svcadm(8)을 검색하려면 섹션에서 8 을 선택하고, 맨 페이지 이름에 svcadm을 입력하고 검색을 누른다.
crypto(4)
CRYPTO(4) BSD Kernel Interfaces Manual CRYPTO(4)
NAME
crypto, cryptodev — user-mode access to hardware-accelerated cryptography
SYNOPSIS
device crypto
device cryptodev
#include <sys/ioctl.h>
#include <sys/time.h>
#include <crypto/cryptodev.h>
DESCRIPTION
The crypto driver gives user-mode applications access to hardware-accel‐
erated cryptographic transforms, as implemented by the crypto(9) in-ker‐
nel interface.
The /dev/crypto special device provides an ioctl(2) based interface.
User-mode applications should open the special device, then issue
ioctl(2) calls on the descriptor. User-mode access to /dev/crypto is
controlled by three sysctl(8) variables, kern.userasymcrypto and
kern.cryptodevallowsoft.
The crypto device provides two distinct modes of operation: one mode for
symmetric-keyed cryptographic requests, and a second mode for both asym‐
metric-key (public-key/private-key) requests, and for modular arithmetic
(for Diffie-Hellman key exchange and other cryptographic protocols). The
two modes are described separately below.
THEORY OF OPERATION
Regardless of whether symmetric-key or asymmetric-key operations are to
be performed, use of the device requires a basic series of steps:
1. Open a file descriptor for the device. See open(2).
2. If any symmetric operation will be performed, create one session,
with CIOCGSESSION. Most applications will require at least one sym‐
metric session. Since cipher and MAC keys are tied to sessions,
many applications will require more. Asymmetric operations do not
use sessions.
3. Submit requests, synchronously with CIOCCRYPT (symmetric),
CIOCCRYPTAEAD (symmetric), or CIOCKEY (asymmetric).
4. Destroy one session with CIOCFSESSION.
5. Close the device with close(2).
SYMMETRIC-KEY OPERATION
The symmetric-key operation mode provides a context-based API to tradi‐
tional symmetric-key encryption (or privacy) algorithms, or to keyed and
unkeyed one-way hash (HMAC and MAC) algorithms. The symmetric-key mode
also permits fused operation, where the hardware performs both a privacy
algorithm and an integrity-check algorithm in a single pass over the
data: either a fused encrypt/HMAC-generate operation, or a fused HMAC-
verify/decrypt operation.
To use symmetric mode, you must first create a session specifying the
algorithm(s) and key(s) to use; then issue encrypt or decrypt requests
against the session.
Algorithms
For a list of supported algorithms, see crypto(7) and crypto(9).
IOCTL Request Descriptions
CRIOGET int *fd
Clone the fd argument to ioctl(2), yielding a new file
descriptor for the creation of sessions.
CIOCFINDDEV struct crypt_find_op *fop
struct crypt_find_op {
int crid; /* driver id + flags */
char name[32]; /* device/driver name */
};
If crid is -1, then find the driver named name and return
the id in crid. If crid is not -1, return the name of the
driver with crid in name. In either case, if the driver is
not found, ENOENT is returned.
CIOCGSESSION struct session_op *sessp
struct session_op {
u_int32_t cipher; /* e.g. CRYPTO_DES_CBC */
u_int32_t mac; /* e.g. CRYPTO_MD5_HMAC */
u_int32_t keylen; /* cipher key */
void * key;
int mackeylen; /* mac key */
void * mackey;
u_int32_t ses; /* returns: ses # */
};
Create a new cryptographic session on a file descriptor for
the device; that is, a persistent object specific to the
chosen privacy algorithm, integrity algorithm, and keys
specified in sessp. The special value 0 for either privacy
or integrity is reserved to indicate that the indicated
operation (privacy or integrity) is not desired for this
session.
Multiple sessions may be bound to a single file descriptor.
The session ID returned in sessp->ses is supplied as a
required field in the symmetric-operation structure
crypt_op for future encryption or hashing requests.
For non-zero symmetric-key privacy algorithms, the privacy
algorithm must be specified in sessp->cipher, the key
length in sessp->keylen, and the key value in the octets
addressed by sessp->key.
For keyed one-way hash algorithms, the one-way hash must be
specified in sessp->mac, the key length in sessp->mackey,
and the key value in the octets addressed by
sessp->mackeylen.
Support for a specific combination of fused privacy and
integrity-check algorithms depends on whether the underly‐
ing hardware supports that combination. Not all combina‐
tions are supported by all hardware, even if the hardware
supports each operation as a stand-alone non-fused opera‐
tion.
