Track session objects in the framework, and pass handles between the framework (OCF), consumers, and drivers. Avoid redundancy and complexity in individual drivers by allocating session memory in the framework and providing it to drivers in ::newsession(). Session handles are no longer integers with information encoded in various high bits. Use of the CRYPTO_SESID2FOO() macros should be replaced with the appropriate crypto_ses2foo() function on the opaque session handle. Convert OCF drivers (in particular, cryptosoft, as well as myriad others) to the opaque handle interface. Discard existing session tracking as much as possible (quick pass). There may be additional code ripe for deletion. Convert OCF consumers (ipsec, geom_eli, krb5, cryptodev) to handle-style interface. The conversion is largely mechnical. The change is documented in crypto.9. Inspired by https://lists.freebsd.org/pipermail/freebsd-arch/2018-January/018835.html . No objection from: ae (ipsec portion) Reported by: jhb
733 lines
22 KiB
Groff
733 lines
22 KiB
Groff
.\" $OpenBSD: crypto.9,v 1.19 2002/07/16 06:31:57 angelos Exp $
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.\"
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.\" The author of this manual page is Angelos D. Keromytis (angelos@cis.upenn.edu)
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.\"
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.\" Copyright (c) 2000, 2001 Angelos D. Keromytis
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.\"
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.\" Permission to use, copy, and modify this software with or without fee
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.\" is hereby granted, provided that this entire notice is included in
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.\" all source code copies of any software which is or includes a copy or
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.\" modification of this software.
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.\"
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.\" THIS SOFTWARE IS BEING PROVIDED "AS IS", WITHOUT ANY EXPRESS OR
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.\" IMPLIED WARRANTY. IN PARTICULAR, NONE OF THE AUTHORS MAKES ANY
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.\" REPRESENTATION OR WARRANTY OF ANY KIND CONCERNING THE
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.\" MERCHANTABILITY OF THIS SOFTWARE OR ITS FITNESS FOR ANY PARTICULAR
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.\" PURPOSE.
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.\"
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.\" $FreeBSD$
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.\"
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.Dd July 17, 2018
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.Dt CRYPTO 9
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.Os
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.Sh NAME
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.Nm crypto
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.Nd API for cryptographic services in the kernel
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.Sh SYNOPSIS
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.In opencrypto/cryptodev.h
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.Ft int32_t
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.Fn crypto_get_driverid device_t size_t int
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.Ft int
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.Fn crypto_register uint32_t int uint16_t uint32_t "int \*[lp]*\*[rp]\*[lp]void *, uint32_t *, struct cryptoini *\*[rp]" "int \*[lp]*\*[rp]\*[lp]void *, uint64_t\*[rp]" "int \*[lp]*\*[rp]\*[lp]void *, struct cryptop *\*[rp]" "void *"
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.Ft int
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.Fn crypto_kregister uint32_t int uint32_t "int \*[lp]*\*[rp]\*[lp]void *, struct cryptkop *\*[rp]" "void *"
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.Ft int
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.Fn crypto_unregister uint32_t int
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.Ft int
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.Fn crypto_unregister_all uint32_t
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.Ft void
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.Fn crypto_done "struct cryptop *"
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.Ft void
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.Fn crypto_kdone "struct cryptkop *"
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.Ft int
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.Fn crypto_find_driver "const char *"
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.Ft int
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.Fn crypto_newsession "crypto_session_t *" "struct cryptoini *" int
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.Ft int
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.Fn crypto_freesession crypto_session_t
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.Ft int
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.Fn crypto_dispatch "struct cryptop *"
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.Ft int
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.Fn crypto_kdispatch "struct cryptkop *"
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.Ft int
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.Fn crypto_unblock uint32_t int
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.Ft "struct cryptop *"
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.Fn crypto_getreq int
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.Ft void
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.Fn crypto_freereq void
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|
.Bd -literal
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#define CRYPTO_SYMQ 0x1
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#define CRYPTO_ASYMQ 0x2
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#define EALG_MAX_BLOCK_LEN 16
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struct cryptoini {
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int cri_alg;
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int cri_klen;
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int cri_mlen;
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caddr_t cri_key;
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uint8_t cri_iv[EALG_MAX_BLOCK_LEN];
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struct cryptoini *cri_next;
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};
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struct cryptodesc {
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int crd_skip;
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int crd_len;
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int crd_inject;
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int crd_flags;
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struct cryptoini CRD_INI;
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#define crd_iv CRD_INI.cri_iv
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#define crd_key CRD_INI.cri_key
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#define crd_alg CRD_INI.cri_alg
