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| -rw-r--r-- | share/man/man9/crypto.9 | 363 |
1 files changed, 192 insertions, 171 deletions
diff --git a/share/man/man9/crypto.9 b/share/man/man9/crypto.9 index 20c4cd18ef5..7f40755076f 100644 --- a/share/man/man9/crypto.9 +++ b/share/man/man9/crypto.9 @@ -1,4 +1,4 @@ -.\" $OpenBSD: crypto.9,v 1.2 2000/04/28 05:51:40 angelos Exp $ +.\" $OpenBSD: crypto.9,v 1.3 2000/04/28 14:03:45 aaron Exp $ .\" .\" The author of this man page is Angelos D. Keromytis (angelos@cis.upenn.edu) .\" @@ -84,14 +84,16 @@ struct cryptop .Sh DESCRIPTION .Nm is a framework for drivers of cryptographic hardware to register with -the kernel so ``consumers'' (other kernel subsystems, and eventually -users through an appropriate device) are able to make use of -it. Drivers register with the framework the algorithms they support, +the kernel so +.Dq consumers +(other kernel subsystems, and eventually +users through an appropriate device) are able to make use of it. +Drivers register with the framework the algorithms they support, and provide entry points (functions) the framework may call to -establish, use, and tear down sessions. Sessions are used to cache -cryptographic information in a particular driver (or associated -hardware), so initialization is not needed with every -request. Consumers of cryptographic services pass a set of +establish, use, and tear down sessions. +Sessions are used to cache cryptographic information in a particular driver +(or associated hardware), so initialization is not needed with every request. +Consumers of cryptographic services pass a set of descriptors that instruct the framework (and the drivers registered with it) of the operations that should be applied on the data (more than one cryptographic operation can be requested). @@ -99,33 +101,37 @@ than one cryptographic operation can be requested). Since the consumers may not be associated with a process, drivers may not use .Xr tsleep 9 . -The same holds for the framework. Thus, a callback mechanism is used +The same holds for the framework. +Thus, a callback mechanism is used to notify a consumer that a request has been completed (the -callback is specified by the consumer on an per-request basis). The -callback is invoked by the framework whether the request was -successfully completed or not. An error indication is provided in the -latter case. A specific error code, -.Va EAGAIN , +callback is specified by the consumer on an per-request basis). +The callback is invoked by the framework whether the request was +successfully completed or not. +An error indication is provided in the latter case. +A specific error code, +.Er EAGAIN , is used to indicate that a session number has changed and that the -request may be re-submitted immediately with the new session -number. Errors are only returned to the invoking function if not +request may be re-submitted immediately with the new session number. +Errors are only returned to the invoking function if not enough information to call the callback is available (meaning, there -was a fatal error in verifying the arguments). For session -initialization and teardown there is no callback mechanism used. +was a fatal error in verifying the arguments). +For session initialization and teardown there is no callback mechanism used. .Pp The .Fn crypto_newsession routine is called by consumers of cryptographic services (such as the .Xr ipsec 4 -stack) that wish to establish a new session with the framework. On -success, the first argument will contain the Session Identifier -(SID). The second argument contains all the necessary information for -the driver to establish the session. The various fields in the -.Va cryptoini +stack) that wish to establish a new session with the framework. +On success, the first argument will contain the Session Identifier (SID). +The second argument contains all the necessary information for +the driver to establish the session. +The various fields in the +.Fa cryptoini structure are: -.Bl -tag -width foobarmoocow -.It cri_alg -Contains an algorithm identifier. Currently supported algorithms are: +.Bl -tag -width foobarmoocow +.It Fa cri_alg +Contains an algorithm identifier. +Currently supported algorithms are: .Bd -literal CRYPTO_DES_CBC CRYPTO_3DES_CBC @@ -138,33 +144,35 @@ CRYPTO_RIPEMD160_HMAC96 CRYPTO_MD5_KPDK CRYPTO_SHA1_KPDK .Ed -.Br -.It cri_klen +.Pp +.It Fa cri_klen Specifies the length of the key in bits, for