.\" $OpenBSD: keynote.3,v 1.38 2004/06/26 12:11:41 jmc Exp $ .\" .\" The author of this code is Angelos D. Keromytis (angelos@dsl.cis.upenn.edu) .\" .\" This code was written by Angelos D. Keromytis in Philadelphia, PA, USA, .\" in April-May 1998 .\" .\" Copyright (C) 1998, 1999 by Angelos D. Keromytis. .\" .\" Permission to use, copy, and modify this software with or without fee .\" is hereby granted, provided that this entire notice is included in .\" all copies of any software which is or includes a copy or .\" modification of this software. .\" You may use this code under the GNU public license if you so wish. Please .\" contribute changes back to the author. .\" .\" THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR .\" IMPLIED WARRANTY. IN PARTICULAR, THE AUTHORS MAKES NO .\" REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE .\" MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR .\" PURPOSE. .\" .Dd April 29, 1999 .Dt KEYNOTE 3 .\" .TH KeyNote 3 local .Os .Sh NAME .Nm keynote .Nd a trust-management system library .Sh SYNOPSIS .Fd #include <sys/types.h> .Fd #include <regex.h> .Fd #include <keynote.h> .Pp .Bd -literal struct environment { char *env_name; char *env_value; int env_flags; regex_t env_regex; struct environment *env_next; }; struct keynote_deckey { int dec_algorithm; void *dec_key; }; struct keynote_binary { int bn_len; char *bn_key; }; struct keynote_keylist { int key_alg; void *key_key; char *key_stringkey; struct keynote_keylist *key_next; }; .Ed .Vt extern int keynote_errno; .Ft int .Fn kn_init "void" .Ft int .Fn kn_add_assertion "int sessid" "char *assertion" "int len" "int flags" .Ft int .Fn kn_remove_assertion "int sessid" "int assertid" .Ft int .Fn kn_add_action "int sessid" "char *name" "char *value" "int flags" .Ft int .Fn kn_remove_action "int sessid" "char *name" .Ft int .Fn kn_add_authorizer "int sessid" "char *principal" .Ft int .Fn kn_remove_authorizer "int sessid" "char *principal" .Ft int .Fn kn_do_query "int sessid" "char **returnvalues" "int numvalues" .Ft int .Fn kn_get_failed "int sessid" "int type" "int seq" .Ft int .Fn kn_cleanup_action_environment "int sessid" .Ft int .Fn kn_close "int sessid" .Ft int .Fn kn_query "struct environment *env" "char **returnvalues, int numvalues" "char **trusted, int *trustedlen, int numtrusted" "char **untrusted, int *untrustedlen, int numuntrusted" "char **authorizers, int numauthauthorizers" .Ft char ** .Fn kn_read_asserts "char *array" "int arraylen" "int *numassertions" .Ft int .Fn kn_keycompare "void *key1" "void *key2" "int algorithm" .Ft void * .Fn kn_get_authorizer "int sessid" "int assertid" "int *algorithm" .Ft struct keynote_keylist * .Fn kn_get_licensees "int sessid" "int assertid" .Ft int .Fn kn_encode_base64 "unsigned char const *src" "unsigned int srclen" "char *dst" "unsigned int dstlen" .Ft int .Fn kn_decode_base64 "char const *src" "unsigned char *dst" "unsigned int dstlen" .Ft int .Fn kn_encode_hex "unsigned char *src" "char **dst" "int srclen" .Ft int .Fn kn_decode_hex "char *src" "char **dst" .Ft char * .Fn kn_encode_key "struct keynote_deckey *dc" "int iencoding" "int encoding" "int keytype" .Ft int .Fn kn_decode_key "struct keynote_deckey *dc" "char *key" "int keytype" .Ft char * .Fn kn_sign_assertion "char *assertion" "int len" "char *key" "char *algorithm" "int vflag" .Ft int .Fn kn_verify_assertion "char *assertion" "int len" .Ft void .Fn kn_free_key "struct keynote_deckey *" .Ft char * .Fn kn_get_string "char *" .Fd Link options: -lkeynote -lm -lcrypto .Sh DESCRIPTION For more details on .Nm keynote , see RFC 2704. .Pp .Va keynote_errno contains an error code if some library call failed. Failed calls return \-1 (if their return value is integer), or .Dv NULL (if their return value is a pointer) and set .Va keynote_errno . The defined error codes are: .Bl -tag -width "ERROR_NOTFOUND" -offset indent .It Li ERROR_MEMORY