diff options
author | Christian Grothoff <christian@grothoff.org> | 2021-08-02 19:38:23 +0200 |
---|---|---|
committer | Christian Grothoff <christian@grothoff.org> | 2021-08-02 19:38:23 +0200 |
commit | c4ae15c1dbecc65b99e42e6c355952e576cfafe0 (patch) | |
tree | ec465fc048591b51bac9a1254746308014ca8795 /src | |
parent | 2e6b8e10de123b446ee77f714c0108dce15cd83e (diff) | |
download | exchange-c4ae15c1dbecc65b99e42e6c355952e576cfafe0.tar.xz |
-strengthen payto validation logic
Diffstat (limited to 'src')
-rw-r--r-- | src/include/taler_json_lib.h | 13 | ||||
-rw-r--r-- | src/include/taler_util.h | 13 | ||||
-rw-r--r-- | src/json/json_wire.c | 426 | ||||
-rw-r--r-- | src/util/payto.c | 398 |
4 files changed, 450 insertions, 400 deletions
diff --git a/src/include/taler_json_lib.h b/src/include/taler_json_lib.h index ea621cea6..bc21957e8 100644 --- a/src/include/taler_json_lib.h +++ b/src/include/taler_json_lib.h @@ -523,19 +523,6 @@ TALER_JSON_exchange_wire_signature_check ( /** - * Validate payto:// account URL (only account information, - * wire subject and amount are ignored). - * - * @param payto_uri URL to parse - * @return #GNUNET_YES if @a payto_uri is a valid payto://iban URI - * #GNUNET_NO if @a payto_uri is a payto URI of an unsupported type (but may be valid) - * #GNUNET_SYSERR if the account incorrect or this is not a payto://-URI at all - */ -enum GNUNET_GenericReturnValue -TALER_JSON_validate_payto (const char *payto_uri); - - -/** * Create a signed wire statement for the given account. * * @param payto_uri account specification diff --git a/src/include/taler_util.h b/src/include/taler_util.h index ad2f46a45..33c126cbc 100644 --- a/src/include/taler_util.h +++ b/src/include/taler_util.h @@ -313,6 +313,7 @@ TALER_payto_get_method (const char *payto_uri); char * TALER_xtalerbank_account_from_payto (const char *payto); + /** * Extract the subject value from the URI parameters. * @@ -323,6 +324,18 @@ TALER_xtalerbank_account_from_payto (const char *payto); char * TALER_payto_get_subject (const char *payto_uri); + +/** + * Check that a payto:// URI is well-formed. + * + * @param payto_uri the URL to check + * @return NULL on success, otherwise an error + * message to be freed by the caller! + */ +char * +TALER_payto_validate (const char *payto_uri); + + /** * Possible values for a binary filter. */ diff --git a/src/json/json_wire.c b/src/json/json_wire.c index a49e7a54a..3d7e8a81b 100644 --- a/src/json/json_wire.c +++ b/src/json/json_wire.c @@ -24,378 +24,6 @@ #include "taler_json_lib.h" -/* Taken from GNU gettext */ - -/** - * Entry in the country table. - */ -struct CountryTableEntry -{ - /** - * 2-Character international country code. - */ - const char *code; - - /** - * Long English name of the country. - */ - const char *english; -}; - - -/* Keep the following table in sync with gettext. - WARNING: the entries should stay sorted according to the code */ -/** - * List of country codes. - */ -static const struct CountryTableEntry country_table[] = { - { "AE", "U.A.E." }, - { "AF", "Afghanistan" }, - { "AL", "Albania" }, - { "AM", "Armenia" }, - { "AN", "Netherlands Antilles" }, - { "AR", "Argentina" }, - { "AT", "Austria" }, - { "AU", "Australia" }, - { "AZ", "Azerbaijan" }, - { "BA", "Bosnia