variable-size key algorithms. -.It cri_rnd +.It Fa cri_rnd Specifies the number of rounds to be used with the algorithm, for variable-round algorithms. -.It cri_key +.It Fa cri_key Contains the key to be used with the algorithm. -.It cri_iv +.It Fa cri_iv Contains an explicit initialization vector (IV), if it does not prefix -the data. This field is ignored during initialization. If no IV is -explicitly passed (see below on details), a random IV is used by the -device driver processing the request. -.It cri_next +the data. +This field is ignored during initialization. +If no IV is explicitly passed (see below on details), a random IV is used +by the device driver processing the request. +.It Fa cri_next Contains a pointer to another -.Va cryptoini -structure. Multiple such structures may be linked, to establish -multi-algorithm sessions ( -.Xr ipsec 4 +.Fa cryptoini +structure. +Multiple such structures may be linked to establish multi-algorithm sessions +.Pf ( Xr ipsec 4 is an example consumer of such a feature). .El .Pp The -.Va cryptoini +.Fa cryptoini structure and its contents will not be modified by the framework (or -the drivers used). Subsequent requests for processing that use the +the drivers used). +Subsequent requests for processing that use the SID returned will avoid the cost of re-initializing the hardware (in essence, SID acts as an index in the session cache of the driver). .Pp @@ -174,44 +182,47 @@ is called with the SID returned by to disestablish the session. .Pp .Fn crypto_dispatch -is called to process a request. The various fields in the -.Va cryptop +is called to process a request. +The various fields in the +.Fa cryptop structure are: .Bl -tag -width crp_alloctype -.It crp_sid +.It Fa crp_sid Contains the SID. -.It crp_ilen +.It Fa crp_ilen Indicates the total length in bytes of the buffer to be processed. -.It crp_olen -On return, contains the total length of the result. For symmetric -crypto operations, this will be the same as the input length. -.It crp_alloctype +.It Fa crp_olen +On return, contains the total length of the result. +For symmetric crypto operations, this will be the same as the input length. +.It Fa crp_alloctype Indicates the type of buffer, as used in the kernel .Xr malloc 9 -routine. This will be used if the framework needs to allocate a new +routine. +This will be used if the framework needs to allocate a new buffer for the result (or for re-formatting the input). -.It crp_callback +.It Fa crp_callback This routine is invoked upon completion of the request, whether -successful or not. If the request was not successful, an error code is -set in the -.Va crp_etype +successful or not. +If the request was not successful, an error code is set in the +.Fa crp_etype field. -.It crp_etype +.It Fa crp_etype Contains the error type, if any errors were encountered, or zero if -the request was successfully processed. If the -.Va EAGAIN -error code is returned, the SID has changed (and has been recorded in -the -.Va crp_sid -field). The consumer should record the new SID 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 +the request was successfully processed. +If the +.Er EAGAIN +error code is returned, the SID has changed (and has been recorded in the +.Fa crp_sid +field). +The consumer should record the new SID 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 . +.Fa crp_callback . Errors are returned to the invoker of .Fn crypto_process only when enough information is not present to call the callback @@ -219,98 +230,104 @@ routine (i.e., if the pointer passed is .Dv NULL or if no callback routine was specified). .It crp_flags -Is a bitmask of flags associated with this request. Currently defined -flags are: +Is a bitmask of flags associated with this request. +Currently defined flags are: .Bl -tag -width CRYPTO_F_IMBUF -.It CRYPTO_F_IMBUF +.It Dv CRYPTO_F_IMBUF The buffer pointed to by -.Va crp_buf +.Fa crp_buf is an mbuf chain. .El -.Br -.It 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 +.Pp +.It Fa 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 (of a type identified by -.Va crp_alloctype ), +.Fa crp_alloctype ) , depending on -.Va crp_flags . -.It crp_opaque1 -.It crp_opaque2 -.It crp_opaque3 -.It crp_opaque4 +.Fa crp_flags . +.It Fa crp_opaque1 , crp_opaque2 , crp_opaque3 , crp_opaque4 These are passed through the crypto framework untouched and are intended for the invoking application's use. -.It crp_desc -This is a linked list of