diff options
Diffstat (limited to 'doc/openssl.txt')
| -rw-r--r-- | doc/openssl.txt | 1254 |
1 files changed, 0 insertions, 1254 deletions
diff --git a/doc/openssl.txt b/doc/openssl.txt deleted file mode 100644 index f8817b0a7199..000000000000 --- a/doc/openssl.txt +++ /dev/null @@ -1,1254 +0,0 @@ - -This is some preliminary documentation for OpenSSL. - -Contents: - - OpenSSL X509V3 extension configuration - X509V3 Extension code: programmers guide - PKCS#12 Library - - -============================================================================== - OpenSSL X509V3 extension configuration -============================================================================== - -OpenSSL X509V3 extension configuration: preliminary documentation. - -INTRODUCTION. - -For OpenSSL 0.9.2 the extension code has be considerably enhanced. It is now -possible to add and print out common X509 V3 certificate and CRL extensions. - -BEGINNERS NOTE - -For most simple applications you don't need to know too much about extensions: -the default openssl.cnf values will usually do sensible things. - -If you want to know more you can initially quickly look through the sections -describing how the standard OpenSSL utilities display and add extensions and -then the list of supported extensions. - -For more technical information about the meaning of extensions see: - -http://www.imc.org/ietf-pkix/ -http://home.netscape.com/eng/security/certs.html - -PRINTING EXTENSIONS. - -Extension values are automatically printed out for supported extensions. - -openssl x509 -in cert.pem -text -openssl crl -in crl.pem -text - -will give information in the extension printout, for example: - - X509v3 extensions: - X509v3 Basic Constraints: - CA:TRUE - X509v3 Subject Key Identifier: - 73:FE:F7:59:A7:E1:26:84:44:D6:44:36:EE:79:1A:95:7C:B1:4B:15 - X509v3 Authority Key Identifier: - keyid:73:FE:F7:59:A7:E1:26:84:44:D6:44:36:EE:79:1A:95:7C:B1:4B:15, DirName:/C=AU/ST=Some-State/O=Internet Widgits Pty Ltd/Email=email@1.address/Email=email@2.address, serial:00 - X509v3 Key Usage: - Certificate Sign, CRL Sign - X509v3 Subject Alternative Name: - email:email@1.address, email:email@2.address - -CONFIGURATION FILES. - -The OpenSSL utilities 'ca' and 'req' can now have extension sections listing -which certificate extensions to include. In each case a line: - -x509_extensions = extension_section - -indicates which section contains the extensions. In the case of 'req' the -extension section is used when the -x509 option is present to create a -self signed root certificate. - -The 'x509' utility also supports extensions when it signs a certificate. -The -extfile option is used to set the configuration file containing the -extensions. In this case a line with: - -extensions = extension_section - -in the nameless (default) section is used. If no such line is included then -it uses the default section. - -You can also add extensions to CRLs: a line - -crl_extensions = crl_extension_section - -will include extensions when the -gencrl option is used with the 'ca' utility. -You can add any extension to a CRL but of the supported extensions only -issuerAltName and authorityKeyIdentifier make any real sense. Note: these are -CRL extensions NOT CRL *entry* extensions which cannot currently be generated. -CRL entry extensions can be displayed. - -NB. At this time Netscape Communicator rejects V2 CRLs: to get an old V1 CRL -you should not include a crl_extensions line in the configuration file. - -As with all configuration files you can use the inbuilt environment expansion -to allow the values to be passed in the environment. Therefore if you have -several extension sections used for different purposes you can have a line: - -x509_extensions = $ENV::ENV_EXT - -and set the ENV_EXT environment variable before calling the relevant utility. - -EXTENSION SYNTAX. - -Extensions have the basic form: - -extension_name=[critical,] extension_options - -the use of the critical option makes the extension critical. Extreme caution -should be made when using the critical flag. If an extension is marked -as critical then any client that does not understand the extension should -reject it as invalid. Some broken software will reject certificates which -have *any* critical extensions (these violates PKIX but we have to live -with it). - -There are three main types of extension: string extensions, multi-valued -extensions, and raw extensions. - -String extensions simply have a string which contains either the value itself -or how it is obtained. - -For example: - -nsComment="This is a Comment" - -Multi-valued extensions have a short form and a long form. The short form -is a list of names and values: - -basicConstraints=critical,CA:true,pathlen:1 - -The long form allows the values to be placed in a separate section: - -basicConstraints=critical,@bs_section - -[bs_section] - -CA=true -pathlen=1 - -Both forms are equivalent. However it should be noted that in some cases the -same name can appear multiple times, for example, - -subjectAltName=email:steve@here,email:steve@there - -in this case an equivalent long form is: - -subjectAltName=@alt_section - -[alt_section] - -email.1=steve@here -email.2=steve@there - -This is because the configuration file code cannot handle the same name -occurring twice in the same section. - -The syntax of raw extensions is governed by the extension code: it can -for example contain data in multiple sections. The correct syntax to -use is defined by the extension code itself: check out the certificate -policies extension for an example. - -There are two ways to encode arbitrary extensions. - -The first way is to use the word ASN1 followed by the extension content -using the same syntax as ASN1_generate_nconf(). For example: - -1.2.3.4=critical,ASN1:UTF8String:Some random data - -1.2.3.4=ASN1:SEQUENCE:seq_sect - -[seq_sect] - -field1 = UTF8:field1 -field2 = UTF8:field2 - -It is also possible to use the word DER to include