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#define crd_klen CRD_INI.cri_klen
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struct cryptodesc *crd_next;
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};
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struct cryptop {
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TAILQ_ENTRY(cryptop) crp_next;
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crypto_session_t crp_session;
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int crp_ilen;
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int crp_olen;
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|
int crp_etype;
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|
int crp_flags;
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|
caddr_t crp_buf;
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|
caddr_t crp_opaque;
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|
struct cryptodesc *crp_desc;
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|
int (*crp_callback) (struct cryptop *);
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|
caddr_t crp_mac;
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|
};
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struct crparam {
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|
caddr_t crp_p;
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u_int crp_nbits;
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};
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#define CRK_MAXPARAM 8
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struct cryptkop {
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TAILQ_ENTRY(cryptkop) krp_next;
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u_int krp_op; /* ie. CRK_MOD_EXP or other */
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u_int krp_status; /* return status */
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|
u_short krp_iparams; /* # of input parameters */
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|
u_short krp_oparams; /* # of output parameters */
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uint32_t krp_hid;
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struct crparam krp_param[CRK_MAXPARAM];
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int (*krp_callback)(struct cryptkop *);
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|
};
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.Ed
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.Sh DESCRIPTION
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|
.Nm
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is a framework for drivers of cryptographic hardware to register with
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|
the kernel so
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.Dq consumers
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|
(other kernel subsystems, and
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|
users through the
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|
.Pa /dev/crypto
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|
device) are able to make use of it.
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|
Drivers register with the framework the algorithms they support,
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|
and provide entry points (functions) the framework may call to
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establish, use, and tear down sessions.
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Sessions are used to cache cryptographic information in a particular driver
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|
(or associated hardware), so initialization is not needed with every request.
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|
Consumers of cryptographic services pass a set of
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|
descriptors that instruct the framework (and the drivers registered
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|
with it) of the operations that should be applied on the data (more
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|
than one cryptographic operation can be requested).
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|
.Pp
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|
Keying operations are supported as well.
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|
Unlike the symmetric operators described above,
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|
these sessionless commands perform mathematical operations using
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|
input and output parameters.
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|
.Pp
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|
Since the consumers may not be associated with a process, drivers may
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|
not
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|
.Xr sleep 9 .
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|
The same holds for the framework.
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|
Thus, a callback mechanism is used
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|
to notify a consumer that a request has been completed (the
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|
callback is specified by the consumer on a per-request basis).
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|
The callback is invoked by the framework whether the request was
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|
successfully completed or not.
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|
An error indication is provided in the latter case.
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|
A specific error code,
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|
.Er EAGAIN ,
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|
is used to indicate that a session handle has changed and that the
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|
request may be re-submitted immediately with the new session.
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|
Errors are only returned to the invoking function if not
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|
enough information to call the callback is available (meaning, there
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|
was a fatal error in verifying the arguments).
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|
For session initialization and teardown no callback mechanism is used.
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|
.Pp
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|
The
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|
.Fn crypto_find_driver
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|
function may be called to return the specific id of the provided name.
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|
If the specified driver could not be found, the returned id is -1.
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|
.Pp
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|
The
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|
.Fn crypto_newsession
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|
routine is called by consumers of cryptographic services (such as the
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|
.Xr ipsec 4
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|
stack) that wish to establish a new session with the framework.
