1 /*-
2 * SPDX-License-Identifier: BSD-2-Clause
3 *
4 * Copyright (c) 2014 Nahanni Systems Inc.
5 * All rights reserved.
6 *
7 * Redistribution and use in source and binary forms, with or without
8 * modification, are permitted provided that the following conditions
9 * are met:
10 * 1. Redistributions of source code must retain the above copyright
11 * notice, this list of conditions and the following disclaimer
12 * in this position and unchanged.
13 * 2. Redistributions in binary form must reproduce the above copyright
14 * notice, this list of conditions and the following disclaimer in the
15 * documentation and/or other materials provided with the distribution.
16 *
17 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27 * SUCH DAMAGE.
28 */
29
30 /*
31 * virtio entropy device emulation.
32 * Randomness is sourced from /dev/random which does not block
33 * once it has been seeded at bootup.
34 */
35
36
37 #include <sys/param.h>
38 #ifndef WITHOUT_CAPSICUM
39 #include <sys/capsicum.h>
40 #endif
41 #include <sys/linker_set.h>
42 #include <sys/uio.h>
43
44 #ifndef WITHOUT_CAPSICUM
45 #include <capsicum_helpers.h>
46 #endif
47 #include <err.h>
48 #include <errno.h>
49 #include <fcntl.h>
50 #include <stdio.h>
51 #include <stdlib.h>
52 #include <string.h>
53 #include <unistd.h>
54 #include <assert.h>
55 #include <pthread.h>
56 #include <sysexits.h>
57
58 #include "bhyverun.h"
59 #include "debug.h"
60 #include "pci_emul.h"
61 #include "virtio.h"
62
63 #define VTRND_RINGSZ 64
64
65
66 static int pci_vtrnd_debug;
67 #define DPRINTF(params) if (pci_vtrnd_debug) PRINTLN params
68 #define WPRINTF(params) PRINTLN params
69
70 /*
71 * Per-device softc
72 */
73 struct pci_vtrnd_softc {
74 struct virtio_softc vrsc_vs;
75 struct vqueue_info vrsc_vq;
76 pthread_mutex_t vrsc_mtx;
77 uint64_t vrsc_cfg;
78 int vrsc_fd;
79 };
80
81 static void pci_vtrnd_reset(void *);
82 static void pci_vtrnd_notify(void *, struct vqueue_info *);
83
84 static struct virtio_consts vtrnd_vi_consts = {
85 .vc_name = "vtrnd",
86 .vc_nvq = 1,
87 .vc_cfgsize = 0,
88 .vc_reset = pci_vtrnd_reset,
89 .vc_qnotify = pci_vtrnd_notify,
90 .vc_hv_caps = 0,
91 };
92
93 static void
pci_vtrnd_reset(void * vsc)94 pci_vtrnd_reset(void *vsc)
95 {
96 struct pci_vtrnd_softc *sc;
97
98 sc = vsc;
99
100 DPRINTF(("vtrnd: device reset requested !"));
101 vi_reset_dev(&sc->vrsc_vs);
102 }
103
104
105 static void
pci_vtrnd_notify(void * vsc,struct vqueue_info * vq)106 pci_vtrnd_notify(void *vsc, struct vqueue_info *vq)
107 {
108 struct iovec iov;
109 struct pci_vtrnd_softc *sc;
110 struct vi_req req;
111 int len, n;
112
113 sc = vsc;
114
115 if (sc->vrsc_fd < 0) {
116 vq_endchains(vq, 0);
117 return;
118 }
119
120 while (vq_has_descs(vq)) {
121 n = vq_getchain(vq, &iov, 1, &req);
122 assert(n == 1);
123
124 len = read(sc->vrsc_fd, iov.iov_base, iov.iov_len);
125
126 DPRINTF(("vtrnd: vtrnd_notify(): %d", len));
127
128 /* Catastrophe if unable to read from /dev/random */
129 assert(len > 0);
130
131 /*
132 * Release this chain and handle more
133 */
134 vq_relchain(vq, req.idx, len);
135 }
136 vq_endchains(vq, 1); /* Generate interrupt if appropriate. */
137 }
138
139
140 static int
pci_vtrnd_init(struct pci_devinst * pi,nvlist_t * nvl __unused)141 pci_vtrnd_init(struct pci_devinst *pi, nvlist_t *nvl __unused)
142 {
143 struct pci_vtrnd_softc *sc;
144 int fd;
145 int len;
146 uint8_t v;
147 #ifndef WITHOUT_CAPSICUM
148 cap_rights_t rights;
149 #endif
150
151 /*
152 * Should always be able to open /dev/random.
153 */
154 fd = open("/dev/random", O_RDONLY | O_NONBLOCK);
155
156 assert(fd >= 0);
157
158 #ifndef WITHOUT_CAPSICUM
159 cap_rights_init(&rights, CAP_READ);
160 if (caph_rights_limit(fd, &rights) == -1)
161 errx(EX_OSERR, "Unable to apply rights for sandbox");
162 #endif
163
164 /*
165 * Check that device is seeded and non-blocking.
166 */
167 len = read(fd, &v, sizeof(v));
168 if (len <= 0) {
169 WPRINTF(("vtrnd: /dev/random not ready, read(): %d", len));
170 close(fd);
171 return (1);
172 }
173
174 sc = calloc(1, sizeof(struct pci_vtrnd_softc));
175
176 pthread_mutex_init(&sc->vrsc_mtx, NULL);
177
178 vi_softc_linkup(&sc->vrsc_vs, &vtrnd_vi_consts, sc, pi, &sc->vrsc_vq);
179 sc->vrsc_vs.vs_mtx = &sc->vrsc_mtx;
180
181 sc->vrsc_vq.vq_qsize = VTRND_RINGSZ;
182
183 /* keep /dev/random opened while emulating */
184 sc->vrsc_fd = fd;
185
186 /* initialize config space */
187 pci_set_cfgdata16(pi, PCIR_DEVICE, VIRTIO_DEV_RANDOM);
188 pci_set_cfgdata16(pi, PCIR_VENDOR, VIRTIO_VENDOR);
189 pci_set_cfgdata8(pi, PCIR_CLASS, PCIC_CRYPTO);
190 pci_set_cfgdata16(pi, PCIR_SUBDEV_0, VIRTIO_ID_ENTROPY);
191 pci_set_cfgdata16(pi, PCIR_SUBVEND_0, VIRTIO_VENDOR);
192
193 if (vi_intr_init(&sc->vrsc_vs, 1, fbsdrun_virtio_msix()))
194 return (1);
195 vi_set_io_bar(&sc->vrsc_vs, 0);
196
197 return (0);
198 }
199
200
201 static const struct pci_devemu pci_de_vrnd = {
202 .pe_emu = "virtio-rnd",
203 .pe_init = pci_vtrnd_init,
204 .pe_barwrite = vi_pci_write,
205 .pe_barread = vi_pci_read,
206 };
207 PCI_EMUL_SET(pci_de_vrnd);
208