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 #include <sys/cdefs.h> 37 38 #include <sys/param.h> 39 #ifndef WITHOUT_CAPSICUM 40 #include <sys/capsicum.h> 41 #endif 42 #include <sys/linker_set.h> 43 #include <sys/uio.h> 44 45 #ifndef WITHOUT_CAPSICUM 46 #include <capsicum_helpers.h> 47 #endif 48 #include <err.h> 49 #include <errno.h> 50 #include <fcntl.h> 51 #include <stdio.h> 52 #include <stdlib.h> 53 #include <string.h> 54 #include <unistd.h> 55 #include <assert.h> 56 #include <pthread.h> 57 #include <sysexits.h> 58 59 #include "bhyverun.h" 60 #include "debug.h" 61 #include "pci_emul.h" 62 #include "virtio.h" 63 64 #define VTRND_RINGSZ 64 65 66 67 static int pci_vtrnd_debug; 68 #define DPRINTF(params) if (pci_vtrnd_debug) PRINTLN params 69 #define WPRINTF(params) PRINTLN params 70 71 /* 72 * Per-device softc 73 */ 74 struct pci_vtrnd_softc { 75 struct virtio_softc vrsc_vs; 76 struct vqueue_info vrsc_vq; 77 pthread_mutex_t vrsc_mtx; 78 uint64_t vrsc_cfg; 79 int vrsc_fd; 80 }; 81 82 static void pci_vtrnd_reset(void *); 83 static void pci_vtrnd_notify(void *, struct vqueue_info *); 84 85 static struct virtio_consts vtrnd_vi_consts = { 86 .vc_name = "vtrnd", 87 .vc_nvq = 1, 88 .vc_cfgsize = 0, 89 .vc_reset = pci_vtrnd_reset, 90 .vc_qnotify = pci_vtrnd_notify, 91 .vc_hv_caps = 0, 92 }; 93 94 static void 95 pci_vtrnd_reset(void *vsc) 96 { 97 struct pci_vtrnd_softc *sc; 98 99 sc = vsc; 100 101 DPRINTF(("vtrnd: device reset requested !")); 102 vi_reset_dev(&sc->vrsc_vs); 103 } 104 105 106 static void 107 pci_vtrnd_notify(void *vsc, struct vqueue_info *vq) 108 { 109 struct iovec iov; 110 struct pci_vtrnd_softc *sc; 111 struct vi_req req; 112 int len, n; 113 114 sc = vsc; 115 116 if (sc->vrsc_fd < 0) { 117 vq_endchains(vq, 0); 118 return; 119 } 120 121 while (vq_has_descs(vq)) { 122 n = vq_getchain(vq, &iov, 1, &req); 123 assert(n == 1); 124 125 len = read(sc->vrsc_fd, iov.iov_base, iov.iov_len); 126 127 DPRINTF(("vtrnd: vtrnd_notify(): %d", len)); 128 129 /* Catastrophe if unable to read from /dev/random */ 130 assert(len > 0); 131 132 /* 133 * Release this chain and handle more 134 */ 135 vq_relchain(vq, req.idx, len); 136 } 137 vq_endchains(vq, 1); /* Generate interrupt if appropriate. */ 138 } 139 140 141 static int 142 pci_vtrnd_init(struct pci_devinst *pi, nvlist_t *nvl __unused) 143 { 144 struct pci_vtrnd_softc *sc; 145 int fd; 146 int len; 147 uint8_t v; 148 #ifndef WITHOUT_CAPSICUM 149 cap_rights_t rights; 150 #endif 151 152 /* 153 * Should always be able to open /dev/random. 154 */ 155 fd = open("/dev/random", O_RDONLY | O_NONBLOCK); 156 157 assert(fd >= 0); 158 159 #ifndef WITHOUT_CAPSICUM 160 cap_rights_init(&rights, CAP_READ); 161 if (caph_rights_limit(fd, &rights) == -1) 162 errx(EX_OSERR, "Unable to apply rights for sandbox"); 163 #endif 164 165 /* 166 * Check that device is seeded and non-blocking. 167 */ 168 len = read(fd, &v, sizeof(v)); 169 if (len <= 0) { 170 WPRINTF(("vtrnd: /dev/random not ready, read(): %d", len)); 171 close(fd); 172 return (1); 173 } 174 175 sc = calloc(1, sizeof(struct pci_vtrnd_softc)); 176 177 pthread_mutex_init(&sc->vrsc_mtx, NULL); 178 179 vi_softc_linkup(&sc->vrsc_vs, &vtrnd_vi_consts, sc, pi, &sc->vrsc_vq); 180 sc->vrsc_vs.vs_mtx = &sc->vrsc_mtx; 181 182 sc->vrsc_vq.vq_qsize = VTRND_RINGSZ; 183 184 /* keep /dev/random opened while emulating */ 185 sc->vrsc_fd = fd; 186 187 /* initialize config space */ 188 pci_set_cfgdata16(pi, PCIR_DEVICE, VIRTIO_DEV_RANDOM); 189 pci_set_cfgdata16(pi, PCIR_VENDOR, VIRTIO_VENDOR); 190 pci_set_cfgdata8(pi, PCIR_CLASS, PCIC_CRYPTO); 191 pci_set_cfgdata16(pi, PCIR_SUBDEV_0, VIRTIO_ID_ENTROPY); 192 pci_set_cfgdata16(pi, PCIR_SUBVEND_0, VIRTIO_VENDOR); 193 194 if (vi_intr_init(&sc->vrsc_vs, 1, fbsdrun_virtio_msix())) 195 return (1); 196 vi_set_io_bar(&sc->vrsc_vs, 0); 197 198 return (0); 199 } 200 201 202 static const struct pci_devemu pci_de_vrnd = { 203 .pe_emu = "virtio-rnd", 204 .pe_init = pci_vtrnd_init, 205 .pe_barwrite = vi_pci_write, 206 .pe_barread = vi_pci_read, 207 }; 208 PCI_EMUL_SET(pci_de_vrnd); 209