arbitrary data in any -extension. - -1.2.3.4=critical,DER:01:02:03:04 -1.2.3.4=DER:01020304 - -The value following DER is a hex dump of the DER encoding of the extension -Any extension can be placed in this form to override the default behaviour. -For example: - -basicConstraints=critical,DER:00:01:02:03 - -WARNING: DER should be used with caution. It is possible to create totally -invalid extensions unless care is taken. - -CURRENTLY SUPPORTED EXTENSIONS. - -If you aren't sure about extensions then they can be largely ignored: its only -when you want to do things like restrict certificate usage when you need to -worry about them. - -The only extension that a beginner might want to look at is Basic Constraints. -If in addition you want to try Netscape object signing the you should also -look at Netscape Certificate Type. - -Literal String extensions. - -In each case the 'value' of the extension is placed directly in the -extension. Currently supported extensions in this category are: nsBaseUrl, -nsRevocationUrl, nsCaRevocationUrl, nsRenewalUrl, nsCaPolicyUrl, -nsSslServerName and nsComment. - -For example: - -nsComment="This is a test comment" - -Bit Strings. - -Bit string extensions just consist of a list of supported bits, currently -two extensions are in this category: PKIX keyUsage and the Netscape specific -nsCertType. - -nsCertType (netscape certificate type) takes the flags: client, server, email, -objsign, reserved, sslCA, emailCA, objCA. - -keyUsage (PKIX key usage) takes the flags: digitalSignature, nonRepudiation, -keyEncipherment, dataEncipherment, keyAgreement, keyCertSign, cRLSign, -encipherOnly, decipherOnly. - -For example: - -nsCertType=server - -keyUsage=digitalSignature, nonRepudiation - -Hints on Netscape Certificate Type. - -Other than Basic Constraints this is the only extension a beginner might -want to use, if you want to try Netscape object signing, otherwise it can -be ignored. - -If you want a certificate that can be used just for object signing then: - -nsCertType=objsign - -will do the job. If you want to use it as a normal end user and server -certificate as well then - -nsCertType=objsign,email,server - -is more appropriate. You cannot use a self signed certificate for object -signing (well Netscape signtool can but it cheats!) so you need to create -a CA certificate and sign an end user certificate with it. - -Side note: If you want to conform to the Netscape specifications then you -should really also set: - -nsCertType=objCA - -in the *CA* certificate for just an object signing CA and - -nsCertType=objCA,emailCA,sslCA - -for everything. Current Netscape software doesn't enforce this so it can -be omitted. - -Basic Constraints. - -This is generally the only extension you need to worry about for simple -applications. If you want your certificate to be usable as a CA certificate -(in addition to an end user certificate) then you set this to: - -basicConstraints=CA:TRUE - -if you want to be certain the certificate cannot be used as a CA then do: - -basicConstraints=CA:FALSE - -The rest of this section describes more advanced usage. - -Basic constraints is a multi-valued extension that supports a CA and an -optional pathlen option. The CA option takes the values true and false and -pathlen takes an integer. Note if the CA option is false the pathlen option -should be omitted. - -The pathlen parameter indicates the maximum number of CAs that can appear -below this one in a chain. So if you have a CA with a pathlen of zero it can -only be used to sign end user certificates and not further CAs. This all -assumes that the software correctly interprets this extension of course. - -Examples: - -basicConstraints=CA:TRUE -basicConstraints=critical,CA:TRUE, pathlen:0 - -NOTE: for a CA to be considered valid it must have the CA option set to -TRUE. An end user certificate MUST NOT have the CA value set to true. -According to PKIX recommendations it should exclude the extension entirely, -however some software may require CA set to FALSE for end entity certificates. - -Extended Key Usage. - -This extensions consists of a list of usages. - -These can either be object short names of the dotted numerical form of OIDs. -While any OID can be used only certain values make sense. In particular the -following PKIX, NS and MS values are meaningful: - -Value Meaning ------ ------- -serverAuth SSL/TLS Web Server Authentication. -clientAuth SSL/TLS Web Client Authentication. -codeSigning Code signing. -emailProtection E-mail Protection (S/MIME). -timeStamping Trusted Timestamping -msCodeInd Microsoft Individual Code Signing (authenticode) -msCodeCom Microsoft Commercial Code Signing (authenticode) -msCTLSign Microsoft Trust List Signing -msSGC Microsoft Server Gated Crypto -msEFS Microsoft Encrypted File System -nsSGC Netscape Server Gated Crypto - -For example, under IE5 a CA can be used for any purpose: by including a list -of the above usages the CA can be restricted to only authorised uses. - -Note: software packages may place additional interpretations on certificate -use, in particular some usages may only work for selected CAs. Don't for example -expect just including msSGC or nsSGC will automatically mean that a certificate -can be used for SGC ("step up" encryption) otherwise anyone could use it. - -Examples: - -extendedKeyUsage=critical,codeSigning,1.2.3.4 -extendedKeyUsage=nsSGC,msSGC - -Subject Key Identifier. - -This is really a string extension and can take two possible values. Either -a hex string giving details of the extension value to include or the word -'hash' which then automatically follow PKIX guidelines in selecting and -appropriate key identifier. The use of the hex string is strongly discouraged. - -Example: subjectKeyIdentifier=hash - -Authority Key Identifier. - -The authority key identifier extension permits two options. keyid and issuer: -both can take the optional value "always". - -If the keyid option is present an