and Herzegovina" }, - { "BD", "Bangladesh" }, - { "BE", "Belgium" }, - { "BG", "Bulgaria" }, - { "BH", "Bahrain" }, - { "BN", "Brunei Darussalam" }, - { "BO", "Bolivia" }, - { "BR", "Brazil" }, - { "BT", "Bhutan" }, - { "BY", "Belarus" }, - { "BZ", "Belize" }, - { "CA", "Canada" }, - { "CG", "Congo" }, - { "CH", "Switzerland" }, - { "CI", "Cote d'Ivoire" }, - { "CL", "Chile" }, - { "CM", "Cameroon" }, - { "CN", "People's Republic of China" }, - { "CO", "Colombia" }, - { "CR", "Costa Rica" }, - { "CS", "Serbia and Montenegro" }, - { "CZ", "Czech Republic" }, - { "DE", "Germany" }, - { "DK", "Denmark" }, - { "DO", "Dominican Republic" }, - { "DZ", "Algeria" }, - { "EC", "Ecuador" }, - { "EE", "Estonia" }, - { "EG", "Egypt" }, - { "ER", "Eritrea" }, - { "ES", "Spain" }, - { "ET", "Ethiopia" }, - { "FI", "Finland" }, - { "FO", "Faroe Islands" }, - { "FR", "France" }, - { "GB", "United Kingdom" }, - { "GD", "Caribbean" }, - { "GE", "Georgia" }, - { "GL", "Greenland" }, - { "GR", "Greece" }, - { "GT", "Guatemala" }, - { "HK", "Hong Kong" }, - { "HK", "Hong Kong S.A.R." }, - { "HN", "Honduras" }, - { "HR", "Croatia" }, - { "HT", "Haiti" }, - { "HU", "Hungary" }, - { "ID", "Indonesia" }, - { "IE", "Ireland" }, - { "IL", "Israel" }, - { "IN", "India" }, - { "IQ", "Iraq" }, - { "IR", "Iran" }, - { "IS", "Iceland" }, - { "IT", "Italy" }, - { "JM", "Jamaica" }, - { "JO", "Jordan" }, - { "JP", "Japan" }, - { "KE", "Kenya" }, - { "KG", "Kyrgyzstan" }, - { "KH", "Cambodia" }, - { "KR", "South Korea" }, - { "KW", "Kuwait" }, - { "KZ", "Kazakhstan" }, - { "LA", "Laos" }, - { "LB", "Lebanon" }, - { "LI", "Liechtenstein" }, - { "LK", "Sri Lanka" }, - { "LT", "Lithuania" }, - { "LU", "Luxembourg" }, - { "LV", "Latvia" }, - { "LY", "Libya" }, - { "MA", "Morocco" }, - { "MC", "Principality of Monaco" }, - { "MD", "Moldava" }, - { "MD", "Moldova" }, - { "ME", "Montenegro" }, - { "MK", "Former Yugoslav Republic of Macedonia" }, - { "ML", "Mali" }, - { "MM", "Myanmar" }, - { "MN", "Mongolia" }, - { "MO", "Macau S.A.R." }, - { "MT", "Malta" }, - { "MV", "Maldives" }, - { "MX", "Mexico" }, - { "MY", "Malaysia" }, - { "NG", "Nigeria" }, - { "NI", "Nicaragua" }, - { "NL", "Netherlands" }, - { "NO", "Norway" }, - { "NP", "Nepal" }, - { "NZ", "New Zealand" }, - { "OM", "Oman" }, - { "PA", "Panama" }, - { "PE", "Peru" }, - { "PH", "Philippines" }, - { "PK", "Islamic Republic of Pakistan" }, - { "PL", "Poland" }, - { "PR", "Puerto Rico" }, - { "PT", "Portugal" }, - { "PY", "Paraguay" }, - { "QA", "Qatar" }, - { "RE", "Reunion" }, - { "RO", "Romania" }, - { "RS", "Serbia" }, - { "RU", "Russia" }, - { "RW", "Rwanda" }, - { "SA", "Saudi Arabia" }, - { "SE", "Sweden" }, - { "SG", "Singapore" }, - { "SI", "Slovenia" }, - { "SK", "Slovak" }, - { "SN", "Senegal" }, - { "SO", "Somalia" }, - { "SR", "Suriname" }, - { "SV", "El Salvador" }, - { "SY", "Syria" }, - { "TH", "Thailand" }, - { "TJ", "Tajikistan" }, - { "TM", "Turkmenistan" }, - { "TN", "Tunisia" }, - { "TR", "Turkey" }, - { "TT", "Trinidad and Tobago" }, - { "TW", "Taiwan" }, - { "TZ", "Tanzania" }, - { "UA", "Ukraine" }, - { "US", "United States" }, - { "UY", "Uruguay" }, - { "VA", "Vatican" }, - { "VE", "Venezuela" }, - { "VN", "Viet