descriptors. Each descriptor provides +.It Fa 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: +on the input buffer. +The various fields are: .Bl -tag -width=crd_inject -.It crd_skip +.It Fa crd_skip The offset in the input buffer where processing should start. -.It crd_len +.It Fa crd_len How many bytes, after -.Va crd_skip , +.Fa Fa crd_skip , should be processed. -.It crd_inject -Offset from the beginning of the buffer to insert any results. For -encryption algorithms, this is where the initialization vector +.It Fa crd_inject +Offset from the beginning of the buffer to insert any results. +For encryption algorithms, this is where the initialization vector (IV) will be inserted when encrypting or where it can be found when decrypting (subject to -.Va crd_flags ). +.Fa Fa crd_flags ) . For MAC algorithms, this is where the result of the keyed hash will be inserted. -.It crd_flags +.It Fa crd_flags The following flags are defined: -.Bl -tag -width=CRD_F_IV_EXPLICIT -.it CRD_F_ENCRYPT +.Bl -tag -width CRD_F_IV_EXPLICIT +.It Dv CRD_F_ENCRYPT For encryption algorithms, this bit is set when encryption is required (when not set, decryption is performed). -.It CRD_F_IV_PRESENT +.It Dv CRD_F_IV_PRESENT For encryption algorithms, this bit is set when the IV already precedes the data, so the -.Va crd_inject -value will be ignored and no IV will be written in the -buffer. Otherwise, the IV used to encrypt the packet will be written +.Fa crd_inject +value will be ignored and no IV will be written in the buffer. +Otherwise, the IV used to encrypt the packet will be written at the location pointed to by -.Va crd_inject . +.Fa crd_inject . The IV length is assumed to be equal to the blocksize of the -encryption algorithm. Some applications that do special ``IV -cooking'', such as the half-IV mode in +encryption algorithm. +Some applications that do special +.Dq IV cooking , +such as the half-IV mode in .Xr ipsec 4 , -can use this flag to indicate the the IV should not be written on the -packet. This flag is typically used in conjunction with the -.Va CRD_F_IV_EXPLICIT +can use this flag to indicate the 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 CRD_F_IV_EXPLICIT +.It Dv CRD_F_IV_EXPLICIT For encryption algorithms, this bit is set when the IV is explicitly provided by the consumer in the -.Va crd_iv -fiels. Otherwise, for encryption operations the IV is provided for by +.Fa crd_iv +fields. +Otherwise, for encryption operations the IV is provided for by the driver used to perform the operation, whereas for decryption operations it is pointed to by the -.Va crd_inject -field. This flag is typically used when the IV is calculated ``on the -fly'' by the consumer, and does not precede the data (some +.Fa 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). .El -.It crd_alg -.It crd_klen -.It crd_rnd -.It crd_key -.It crd_iv +.It Xo Fa crd_alg , crd_klen , crd_rnd , +.Fa crd_key , crd_iv +.Xc These have the exact same meaning as the corresponding fields in the -.Va cryptoini -structure. These fields will not be modified by the framework or the -device drivers. Since this information accompanies every cryptographic +.Fa cryptoini +structure. +These fields 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 +(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 crd_next -Point to the next descriptor. Linked operations are useful in -protocols such as +.It Fa 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. @@ -319,20 +336,21 @@ block of data. .Pp .Fn crypto_getreq allocates a -.Va cryptop +.Fa cryptop structure with a linked list of as many -.Va cryptodesc +.Fa cryptodesc structures as were specified in the argument passed to it. .Pp .Fn crypto_freereq deallocates a structure -.Va cryptop +.Fa cryptop and any -.Va cryptodesc -structures linked to it. Note that it is the responsibility of the +.Fa cryptodesc +structures linked to it. +Note that it is the responsibility of the callback routine to do the necessary cleanups associated with the opaque fields in the -.Va cryptop +.Fa cryptop structure. .Pp .Sh DRIVER-SIDE API @@ -343,23 +361,25 @@ and .Fn crypto_unregister routines are used by drivers that provide support for cryptographic primitives to register and unregister with the kernel crypto services -framework. Drivers must first use the +framework. +Drivers must first use the .Fn crypto_get_driverid -function to acquire a driver identifier. For each algorithm the driver -supports, it must then call +function to acquire a driver identifier. +For each algorithm the driver supports, it must then call .Fn crypto_register . -The first two arguments are the driver and algorithm identifiers. The -last three arguments must be provided in the first call to +The first two arguments are the driver and algorithm identifiers. +The last three arguments must be provided in the first call to .Fn crypto_register -and are ignored in all subsequent calls. They are pointers to three +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.) .