OBJ_nid2obj.pod 7.4 KB

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  1. =pod
  2. =head1 NAME
  3. i2t_ASN1_OBJECT,
  4. OBJ_length, OBJ_get0_data, OBJ_nid2obj, OBJ_nid2ln,
  5. OBJ_nid2sn, OBJ_obj2nid, OBJ_txt2nid, OBJ_ln2nid, OBJ_sn2nid, OBJ_cmp,
  6. OBJ_dup, OBJ_txt2obj, OBJ_obj2txt, OBJ_create, OBJ_cleanup, OBJ_add_sigid
  7. - ASN1 object utility functions
  8. =head1 SYNOPSIS
  9. #include <openssl/objects.h>
  10. ASN1_OBJECT *OBJ_nid2obj(int n);
  11. const char *OBJ_nid2ln(int n);
  12. const char *OBJ_nid2sn(int n);
  13. int OBJ_obj2nid(const ASN1_OBJECT *o);
  14. int OBJ_ln2nid(const char *ln);
  15. int OBJ_sn2nid(const char *sn);
  16. int OBJ_txt2nid(const char *s);
  17. ASN1_OBJECT *OBJ_txt2obj(const char *s, int no_name);
  18. int OBJ_obj2txt(char *buf, int buf_len, const ASN1_OBJECT *a, int no_name);
  19. int i2t_ASN1_OBJECT(char *buf, int buf_len, const ASN1_OBJECT *a);
  20. int OBJ_cmp(const ASN1_OBJECT *a, const ASN1_OBJECT *b);
  21. ASN1_OBJECT *OBJ_dup(const ASN1_OBJECT *o);
  22. int OBJ_create(const char *oid, const char *sn, const char *ln);
  23. size_t OBJ_length(const ASN1_OBJECT *obj);
  24. const unsigned char *OBJ_get0_data(const ASN1_OBJECT *obj);
  25. int OBJ_add_sigid(int signid, int dig_id, int pkey_id);
  26. The following function has been deprecated since OpenSSL 1.1.0, and can be
  27. hidden entirely by defining B<OPENSSL_API_COMPAT> with a suitable version value,
  28. see L<openssl_user_macros(7)>:
  29. void OBJ_cleanup(void);
  30. =head1 DESCRIPTION
  31. The ASN1 object utility functions process ASN1_OBJECT structures which are
  32. a representation of the ASN1 OBJECT IDENTIFIER (OID) type.
  33. For convenience, OIDs are usually represented in source code as numeric
  34. identifiers, or B<NID>s. OpenSSL has an internal table of OIDs that
  35. are generated when the library is built, and their corresponding NIDs
  36. are available as defined constants. For the functions below, application
  37. code should treat all returned values -- OIDs, NIDs, or names -- as
  38. constants.
  39. OBJ_nid2obj(), OBJ_nid2ln() and OBJ_nid2sn() convert the NID I<n> to
  40. an ASN1_OBJECT structure, its long name and its short name respectively,
  41. or B<NULL> if an error occurred.
  42. OBJ_obj2nid(), OBJ_ln2nid(), OBJ_sn2nid() return the corresponding NID
  43. for the object I<o>, the long name I<ln> or the short name I<sn> respectively
  44. or NID_undef if an error occurred.
  45. OBJ_txt2nid() returns NID corresponding to text string I<s>. I<s> can be
  46. a long name, a short name or the numerical representation of an object.
  47. OBJ_txt2obj() converts the text string I<s> into an ASN1_OBJECT structure.
  48. If I<no_name> is 0 then long names and short names will be interpreted
  49. as well as numerical forms. If I<no_name> is 1 only the numerical form
  50. is acceptable.
  51. OBJ_obj2txt() converts the B<ASN1_OBJECT> I<a> into a textual representation.
  52. Unless I<buf> is NULL,
  53. the representation is written as a NUL-terminated string to I<buf>, where
  54. at most I<buf_len> bytes are written, truncating the result if necessary.
  55. In any case it returns the total string length, excluding the NUL character,
  56. required for non-truncated representation, or -1 on error.
  57. If I<no_name> is 0 then if the object has a long or short name
  58. then that will be used, otherwise the numerical form will be used.
  59. If I<no_name> is 1 then the numerical form will always be used.
  60. i2t_ASN1_OBJECT() is the same as OBJ_obj2txt() with the I<no_name> set to zero.