attempt is made to copy the subject key -identifier from the parent certificate. If the value "always" is present -then an error is returned if the option fails. - -The issuer option copies the issuer and serial number from the issuer -certificate. Normally this will only be done if the keyid option fails or -is not included: the "always" flag will always include the value. - -Subject Alternative Name. - -The subject alternative name extension allows various literal values to be -included in the configuration file. These include "email" (an email address) -"URI" a uniform resource indicator, "DNS" (a DNS domain name), RID (a -registered ID: OBJECT IDENTIFIER), IP (and IP address) and otherName. - -Also the email option include a special 'copy' value. This will automatically -include and email addresses contained in the certificate subject name in -the extension. - -otherName can include arbitrary data associated with an OID: the value -should be the OID followed by a semicolon and the content in standard -ASN1_generate_nconf() format. - -Examples: - -subjectAltName=email:copy,email:my@other.address,URI:http://my.url.here/ -subjectAltName=email:my@other.address,RID:1.2.3.4 -subjectAltName=otherName:1.2.3.4;UTF8:some other identifier - -Issuer Alternative Name. - -The issuer alternative name option supports all the literal options of -subject alternative name. It does *not* support the email:copy option because -that would not make sense. It does support an additional issuer:copy option -that will copy all the subject alternative name values from the issuer -certificate (if possible). - -Example: - -issuserAltName = issuer:copy - -Authority Info Access. - -The authority information access extension gives details about how to access -certain information relating to the CA. Its syntax is accessOID;location -where 'location' has the same syntax as subject alternative name (except -that email:copy is not supported). accessOID can be any valid OID but only -certain values are meaningful for example OCSP and caIssuers. OCSP gives the -location of an OCSP responder: this is used by Netscape PSM and other software. - -Example: - -authorityInfoAccess = OCSP;URI:http://ocsp.my.host/ -authorityInfoAccess = caIssuers;URI:http://my.ca/ca.html - -CRL distribution points. - -This is a multi-valued extension that supports all the literal options of -subject alternative name. Of the few software packages that currently interpret -this extension most only interpret the URI option. - -Currently each option will set a new DistributionPoint with the fullName -field set to the given value. - -Other fields like cRLissuer and reasons cannot currently be set or displayed: -at this time no examples were available that used these fields. - -If you see this extension with <UNSUPPORTED> when you attempt to print it out -or it doesn't appear to display correctly then let me know, including the -certificate (mail me at steve@openssl.org) . - -Examples: - -crlDistributionPoints=URI:http://www.myhost.com/myca.crl -crlDistributionPoints=URI:http://www.my.com/my.crl,URI:http://www.oth.com/my.crl - -Certificate Policies. - -This is a RAW extension. It attempts to display the contents of this extension: -unfortunately this extension is often improperly encoded. - -The certificate policies extension will rarely be used in practice: few -software packages interpret it correctly or at all. IE5 does partially -support this extension: but it needs the 'ia5org' option because it will -only correctly support a broken encoding. Of the options below only the -policy OID, explicitText and CPS options are displayed with IE5. - -All the fields of this extension can be set by using the appropriate syntax. - -If you follow the PKIX recommendations of not including any qualifiers and just -using only one OID then you just include the value of that OID. Multiple OIDs -can be set separated by commas, for example: - -certificatePolicies= 1.2.4.5, 1.1.3.4 - -If you wish to include qualifiers then the policy OID and qualifiers need to -be specified in a separate section: this is done by using the @section syntax -instead of a literal OID value. - -The section referred to must include the policy OID using the name -policyIdentifier, cPSuri qualifiers can be included using the syntax: - -CPS.nnn=value - -userNotice qualifiers can be set using the syntax: - -userNotice.nnn=@notice - -The value of the userNotice qualifier is specified in the relevant section. -This section can include explicitText, organization and noticeNumbers -options. explicitText and organization are text strings, noticeNumbers is a -comma separated list of numbers. The organization and noticeNumbers options -(if included) must BOTH be present. If you use the userNotice option with IE5 -then you need the 'ia5org' option at the top level to modify the encoding: -otherwise it will not be interpreted properly. - -Example: - -certificatePolicies=ia5org,1.2.3.4,1.5.6.7.8,@polsect - -[polsect] - -policyIdentifier = 1.3.5.8 -CPS.1="http://my.host.name/" -CPS.2="http://my.your.name/" -userNotice.1=@notice - -[notice] - -explicitText="Explicit Text Here" -organization="Organisation Name" -noticeNumbers=1,2,3,4 - -TECHNICAL NOTE: the ia5org option changes the type of the 'organization' field, -according to PKIX it should be of type DisplayText but Verisign uses an -IA5STRING and IE5 needs this too. - -Display only extensions. - -Some extensions are only partially supported and currently are only displayed -but cannot be set. These include private key usage period, CRL number, and -CRL reason. - -============================================================================== - X509V3 Extension code: programmers guide -============================================================================== - -The purpose of the extension code is twofold. It allows an extension to be -created from a string or structure describing its contents and it prints out an -extension