Nam" }, - { "YE", "Yemen" }, - { "ZA", "South Africa" }, - { "ZW", "Zimbabwe" } -}; - - -/** - * Country code comparator function, for binary search with bsearch(). - * - * @param ptr1 pointer to a `struct table_entry` - * @param ptr2 pointer to a `struct table_entry` - * @return result of memcmp()'ing the 2-digit country codes of the entries - */ -static int -cmp_country_code (const void *ptr1, - const void *ptr2) -{ - const struct CountryTableEntry *cc1 = ptr1; - const struct CountryTableEntry *cc2 = ptr2; - - return memcmp (cc1->code, - cc2->code, - 2); -} - - -/** - * Validates given IBAN according to the European Banking Standards. See: - * http://www.europeanpaymentscouncil.eu/documents/ECBS%20IBAN%20standard%20EBS204_V3.2.pdf - * - * @param iban the IBAN number to validate - * @return #GNUNET_YES if correctly formatted; #GNUNET_NO if not - */ -static enum GNUNET_GenericReturnValue -validate_iban (const char *iban) -{ - char cc[2]; - char ibancpy[35]; - struct CountryTableEntry cc_entry; - unsigned int len; - char *nbuf; - unsigned long long dividend; - unsigned long long remainder; - unsigned int i; - unsigned int j; - - len = strlen (iban); - if (len > 34) - { - GNUNET_log (GNUNET_ERROR_TYPE_INFO, - "IBAN number too long to be valid\n"); - return GNUNET_NO; - } - memcpy (cc, iban, 2); - memcpy (ibancpy, iban + 4, len - 4); - memcpy (ibancpy + len - 4, iban, 4); - ibancpy[len] = '\0'; - cc_entry.code = cc; - cc_entry.english = NULL; - if (NULL == - bsearch (&cc_entry, - country_table, - sizeof (country_table) / sizeof (struct CountryTableEntry), - sizeof (struct CountryTableEntry), - &cmp_country_code)) - { - GNUNET_log (GNUNET_ERROR_TYPE_INFO, - "Country code `%c%c' not supported\n", - cc[0], - cc[1]); - return GNUNET_NO; - } - nbuf = GNUNET_malloc ((len * 2) + 1); - for (i = 0, j = 0; i < len; i++) - { - if (isalpha ((unsigned char) ibancpy[i])) - { - if (2 != snprintf (&nbuf[j], - 3, - "%2u", - (ibancpy[i] - 'A' + 10))) - { - GNUNET_free (nbuf); - return GNUNET_NO; - } - j += 2; - continue; - } - nbuf[j] = ibancpy[i]; - j++; - } - for (j = 0; '\0' != nbuf[j]; j++) - { - if (! isdigit ( (unsigned char) nbuf[j])) - { - GNUNET_log (GNUNET_ERROR_TYPE_WARNING, - "IBAN `%s' didn't convert to numeric format\n", - iban); - return GNUNET_NO; - } - } - GNUNET_assert (sizeof(dividend) >= 8); - remainder = 0; - for (unsigned int i = 0; i<j; i += 16) - { - int nread; - - if (1 != - sscanf (&nbuf[i], - "%16llu %n", - ÷nd, - &nread)) - { - GNUNET_free (nbuf); - GNUNET_break_op (0); - return GNUNET_NO; - } - if (0 != remainder) - dividend += remainder * (pow (10, nread)); - remainder = dividend % 97; - } - GNUNET_free (nbuf); - if (1 != remainder) - { - GNUNET_log (GNUNET_ERROR_TYPE_WARNING, - "IBAN `%s' has the wrong checksum\n", - iban); - return GNUNET_NO; - } - return GNUNET_YES; -} - - -/** - * Validate payto://iban/ account URL (only account information, - * wire subject and amount are ignored). - * - * @param account_url URL to parse - * @return #GNUNET_YES if @a account_url is a valid payto://iban URI, - * #GNUNET_NO if @a account_url is a payto URI of a different type, - * #GNUNET_SYSERR if the IBAN (checksum) is incorrect or this is not a payto://-URI - */ -static