/* * CDDL HEADER START * * The contents of this file are subject to the terms of the * Common Development and Distribution License (the "License"). * You may not use this file except in compliance with the License. * * You can obtain a copy of the license at usr/src/OPENSOLARIS.LICENSE * or http://www.opensolaris.org/os/licensing. * See the License for the specific language governing permissions * and limitations under the License. * * When distributing Covered Code, include this CDDL HEADER in each * file and include the License file at usr/src/OPENSOLARIS.LICENSE. * If applicable, add the following below this CDDL HEADER, with the * fields enclosed by brackets "[]" replaced with your own identifying * information: Portions Copyright [yyyy] [name of copyright owner] * * CDDL HEADER END * * Copyright 2009 Sun Microsystems, Inc. All rights reserved. * Use is subject to license terms. */ /* * Random number generator pseudo-driver * * This is a lightweight driver which calls in to the Kernel Cryptographic * Framework to do the real work. Kernel modules should NOT depend on this * driver for /dev/random kernel API. * * Applications may ask for 2 types of random bits: * . High quality random by reading from /dev/random. The output is extracted * only when a minimum amount of entropy is available. * . Pseudo-random, by reading from /dev/urandom, that can be generated any * time. */ #include <sys/types.h> #include <sys/errno.h> #include <sys/stat.h> #include <sys/file.h> #include <sys/open.h> #include <sys/poll.h> #include <sys/uio.h> #include <sys/cred.h> #include <sys/modctl.h> #include <sys/conf.h> #include <sys/ddi.h> #include <sys/sunddi.h> #include <sys/random.h> #include <sys/crypto/impl.h> #define DEVRANDOM 0 #define DEVURANDOM 1 #define HASHSIZE 20 /* Assuming a SHA1 hash algorithm */ #define WRITEBUFSIZE 512 /* Size of buffer for write request */ #define MAXRETBYTES 1040 /* Max bytes returned per read. */ /* Must be a multiple of HASHSIZE */ static dev_info_t *rnd_dip; static int rnd_open(dev_t *, int, int, cred_t *); static int rnd_close(dev_t, int, int, cred_t *); static int rnd_read(dev_t, struct uio *, cred_t *); static int rnd_write(dev_t, struct uio *, cred_t *); static int rnd_chpoll(dev_t, short, int, short *, struct pollhead **); static int rnd_attach(dev_info_t *, ddi_attach_cmd_t); static int rnd_detach(dev_info_t *, ddi_detach_cmd_t); static int rnd_getinfo(dev_info_t *, ddi_info_cmd_t, void *, void **); /* DDI declarations */ static struct cb_ops rnd_cb_ops = { rnd_open, /* open */ rnd_close, /* close */ nodev, /* strategy */ nodev, /* print */ nodev, /* dump */ rnd_read, /* read */ rnd_write, /* write */ nodev, /* ioctl */ nodev, /* devmap */ nodev, /* mmap */ nodev, /* segmap */ rnd_chpoll, /* chpoll */ ddi_prop_op, /* prop_op */ NULL, /* streamtab */ (D_NEW | D_MP), /* cb_flag */ CB_REV, /* cb_rev */ nodev, /* aread */ nodev /* awrite */ }; static struct dev_ops rnd_ops = { DEVO_REV, /* devo_rev, */ 0, /* refcnt */ rnd_getinfo, /* get_dev_info */ nulldev, /* identify */ nulldev, /* probe */ rnd_attach, /* attach */ rnd_detach, /* detach */ nodev, /* reset */ &rnd_cb_ops, /* driver operations */ NULL, /* bus operations */ NULL, /* power */ ddi_quiesce_not_needed, /* quiesce */ }; /* Modlinkage */ static struct modldrv modldrv = { &mod_driverops, "random number device", &rnd_ops }; static struct modlinkage modlinkage = { MODREV_1, { &modldrv, NULL } }; /* DDI glue */ int _init(void) { return (mod_install(&modlinkage)); } int _fini(void) { return (mod_remove(&modlinkage)); } int _info(struct modinfo *modinfop) { return (mod_info(&modlinkage, modinfop)); } static int rnd_attach(dev_info_t *dip, ddi_attach_cmd_t