in a human or machine readable form. - -1. Initialisation and cleanup. - -No special initialisation is needed before calling the extension functions. -You used to have to call X509V3_add_standard_extensions(); but this is no longer -required and this function no longer does anything. - -void X509V3_EXT_cleanup(void); - -This function should be called to cleanup the extension code if any custom -extensions have been added. If no custom extensions have been added then this -call does nothing. After this call all custom extension code is freed up but -you can still use the standard extensions. - -2. Printing and parsing extensions. - -The simplest way to print out extensions is via the standard X509 printing -routines: if you use the standard X509_print() function, the supported -extensions will be printed out automatically. - -The following functions allow finer control over extension display: - -int X509V3_EXT_print(BIO *out, X509_EXTENSION *ext, int flag, int indent); -int X509V3_EXT_print_fp(FILE *out, X509_EXTENSION *ext, int flag, int indent); - -These two functions print out an individual extension to a BIO or FILE pointer. -Currently the flag argument is unused and should be set to 0. The 'indent' -argument is the number of spaces to indent each line. - -void *X509V3_EXT_d2i(X509_EXTENSION *ext); - -This function parses an extension and returns its internal structure. The -precise structure you get back depends on the extension being parsed. If the -extension if basicConstraints you will get back a pointer to a -BASIC_CONSTRAINTS structure. Check out the source in crypto/x509v3 for more -details about the structures returned. The returned structure should be freed -after use using the relevant free function, BASIC_CONSTRAINTS_free() for -example. - -void * X509_get_ext_d2i(X509 *x, int nid, int *crit, int *idx); -void * X509_CRL_get_ext_d2i(X509_CRL *x, int nid, int *crit, int *idx); -void * X509_REVOKED_get_ext_d2i(X509_REVOKED *x, int nid, int *crit, int *idx); -void * X509V3_get_d2i(STACK_OF(X509_EXTENSION) *x, int nid, int *crit, int *idx); - -These functions combine the operations of searching for extensions and -parsing them. They search a certificate, a CRL a CRL entry or a stack -of extensions respectively for extension whose NID is 'nid' and return -the parsed result of NULL if an error occurred. For example: - -BASIC_CONSTRAINTS *bs; -bs = X509_get_ext_d2i(cert, NID_basic_constraints, NULL, NULL); - -This will search for the basicConstraints extension and either return -it value or NULL. NULL can mean either the extension was not found, it -occurred more than once or it could not be parsed. - -If 'idx' is NULL then an extension is only parsed if it occurs precisely -once. This is standard behaviour because extensions normally cannot occur -more than once. If however more than one extension of the same type can -occur it can be used to parse successive extensions for example: - -int i; -void *ext; - -i = -1; -for(;;) { - ext = X509_get_ext_d2i(x, nid, crit, &idx); - if(ext == NULL) break; - /* Do something with ext */ -} - -If 'crit' is not NULL and the extension was found then the int it points to -is set to 1 for critical extensions and 0 for non critical. Therefore if the -function returns NULL but 'crit' is set to 0 or 1 then the extension was -found but it could not be parsed. - -The int pointed to by crit will be set to -1 if the extension was not found -and -2 if the extension occurred more than once (this will only happen if -idx is NULL). In both cases the function will return NULL. - -3. Generating extensions. - -An extension will typically be generated from a configuration file, or some -other kind of configuration database. - -int X509V3_EXT_add_conf(LHASH *conf, X509V3_CTX *ctx, char *section, - X509 *cert); -int X509V3_EXT_CRL_add_conf(LHASH *conf, X509V3_CTX *ctx, char *section, - X509_CRL *crl); - -These functions add all the extensions in the given section to the given -certificate or CRL. They will normally be called just before the certificate -or CRL is due to be signed. Both return 0 on error on non zero for success. - -In each case 'conf' is the LHASH pointer of the configuration file to use -and 'section' is the section containing the extension details. - -See the 'context functions' section for a description of the ctx parameter. - - -X509_EXTENSION *X509V3_EXT_conf(LHASH *conf, X509V3_CTX *ctx, char *name, - char *value); - -This function returns an extension based on a name and value pair, if the -pair will not need to access other sections in a config file (or there is no -config file) then the 'conf' parameter can be set to NULL. - -X509_EXTENSION *X509V3_EXT_conf_nid(char *conf, X509V3_CTX *ctx, int nid, - char *value); - -This function creates an extension in the same way as X509V3_EXT_conf() but -takes the NID of the extension rather than its name. - -For example to produce basicConstraints with the CA flag and a path length of -10: - -x = X509V3_EXT_conf_nid(NULL, NULL, NID_basic_constraints,"CA:TRUE,pathlen:10"); - - -X509_EXTENSION *X509V3_EXT_i2d(int ext_nid, int crit, void *ext_struc); - -This function sets up an extension from its internal structure. The ext_nid -parameter is the NID of the extension and 'crit' is the critical flag. - -4. Context functions. - -The following functions set and manipulate an extension context structure. -The purpose of the extension context is to allow the extension code to -access various structures relating to the "environment" of the certificate: -for example the issuers certificate or the certificate request. - -void X509V3_set_ctx(X509V3_CTX *ctx, X509 *issuer, X509 *subject, - X509_REQ *req, X509_CRL *crl, int flags); - -This function sets up an X509V3_CTX structure with details of the certificate -environment: specifically the issuers certificate, the subject certificate, -the certificate request and the CRL: if these are not relevant or not -available then they