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 +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 .Xr pcmcia 4 crypto cards that are being ejected will invoke this routine for all algorithms supported by the card. @@ -376,29 +396,30 @@ On invocation, the first argument to contains the driver identifier obtained via .Fn crypto_get_driverid . On successfully returning, it should contain a driver-specific session -identifier. The second argument is identical to that of +identifier. +The second argument is identical to that of .Fn crypto_newsession . .Pp The .Fn freesession routine takes as argument the SID (which is the concatenation of the -driver identifier and the driver-specific session identifier). It -should clear any context associated with the session (clear hardware -registers, memory, etc.) +driver identifier and the driver-specific session identifier). +It should clear any context associated with the session (clear hardware +registers, memory, etc.). .Pp The .Fn process -routine is invoked with a request to perform crypto 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 error, the error indication must be -placed in the -.Va crp_etype +routine is invoked with a request to perform crypto 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 error, the error indication must be placed in the +.Fa crp_etype field of the -.Va cryptop +.Fa cryptop structure, and the callback routine invoked as well, to perform the -necessary cleanup or to re-issue the request. Session migration may be -performed, as mentioned previously. +necessary cleanup or to re-issue the request. +Session migration may be performed, as mentioned previously. .Pp .Sh RETURN VALUES .Fn crypto_register , @@ -408,47 +429,47 @@ and .Fn crypto_freesession 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. +returns a non-negative value on error, and \-1 on failure. .Fn crypto_getreq returns a pointer to a -.Va cryptop +.Fa cryptop structure and .Dv NULL on failure. .Fn crypto_dispatch returns -.Dv EINVAL +.Er EINVAL is 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 +and 0 otherwise. +The callback is provided with an error code in case of failure, in the +.Fa crp_etype field. -.Br -.Sh CODE REFERENCES -Most of the framework code can be found in -.Pa sys/crypto/crypto.c -.Br +.Sh FILES +.Bl -tag -width sys/crypto/crypto.c +.It Pa sys/crypto/crypto.c +most of the framework code +.El .Sh SEE ALSO .Xr ipsec 4 , -.Xr malloc 9 , .Xr pcmcia 4 , +.Xr malloc 9 , .Xr tsleep 9 -.Br .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's not the -case, session initialization will fail. +operation must be available by the same driver. +If that's 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. +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. Note that 3DES is considered one algorithm (and not three -instances of DES). Thus, 3DES and DES could be mixed in the same -request. +supported. +Note that 3DES is considered one algorithm (and not three +instances of DES). +Thus, 3DES and DES could be mixed in the same request. .Pp A queue for completed operations should be implemented and processed at some software @@ -456,11 +477,11 @@ at some software level, to avoid overall system latency issues, and potential kernel stack exhaustion while processing a callback. .Pp -We need a userland device for exposing the framework to userland. This -will be particularly useful for public key operations in hardware. +We need a userland device for exposing the framework to userland. +This will be particularly useful for public key operations in hardware. .Pp -We have not experimented yet with public key operations hardware. The -framework should support this. +We have not experimented yet with public key operations hardware. +The framework should support this. .Pp When SMP time comes, we will support use of a second processor (or more) as a crypto device (this is actually AMP, but we need the same |