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The second argument contains all the necessary information for
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the driver to establish the session.
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The third argument is either a specific driver id, or one or both
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|
of
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.Dv CRYPTOCAP_F_HARDWARE ,
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|
to select hardware devices,
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|
or
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|
.Dv CRYPTOCAP_F_SOFTWARE ,
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|
to select software devices.
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|
If both are specified, a hardware device will be returned
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|
before a software device will be.
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On success, the value pointed to by the first argument will be the opaque
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|
session handle.
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|
The various fields in the
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|
.Vt cryptoini
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|
structure are:
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|
.Bl -tag -width ".Va cri_next"
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.It Va cri_alg
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Contains an algorithm identifier.
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|
Currently supported algorithms are:
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|
.Pp
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.Bl -tag -width ".Dv CRYPTO_RIPEMD160_HMAC" -compact
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|
.It Dv CRYPTO_AES_128_NIST_GMAC
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|
.It Dv CRYPTO_AES_192_NIST_GMAC
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|
.It Dv CRYPTO_AES_256_NIST_GMAC
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.It Dv CRYPTO_AES_CBC
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.It Dv CRYPTO_AES_ICM
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|
.It Dv CRYPTO_AES_NIST_GCM_16
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|
.It Dv CRYPTO_AES_NIST_GMAC
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|
.It Dv CRYPTO_AES_XTS
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|
.It Dv CRYPTO_ARC4
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.It Dv CRYPTO_BLF_CBC
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.It Dv CRYPTO_CAMELLIA_CBC
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|
.It Dv CRYPTO_CAST_CBC
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|
.It Dv CRYPTO_DEFLATE_COMP
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|
.It Dv CRYPTO_DES_CBC
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|
.It Dv CRYPTO_3DES_CBC
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|
.It Dv CRYPTO_MD5
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|
.It Dv CRYPTO_MD5_HMAC
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|
.It Dv CRYPTO_MD5_KPDK
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|
.It Dv CRYPTO_NULL_HMAC
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|
.It Dv CRYPTO_NULL_CBC
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|
.It Dv CRYPTO_RIPEMD160_HMAC
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|
.It Dv CRYPTO_SHA1
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.It Dv CRYPTO_SHA1_HMAC
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|
.It Dv CRYPTO_SHA1_KPDK
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|
.It Dv CRYPTO_SHA2_256_HMAC
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|
.It Dv CRYPTO_SHA2_384_HMAC
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|
.It Dv CRYPTO_SHA2_512_HMAC
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|
.It Dv CRYPTO_SKIPJACK_CBC
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|
.El
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|
.It Va cri_klen
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|
Specifies the length of the key in bits, for variable-size key
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|
algorithms.
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|
.It Va cri_mlen
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|
Specifies how many bytes from the calculated hash should be copied back.
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|
0 means entire hash.
|
|
.It Va cri_key
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|
Contains the key to be used with the algorithm.
|
|
.It Va cri_iv
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|
Contains an explicit initialization vector (IV), if it does not prefix
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|
the data.
|
|
This field is ignored during initialization
|
|
.Pq Nm crypto_newsession .
|
|
If no IV is explicitly passed (see below on details), a random IV is used
|
|
by the device driver processing the request.
|
|
.It Va cri_next
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|
Contains a pointer to another
|
|
.Vt cryptoini
|
|
structure.
|
|
Multiple such structures may be linked to establish multi-algorithm sessions
|
|
.Xr ( ipsec 4
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|
is an example consumer of such a feature).
|
|
.El
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|
.Pp
|
|
The
|
|
.Vt cryptoini
|
|
structure and its contents will not be modified by the framework (or
|
|
the drivers used).
|
|
.Pp
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|
.Fn crypto_freesession
|
|
is called with the session handle returned by
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|
.Fn crypto_newsession
|
|
to free the session.
|
|
.Pp
|
|
.Fn crypto_dispatch
|
|
is called to process a request.
|
|
The various fields in the
|
|
.Vt cryptop
|
|
structure are:
|
|
.Bl -tag -width ".Va crp_callback"
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|
.It Va crp_session
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|
Contains the session handle.