can be set to NULL. The 'flags' parameter should be set -to zero. - -X509V3_set_ctx_test(ctx) - -This macro is used to set the 'ctx' structure to a 'test' value: this is to -allow the syntax of an extension (or configuration file) to be tested. - -X509V3_set_ctx_nodb(ctx) - -This macro is used when no configuration database is present. - -void X509V3_set_conf_lhash(X509V3_CTX *ctx, LHASH *lhash); - -This function is used to set the configuration database when it is an LHASH -structure: typically a configuration file. - -The following functions are used to access a configuration database: they -should only be used in RAW extensions. - -char * X509V3_get_string(X509V3_CTX *ctx, char *name, char *section); - -This function returns the value of the parameter "name" in "section", or NULL -if there has been an error. - -void X509V3_string_free(X509V3_CTX *ctx, char *str); - -This function frees up the string returned by the above function. - -STACK_OF(CONF_VALUE) * X509V3_get_section(X509V3_CTX *ctx, char *section); - -This function returns a whole section as a STACK_OF(CONF_VALUE) . - -void X509V3_section_free( X509V3_CTX *ctx, STACK_OF(CONF_VALUE) *section); - -This function frees up the STACK returned by the above function. - -Note: it is possible to use the extension code with a custom configuration -database. To do this the "db_meth" element of the X509V3_CTX structure should -be set to an X509V3_CTX_METHOD structure. This structure contains the following -function pointers: - -char * (*get_string)(void *db, char *section, char *value); -STACK_OF(CONF_VALUE) * (*get_section)(void *db, char *section); -void (*free_string)(void *db, char * string); -void (*free_section)(void *db, STACK_OF(CONF_VALUE) *section); - -these will be called and passed the 'db' element in the X509V3_CTX structure -to access the database. If a given function is not implemented or not required -it can be set to NULL. - -5. String helper functions. - -There are several "i2s" and "s2i" functions that convert structures to and -from ASCII strings. In all the "i2s" cases the returned string should be -freed using Free() after use. Since some of these are part of other extension -code they may take a 'method' parameter. Unless otherwise stated it can be -safely set to NULL. - -char *i2s_ASN1_OCTET_STRING(X509V3_EXT_METHOD *method, ASN1_OCTET_STRING *oct); - -This returns a hex string from an ASN1_OCTET_STRING. - -char * i2s_ASN1_INTEGER(X509V3_EXT_METHOD *meth, ASN1_INTEGER *aint); -char * i2s_ASN1_ENUMERATED(X509V3_EXT_METHOD *meth, ASN1_ENUMERATED *aint); - -These return a string decimal representations of an ASN1_INTEGER and an -ASN1_ENUMERATED type, respectively. - -ASN1_OCTET_STRING *s2i_ASN1_OCTET_STRING(X509V3_EXT_METHOD *method, - X509V3_CTX *ctx, char *str); - -This converts an ASCII hex string to an ASN1_OCTET_STRING. - -ASN1_INTEGER * s2i_ASN1_INTEGER(X509V3_EXT_METHOD *meth, char *value); - -This converts a decimal ASCII string into an ASN1_INTEGER. - -6. Multi valued extension helper functions. - -The following functions can be used to manipulate STACKs of CONF_VALUE -structures, as used by multi valued extensions. - -int X509V3_get_value_bool(CONF_VALUE *value, int *asn1_bool); - -This function expects a boolean value in 'value' and sets 'asn1_bool' to -it. That is it sets it to 0 for FALSE or 0xff for TRUE. The following -strings are acceptable: "TRUE", "true", "Y", "y", "YES", "yes", "FALSE" -"false", "N", "n", "NO" or "no". - -int X509V3_get_value_int(CONF_VALUE *value, ASN1_INTEGER **aint); - -This accepts a decimal integer of arbitrary length and sets an ASN1_INTEGER. - -int X509V3_add_value(const char *name, const char *value, - STACK_OF(CONF_VALUE) **extlist); - -This simply adds a string name and value pair. - -int X509V3_add_value_uchar(const char *name, const unsigned char *value, - STACK_OF(CONF_VALUE) **extlist); - -The same as above but for an unsigned character value. - -int X509V3_add_value_bool(const char *name, int asn1_bool, - STACK_OF(CONF_VALUE) **extlist); - -This adds either "TRUE" or "FALSE" depending on the value of 'asn1_bool' - -int X509V3_add_value_bool_nf(char *name, int asn1_bool, - STACK_OF(CONF_VALUE) **extlist); - -This is the same as above except it adds nothing if asn1_bool is FALSE. - -int X509V3_add_value_int(const char *name, ASN1_INTEGER *aint, - STACK_OF(CONF_VALUE) **extlist); - -This function adds the value of the ASN1_INTEGER in decimal form. - -7. Other helper functions. - -<to be added> - -ADDING CUSTOM EXTENSIONS. - -Currently there are three types of supported extensions. - -String extensions are simple strings where the value is placed directly in the -extensions, and the string returned is printed out. - -Multi value extensions are passed a STACK_OF(CONF_VALUE) name and value pairs -or return a STACK_OF(CONF_VALUE). - -Raw extensions are just passed a BIO or a value and it is the extensions -responsibility to handle all the necessary printing. - -There are two ways to add an extension. One is simply as an alias to an already -existing extension. An alias is an extension that is identical in ASN1 structure -to an existing extension but has a different OBJECT IDENTIFIER. This can be -done by calling: - -int X509V3_EXT_add_alias(int nid_to, int nid_from); - -'nid_to' is the new extension NID and 'nid_from' is the already existing -extension NID. - -Alternatively an extension can be written from scratch. This involves writing -the ASN1 code to encode and decode the extension and functions to print out and -generate the extension from strings. The relevant functions are then placed in -a X509V3_EXT_METHOD structure and int X509V3_EXT_add(X509V3_EXT_METHOD *ext); -called. - -The X509V3_EXT_METHOD structure is described below. - -struct { -int ext_nid; -int ext_flags; -X509V3_EXT_NEW ext_new; -X509V3_EXT_FREE ext_free; -X509V3_EXT_D2I d2i; -X509V3_EXT_I2D i2d; -X509V3_EXT_I2S i2s; -X509V3_EXT_S2I s2i; -X509V3_EXT_I2V i2v; -X509V3_EXT_V2I