enum GNUNET_GenericReturnValue -validate_payto_iban (const char *account_url) -{ - const char *iban; - const char *q; - char *result; - -#define IBAN_PREFIX "payto://iban/" - if (0 != strncasecmp (account_url, - IBAN_PREFIX, - strlen (IBAN_PREFIX))) - return GNUNET_NO; - - iban = strrchr (account_url, '/') + 1; -#undef IBAN_PREFIX - q = strchr (iban, - '?'); - if (NULL != q) - { - result = GNUNET_strndup (iban, - q - iban); - } - else - { - result = GNUNET_strdup (iban); - } - if (GNUNET_OK != - validate_iban (result)) - { - GNUNET_free (result); - return GNUNET_SYSERR; - } - GNUNET_free (result); - return GNUNET_YES; -} - - -enum GNUNET_GenericReturnValue -TALER_JSON_validate_payto (const char *payto_uri) -{ - enum GNUNET_GenericReturnValue ret; - const char *start; - const char *end; - -#define PAYTO_PREFIX "payto://" - if (0 != strncasecmp (payto_uri, - PAYTO_PREFIX, - strlen (PAYTO_PREFIX))) - return GNUNET_SYSERR; /* not payto */ - start = &payto_uri[strlen (PAYTO_PREFIX)]; -#undef PAYTO_PREFIX - end = strchr (start, - (unsigned char) '/'); - if (NULL == end) - return GNUNET_SYSERR; - if (GNUNET_NO != (ret = validate_payto_iban (payto_uri))) - { - GNUNET_break_op (GNUNET_SYSERR != ret); - return ret; /* got a definitive answer */ - } - /* Insert other bank account validation methods here later! */ - return GNUNET_NO; -} - - /** * Compute the hash of the given wire details. The resulting * hash is what is put into the contract. @@ -429,11 +57,19 @@ TALER_JSON_merchant_wire_signature_hash (const json_t *wire_s, GNUNET_log (GNUNET_ERROR_TYPE_DEBUG, "Validating `%s'\n", payto_uri); - if (GNUNET_SYSERR == - TALER_JSON_validate_payto (payto_uri)) { - GNUNET_break_op (0); - return GNUNET_SYSERR; + char *err; + + err = TALER_payto_validate (payto_uri); + if (NULL != err) + { + GNUNET_log (GNUNET_ERROR_TYPE_WARNING, + "URI `%s' ill-formed: %s\n", + payto_uri, + err); + GNUNET_free (err); + return GNUNET_SYSERR; + } } TALER_merchant_wire_signature_hash (payto_uri, salt, @@ -472,11 +108,19 @@ TALER_JSON_exchange_wire_signature_check ( return GNUNET_SYSERR; } - if (GNUNET_SYSERR == - TALER_JSON_validate_payto (payto_uri)) { - GNUNET_break_op (0); - return GNUNET_SYSERR; + char *err; + + err = TALER_payto_validate (payto_uri); + if (NULL != err) + { + GNUNET_log (GNUNET_ERROR_TYPE_WARNING, + "URI `%s' ill-formed: %s\n", + payto_uri, + err); + GNUNET_free (err); + return GNUNET_SYSERR; + } } return TALER_exchange_wire_signature_check (payto_uri, @@ -498,11 +142,16 @@ TALER_JSON_exchange_wire_signature_make ( const struct TALER_MasterPrivateKeyP *master_priv) { struct TALER_MasterSignatureP master_sig; + char *err; - if (GNUNET_SYSERR == - TALER_JSON_validate_payto (payto_uri)) + if (NULL != + (err = TALER_payto_validate (payto_uri))) { - GNUNET_break_op (0); + GNUNET_log (GNUNET_ERROR_TYPE_ERROR, + "Invalid payto URI `%s': %s\n", + payto_uri, + err); + GNUNET_free (err); return NULL; } TALER_exchange_wire_signature_make (payto_uri, @@ -528,6 +177,7 @@ TALER_JSON_wire_to_payto (const json_t *wire_s) { json_t *payto_o; const char *payto_str; + char *err; payto_o = json_object_get (wire_s, "payto_uri"); @@ -538,12 +188,14 @@ TALER_JSON_wire_to_payto (const json_t *wire_s) "Malformed wire