump (&buf, + val); + } + else if ( (1 == mbl) && ('\\' == *pos) ) + { + switch (*(pos + 1)) + { + case '\\': + mbl = 2; + GNUNET_buffer_write (&buf, + pos, + mbl); + break; + case 'u': + { + unsigned int num; + uint32_t n32; + unsigned char res[8]; + size_t rlen; + + GNUNET_assert ( (1 == + sscanf (pos + 2, + "%4x", + &num)) || + (1 == + sscanf (pos + 2, + "%4X", + &num)) ); + mbl = 6; + n32 = (uint32_t) num; + rlen = sizeof (res); + u32_to_u8 (&n32, + 1, + res, + &rlen); + if ( (1 == rlen) && + (res[0] <= 0x1F) ) + { + lowdump (&buf, + res[0]); + } + else + { + GNUNET_buffer_write (&buf, + (const char *) res, + rlen); + } + } + break; + default: + mbl = 2; + GNUNET_buffer_write (&buf, + pos, + mbl); + break; + } + } + else + { + GNUNET_buffer_write (&buf, + pos, + mbl); + } + left -= mbl; + pos += mbl; + } + + /* 0-terminate buffer */ + GNUNET_buffer_write (&buf, + "", + 1); + GNUNET_free (in); + *inp = GNUNET_buffer_reap (&buf, + &olen); + return olen; +} + + +/** * Hash normalized @a j JSON object or array and * store the result in @a hc. * @@ -221,11 +386,11 @@ TALER_json_hash (const json_t *j, cstr = json_dumps (j, JSON_COMPACT | JSON_SORT_KEYS); GNUNET_assert (NULL != cstr); - clen = strlen (cstr); + clen = TALER_rfc8785encode (&cstr); GNUNET_CRYPTO_hash (cstr, clen, hc); - free (cstr); + GNUNET_free (cstr); } |