cmd) { if (cmd != DDI_ATTACH) return (DDI_FAILURE); if (ddi_create_minor_node(dip, "random", S_IFCHR, DEVRANDOM, DDI_PSEUDO, 0) == DDI_FAILURE) { ddi_remove_minor_node(dip, NULL); return (DDI_FAILURE); } if (ddi_create_minor_node(dip, "urandom", S_IFCHR, DEVURANDOM, DDI_PSEUDO, 0) == DDI_FAILURE) { ddi_remove_minor_node(dip, NULL); return (DDI_FAILURE); } rnd_dip = dip; return (DDI_SUCCESS); } static int rnd_detach(dev_info_t *dip, ddi_detach_cmd_t cmd) { if (cmd != DDI_DETACH) return (DDI_FAILURE); rnd_dip = NULL; ddi_remove_minor_node(dip, NULL); return (DDI_SUCCESS); } /*ARGSUSED*/ static int rnd_getinfo(dev_info_t *dip, ddi_info_cmd_t infocmd, void *arg, void **result) { int error; switch (infocmd) { case DDI_INFO_DEVT2DEVINFO: *result = rnd_dip; error = DDI_SUCCESS; break; case DDI_INFO_DEVT2INSTANCE: *result = (void *)0; error = DDI_SUCCESS; break; default: error = DDI_FAILURE; } return (error); } /*ARGSUSED3*/ static int rnd_open(dev_t *devp, int flag, int otyp, cred_t *credp) { switch (getminor(*devp)) { case DEVRANDOM: if (!kcf_rngprov_check()) return (ENXIO); break; case DEVURANDOM: break; default: return (ENXIO); } if (otyp != OTYP_CHR) return (EINVAL); if (flag & FEXCL) return (EINVAL); return (0); } /*ARGSUSED*/ static int rnd_close(dev_t dev, int flag, int otyp, cred_t *credp) { return (0); } /*ARGSUSED2*/ static int rnd_read(dev_t dev, struct uio *uiop, cred_t *credp) { size_t len; minor_t devno; int error = 0; int nbytes = 0; uint8_t random_bytes[2 * HASHSIZE]; devno = getminor(dev); while (error == 0 && uiop->uio_resid > 0) { len = min(sizeof (random_bytes), uiop->uio_resid); switch (devno) { case DEVRANDOM: error = kcf_rnd_get_bytes(random_bytes, len, uiop->uio_fmode & (FNDELAY|FNONBLOCK)); break; case DEVURANDOM: error = kcf_rnd_get_pseudo_bytes(random_bytes, len); break; default: return (ENXIO); } if (error == 0) { /* * /dev/[u]random is not a seekable device. To prevent * uio offset from growing and eventually exceeding * the maximum, reset the offset here for every call. */ uiop->uio_loffset = 0; error = uiomove(random_bytes, len, UIO_READ, uiop); nbytes += len; if (devno == DEVRANDOM && nbytes >= MAXRETBYTES) break; } else if ((error == EAGAIN) && (nbytes > 0)) { error = 0; break; } } return (error); } /*ARGSUSED*/ static int rnd_write(dev_t dev, struct uio *uiop, cred_t *credp) { int error; uint8_t buf[WRITEBUFSIZE]; size_t bytes; minor_t devno; devno = getminor(dev); while (uiop->uio_resid > 0) { bytes = min(sizeof (buf), uiop->uio_resid); /* See comments in rnd_read() */ uiop->uio_loffset = 0; if ((error = uiomove(buf, bytes, UIO_WRITE, uiop)) != 0) return (error); switch (devno) { case DEVRANDOM: if ((error = random_add_entropy(buf, bytes, 0)) != 0) return (error); break; case DEVURANDOM: if ((error = random_add_pseudo_entropy(buf, bytes, 0)) != 0) return (error); break; default: return (ENXIO); } } return (0); } static struct pollhead urnd_pollhd; /* * poll(2) is supported as follows: * . Only POLLIN, POLLOUT, and POLLRDNORM events are supported. * . POLLOUT always succeeds. * . POLLIN and POLLRDNORM from /dev/urandom always succeeds. * . POLLIN and POLLRDNORM from /dev/random will block until a * minimum amount of entropy is available. */ static int rnd_chpoll(dev_t dev, short events, int anyyet, short *reventsp, struct pollhead **phpp) { switch (getminor(dev)) { case DEVURANDOM: *reventsp = events & (POLLOUT | POLLIN | POLLRDNORM); /* * A non NULL pollhead pointer should be returned in case * user polls for 0 events. */ if (*reventsp == 0 && !anyyet) *phpp = &urnd_pollhd; break; case DEVRANDOM: kcf_rnd_chpoll(events, anyyet, reventsp, phpp); break; default: return (ENXIO); } return (0); }