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|
.It Va crp_ilen
|
|
Indicates the total length in bytes of the buffer to be processed.
|
|
.It Va crp_olen
|
|
On return, contains the total length of the result.
|
|
For symmetric crypto operations, this will be the same as the input length.
|
|
This will be used if the framework needs to allocate a new
|
|
buffer for the result (or for re-formatting the input).
|
|
.It Va crp_callback
|
|
This routine is invoked upon completion of the request, whether
|
|
successful or not.
|
|
It is invoked through the
|
|
.Fn crypto_done
|
|
routine.
|
|
If the request was not successful, an error code is set in the
|
|
.Va crp_etype
|
|
field.
|
|
It is the responsibility of the callback routine to set the appropriate
|
|
.Xr spl 9
|
|
level.
|
|
.It Va crp_etype
|
|
Contains the error type, if any errors were encountered, or zero if
|
|
the request was successfully processed.
|
|
If the
|
|
.Er EAGAIN
|
|
error code is returned, the session handle has changed (and has been recorded
|
|
in the
|
|
.Va crp_session
|
|
field).
|
|
The consumer should record the new session handle and use it in all subsequent
|
|
requests.
|
|
In this case, the request may be re-submitted immediately.
|
|
This mechanism is used by the framework to perform
|
|
session migration (move a session from one driver to another, because
|
|
of availability, performance, or other considerations).
|
|
.Pp
|
|
Note that this field only makes sense when examined by
|
|
the callback routine specified in
|
|
.Va crp_callback .
|
|
Errors are returned to the invoker of
|
|
.Fn crypto_process
|
|
only when enough information is not present to call the callback
|
|
routine (i.e., if the pointer passed is
|
|
.Dv NULL
|
|
or if no callback routine was specified).
|
|
.It Va crp_flags
|
|
Is a bitmask of flags associated with this request.
|
|
Currently defined flags are:
|
|
.Bl -tag -width ".Dv CRYPTO_F_CBIFSYNC"
|
|
.It Dv CRYPTO_F_IMBUF
|
|
The buffer pointed to by
|
|
.Va crp_buf
|
|
is an mbuf chain.
|
|
.It Dv CRYPTO_F_IOV
|
|
The buffer pointed to by
|
|
.Va crp_buf
|
|
is an
|
|
.Vt uio
|
|
structure.
|
|
.It Dv CRYPTO_F_BATCH
|
|
Batch operation if possible.
|
|
.It Dv CRYPTO_F_CBIMM
|
|
Do callback immediately instead of doing it from a dedicated kernel thread.
|
|
.It Dv CRYPTO_F_DONE
|
|
Operation completed.
|
|
.It Dv CRYPTO_F_CBIFSYNC
|
|
Do callback immediately if operation is synchronous (that the driver
|
|
specified the
|
|
.Dv CRYPTOCAP_F_SYNC
|
|
flag).
|
|
.It Dv CRYPTO_F_ASYNC
|
|
Try to do the crypto operation in a pool of workers
|
|
if the operation is synchronous (that is, if the driver specified the
|
|
.Dv CRYPTOCAP_F_SYNC
|
|
flag).
|
|
It aims to speed up processing by dispatching crypto operations
|
|
on different processors.
|
|
.It Dv CRYPTO_F_ASYNC_KEEPORDER
|
|
Dispatch callbacks in the same order they are posted.
|
|
Only relevant if the
|
|
.Dv CRYPTO_F_ASYNC
|
|
flag is set and if the operation is synchronous.
|
|
.El
|
|
.It Va crp_buf
|
|
Points to the input buffer.