Some memory allocation or usage error was encountered. .It Li ERROR_SYNTAX Some syntactic or logical error was encountered. .It Li ERROR_NOTFOUND One of the arguments referred to a nonexistent structure or entry. .El .Pp If no errors were encountered, .Va keynote_errno will be set to 0. This variable should be reset to 0 if an error was encountered, prior to calling other library routines. .Pp The main interface to .Nm is centered around the concept of a session. A session describes a collection of policies, assertions, action authorizers, return values, and action attributes that the .Nm system uses to evaluate a query. Information is not shared between sessions. Policies, credentials, action authorizers, and action attributes can be added or deleted at any point during the lifetime of a session. Furthermore, an application can discover which assertions failed to be evaluated, and in what way, during a query. .Pp For those applications that only need to do a simple query, there exists a single call that takes as arguments all the necessary information and performs all the necessary steps. This is essentially a wrapper that calls the session API functions as necessary. .Pp Finally, there exist functions for doing ASCII to hexadecimal and Base64 encoding (and vice versa), for encoding/decoding keys between ASCII and binary formats, and for signing and verifying assertions. .Pp The description of all .Nm library functions follows. .Pp .Fn kn_init creates a new .Nm session, and performs any necessary initializations. On success, this function returns the new session ID, which is used by all subsequent calls with a .Fa sessid argument. On failure, it returns \-1 and sets .Va keynote_errno to .Er ERROR_MEMORY . .Pp .Fn kn_add_assertion adds the assertion pointed to by the array .Fa assertion , of length .Fa len in the session identified by .Fa sessid . The first argument can be discarded after the call to this function. The following flags are defined: .Bl -tag -width ASSERT_FLAG_LOCAL -offset indent .It ASSERT_FLAG_LOCAL Mark this assertion as ultimately trusted. Trusted assertions need not be signed, and the .Fa Authorizer and .Fa Licensees fields can have non-key entries. .El .Pp At least one (trusted) assertion should have .Dv POLICY as the .Fa Authorizer . On success, this function will return an assertion ID which can be used to remove the assertion from the session, by using .Xr kn_remove_assertion 3 . On failure, \-1 is returned, and .Va keynote_errno is set to .Er ERROR_NOTFOUND if the session was not found, .Er ERROR_SYNTAX if the assertion was syntactically incorrect, or .Er ERROR_MEMORY if necessary memory could not be allocated. .Pp .Fn kn_remove_assertion removes the assertion identified by .Fa assertid from the session identified by .Fa sessid . On success, this function returns 0. On failure, it returns \-1 and sets .Va keynote_errno to .Er ERROR_NOTFOUND . .Pp .Fn kn_add_action inserts the variable .Fa name in the action environment of session .Fa sessid , with the value .Fa value . The same attribute may be added more than once, but only the last instance will be used (memory resources are consumed however). .Pp The .Fa flags specified are formed by or'ing the following values: .Bl -tag -width ENVIRONMENT_FLAG_REGEX -offset indent .It ENVIRONMENT_FLAG_FUNC In this case, .Fa value is a pointer to a function that takes as argument a string and returns a string. This is used to implement callbacks for getting action attribute values. The argument passed to such a callback function is a string identifying the action attribute whose value is requested, and should return a pointer to string containing that value (this pointer will not be freed by the library), the empty string if the value was not found, or a .Dv NULL to indicate an error (and may set .Va keynote_errno appropriately). Prior to first use (currently, at the time