v2i; -X509V3_EXT_R2I r2i; -X509V3_EXT_I2R i2r; - -void *usr_data; -}; - -The elements have the following meanings. - -ext_nid is the NID of the object identifier of the extension. - -ext_flags is set of flags. Currently the only external flag is - X509V3_EXT_MULTILINE which means a multi valued extensions - should be printed on separate lines. - -usr_data is an extension specific pointer to any relevant data. This - allows extensions to share identical code but have different - uses. An example of this is the bit string extension which uses - usr_data to contain a list of the bit names. - -All the remaining elements are function pointers. - -ext_new is a pointer to a function that allocates memory for the - extension ASN1 structure: for example ASN1_OBJECT_new(). - -ext_free is a pointer to a function that free up memory of the extension - ASN1 structure: for example ASN1_OBJECT_free(). - -d2i is the standard ASN1 function that converts a DER buffer into - the internal ASN1 structure: for example d2i_ASN1_IA5STRING(). - -i2d is the standard ASN1 function that converts the internal - structure into the DER representation: for example - i2d_ASN1_IA5STRING(). - -The remaining functions are depend on the type of extension. One i2X and -one X2i should be set and the rest set to NULL. The types set do not need -to match up, for example the extension could be set using the multi valued -v2i function and printed out using the raw i2r. - -All functions have the X509V3_EXT_METHOD passed to them in the 'method' -parameter and an X509V3_CTX structure. Extension code can then access the -parent structure via the 'method' parameter to for example make use of the value -of usr_data. If the code needs to use detail relating to the request it can -use the 'ctx' parameter. - -A note should be given here about the 'flags' member of the 'ctx' parameter. -If it has the value CTX_TEST then the configuration syntax is being checked -and no actual certificate or CRL exists. Therefore any attempt in the config -file to access such information should silently succeed. If the syntax is OK -then it should simply return a (possibly bogus) extension, otherwise it -should return NULL. - -char *i2s(struct v3_ext_method *method, void *ext); - -This function takes the internal structure in the ext parameter and returns -a Malloc'ed string representing its value. - -void * s2i(struct v3_ext_method *method, struct v3_ext_ctx *ctx, char *str); - -This function takes the string representation in the ext parameter and returns -an allocated internal structure: ext_free() will be used on this internal -structure after use. - -i2v and v2i handle a STACK_OF(CONF_VALUE): - -typedef struct -{ - char *section; - char *name; - char *value; -} CONF_VALUE; - -Only the name and value members are currently used. - -STACK_OF(CONF_VALUE) * i2v(struct v3_ext_method *method, void *ext); - -This function is passed the internal structure in the ext parameter and -returns a STACK of CONF_VALUE structures. The values of name, value, -section and the structure itself will be freed up with Free after use. -Several helper functions are available to add values to this STACK. - -void * v2i(struct v3_ext_method *method, struct v3_ext_ctx *ctx, - STACK_OF(CONF_VALUE) *values); - -This function takes a STACK_OF(CONF_VALUE) structures and should set the -values of the external structure. This typically uses the name element to -determine which structure element to set and the value element to determine -what to set it to. Several helper functions are available for this -purpose (see above). - -int i2r(struct v3_ext_method *method, void *ext, BIO *out, int indent); - -This function is passed the internal extension structure in the ext parameter -and sends out a human readable version of the extension to out. The 'indent' -parameter should be noted to determine the necessary amount of indentation -needed on the output. - -void * r2i(struct v3_ext_method *method, struct v3_ext_ctx *ctx, char *str); - -This is just passed the string representation of the extension. It is intended -to be used for more elaborate extensions where the standard single and multi -valued options are insufficient. They can use the 'ctx' parameter to parse the -configuration database themselves. See the context functions section for details -of how to do this. - -Note: although this type takes the same parameters as the "r2s" function there -is a subtle difference. Whereas an "r2i" function can access a configuration -database an "s2i" function MUST NOT. This is so the internal code can safely -assume that an "s2i" function will work without a configuration database. - -============================================================================== - PKCS#12 Library -============================================================================== - -This section describes the internal PKCS#12 support. There are very few -differences between the old external library and the new internal code at -present. This may well change because the external library will not be updated -much in future. - -This version now includes a couple of high level PKCS#12 functions which -generally "do the right thing" and should make it much easier to handle PKCS#12 -structures. - -HIGH LEVEL FUNCTIONS. - -For most applications you only need concern yourself with the high level -functions. They can parse and generate simple PKCS#12 files as produced by -Netscape and MSIE or indeed any compliant PKCS#12 file containing a single -private key and certificate pair. - -1. Initialisation and cleanup. - -No special initialisation is needed for the internal PKCS#12 library: the -standard SSLeay_add_all_algorithms() is sufficient. If you do not wish to -add all algorithms (you should at least add SHA1 though) then you can manually -initialise the PKCS#12 library with: - -PKCS12_PBE_add(); - -The memory allocated by the PKCS#12 library is freed up when EVP_cleanup() is -called or it can