  61. OBJ_cmp() compares I<a> to I<b>. If the two are identical 0 is returned.
  62. OBJ_dup() returns a copy of I<o>.
  63. OBJ_create() adds a new object to the internal table. I<oid> is the
  64. numerical form of the object, I<sn> the short name and I<ln> the
  65. long name. A new NID is returned for the created object in case of
  66. success and NID_undef in case of failure. Any of I<oid>, I<sn> and
  67. I<ln> may be NULL, but not all at once.
  68. OBJ_length() returns the size of the content octets of I<obj>.
  69. OBJ_get0_data() returns a pointer to the content octets of I<obj>.
  70. The returned pointer is an internal pointer which B<must not> be freed.
  71. OBJ_add_sigid() creates a new composite "Signature Algorithm" that associates a
  72. given NID with two other NIDs - one representing the underlying signature
  73. algorithm and the other representing a digest algorithm to be used in
  74. conjunction with it. I<signid> represents the NID for the composite "Signature
  75. Algorithm", I<dig_id> is the NID for the digest algorithm and I<pkey_id> is the
  76. NID for the underlying signature algorithm. As there are signature algorithms
  77. that do not require a digest, NID_undef is a valid I<dig_id>.
  78. OBJ_cleanup() releases any resources allocated by creating new objects.
  79. =head1 NOTES
  80. Objects in OpenSSL can have a short name, a long name and a numerical
  81. identifier (NID) associated with them. A standard set of objects is
  82. represented in an internal table. The appropriate values are defined
  83. in the header file B<objects.h>.
  84. For example the OID for commonName has the following definitions:
  85. #define SN_commonName "CN"
  86. #define LN_commonName "commonName"
  87. #define NID_commonName 13
  88. New objects can be added by calling OBJ_create().
  89. Table objects have certain advantages over other objects: for example
  90. their NIDs can be used in a C language switch statement. They are
  91. also static constant structures which are shared: that is there
  92. is only a single constant structure for each table object.
  93. Objects which are not in the table have the NID value NID_undef.
  94. Objects do not need to be in the internal tables to be processed,
  95. the functions OBJ_txt2obj() and OBJ_obj2txt() can process the numerical
  96. form of an OID.
  97. Some objects are used to represent algorithms which do not have a
  98. corresponding ASN.1 OBJECT IDENTIFIER encoding (for example no OID currently
  99. exists for a particular algorithm). As a result they B<cannot> be encoded or
  100. decoded as part of ASN.1 structures. Applications can determine if there
  101. is a corresponding OBJECT IDENTIFIER by checking OBJ_length() is not zero.
  102. These functions cannot return B<const> because an B<ASN1_OBJECT> can
  103. represent both an internal, constant, OID and a dynamically-created one.
  104. The latter cannot be constant because it needs to be freed after use.
  105. These functions were not thread safe in OpenSSL 3.0 and before.
  106. =head1 RETURN VALUES
  107. OBJ_nid2obj() returns an B<ASN1_OBJECT> structure or B<NULL> is an
  108. error occurred.
  109. OBJ_nid2ln() and OBJ_nid2sn() returns a valid string or B<NULL>
  110. on error.
  111. OBJ_obj2nid(), OBJ_ln2nid(), OBJ_sn2nid() and OBJ_txt2nid() return
  112. a NID or B<NID_undef> on error.
  113. OBJ_add_sigid() returns 1 on success or 0 on error.
  114. i2t_ASN1_OBJECT() an OBJ_obj2txt() return -1 on error.
  115. On success, they return the length of the string written to I<buf> if I<buf> is
  116. not NULL and I<buf_len> is big enough, otherwise the total string length.
  117. Note that this does not count the trailing NUL character.
  118. =head1 EXAMPLES
  119. Create an object for B<commonName>:
  120. ASN1_OBJECT *o = OBJ_nid2obj(NID_commonName);
  121. Check if an object is B<commonName>
  122. if (OBJ_obj2nid(obj) == NID_commonName)
  123. /* Do something */
  124. Create a new NID and initialize an object from it:
  125. int new_nid = OBJ_create("1.2.3.4", "NewOID", "New Object Identifier");
  126. ASN1_OBJECT *obj = OBJ_nid2obj(new_nid);
  127. Create a new object directly:
  128. obj = OBJ_txt2obj("1.2.3.4", 1);
  129. =head1 SEE ALSO
  130. L<ERR_get_error(3)>
  131. =head1 HISTORY
  132. OBJ_cleanup() was deprecated in OpenSSL 1.1.0 by L<OPENSSL_init_crypto(3)>
  133. and should not be used.
  134. =head1 COPYRIGHT
  135. Copyright 2002-2021 The OpenSSL Project Authors. All Rights Reserved.
  136. Licensed under the Apache License 2.0 (the "License"). You may not use
  137. this file except in compliance with the License. You can obtain a copy
  138. in the file LICENSE in the source distribution or at
  139. L<https://www.openssl.org/source/license.html>.
  140. =cut