|
|
On return (when the callback is invoked),
|
|
it contains the result of the request.
|
|
The input buffer may be an mbuf
|
|
chain or a contiguous buffer,
|
|
depending on
|
|
.Va crp_flags .
|
|
.It Va crp_opaque
|
|
This is passed through the crypto framework untouched and is
|
|
intended for the invoking application's use.
|
|
.It Va crp_desc
|
|
This is a linked list of descriptors.
|
|
Each descriptor provides
|
|
information about what type of cryptographic operation should be done
|
|
on the input buffer.
|
|
The various fields are:
|
|
.Bl -tag -width ".Va crd_inject"
|
|
.It Va crd_iv
|
|
When the flag
|
|
.Dv CRD_F_IV_EXPLICIT
|
|
is set, this field contains the IV.
|
|
.It Va crd_key
|
|
When the
|
|
.Dv CRD_F_KEY_EXPLICIT
|
|
flag is set, the
|
|
.Va crd_key
|
|
points to a buffer with encryption or authentication key.
|
|
.It Va crd_alg
|
|
An algorithm to use.
|
|
Must be the same as the one given at newsession time.
|
|
.It Va crd_klen
|
|
The
|
|
.Va crd_key
|
|
key length.
|
|
.It Va crd_skip
|
|
The offset in the input buffer where processing should start.
|
|
.It Va crd_len
|
|
How many bytes, after
|
|
.Va crd_skip ,
|
|
should be processed.
|
|
.It Va crd_inject
|
|
The
|
|
.Va crd_inject
|
|
field specifies an offset in bytes from the beginning of the buffer.
|
|
For encryption algorithms, this may be where the IV will be inserted
|
|
when encrypting or where the IV may be found for
|
|
decryption (subject to
|
|
.Va crd_flags ) .
|
|
For MAC algorithms, this is where the result of the keyed hash will be
|
|
inserted.
|
|
.It Va crd_flags
|
|
The following flags are defined:
|
|
.Bl -tag -width 3n
|
|
.It Dv CRD_F_ENCRYPT
|
|
For encryption algorithms, this bit is set when encryption is required
|
|
(when not set, decryption is performed).
|
|
.It Dv CRD_F_IV_PRESENT
|
|
.\" This flag name has nothing to do w/ it's behavior, fix the name.
|
|
For encryption, if this bit is not set the IV used to encrypt the packet
|
|
will be written at the location pointed to by
|
|
.Va crd_inject .
|
|
The IV length is assumed to be equal to the blocksize of the
|
|
encryption algorithm.
|
|
For encryption, if this bit is set, nothing is done.
|
|
For decryption, this flag has no meaning.
|
|
Applications that do special
|
|
.Dq "IV cooking" ,
|
|
such as the half-IV mode in
|
|
.Xr ipsec 4 ,
|
|
can use this flag to indicate that the IV should not be written on the packet.
|
|
This flag is typically used in conjunction with the
|
|
.Dv CRD_F_IV_EXPLICIT
|
|
flag.
|
|
.It Dv CRD_F_IV_EXPLICIT
|
|
This bit is set when the IV is explicitly
|
|
provided by the consumer in the
|
|
.Va crd_iv
|
|
field.
|
|
Otherwise, for encryption operations the IV is provided for by
|
|
the driver used to perform the operation, whereas for decryption
|
|
operations the offset of the IV is provided by the
|
|
.Va crd_inject
|
|
field.
|
|
This flag is typically used when the IV is calculated
|
|
.Dq "on the fly"
|
|
by the consumer, and does not precede the data (some
|
|
.Xr ipsec 4
|
|
configurations, and the encrypted swap are two such examples).
|
|
.It Dv CRD_F_KEY_EXPLICIT
|
|
For encryption and authentication (MAC) algorithms, this bit is set when the key
|
|
is explicitly provided by the consumer in the
|
|
.Va crd_key
|
|
field for the given operation.