be directly freed with: - -EVP_PBE_cleanup(); - -after this call (or EVP_cleanup() ) no more PKCS#12 library functions should -be called. - -2. I/O functions. - -i2d_PKCS12_bio(bp, p12) - -This writes out a PKCS12 structure to a BIO. - -i2d_PKCS12_fp(fp, p12) - -This is the same but for a FILE pointer. - -d2i_PKCS12_bio(bp, p12) - -This reads in a PKCS12 structure from a BIO. - -d2i_PKCS12_fp(fp, p12) - -This is the same but for a FILE pointer. - -3. High level functions. - -3.1 Parsing with PKCS12_parse(). - -int PKCS12_parse(PKCS12 *p12, char *pass, EVP_PKEY **pkey, X509 **cert, - STACK **ca); - -This function takes a PKCS12 structure and a password (ASCII, null terminated) -and returns the private key, the corresponding certificate and any CA -certificates. If any of these is not required it can be passed as a NULL. -The 'ca' parameter should be either NULL, a pointer to NULL or a valid STACK -structure. Typically to read in a PKCS#12 file you might do: - -p12 = d2i_PKCS12_fp(fp, NULL); -PKCS12_parse(p12, password, &pkey, &cert, NULL); /* CAs not wanted */ -PKCS12_free(p12); - -3.2 PKCS#12 creation with PKCS12_create(). - -PKCS12 *PKCS12_create(char *pass, char *name, EVP_PKEY *pkey, X509 *cert, - STACK *ca, int nid_key, int nid_cert, int iter, - int mac_iter, int keytype); - -This function will create a PKCS12 structure from a given password, name, -private key, certificate and optional STACK of CA certificates. The remaining -5 parameters can be set to 0 and sensible defaults will be used. - -The parameters nid_key and nid_cert are the key and certificate encryption -algorithms, iter is the encryption iteration count, mac_iter is the MAC -iteration count and keytype is the type of private key. If you really want -to know what these last 5 parameters do then read the low level section. - -Typically to create a PKCS#12 file the following could be used: - -p12 = PKCS12_create(pass, "My Certificate", pkey, cert, NULL, 0,0,0,0,0); -i2d_PKCS12_fp(fp, p12); -PKCS12_free(p12); - -3.3 Changing a PKCS#12 structure password. - -int PKCS12_newpass(PKCS12 *p12, char *oldpass, char *newpass); - -This changes the password of an already existing PKCS#12 structure. oldpass -is the old password and newpass is the new one. An error occurs if the old -password is incorrect. - -LOW LEVEL FUNCTIONS. - -In some cases the high level functions do not provide the necessary -functionality. For example if you want to generate or parse more complex -PKCS#12 files. The sample pkcs12 application uses the low level functions -to display details about the internal structure of a PKCS#12 file. - -Introduction. - -This is a brief description of how a PKCS#12 file is represented internally: -some knowledge of PKCS#12 is assumed. - -A PKCS#12 object contains several levels. - -At the lowest level is a PKCS12_SAFEBAG. This can contain a certificate, a -CRL, a private key, encrypted or unencrypted, a set of safebags (so the -structure can be nested) or other secrets (not documented at present). -A safebag can optionally have attributes, currently these are: a unicode -friendlyName (a Unicode string) or a localKeyID (a string of bytes). - -At the next level is an authSafe which is a set of safebags collected into -a PKCS#7 ContentInfo. This can be just plain data, or encrypted itself. - -At the top level is the PKCS12 structure itself which contains a set of -authSafes in an embedded PKCS#7 Contentinfo of type data. In addition it -contains a MAC which is a kind of password protected digest to preserve -integrity (so any unencrypted stuff below can't be tampered with). - -The reason for these levels is so various objects can be encrypted in various -ways. For example you might want to encrypt a set of private keys with -triple-DES and then include the related certificates either unencrypted or -with lower encryption. Yes it's the dreaded crypto laws at work again which -allow strong encryption on private keys and only weak encryption on other -stuff. - -To build one of these things you turn all certificates and keys into safebags -(with optional attributes). You collect the safebags into (one or more) STACKS -and convert these into authsafes (encrypted or unencrypted). The authsafes -are collected into a STACK and added to a PKCS12 structure. Finally a MAC -inserted. - -Pulling one apart is basically the reverse process. The MAC is verified against -the given password. The authsafes are extracted and each authsafe split into -a set of safebags (possibly involving decryption). Finally the safebags are -decomposed into the original keys and certificates and the attributes used to -match up private key and certificate pairs. - -Anyway here are the functions that do the dirty work. - -1. Construction functions. - -1.1 Safebag functions. - -M_PKCS12_x5092certbag(x509) - -This macro takes an X509 structure and returns a certificate bag. The -X509 structure can be freed up after calling this function. - -M_PKCS12_x509crl2certbag(crl) - -As above but for a CRL. - -PKCS8_PRIV_KEY_INFO *PKEY2PKCS8(EVP_PKEY *pkey) - -Take a private key and convert it into a PKCS#8 PrivateKeyInfo structure. -Works for both RSA and DSA private keys. NB since the PKCS#8 PrivateKeyInfo -structure contains a private key data in plain text form it should be free'd -up as soon as it has been encrypted for security reasons (freeing up the -structure zeros out the sensitive data). This can be done with -PKCS8_PRIV_KEY_INFO_free(). - -PKCS8_add_keyusage(PKCS8_PRIV_KEY_INFO *p8, int usage) - -This sets the key type when a key is imported into MSIE or Outlook 98. Two -values are currently supported: KEY_EX and KEY_SIG. KEY_EX is an exchange type -key that can also be used for signing but its size is limited in the export -versions of MS software to 512 bits, it is also the default. KEY_SIG is a -signing only key but the keysize is unlimited (well 16K is supposed to work). -If you are using the domestic version of MSIE then you