CIOCCRYPT struct crypt_op *cr_op
struct crypt_op {
u_int32_t ses;
u_int16_t op; /* e.g. COP_ENCRYPT */
u_int16_t flags;
u_int len;
caddr_t src, dst;
caddr_t mac; /* must be large enough for result */
caddr_t iv;
};
Request a symmetric-key (or hash) operation. The file
descriptor argument to ioctl(2) must have been bound to a
valid session. To encrypt, set cr_op->op to COP_ENCRYPT.
To decrypt, set cr_op->op to COP_DECRYPT. The field
cr_op->len supplies the length of the input buffer; the
fields cr_op->src, cr_op->dst, cr_op->mac, cr_op->iv supply
the addresses of the input buffer, output buffer, one-way
hash, and initialization vector, respectively. If a ses‐
sion is using both a privacy algorithm and a hash algo‐
rithm, the request will generate a hash of the input buffer
before generating the output buffer by default. If the
COP_F_CIPHER_FIRST flag is included in the cr_op->flags
field, then the request will generate a hash of the output
buffer after executing the privacy algorithm.
CIOCCRYPTAEAD struct crypt_aead *cr_aead
struct crypt_aead {
u_int32_t ses;
u_int16_t op; /* e.g. COP_ENCRYPT */
u_int16_t flags;
u_int len;
u_int aadlen;
u_int ivlen;
caddr_t src, dst;
caddr_t aad;
caddr_t tag; /* must be large enough for result */
caddr_t iv;
};
The CIOCCRYPTAEAD is similar to the CIOCCRYPT but provides
additional data in cr_aead->aad to include in the authenti‐
cation mode.
CIOCFSESSION u_int32_t ses_id
Destroys the /dev/crypto session associated with the file-
descriptor argument.
CIOCNFSESSION struct crypt_sfop *sfop;
struct crypt_sfop {
size_t count;
u_int32_t *sesid;
};
Destroys the sfop->count sessions specified by the sfop
array of session identifiers.
ASYMMETRIC-KEY OPERATION
Asymmetric-key algorithms
Contingent upon hardware support, the following asymmetric (public-
key/private-key; or key-exchange subroutine) operations may also be
available:
Algorithm Input parameter Output parameter
Count Count
CRK_MOD_EXP 3 1
CRK_MOD_EXP_CRT 6 1
CRK_DSA_SIGN 5 2
CRK_DSA_VERIFY 7 0
CRK_DH_COMPUTE_KEY 3 1
See below for discussion of the input and output parameter counts.
Asymmetric-key commands
CIOCASYMFEAT int *feature_mask
Returns a bitmask of supported asymmetric-key operations. Each
of the above-listed asymmetric operations is present if and only
if the bit position numbered by the code for that operation is
set. For example, CRK_MOD_EXP is available if and only if the
bit (1 << CRK_MOD_EXP) is set.
CIOCKEY struct crypt_kop *kop
struct crypt_kop {
u_int crk_op; /* e.g. CRK_MOD_EXP */
u_int crk_status; /* return status */
u_short crk_iparams; /* # of input params */
u_short crk_oparams; /* # of output params */
u_int crk_pad1;
struct crparam crk_param[CRK_MAXPARAM];
};
/* Bignum parameter, in packed bytes. */
struct crparam {
void * crp_p;
u_int crp_nbits;
};
Performs an asymmetric-key operation from the list above. The
specific operation is supplied in kop->crk_op; final status for
the operation is returned in kop->crk_status. The number of
input arguments and the number of output arguments is specified
in kop->crk_iparams and kop->crk_iparams, respectively. The
field crk_param[] must be filled in with exactly
kop->crk_iparams + kop->crk_oparams arguments, each encoded as a
struct crparam (address, bitlength) pair.
The semantics of these arguments are currently undocumented.
SEE ALSO
aesni(4), hifn(4), ipsec(4), padlock(4), safe(4), ubsec(4), crypto(7),
geli(8), crypto(9)
HISTORY
The crypto driver first appeared in OpenBSD 3.0. The crypto driver was
imported to FreeBSD 5.0.
BUGS
Error checking and reporting is weak.
The values specified for symmetric-key key sizes to CIOCGSESSION must
exactly match the values expected by opencrypto(9). The output buffer
and MAC buffers supplied to CIOCCRYPT must follow whether privacy or
integrity algorithms were specified for session: if you request a
non-NULL algorithm, you must supply a suitably-sized buffer.
The scheme for passing arguments for asymmetric requests is baroque.
The naming inconsistency between CRIOGET and the various CIOC* names is
an unfortunate historical artifact.
BSD September 21, 2017 BSD