the attribute is added to the session environment), such functions are called with .Dv KEYNOTE_CALLBACK_INITIALIZE as the argument (defined in keynote.h) so that they can perform any special initializations. Furthermore, when the session is deleted, all such functions will be called with .Dv KEYNOTE_CALLBACK_CLEANUP to perform any special cleanup (such as free any allocated memory). A function may be called with either of these arguments more than once, if it has been defined as the callback function for more than one attribute. .It ENVIRONMENT_FLAG_REGEX In this case, .Fa name is a regular expression that may match more than one attribute. In case of conflict between a regular expression and a .Dq simple attribute, the latter will be given priority. In case of conflict between two regular expression attributes, the one added later will be given priority. A callback function should never change the current .Nm session, start/invoke/operate on another session, or call one of the session-API functions. .El .Pp The combination of the two flags may be used to specify callback functions that handle large sets of attributes (even to the extent of having one callback function handling all attribute references). This is particularly useful when the action attribute set is particularly large. .Pp On success, .Xr kn_add_action 3 returns 0. On failure, it returns \-1 and sets .Va keynote_errno to .Er ERROR_NOTFOUND if the session was not found, .Er ERROR_SYNTAX if the .Fa name was invalid (e.g., started with an underscore character) or was .Dv NULL , or .Er ERROR_MEMORY if necessary memory could not be allocated. .Pp .Fn kn_remove_action removes action attribute .Fa name from the environment of session .Fa sessid . Notice that if more than one instances of .Fa name exist, only the one added last will be deleted. On success, this function returns 0. On failure, it returns \-1 and .Va keynote_errno is set to .Er ERROR_NOTFOUND if the session or the attribute were not found, or .Er ERROR_SYNTAX if the name was invalid. If the attribute value was a callback, that function will be called with the define .Dv KEYNOTE_CALLBACK_CLEANUP as the argument. .Pp .Fn kn_add_authorizer adds the principal pointed to by .Fa principal to the action authorizers list of session .Fa sessid . The principal is typically an ASCII-encoded key. On success, this function will return 0. On failure, it returns \-1 and sets .Va keynote_errno to .Er ERROR_NOTFOUND if the session was not found, .Er ERROR_SYNTAX if the encoding was invalid, or .Er ERROR_MEMORY if necessary memory could not be allocated. .Pp .Fn kn_remove_authorizer removes .Fa principal from the action authorizer list of session .Fa sessid . On success, this function returns 0. On failure, it returns \-1 and sets .Va keynote_errno to .Er ERROR_NOTFOUND if the session was not found. .Pp .Fn kn_do_query evaluates the request based on the assertions, action attributes, and action authorizers added to session .Fa sessid . .Fa returnvalues is an ordered array of strings that contain the return values. The lowest-ordered return value is contained in .Fa returnvalues[0] , and the highest-ordered value is .Fa returnvalues[numvalues - 1] . If .Fa returnvalues is .Dv NULL , the .Fa returnvalues from the previous call to .Xr kn_do_query 3 will be used. The programmer SHOULD NOT free .Fa returnvalues after the call to .Xr kn_do_query 3 if this feature is used, as the array is not replicated internally. On success, this function returns an index into the .Fa returnvalues array. On failure, it returns \-1 and sets .Va keynote_errno to .Er ERROR_NOTFOUND if the session was not found or the authorizers list was empty, .Er ERROR_SYNTAX if no .Fa returnvalues have been specified, or .Er ERROR_MEMORY if necessary memory could not be allocated. .Pp .Fn kn_get_failed returns the assertion ID of the .Fa num'th assertion (starting from