can ignore this because -KEY_EX is not limited and can be used for both. - -PKCS12_SAFEBAG *PKCS12_MAKE_KEYBAG(PKCS8_PRIV_KEY_INFO *p8) - -Convert a PKCS8 private key structure into a keybag. This routine embeds the -p8 structure in the keybag so p8 should not be freed up or used after it is -called. The p8 structure will be freed up when the safebag is freed. - -PKCS12_SAFEBAG *PKCS12_MAKE_SHKEYBAG(int pbe_nid, unsigned char *pass, int passlen, unsigned char *salt, int saltlen, int iter, PKCS8_PRIV_KEY_INFO *p8) - -Convert a PKCS#8 structure into a shrouded key bag (encrypted). p8 is not -embedded and can be freed up after use. - -int PKCS12_add_localkeyid(PKCS12_SAFEBAG *bag, unsigned char *name, int namelen) -int PKCS12_add_friendlyname(PKCS12_SAFEBAG *bag, unsigned char *name, int namelen) - -Add a local key id or a friendlyname to a safebag. - -1.2 Authsafe functions. - -PKCS7 *PKCS12_pack_p7data(STACK *sk) -Take a stack of safebags and convert them into an unencrypted authsafe. The -stack of safebags can be freed up after calling this function. - -PKCS7 *PKCS12_pack_p7encdata(int pbe_nid, unsigned char *pass, int passlen, unsigned char *salt, int saltlen, int iter, STACK *bags); - -As above but encrypted. - -1.3 PKCS12 functions. - -PKCS12 *PKCS12_init(int mode) - -Initialise a PKCS12 structure (currently mode should be NID_pkcs7_data). - -M_PKCS12_pack_authsafes(p12, safes) - -This macro takes a STACK of authsafes and adds them to a PKCS#12 structure. - -int PKCS12_set_mac(PKCS12 *p12, unsigned char *pass, int passlen, unsigned char *salt, int saltlen, int iter, EVP_MD *md_type); - -Add a MAC to a PKCS12 structure. If EVP_MD is NULL use SHA-1, the spec suggests -that SHA-1 should be used. - -2. Extraction Functions. - -2.1 Safebags. - -M_PKCS12_bag_type(bag) - -Return the type of "bag". Returns one of the following - -NID_keyBag -NID_pkcs8ShroudedKeyBag 7 -NID_certBag 8 -NID_crlBag 9 -NID_secretBag 10 -NID_safeContentsBag 11 - -M_PKCS12_cert_bag_type(bag) - -Returns type of certificate bag, following are understood. - -NID_x509Certificate 14 -NID_sdsiCertificate 15 - -M_PKCS12_crl_bag_type(bag) - -Returns crl bag type, currently only NID_crlBag is recognised. - -M_PKCS12_certbag2x509(bag) - -This macro extracts an X509 certificate from a certificate bag. - -M_PKCS12_certbag2x509crl(bag) - -As above but for a CRL. - -EVP_PKEY * PKCS82PKEY(PKCS8_PRIV_KEY_INFO *p8) - -Extract a private key from a PKCS8 private key info structure. - -M_PKCS12_decrypt_skey(bag, pass, passlen) - -Decrypt a shrouded key bag and return a PKCS8 private key info structure. -Works with both RSA and DSA keys - -char *PKCS12_get_friendlyname(bag) - -Returns the friendlyName of a bag if present or NULL if none. The returned -string is a null terminated ASCII string allocated with Malloc(). It should -thus be freed up with Free() after use. - -2.2 AuthSafe functions. - -M_PKCS12_unpack_p7data(p7) - -Extract a STACK of safe bags from a PKCS#7 data ContentInfo. - -#define M_PKCS12_unpack_p7encdata(p7, pass, passlen) - -As above but for an encrypted content info. - -2.3 PKCS12 functions. - -M_PKCS12_unpack_authsafes(p12) - -Extract a STACK of authsafes from a PKCS12 structure. - -M_PKCS12_mac_present(p12) - -Check to see if a MAC is present. - -int PKCS12_verify_mac(PKCS12 *p12, unsigned char *pass, int passlen) - -Verify a MAC on a PKCS12 structure. Returns an error if MAC not present. - - -Notes. - -1. All the function return 0 or NULL on error. -2. Encryption based functions take a common set of parameters. These are -described below. - -pass, passlen -ASCII password and length. The password on the MAC is called the "integrity -password" the encryption password is called the "privacy password" in the -PKCS#12 documentation. The passwords do not have to be the same. If -1 is -passed for the length it is worked out by the function itself (currently -this is sometimes done whatever is passed as the length but that may change). - -salt, saltlen -A 'salt' if salt is NULL a random salt is used. If saltlen is also zero a -default length is used. - -iter -Iteration count. This is a measure of how many times an internal function is -called to encrypt the data. The larger this value is the longer it takes, it -makes dictionary attacks on passwords harder. NOTE: Some implementations do -not support an iteration count on the MAC. If the password for the MAC and -encryption is the same then there is no point in having a high iteration -count for encryption if the MAC has no count. The MAC could be attacked -and the password used for the main decryption. - -pbe_nid -This is the NID of the password based encryption method used. The following are -supported. -NID_pbe_WithSHA1And128BitRC4 -NID_pbe_WithSHA1And40BitRC4 -NID_pbe_WithSHA1And3_Key_TripleDES_CBC -NID_pbe_WithSHA1And2_Key_TripleDES_CBC -NID_pbe_WithSHA1And128BitRC2_CBC -NID_pbe_WithSHA1And40BitRC2_CBC - -Which you use depends on the implementation you are exporting to. "Export -grade" (i.e. cryptographically challenged) products cannot support all -algorithms. Typically you may be able to use any encryption on shrouded key -bags but they must then be placed in an unencrypted authsafe. Other authsafes -may only support 40bit encryption. Of course if you are using SSLeay -throughout you can strongly encrypt everything and have high iteration counts -on everything. - -3. For decryption routines only the password and length are needed. - -4. Unlike the external version the nid's of objects are the values of the -constants: that is NID_certBag is the real nid, therefore there is no -PKCS12_obj_offset() function. Note the object constants are not the same as -those of the external version. If you use these constants then you will need -to recompile your code. - -5. With the exception of PKCS12_MAKE_KEYBAG(), after calling any function or -macro of the form PKCS12_MAKE_SOMETHING(other) the "other" structure can be -reused or freed up safely. - |