|
|
Otherwise, the key is taken at newsession time from the
|
|
.Va cri_key
|
|
field.
|
|
As calculating the key schedule may take a while, it is recommended that often
|
|
used keys are given their own session.
|
|
.It Dv CRD_F_COMP
|
|
For compression algorithms, this bit is set when compression is required (when
|
|
not set, decompression is performed).
|
|
.El
|
|
.It Va CRD_INI
|
|
This
|
|
.Vt cryptoini
|
|
structure will not be modified by the framework or the device drivers.
|
|
Since this information accompanies every cryptographic
|
|
operation request, drivers may re-initialize state on-demand
|
|
(typically an expensive operation).
|
|
Furthermore, the cryptographic
|
|
framework may re-route requests as a result of full queues or hardware
|
|
failure, as described above.
|
|
.It Va crd_next
|
|
Point to the next descriptor.
|
|
Linked operations are useful in protocols such as
|
|
.Xr ipsec 4 ,
|
|
where multiple cryptographic transforms may be applied on the same
|
|
block of data.
|
|
.El
|
|
.El
|
|
.Pp
|
|
.Fn crypto_getreq
|
|
allocates a
|
|
.Vt cryptop
|
|
structure with a linked list of as many
|
|
.Vt cryptodesc
|
|
structures as were specified in the argument passed to it.
|
|
.Pp
|
|
.Fn crypto_freereq
|
|
deallocates a structure
|
|
.Vt cryptop
|
|
and any
|
|
.Vt cryptodesc
|
|
structures linked to it.
|
|
Note that it is the responsibility of the
|
|
callback routine to do the necessary cleanups associated with the
|
|
opaque field in the
|
|
.Vt cryptop
|
|
structure.
|
|
.Pp
|
|
.Fn crypto_kdispatch
|
|
is called to perform a keying operation.
|
|
The various fields in the
|
|
.Vt cryptkop
|
|
structure are:
|
|
.Bl -tag -width ".Va krp_callback"
|
|
.It Va krp_op
|
|
Operation code, such as
|
|
.Dv CRK_MOD_EXP .
|
|
.It Va krp_status
|
|
Return code.
|
|
This
|
|
.Va errno Ns -style
|
|
variable indicates whether lower level reasons
|
|
for operation failure.
|
|
.It Va krp_iparams
|
|
Number if input parameters to the specified operation.
|
|
Note that each operation has a (typically hardwired) number of such parameters.
|
|
.It Va krp_oparams
|
|
Number if output parameters from the specified operation.
|
|
Note that each operation has a (typically hardwired) number of such parameters.
|
|
.It Va krp_kvp
|
|
An array of kernel memory blocks containing the parameters.
|
|
.It Va krp_hid
|
|
Identifier specifying which low-level driver is being used.
|
|
.It Va krp_callback
|
|
Callback called on completion of a keying operation.
|
|
.El
|
|
.Sh DRIVER-SIDE API
|
|
The
|
|
.Fn crypto_get_driverid ,
|
|
.Fn crypto_get_driver_session ,
|
|
.Fn crypto_register ,
|
|
.Fn crypto_kregister ,
|
|
.Fn crypto_unregister ,
|
|
.Fn crypto_unblock ,
|
|
and
|
|
.Fn crypto_done
|
|
routines are used by drivers that provide support for cryptographic
|
|
primitives to register and unregister with the kernel crypto services
|
|
framework.
|
|
.Pp
|
|
Drivers must first use the
|
|
.Fn crypto_get_driverid
|
|
function to acquire a driver identifier, specifying the
|
|
.Fa flags
|
|
as an argument.
|
|
One of
|
|
.Dv CRYPTOCAP_F_SOFTWARE
|
|
or
|
|
.Dv CRYPTOCAP_F_HARDWARE
|
|
must be specified.
|
|
The
|
|
.Dv CRYPTOCAP_F_SYNC
|
|
may also be specified, and should be specified if the driver does all of
|
|
it's operations synchronously.