zero) in session .Fa sessid that was somehow invalid during evaluation. This function is typically called after .Xr kn_do_query 3 is used to evaluate a request. .Fa type specifies the type of failure the application is interested in. It can be set to: .Bl -tag -width KEYNOTE_ERROR_SIGNATURE -offset indent .It KEYNOTE_ERROR_ANY to indicate interest in any error. .It KEYNOTE_ERROR_SYNTAX for syntactic or semantic errors. .It KEYNOTE_ERROR_MEMORY for memory-related problems. .It KEYNOTE_ERROR_SIGNATURE if the assertion could not be cryptographically verified. .El .Pp These values are defined in keynote.h. An application can then delete the offending assertion using .Xr kn_remove_assertion 3 . For example, to remove all assertion whose signature failed, an application could do something like: .Bd -literal while ((assertid = kn_get_failed(sessid, KEYNOTE_ERROR_SIGNATURE, 0) != -1) kn_remove_assertion(sessid, assertid); .Ed .Pp On success, .Xr kn_get_failed 3 returns an assertion ID. On failure, or when no assertion matching the given criteria is found, it returns \-1 and set .Va keynote_errno to .Er ERROR_NOTFOUND . .Pp .Fn kn_cleanup_action_environment removes all action attributes from the action environment of session .Fa sessid . It returns 0 on success. .Pp .Fn kn_close closes session .Fa sessid and frees all related resources, deleting action attributes, action authorizers, and assertions. On success, this function returns 0. On failure, it returns \-1 and sets .Va keynote_errno to .Er ERROR_NOTFOUND if the session was not found. .Pp .Fn kn_read_asserts parses the string .Fa array of length .Fa arraylen and returns an array of pointers to strings containing copies of the assertions found in .Fa array . Both the array of pointers and the strings are allocated by .Fn kn_read_asserts dynamically, and thus should be freed by the programmer when they are no longer needed. .Fa numassertions contains the number of assertions (and thus strings in the returned array) found in .Fa array . On failure, this function returns .Dv NULL and sets .Va keynote_errno to .Er ERROR_MEMORY if necessary memory could not be allocated, or .Er ERROR_SYNTAX if .Fa array was .Dv NULL . Note that if there were no assertions found in .Fa array , a valid pointer will be returned, but .Fa numassertions will contain the value zero on return. The returned pointer should be freed by the programmer. .Pp .Fn kn_keycompare compares .Fa key1 and .Fa key2 (which must be of the same .Fa algorithm ) and returns 1 if equal and 0 otherwise. .Pp .Fn kn_get_authorizer returns the authorizer key (in binary format) for assertion .Fa assertid in session .Fa sessid . It also sets the .Fa algorithm argument to the algorithm of the authorizer key. On failure, .Fn kn_get_authorizer returns .Dv NULL , and sets .Va keynote_errno to .Er ERROR_NOTFOUND . .Pp .Fn kn_get_licensees returns the licensee key(s) for assertion .Fa assertid in session .Fa sessid . The keys are returned in a linked list of .Fa struct keynote_keylist structures. On failure, .Fn kn_get_licensees returns .Dv NULL . and sets .Va keynote_errno to .Er ERROR_NOTFOUND . .Pp .Fn kn_query takes as arguments a list of action attributes in .Fa env , a list of return values in .Fa returnvalues (the number of returnvalues is indicated by .Fa numvalues ) , a number .Pf ( Fa numtrusted ) of locally-trusted assertions in .Fa trusted (the length of each assertion is given by the respective element of .Fa trustedlen ) , a number .Pf ( Fa numuntrusted ) of assertions that need to be cryptographically verified in .Fa untrusted (the length of each assertion is given by the respective element of .Fa untrustedlen ) , and a number .Pf ( Fa numauthorizers ) of action authorizers in .Fa authorizers . .Fa env is a linked list of .Fa struct environment structures. The .Fa env_name , .Fa env_value , and .Fa env_flags fields correspond to the .Fa name , .Fa value , and .Fa flags arguments to .Xr kn_add_assertion 3 respectively. .Fa env_regex is not used. On success, this function returns an index in .Fa returnvalues indicating the returned value to the query. On failure, it returns \-1 and sets .Va keynote_errno to the same values as .Xr kn_do_query 3 , or to .Er ERROR_MEMORY if a trusted or untrusted assertion could not be added to the session due to lack of memory resources. Syntax errors in assertions will not be reported by .Fn kn_query . .Pp .Fn kn_encode_base64 converts the data of length .Fa srclen contained in .Fa src in Base64 encoding and stores them in .Fa dst which is of length .Fa dstlen . The actual length of the encoding stored in .Fa dst is returned. .Fa dst should be long enough to also contain the trailing string terminator. If .Fa srclen is not a multiple of 4, or .Fa dst is not long enough to contain the encoded data, this function returns \-1 and sets .Va keynote_errno to .Er ERROR_SYNTAX . .Pp .Fn kn_decode_base64 decodes the Base64-encoded data stored in .Fa src and stores the result in .Fa dst , which is of length .Fa dstlen . The actual length of the decoded data is returned on success. On failure, this function returns \-1 and sets .Va keynote_errno to .Er ERROR_SYNTAX , denoting either an invalid Base64 encoding or insufficient space in .Fa dst . .Pp .Fn kn_encode_hex encodes in ASCII-hexadecimal format the data of length .Fa srclen contained in .Fa src . This function allocates a chunk of memory to store the result, which is returned in .Fa dst . Thus, this function should be used as follows: .Bd -literal char *dst; kn_encode_hex(src, &dst, srclen); .Ed .Pp The length of the allocated buffer will be (2 * srclen + 1). On success, this function returns 0. On failure, it returns \-1 and sets .Va keynote_errno to .Er ERROR_MEMORY if it failed to allocate enough memory, .Er ERROR_SYNTAX if .Fa dst was .Dv NULL . .Pp .Fn kn_decode_hex decodes the ASCII hex-encoded string in .Fa src and stores the result in a memory chunk allocated by the function. A pointer to that memory is stored in .Fa dst . The length of the allocated memory will be (strlen(src) / 2). On success, this function returns 0. On failure, it returns \-1 and sets .Va keynote_errno to .Er ERROR_MEMORY if it could not allocate enough memory, or .Er ERROR_SYNTAX if .Fa dst was .Dv NULL , or the length of .Fa src is not even. .Pp .Fn kn_encode_key ASCII-encodes a cryptographic key. The binary representation of the key is contained in .Fa dc . The field .Fa dec_key in that structure is a pointer to some cryptographic algorithm dependent information describing the key. In this implementation, this pointer should be a .Fa DSA * or .Fa RSA * for DSA or RSA keys respectively, as used in the SSL library, or a .Fa keynote_binary * for cryptographic keys whose algorithm .Nm does not know about but the application wishes to include in the action authorizers (and thus need to be canonicalized). The field .Fa dec_algorithm describes the cryptographic algorithm, and may be one of .Dv KEYNOTE_ALGORITHM_DSA , .Dv KEYNOTE_ALGORITHM_RSA , or .Dv KEYNOTE_ALGORITHM_BINARY in this implementation. .Pp .Fa iencoding describes how the key should be binary-encoded. This implementation supports .Dv INTERNAL_ENC_PKCS1 for RSA keys, .Dv INTERNAL_ENC_ASN1 for DSA keys, and .Dv INTERNAL_ENC_NONE for BINARY keys. .Fa encoding describes what ASCII encoding should be applied to the key. Valid values are .Dv ENCODING_HEX and .Dv ENCODING_BASE64 , for hexadecimal and Base64 encoding respectively. .Fa keytype is one of .Dv KEYNOTE_PUBLIC_KEY or .Dv KEYNOTE_PRIVATE_KEY to indicate whether the key is public or private. Private keys have the string .Dv KEYNOTE_PRIVATE_KEY_PREFIX (defined in keynote.h) prefixed to the algorithm name. On success, this function returns a string containing the encoded key. On failure, it returns .Dv NULL and sets .Va keynote_errno to .Er ERROR_NOTFOUND if the .Fa dc argument was invalid, .Er ERROR_MEMORY if it failed to allocate the necessary memory, or .Er ERROR_SYNTAX if the key to be converted was invalid. .Pp .Fn kn_decode_key decodes the ASCII-encoded string contained in .Fa key . The result is placed in .Fa dc , with .Fa dec_algorithm describing the algorithm (see .Xr kn_encode_key 3 ) , and .Fa dec_key pointing to an algorithm-dependent structure. In this implementation, this is an SSLeay/OpenSSL-defined .Fa DSA * for DSA keys, .Fa RSA * for RSA and X509-based keys, and a .Fa keynote_binary * for BINARY keys. .Fa keytype takes the values .Dv KEYNOTE_PUBLIC_KEY or .Dv KEYNOTE_PRIVATE_KEY to specify a public or private key, where applicable. On success, this function returns 0. On failure, it returns \-1 and sets .Va keynote_errno to .Er ERROR_MEMORY if necessary memory could not be allocated, or .Er ERROR_SYNTAX if the key or the ASCII encoding was malformed. .Pp .Fn kn_sign_assertion produces the cryptographic signature for the assertion of length .Fa len stored in .Fa assertion , using the ASCII-encoded cryptographic key contained in .Fa key . The type of signature to be produced is described by the string .Fa algorithm . Possible values for this string are .Dv SIG_RSA_SHA1_PKCS1_HEX , .Dv SIG_RSA_SHA1_PKCS1_BASE64 , .Dv SIG_RSA_MD5_HEX and .Dv SIG_RSA_MD5_HEX for RSA keys, .Dv SIG_DSA_SHA1_HEX and .Dv SIG_DSA_SHA1_BASE64 for DSA keys, .Dv SIG_X509_SHA1_HEX and .Dv SIG_X509_SHA1_BASE64 for X509-based keys. No other cryptographic signatures are currently supported by this implementation. If .Fa vflag is set to 1, then the generated signature will also be verified. On success, this function returns a string containing the ASCII-encoded signature, without modifying the .Fa assertion . On failure, it returns .Dv NULL and sets .Va keynote_errno to .Er ERROR_NOTFOUND if one of the arguments was .Dv NULL , .Er ERROR_MEMORY if necessary memory could not be allocated, or .Er ERROR_SYNTAX if the .Fa algorithm , the .Fa key , or the .Fa assertion (if signature verification was requested) was invalid. .Pp .Fn kn_verify_assertion verifies the cryptographic signature on the assertion of length .Fa len contained in string .Fa assertion . On success, this function returns .Dv SIGRESULT_TRUE if the signature could be verified, or .Dv SIGRESULT_FALSE otherwise. On failure, this function returns \-1 and sets .Va keynote_errno to .Er ERROR_MEMORY if necessary memory could not be allocated, or .Er ERROR_SYNTAX if the assertion contained a syntactic error, or the cryptographic algorithm was not supported. .Pp .Fn kn_free_key frees a cryptographic key. .Pp .Fn kn_get_string parses the argument, treating it as a .Xr keynote 4 (quoted) string. This is useful for parsing key files. On success, this function returns a pointer to the parsing result. The result is dynamically allocated and should be freed after use. On failure, .Dv NULL is returned. .Sh FILES .Bl -tag -width libkeynote.a -compact .It Pa keynote.h .It Pa libkeynote.a .El .Sh SEE ALSO .Xr keynote 1 , .Xr keynote 4 , .Xr keynote 5 .Rs .%A M. Blaze .%A J. Feigenbaum .%A A. D. Keromytis .%T "The KeyNote Trust-Management System, Version 2" .%N RFC 2704 .%D 1999 .Re .Rs .%A M. Blaze .%A J. Feigenbaum .%A J. Lacy .%T Decentralized Trust Management .%J IEEE Conference on Privacy and Security .%D 1996 .Re .Rs .%A M. Blaze .%A J. Feigenbaum .%A M. Strauss .%T Compliance-Checking in the PolicyMaker Trust Management System .%J Financial Crypto Conference .%D 1998 .Re .Sh AUTHORS .An Angelos D. Keromytis Aq angelos@dsl.cis.upenn.edu .Sh WEB PAGE .Pa http://www.cis.upenn.edu/~keynote .Sh DIAGNOSTICS The return values of all the functions have been given along with the function description above. .Sh BUGS None that we know of. If you find any, please report them to .Dl Aq keynote@research.att.com