xref: /onnv-gate/usr/src/lib/libcryptoutil/README (revision 12575:6d803152496b)

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This is an internal library for use only by:
	usr/src/cmd/cmd-crypto
	usr/src/lib/pkcs11
	usr/src/lib/libkmf

The library and the header file are installed into the proto area but
are not included in any pacakges.


			libcryptoutil Design

1. Introduction

There are a number of common code components and general utility functions
needed that are shared by various userland parts of the crypto framework.

The originally approved ARC materials (PSARC/2001/488 & PSARC/2001/553)
didn't have a library that was included by all user land libraries,
plugins and commands.

The solution to this is to follow what other project teams have done in the
past and create a project private util library.

2. Contents

Any code that is generic enough to be shared by multiple parts of the
user crypto framework is eligible.

The current contents are:

2.1 Error & Debug Functions

	cryptodebug_init(),
	cryptodebug()
	cryptoerror()

These functions log debug or error information to stderr and/or
syslog or a file.  Debug is off by default but the code is always
compiled in.

The cryptodebug_init() routine allows the caller to set a message
prefix for error and debug output.

The environment variable SUNW_CRYPTO_DEBUG determines wither or not
debug output is generated at run time, valid values are "syslog" or "stderr"

For example elfsign(1) could do:

	cryptodebug_init("elfsign");

and later:
	cryptoerror(LOG_STDERR, gettext("invalid number of arguments"));

This would cause an error message on stderr thus:

	"elfsign: invalid number of arguments"

The first argument to cryptoerror is either LOG_STDERR or a syslog(3c)
priority.  All messages include the PID and are logged at LOG_USER.

for debug output:

	cryptodebug("scmd=request opts=%s", opts);

This would go to the location defined by $SUNW_CRYPTO_DEBUG, ie
syslog, stderr or not be generated at all.

2.2 PKCS#11 Mechanism Type to and from Strings

	pkcs11_mech2str() and pkcs11_str2mech()

These functions use a table built at compile time from the contents of
the pkcs11t.h file to map mechanism numbers to the corresponding string
value.

pkcs11_mech2str() returns a pointer to a string that should be free(3c)'d
by the caller.

Consumers:

	digest(1), mac(1), encrypt(1), decrypt(1) for translating
	command line args to mech numbers.  They will need to
	add the "CKM_" prefix before calling pkc11_str2mech()

	cryptoadm(1m) for output to user, and for storing in pkcs11.conf
	file.

	Debug code.

2.3 The "pkcs11.conf" configuration file Parsing code.

The "pkcs11.conf" configuration file parsing code and data structures are
shared between:
	cryptoadm(1m), libpkcs11(3crypto).

2.3.1 Data Structures:

	#define MECH_ID_HEX_LEN 11 /* length of mechanism id in hex form */

	typedef char libname_t[MAXPATHLEN];
	typedef char midstr_t[MECH_ID_HEX_LEN];

	/* The policy list for an entry in the config file  */
	typedef struct umechlist {
        	midstr_t                name;
	        struct umechlist        *next;
	} umechlist_t;

	/* An entry in the pkcs11.conf file */
	typedef struct uentry {
        	libname_t       name;
	        boolean_t       flag_enabledlist; /* TRUE if an enabledlist */
        	umechlist_t     *policylist; /* disabledlist or enabledlist */
	        int             count;
	} uentry_t;

	/* The entry list for the entire pkcs11.conf file */
	typedef struct uentrylist {
        	uentry_t               *pent;
	        struct uentrylist      *next;
	} uentrylist_t;


2.3.2 Functions:

extern int get_pkcs11conf_info(uentrylist_t **ppliblist);
$
    Retrieve the user-level provider info from the pkcs11.conf file.
    If successful, the result is returned from the ppliblist argument.
    This function returns SUCCESS if successfully done; otherwise it returns
    FAILURE.  The caller should use free_uentrylist() to free the space
    allocated for "ppliblist".

extern umechlist_t *create_umech(char *mechname);

    Create one item of type umechlist_t with the mechanism name in hex form.
    A NULL is returned when the input name is NULL or the heap memory is
    insufficient.  The Caller should use free_umechlist() to free the space
    allocated for the returning data.

extern void free_uentrylist(uentrylist_t *ptr);

    Free space allocated for an pointer to the struct "uentrylist_t".

extern void free_uentry(uentry_t *ptr);

    Free space allocated for an pointer to the struct "uentry_t".

extern void free_umechlist(umechlist_t *ptr);

    Free space allocated for an pointer to the struct "umechlist_t".

2.4 PKCS#11 Mechanism Type to key type

	pkcs11_mech2keytype()

This function is used to get the key type for a mechanism.

Consumers:

	encrypt(1), decrypt(1), and libpkcs11(3crypto) for getting
	the key type when creating an object for use with a
	specific mechanism.

2.5 PKCS#11 return code to string

	pkcs11_strerror()

This function returns a string representation of any given PKCS11 return
code.

Consumer:

	encrypt(1) and decrypt(1) uses this function for reporting errors.

2.5 PKCS#11 URI parsing code

	pkcs11_parse_uri()
	pkcs11_free_uri()

This function parses a PKCS#11 URI and fills up a pkcs11_uri_t structure. It
also reads the PIN if the PKCS#11 URI specifies a passphrase dialog. The
pkcs11_uri_t is described in cryptoutil.h, explanation of the return codes for
the pkcs11_parse_uri() function is in the function's comment in pk11_uri.c. The
pkcs11_parse_uri() function allocates the URI's fields and the caller is
responsible for calling pkcs11_free_uri() after it's done with the URI
structure.

Consumer:

	SunSSH will use the functions for parsing PKCS#11 URIs.

3. Non-Contents

Code for cryptographic algorithms does not belong in here.  That
comes from usr/src/common/<algorithm> since it is shared between user and
kernel.

PKCS#11 header files although they are common to various parts of the
user land framework come from usr/src/pkcs11/include

4. Interface Taxonomy

Everything in this library is Project Private or Internal.  The
exported symbols will all be marked as SUNWprivate_1.0 in the library
spec file.

5. Static vs Dynamic

The initial design was to only use a static archive library to avoid
exposing a new interface (even though it is all private).  However while
this is fine for initial delivery it creates difficulties later with
patching.  As such a Dynamic version will be build.

Libraries for lint and header files will not be shipped in any Sun packages
since this is all Project Private.  Similarly the abi_ file will not be
shipped even though a spec file will be used in the source gate.

6. Library location

At present all of the consumers of the library are in /usr/ so the
library is /usr/lib/{sparcv9}/libcryptoutil.so.1.  If kcfd ever moves
to /lib/crypto/kcf as a result of PSARC/2002/117 allowing it, then
libcryptoutil needs to move as well.