|
|
Drivers must pass the size of their session struct as the second argument.
|
|
An appropriately sized memory will be allocated by the framework, zeroed, and
|
|
passed to the driver's
|
|
.Fn newsession
|
|
method.
|
|
.Pp
|
|
For each algorithm the driver supports, it must then call
|
|
.Fn crypto_register .
|
|
The first two arguments are the driver and algorithm identifiers.
|
|
The next two arguments specify the largest possible operator length (in bits,
|
|
important for public key operations) and flags for this algorithm.
|
|
The last four arguments must be provided in the first call to
|
|
.Fn crypto_register
|
|
and are ignored in all subsequent calls.
|
|
They are pointers to three
|
|
driver-provided functions that the framework may call to establish new
|
|
cryptographic context with the driver, free already established
|
|
context, and ask for a request to be processed (encrypt, decrypt,
|
|
etc.); and an opaque parameter to pass when calling each of these routines.
|
|
.Pp
|
|
.Fn crypto_unregister
|
|
is called by drivers that wish to withdraw support for an algorithm.
|
|
The two arguments are the driver and algorithm identifiers, respectively.
|
|
Typically, drivers for
|
|
PCMCIA
|
|
crypto cards that are being ejected will invoke this routine for all
|
|
algorithms supported by the card.
|
|
.Fn crypto_unregister_all
|
|
will unregister all algorithms registered by a driver
|
|
and the driver will be disabled (no new sessions will be allocated on
|
|
that driver, and any existing sessions will be migrated to other
|
|
drivers).
|
|
The same will be done if all algorithms associated with a driver are
|
|
unregistered one by one.
|
|
After a call to
|
|
.Fn crypto_unregister_all
|
|
there will be no threads in either the newsession or freesession function
|
|
of the driver.
|
|
.Pp
|
|
The calling convention for the driver-supplied routines are:
|
|
.Pp
|
|
.Bl -item -compact
|
|
.It
|
|
.Ft int
|
|
.Fn \*[lp]*newsession\*[rp] "device_t" "crypto_session_t" "struct cryptoini *" ;
|
|
.It
|
|
.Ft void
|
|
.Fn \*[lp]*freesession\*[rp] "device_t" "crypto_session_t" ;
|
|
.It
|
|
.Ft int
|
|
.Fn \*[lp]*process\*[rp] "device_t" "struct cryptop *" "int" ;
|
|
.It
|
|
.Ft int
|
|
.Fn \*[lp]*kprocess\*[rp] "device_t" "struct cryptkop *" "int" ;
|
|
.El
|
|
.Pp
|
|
On invocation, the first argument to
|
|
all routines is the
|
|
.Fa device_t
|
|
that was provided to
|
|
.Fn crypto_get_driverid .
|
|
The second argument to
|
|
.Fn newsession
|
|
is the opaque session handle for the new session.
|
|
The third argument is identical to that of
|
|
.Fn crypto_newsession .
|
|
.Pp
|
|
Drivers obtain a pointer to their session memory by invoking
|
|
.Fn crypto_get_driver_session
|
|
on the opaque
|
|
.Vt crypto_session_t
|
|
handle.
|
|
.Pp
|
|
The
|
|
.Fn freesession
|
|
routine takes as arguments the opaque data value and the session handle.
|
|
It should clear any context associated with the session (clear hardware
|
|
registers, memory, etc.).
|
|
If no resources need to be released other than the contents of session memory,
|
|
the method is optional.
|
|
The
|
|
.Nm
|
|
framework will zero and release the allocated session memory (after running the
|
|
.Fn freesession
|
|
method, if one exists).
|
|
.Pp
|
|
The
|
|
.Fn process
|
|
routine is invoked with a request to perform crypto processing.
|
|
This routine must not block or sleep, but should queue the request and return
|
|
immediately or process the request to completion.