record encountered: lacks payto://-url\n"); return NULL; } - if (GNUNET_SYSERR == - TALER_JSON_validate_payto (payto_str)) + if (NULL != + (err = TALER_payto_validate (payto_str))) { GNUNET_log (GNUNET_ERROR_TYPE_ERROR, - "Malformed wire record encountered: payto URI `%s' invalid\n", - payto_str); + "Malformed wire record encountered: payto URI `%s' invalid: %s\n", + payto_str, + err); + GNUNET_free (err); return NULL; } return GNUNET_strdup (payto_str); diff --git a/src/util/payto.c b/src/util/payto.c index 54072d667..7819184e8 100644 --- a/src/util/payto.c +++ b/src/util/payto.c @@ -128,3 +128,401 @@ TALER_xtalerbank_account_from_payto (const char *payto) return GNUNET_strndup (beg, end - beg); } + + +/* Country table taken from GNU gettext */ + +/** + * Entry in the country table. + */ +struct CountryTableEntry +{ + /** + * 2-Character international country code. + */ + const char *code; + + /** + * Long English name of the country. + */ + const char *english; +}; + + +/* Keep the following table in sync with gettext. + WARNING: the entries should stay sorted according to the code */ +/** + * List of country codes. + */ +static const struct CountryTableEntry country_table[] = { + { "AE", "U.A.E." }, + { "AF", "Afghanistan" }, + { "AL", "Albania" }, + { "AM", "Armenia" }, + { "AN", "Netherlands Antilles" }, + { "AR", "Argentina" }, + { "AT", "Austria" }, + { "AU", "Australia" }, + { "AZ", "Azerbaijan" }, + { "BA", "Bosnia and Herzegovina" }, + { "BD", "Bangladesh" }, + { "BE", "Belgium" }, + { "BG", "Bulgaria" }, + { "BH", "Bahrain" }, + { "BN", "Brunei Darussalam" }, + { "BO", "Bolivia" }, + { "BR", "Brazil" }, + { "BT", "Bhutan" }, + { "BY", "Belarus" }, + { "BZ", "Belize" }, + { "CA", "Canada" }, + { "CG", "Congo" }, + { "CH", "Switzerland" }, + { "CI", "Cote d'Ivoire" }, + { "CL", "Chile" }, + { "CM", "Cameroon" }, + { "CN", "People's Republic of China" }, + { "CO", "Colombia" }, + { "CR", "Costa Rica" }, + { "CS", "Serbia and Montenegro" }, + { "CZ", "Czech Republic" }, + { "DE", "Germany" }, + { "DK", "Denmark" }, + { "DO", "Dominican Republic" }, + { "DZ", "Algeria" }, + { "EC", "Ecuador" }, + { "EE", "Estonia" }, + { "EG", "Egypt" }, + { "ER", "Eritrea" }, + { "ES", "Spain" }, + { "ET", "Ethiopia" }, + { "FI", "Finland" }, + { "FO", "Faroe Islands" }, + { "FR", "France" }, + { "GB", "United Kingdom" }, + { "GD", "Caribbean" }, + { "GE", "Georgia" }, + { "GL", "Greenland" }, + { "GR", "Greece" }, + { "GT", "Guatemala" }, + { "HK", "Hong Kong" }, + { "HK", "Hong Kong S.A.R." }, + { "HN", "Honduras" }, + { "HR", "Croatia" }, + { "HT", "Haiti" }, + { "HU", "Hungary" }, + { "ID", "Indonesia" }, + { "IE", "Ireland" }, + { "IL", "Israel" }, + { "IN", "India" }, + { "IQ", "Iraq" }, + { "IR", "Iran" }, + { "IS", "Iceland" }, + { "IT", "Italy" }, + { "JM", "Jamaica" }, + { "JO", "Jordan" }, + { "JP", "Japan" }, + { "KE", "Kenya" }, + { "KG", "Kyrgyzstan" }, + { "KH", "Cambodia" }, + { "KR", "South Korea" }, + { "KW", "Kuwait" }, + { "KZ", "Kazakhstan" }, + { "LA", "Laos" }, + { "LB", "Lebanon" }, + { "LI", "Liechtenstein" }, + { "LK", "Sri Lanka" }, + { "LT", "Lithuania" }, + { "LU", "Luxembourg" }, + { "LV", "Latvia" }, + { "LY", "Libya" }, + { "MA", "Morocco" }, + { "MC", "Principality