keynote(3)                OpenBSD Programmer's Manual               keynote(3)

NAME
     keynote - a trust-management system library

SYNOPSIS
     #include <sys/types.h>
     #include <regex.h>
     #include <keynote.h>

     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;
     };

     int keynote_errno;

     int
     kn_init(void);

     int
     kn_add_assertion(int sessid, char *assertion, int len, int flags);

     int
     kn_remove_assertion(int sessid, int assertid);

     int
     kn_add_action(int sessid, char *name, char *value, int flags);

     int
     kn_remove_action(int sessid, char *name);

     int
     kn_add_authorizer(int sessid, char *principal);

     int
     kn_remove_authorizer(int sessid, char *principal);

     int
     kn_do_query(int sessid, char **returnvalues, int numvalues);

     int
     kn_get_failed(int sessid, int type, int seq);

     int
     kn_cleanup_action_environment(int sessid);

     int
     kn_close(int sessid);

     int
     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);

     char **
     kn_read_asserts(char *array, int arraylen, int *numassertions);

     int
     kn_keycompare(void *key1, void *key2, int algorithm);

     void *
     kn_get_authorizer(int sessid, int assertid, int *algorithm);

     struct keynote_keylist *
     kn_get_licensees(int sessid, int assertid);

     int
     kn_encode_base64(unsigned char const *src, unsigned int srclen,
             char *dst, unsigned int dstlen);

     int
     kn_decode_base64(char const *src, unsigned char *dst,
             unsigned int dstlen);

     int
     kn_encode_hex(unsigned char *src, char **dst, int srclen);

     int
     kn_decode_hex(char *src, char **dst);

     char *
     kn_encode_key(struct keynote_deckey *dc, int iencoding, int encoding,
             int keytype);

     int
     kn_decode_key(struct keynote_deckey *dc, char *key, int keytype);

     char *
     kn_sign_assertion(char *assertion, int len, char *key, char *algorithm,
             int vflag);

     int
     kn_verify_assertion(char *assertion, int len);

     Link options: -lkeynote -lm -lcrypto

DESCRIPTION
     For more details on KeyNote, see RFC 2704.

     keynote_errno contains an error code if some library call failed. Failed
     calls return -1 (if their return value is integer), or NULL (if their re-
     turn value is a pointer) and set keynote_errno. The defined error codes
     are:

           ERROR_MEMORY    Some memory allocation or usage error was encoun-

                           tered.

           ERROR_SYNTAX    Some syntactic or logical error was encountered.

           ERROR_NOTFOUND  One of the arguments referred to a nonexistent
                           structure or entry.

     If no errors were encountered, keynote_errno will be set to 0. This vari-
     able should be reset to 0 if an error was encountered, prior to calling
     other library routines.

     The main interface to KeyNote is centered around the concept of a ses-
     sion. A session describes a collection of policies, assertions, action
     authorizers, return values, and action attributes that the KeyNote 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. Further-
     more, an application can discover which assertions failed to be evaluat-
     ed, and in what way, during a query.

     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.

     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.

     The description of all KeyNote library functions follows.

     kn_init() creates a new KeyNote session, and performs any necessary ini-
     tializations. On success, this function returns the new session ID, which
     is used by all subsequent calls with a sessid argument.  On failure, it
     returns -1 and sets keynote_errno to ERROR_MEMORY.

     kn_add_assertion() adds the assertion pointed to by the array assertion,
     of length len in the session identified by sessid. The first argument can
     be discarded after the call to this function.  The following flags are
     defined:

           ASSERT_FLAG_LOCAL  Mark this assertion as ultimately trusted.
                              Trusted assertions need not be signed, and the
                              Authorizer and Licensees fields can have non-key
                              entries.

     At least one (trusted) assertion should have POLICY as the Authorizer. On
     success, this function will return an assertion ID which can be used to
     remove the assertion from the session, by using kn_remove_assertion(3).
     On failure, -1 is returned, and keynote_errno is set to ERROR_NOTFOUND if
     the session was not found, ERROR_SYNTAX if the assertion was syntactical-
     ly incorrect, or ERROR_MEMORY if necessary memory could not be allocated.

     kn_remove_assertion() removes the assertion identified by assertid from
     the session identified by sessid. On success, this function returns 0. On
     failure, it returns -1 and sets keynote_errno to ERROR_NOTFOUND.

     kn_add_action() inserts the variable name in the action environment of
     session sessid, with the value value. The same attribute may be added
     more than once, but only the last instance will be used (memory resources
     are consumed however).