|
|
In case of an unrecoverable error, the error indication must be placed in the
|
|
.Va crp_etype
|
|
field of the
|
|
.Vt cryptop
|
|
structure.
|
|
When the request is completed, or an error is detected, the
|
|
.Fn process
|
|
routine must invoke
|
|
.Fn crypto_done .
|
|
Session migration may be performed, as mentioned previously.
|
|
.Pp
|
|
In case of a temporary resource exhaustion, the
|
|
.Fn process
|
|
routine may return
|
|
.Er ERESTART
|
|
in which case the crypto services will requeue the request, mark the driver
|
|
as
|
|
.Dq blocked ,
|
|
and stop submitting requests for processing.
|
|
The driver is then responsible for notifying the crypto services
|
|
when it is again able to process requests through the
|
|
.Fn crypto_unblock
|
|
routine.
|
|
This simple flow control mechanism should only be used for short-lived
|
|
resource exhaustion as it causes operations to be queued in the crypto
|
|
layer.
|
|
Doing so is preferable to returning an error in such cases as
|
|
it can cause network protocols to degrade performance by treating the
|
|
failure much like a lost packet.
|
|
.Pp
|
|
The
|
|
.Fn kprocess
|
|
routine is invoked with a request to perform crypto key processing.
|
|
This routine must not block, but should queue the request and return
|
|
immediately.
|
|
Upon processing the request, the callback routine should be invoked.
|
|
In case of an unrecoverable error, the error indication must be placed in the
|
|
.Va krp_status
|
|
field of the
|
|
.Vt cryptkop
|
|
structure.
|
|
When the request is completed, or an error is detected, the
|
|
.Fn kprocess
|
|
routine should invoked
|
|
.Fn crypto_kdone .
|
|
.Sh RETURN VALUES
|
|
.Fn crypto_register ,
|
|
.Fn crypto_kregister ,
|
|
.Fn crypto_unregister ,
|
|
.Fn crypto_newsession ,
|
|
.Fn crypto_freesession ,
|
|
and
|
|
.Fn crypto_unblock
|
|
return 0 on success, or an error code on failure.
|
|
.Fn crypto_get_driverid
|
|
returns a non-negative value on error, and \-1 on failure.
|
|
.Fn crypto_getreq
|
|
returns a pointer to a
|
|
.Vt cryptop
|
|
structure and
|
|
.Dv NULL
|
|
on failure.
|
|
.Fn crypto_dispatch
|
|
returns
|
|
.Er EINVAL
|
|
if its argument or the callback function was
|
|
.Dv NULL ,
|
|
and 0 otherwise.
|
|
The callback is provided with an error code in case of failure, in the
|
|
.Va crp_etype
|
|
field.
|
|
.Sh FILES
|
|
.Bl -tag -width ".Pa sys/opencrypto/crypto.c"
|
|
.It Pa sys/opencrypto/crypto.c
|
|
most of the framework code
|
|
.El
|
|
.Sh SEE ALSO
|
|
.Xr crypto 4 ,
|
|
.Xr ipsec 4 ,
|
|
.Xr crypto 7 ,
|
|
.Xr malloc 9 ,
|
|
.Xr sleep 9
|
|
.Sh HISTORY
|
|
The cryptographic framework first appeared in
|
|
.Ox 2.7
|
|
and was written by
|
|
.An Angelos D. Keromytis Aq Mt angelos@openbsd.org .
|
|
.Sh BUGS
|
|
The framework currently assumes that all the algorithms in a
|
|
.Fn crypto_newsession
|
|
operation must be available by the same driver.
|
|
If that is not the case, session initialization will fail.
|
|
.Pp
|
|
The framework also needs a mechanism for determining which driver is
|
|
best for a specific set of algorithms associated with a session.
|
|
Some type of benchmarking is in order here.
|
|
.Pp
|
|
Multiple instances of the same algorithm in the same session are not
|
|
supported.
|