of Monaco" }, + { "MD", "Moldava" }, + { "MD", "Moldova" }, + { "ME", "Montenegro" }, + { "MK", "Former Yugoslav Republic of Macedonia" }, + { "ML", "Mali" }, + { "MM", "Myanmar" }, + { "MN", "Mongolia" }, + { "MO", "Macau S.A.R." }, + { "MT", "Malta" }, + { "MV", "Maldives" }, + { "MX", "Mexico" }, + { "MY", "Malaysia" }, + { "NG", "Nigeria" }, + { "NI", "Nicaragua" }, + { "NL", "Netherlands" }, + { "NO", "Norway" }, + { "NP", "Nepal" }, + { "NZ", "New Zealand" }, + { "OM", "Oman" }, + { "PA", "Panama" }, + { "PE", "Peru" }, + { "PH", "Philippines" }, + { "PK", "Islamic Republic of Pakistan" }, + { "PL", "Poland" }, + { "PR", "Puerto Rico" }, + { "PT", "Portugal" }, + { "PY", "Paraguay" }, + { "QA", "Qatar" }, + { "RE", "Reunion" }, + { "RO", "Romania" }, + { "RS", "Serbia" }, + { "RU", "Russia" }, + { "RW", "Rwanda" }, + { "SA", "Saudi Arabia" }, + { "SE", "Sweden" }, + { "SG", "Singapore" }, + { "SI", "Slovenia" }, + { "SK", "Slovak" }, + { "SN", "Senegal" }, + { "SO", "Somalia" }, + { "SR", "Suriname" }, + { "SV", "El Salvador" }, + { "SY", "Syria" }, + { "TH", "Thailand" }, + { "TJ", "Tajikistan" }, + { "TM", "Turkmenistan" }, + { "TN", "Tunisia" }, + { "TR", "Turkey" }, + { "TT", "Trinidad and Tobago" }, + { "TW", "Taiwan" }, + { "TZ", "Tanzania" }, + { "UA", "Ukraine" }, + { "US", "United States" }, + { "UY", "Uruguay" }, + { "VA", "Vatican" }, + { "VE", "Venezuela" }, + { "VN", "Viet Nam" }, + { "YE", "Yemen" }, + { "ZA", "South Africa" }, + { "ZW", "Zimbabwe" } +}; + + +/** + * Country code comparator function, for binary search with bsearch(). + * + * @param ptr1 pointer to a `struct table_entry` + * @param ptr2 pointer to a `struct table_entry` + * @return result of memcmp()'ing the 2-digit country codes of the entries + */ +static int +cmp_country_code (const void *ptr1, + const void *ptr2) +{ + const struct CountryTableEntry *cc1 = ptr1; + const struct CountryTableEntry *cc2 = ptr2; + + return memcmp (cc1->code, + cc2->code, + 2); +} + + +/** + * Validates given IBAN according to the European Banking Standards. See: + * http://www.europeanpaymentscouncil.eu/documents/ECBS%20IBAN%20standard%20EBS204_V3.2.pdf + * + * @param iban the IBAN number to validate + * @return NULL if correctly formatted; error message if not + */ +static char * +validate_iban (const char *iban) +{ + char cc[2]; + char ibancpy[35]; + struct CountryTableEntry cc_entry; + unsigned int len; + char *nbuf; + unsigned long long dividend; + unsigned long long remainder; + unsigned int i; + unsigned int j; + + len = strlen (iban); + if (len > 34) + return GNUNET_strdup ("IBAN number too long to be valid"); + memcpy (cc, iban, 2); + memcpy (ibancpy, iban + 4, len - 4); + memcpy (ibancpy + len - 4, iban, 4); + ibancpy[len] = '\0'; + cc_entry.code = cc; + cc_entry.english = NULL; + if (NULL == + bsearch (&cc_entry, + country_table, + sizeof (country_table) / sizeof (struct CountryTableEntry), + sizeof (struct CountryTableEntry), + &cmp_country_code)) + { + char *msg; + + GNUNET_asprintf (&msg, + "Country code `%c%c' not supported\n", + cc[0], + cc[1]); + return msg; + } + nbuf = GNUNET_malloc ((len * 2) + 1); + for (i = 0, j = 0; i < len; i++) + { + if (isalpha ((unsigned