     The flags specified are formed by or'ing the following values:

           ENVIRONMENT_FLAG_FUNC   In this case, value is a pointer to a func-
                                   tion that takes as argument a string and
                                   returns a string. This is used to implement
                                   callbacks for getting action attribute val-
                                   ues. 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 contain-
                                   ing that value (this pointer will not be
                                   freed by the library), the empty string if
                                   the value was not found, or a NULL to indi-
                                   cate an error (and may set keynote_errno
                                   appropriately). Prior to first use (cur-
                                   rently, at the time the attribute is added
                                   to the session environment), such functions
                                   are called with KEYNOTE_CALLBACK_INITIALIZE
                                   as the argument (defined in keynote.h) so
                                   that they can perform any special initial-
                                   izations. Furthermore, when the session is
                                   deleted, all such functions will be called
                                   with KEYNOTE_CALLBACK_CLEANUP to perform
                                   any special cleanup (such as free any allo-
                                   cated memory). A function may be called
                                   with either of these arguments more than
                                   once, if it has been defined as the call-
                                   back function for more than one attribute.

           ENVIRONMENT_FLAG_REGEX  In this case, name is a regular expression
                                   that may match more than one attribute.  In
                                   case of conflict between a regular expres-
                                   sion and a ``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 KeyNote session, start/invoke/oper-
                                   ate on another session, or call one of the
                                   session-API functions.

     The combination of the two flags may be used to specify callback func-
     tions that handle large sets of attributes (even to the extent of having
     one callback function handling all attribute references). This is partic-
     ularly useful when the action attribute set is particularly large.

     On success, keynote_add_action(3) returns 0. On failure, it returns -1
     and sets keynote_errno to ERROR_NOTFOUND if the session was not found,
     ERROR_SYNTAX if the name was invalid (e.g., started with an underscore
     character) or was NULL, or ERROR_MEMORY if necessary memory could not be
     allocated.

     kn_remove_action() removes action attribute name from the environment of
     session sessid. Notice that if more than one instances of name exist, on-
     ly the one added last will be deleted.  On success, this function returns
     0. On failure, it returns -1 and keynote_errno is set to ERROR_NOTFOUND
     if the session or the attribute were not found, or ERROR_SYNTAX if the
     name was invalid. If the attribute value was a callback, that function
     will be called with the define KEYNOTE_CALLBACK_CLEANUP as the argument.

     kn_add_authorizer() adds the principal pointed to by principal to the ac-
     tion authorizers list of session sessid. The principal is typically an
     ASCII-encoded key. On success, this function will return 0. On failure,
     it returns -1 and sets keynote_errno to ERROR_NOTFOUND if the session was
     not found, ERROR_SYNTAX if the encoding was invalid, or ERROR_MEMORY if
     necessary memory could not be allocated.

     kn_remove_authorizer() removes principal from the action authorizer list
     of session sessid. On success, this function returns 0. On failure, it
     returns -1 and sets keynote_errno to ERROR_NOTFOUND if the session was
     not found.

     kn_do_query() evaluates the request based on the assertions, action at-
     tributes, and action authorizers added to session sessid. returnvalues is
     an ordered array of strings that contain the return values. The lowest-
     ordered return value is contained in returnvalues[0], and the highest-or-
     dered value is returnvalues[numvalues - 1]. If returnvalues is NULL, the
     returnvalues from the previous call to kn_do_query(3) will be used. The
     programmer SHOULD NOT free returnvalues after the call to 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 returnvalues array. On
     failure, it returns -1 and sets keynote_errno to ERROR_NOTFOUND if the
     session was not found or the authorizers list was empty, ERROR_SYNTAX if
     no returnvalues have been specified, or ERROR_MEMORY if necessary memory
     could not be allocated.

     kn_get_failed() returns the assertion ID of the num'th assertion (start-
     ing from zero) in session sessid that was somehow invalid during evalua-
     tion. This function is typically called after kn_do_query(3) is used to
     evaluate a request.  type specifies the type of failure the application
     is interested in. It can be set to:

           KEYNOTE_ERROR_ANY        to indicate interest in any error.

           KEYNOTE_ERROR_SYNTAX     for syntactic or semantic errors.

           KEYNOTE_ERROR_MEMORY     for memory-related problems.

           KEYNOTE_ERROR_SIGNATURE  if the assertion could not be cryptograph-
                                    ically verified.

