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use same canonicalization of JSON as for contract hashes when doing normal JSON hashing

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This commit is contained in:
Christian Grothoff 2023-05-02 17:29:41 +02:00
parent 41cb79c685
commit ffd4057c61
No known key found for this signature in database
GPG Key ID: 939E6BE1E29FC3CC
2 changed files with 169 additions and 168 deletions
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168
src/json/json.c
View File

@ -61,170 +61,6 @@ contains_real (const json_t *json)
}
/**
* 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
*/
static size_t
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;
}
/**
* Dump the @a json to a string and hash it.
*
@ -262,7 +98,7 @@ dump_and_hash (const json_t *json,
GNUNET_break (0);
return GNUNET_SYSERR;
}
len = rfc8785encode (&wire_enc);
len = TALER_rfc8785encode (&wire_enc);
if (NULL == salt)
{
GNUNET_CRYPTO_hash (wire_enc,
@ -1031,7 +867,7 @@ TALER_JSON_canonicalize (const json_t *input)
GNUNET_break (0);
return NULL;
}
rfc8785encode (&wire_enc);
TALER_rfc8785encode (&wire_enc);
return wire_enc;
}

169
src/util/util.c
View File

@ -25,6 +25,7 @@
#include "taler_util.h"
#include "taler_attributes.h"
#include <gnunet/gnunet_json_lib.h>
#include <unistr.h>
const char *
@ -204,6 +205,170 @@ 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);
}