char) ibancpy[i])) + { + if (2 != snprintf (&nbuf[j], + 3, + "%2u", + (ibancpy[i] - 'A' + 10))) + { + GNUNET_break (0); + return GNUNET_strdup ("internal invariant violation"); + } + j += 2; + continue; + } + nbuf[j] = ibancpy[i]; + j++; + } + for (j = 0; '\0' != nbuf[j]; j++) + { + if (! isdigit ( (unsigned char) nbuf[j])) + { + char *msg; + + GNUNET_asprintf (&msg, + "digit expected at `%s'", + &nbuf[j]); + GNUNET_free (nbuf); + return msg; + } + } + GNUNET_assert (sizeof(dividend) >= 8); + remainder = 0; + for (unsigned int i = 0; i<j; i += 16) + { + int nread; + + if (1 != + sscanf (&nbuf[i], + "%16llu %n", + ÷nd, + &nread)) + { + char *msg; + + GNUNET_asprintf (&msg, + "wrong input for checksum calculation at `%s'", + &nbuf[i]); + GNUNET_free (nbuf); + return msg; + } + if (0 != remainder) + dividend += remainder * (pow (10, nread)); + remainder = dividend % 97; + } + GNUNET_free (nbuf); + if (1 != remainder) + return GNUNET_strdup ("IBAN checksum is wrong"); + return NULL; +} + + +/** + * Validate payto://iban/ account URL (only account information, + * wire subject and amount are ignored). + * + * @param account_url URL to parse + * @return NULL on success, otherwise an error message + * to be freed by the caller + */ +static char * +validate_payto_iban (const char *account_url) +{ + const char *iban; + const char *q; + char *result; + char *err; + +#define IBAN_PREFIX "payto://iban/" + if (0 != strncasecmp (account_url, + IBAN_PREFIX, + strlen (IBAN_PREFIX))) + return NULL; /* not an IBAN */ + + iban = strrchr (account_url, '/') + 1; +#undef IBAN_PREFIX + q = strchr (iban, + '?'); + if (NULL != q) + { + result = GNUNET_strndup (iban, + q - iban); + } + else + { + result = GNUNET_strdup (iban); + } + if (NULL != + (err = validate_iban (result))) + { + GNUNET_free (result); + return err; + } + GNUNET_free (result); + return NULL; +} + + +/** + * Check that a payto:// URI is well-formed. + * + * @param payto_uri the URL to check + * @return NULL on success, otherwise an error + * message to be freed by the caller! + */ +char * +TALER_payto_validate (const char *payto_uri) +{ + char *ret; + const char *start; + const char *end; + + if (0 != strncasecmp (payto_uri, + PAYTO, + strlen (PAYTO))) + return GNUNET_strdup ("invalid prefix"); + for (unsigned int i = 0; '\0' != payto_uri[i]; i++) + { + /* This is more strict than RFC 8905, alas we do not need to support messages/instructions/etc., + and it is generally better to start with a narrow whitelist; we can be more permissive later ...*/ +#define ALLOWED_CHARACTERS \ + "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789/:&?-.,=" + if (NULL == strchr (ALLOWED_CHARACTERS, + (int) payto_uri[i])) + { + char *ret; + + GNUNET_asprintf (&ret, + "Encountered invalid character `%c' at offset %u in payto URI `%s'", + payto_uri[i], + i, + payto_uri); + return ret; + } +#undef ALLOWED_CHARACTERS + } + + start = &payto_uri[strlen (PAYTO)]; + end = strchr (start, + (unsigned char) '/'); + if (NULL == end) + return GNUNET_strdup ("missing '/' in payload"); + + if (NULL != (ret = validate_payto_iban (payto_uri))) + return ret; /* got a definitive answer */ + + /* Insert other bank account validation methods here later! */ + + return NULL; +} |