     These values are defined in keynote.h. An application can then delete the
     offending assertion using kn_remove_assertion(3).  For example, to remove
     all assertion whose signature failed, an application could do something
     like:

       while ((assertid = kn_get_failed(sessid, KEYNOTE_ERROR_SIGNATURE, 0)
              != -1)
         kn_remove_assertion(sessid, assertid);

     On success, 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
     keynote_errno to ERROR_NOTFOUND.

     kn_cleanup_action_environment() removes all action attributes from the
     action environment of session sessid. It returns 0 on success.

     kn_close() closes session sessid and frees all related resources, delet-
     ing action attributes, action authorizers, and assertions. On success,
     this function returns 0. On failure, it returns -1 and sets keynote_errno
     to ERROR_NOTFOUND if the session was not found.

     kn_read_asserts() parses the string array of length arraylen and returns
     an array of strings containing the assertions found in array.
     numassertions contains the number of assertions (and thus strings in the
     returned array) found in array. On failure, this function returns -1 and
     sets keynote_errno to ERROR_MEMORY if necessary memory could not be allo-
     cated, or ERROR_SYNTAX if array was NULL.

     kn_keycompare() compares key1 and key2 (which must be of the same
     algorithm) and returns 1 if equal and 0 otherwise.

     kn_get_authorizer() returns the authorizer key (in binary format) for as-
     sertion assertid in session sessid. It also sets the algorithm argument
     to the algorithm of the authorizer key.  On failure, kn_get_authorizer()
     returns and sets keynote_errno to ERROR_NOTFOUND.

     kn_get_licensees() returns the licensee key(s) for assertion assertid in
     session sessid. The keys are returned in a linked list of struct
     keynote_keylist structures.  On failure, kn_get_licensees() returns and
     sets keynote_errno to ERROR_NOTFOUND.

     kn_query() takes as arguments a list of action attributes in env, a list
     of return values in returnvalues (the number of returnvalues in indicated
     by numvalues ), a number ( numtrusted) of locally-trusted assertions in
     trusted (the length of each assertion is given by the respective element
     of trustedlen ), a number ( numuntrusted) of assertions that need to be
     cryptographically verified in untrusted (the length of each assertion is
     given by the respective element of untrustedlen ), and a number (
     numauthorizers) of action authorizers in authorizers. env is a linked
     list of struct environment structures. The env_name, env_value, and
     env_flags fields correspond to the name, value, and flags arguments to
     kn_add_assertion(3) respectively.  env_regex is not used. On success,
     this function returns an index in returnvalues indicating the returned
     value to the query. On failure, it returns -1 and sets keynote_errno to
     the same values as kn_do_query(3),  or to ERROR_MEMORY if a trusted or
     untrusted assertion could not be added to the session due to lack of mem-
     ory resources. Syntax errors in assertions will not be reported by
     kn_query().

     kn_encode_base64() converts the data of length srclen contained in src in
     Base64 encoding and stores them in dst which is of length dstlen. The ac-
     tual length of the encoding stored in dst is returned.  dst should be
     long enough to also contain the dst0 string terminator. If srclen is not
     a multiple of 4, or dst is not long enough to contain the encoded data,
     this function returns -1 and sets keynote_errno to ERROR_SYNTAX.

     kn_decode_base64() decodes the Base64-encoded data stored in src and
     stores the result in dst, which is of length dstlen. The actual length of
     the decoded data is returned on success. On failure, this function re-
     turns -1 and sets keynote_errno to ERROR_SYNTAX, denoting either an in-
     valid Base64 encoding or insufficient space in dst.

     kn_encode_hex() encodes in ASCII-hexadecimal format the data of length
     srclen contained in src. This function allocates a chunk of memory to
     store the result, which is returned in dst. Thus, this function should be
     used as follows:

       char *dst;

       kn_encode_hex(src, &dst, srclen);

     The length of the allocated buffer will be (2 * srclen + 1). On success,
     this function returns 0. On failure, it returns -1 and sets keynote_errno
     to ERROR_MEMORY if it failed to allocate enough memory, ERROR_SYNTAX if
     dst was NULL.

     kn_decode_hex() decodes the ASCII hex-encoded string in src and stores
     the result in a memory chunk allocated by the function. A pointer to that
     memory is stored in 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 keynote_errno to ERROR_MEMORY if it could not allo-
     cate enough memory, or ERROR_SYNTAX if dst was NULL, or the length of src
     is not even.

     kn_encode_key() ASCII-encodes a cryptographic key. The binary representa-
     tion of the key is contained in dc. The field dec_key in that structure
     is a pointer to some cryptographic algorithm dependent information de-
     scribing the key. In this implementation, this pointer should be a DSA *
     or RSA * for DSA or RSA keys respectively, as used in the SSL library, or
     a keynote_binary * for cryptographic keys whose algorithm KeyNote does
     not know about but the application wishes to include in the action autho-
     rizers (and thus need to be canonicalized). The field dec_algorithm de-
     scribes the cryptographic algorithm, and may be one of
     KEYNOTE_ALGORITHM_DSA, KEYNOTE_ALGORITHM_RSA, or KEYNOTE_ALGORITHM_BINARY
     in this implementation.

     iencoding describes how the key should be binary-encoded. This implemen-
     tation supports for RSA keys, INTERNAL_ENC_ASN1 for DSA keys, and
     INTERNAL_ENC_NONE for BINARY keys.  encoding describes what ASCII encod-
     ing should be applied to the key. Valid values are ENCODING_HEX and
     ENCODING_BASE64, for hexadecimal and Base64 encoding respectively.
     keytype is one of KEYNOTE_PUBLIC_KEY or KEYNOTE_PRIVATE_KEY to indicate
     whether the key is public or private. Private keys have the string
     KEYNOTE_PRIVATE_KEY_PREFIX (defined in keynote.h) prefixed to the algo-
     rithm name. On success, this function returns a string containing the en-
     coded key. On failure, it returns NULL and sets keynote_errno to
     ERROR_NOTFOUND if the dc argument was invalid, ERROR_MEMORY if it failed
     to allocate the necessary memory, or ERROR_SYNTAX if the key to be con-
     verted was invalid.

     kn_decode_key() decodes the ASCII-encoded string contained in key. The
     result is placed in dc, with dec_algorithm describing the algorithm (see
     kn_encode_key(3)),  and dec_key pointing to an algorithm-dependent struc-
     ture. In this implementation, this is an SSLeay/OpenSSL-defined DSA * for
     DSA keys, RSA * for RSA and X509-based keys, and a keynote_binary * for
     BINARY keys.  keytype takes the values KEYNOTE_PUBLIC_KEY or
     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
     keynote_errno to ERROR_MEMORY if necessary memory could not be allocated,
     or ERROR_SYNTAX if the key or the ASCII encoding was malformed.

     kn_sign_assertion() produces the cryptographic signature for the asser-
     tion of length len stored in assertion, using the ASCII-encoded crypto-
     graphic key contained in key. The type of signature to be produced is de-
     scribed by the string algorithm. Possible values for this string are
     SIG_RSA_SHA1_HEX SIG_RSA_SHA1_BASE64, SIG_RSA_MD5_HEX, and
     SIG_RSA_MD5_HEX for RSA keys, SIG_DSA_SHA1_HEX and SIG_DSA_SHA1_BASE64
     for DSA keys, SIG_X509_SHA1_HEX, and SIG_X509_SHA1_BASE64 for X509-based
     keys.  No other cryptographic signatures are currently supported by this
     implementation. If 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 assertion. On failure,
     it returns NULL and sets keynote_errno to ERROR_NOTFOUND if one of the
     arguments was NULL, ERROR_MEMORY if necessary memory could not be allo-
     cated, or ERROR_SYNTAX if the algorithm, the key, or the assertion (if
     signature verification was requested) was invalid.

     kn_verify_assertion() verifies the cryptographic signature on the asser-
     tion of length len contained in string assertion. On success, this func-
     tion returns SIGRESULT_TRUE if the signature could be verified, or
     SIGRESULT_FALSE otherwise. On failure, this function returns -1 and sets
     keynote_errno to ERROR_MEMORY if necessary memory could not be allocated,
     or ERROR_SYNTAX if the assertion contained a syntactic error, or the
     cryptographic algorithm was not supported.

FILES
     keynote.h
     libkeynote.a

SEE ALSO
     keynote(1),  keynote(4),  keynote(5)

     ``The KeyNote Trust-Management System, Version 2''
              M. Blaze, J. Feigenbaum, A. D. Keromytis, Internet Drafts, RFC


              2704.

     ``Decentralized Trust Management''
              M. Blaze, J. Feigenbaum, J. Lacy, 1996 IEEE Conference on Priva-
              cy and Security

     ``Compliance-Checking in the PolicyMaker Trust Management System''
              M. Blaze, J. Feigenbaum, M. Strauss, 1998 Financial Crypto Con-
              ference

AUTHOR
     Angelos D. Keromytis (angelos@dsl.cis.upenn.edu)

WEB PAGE
     http://www.cis.upenn.edu/~keynote

DIAGNOSTICS
     The return values of all the functions have been given along with the
     function description above.

BUGS
     None that we know of.  If you find any, please report them at
           keynote@research.att.com

OpenBSD 2.6                     April 29, 1999                               8
