1 /*- 2 * SPDX-License-Identifier: BSD-2-Clause-FreeBSD 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 __FBSDID("$FreeBSD$"); 38 39 #include <sys/param.h> 40 #ifndef WITHOUT_CAPSICUM 41 #include <sys/capsicum.h> 42 #endif 43 #include <sys/linker_set.h> 44 #include <sys/uio.h> 45 46 #ifndef WITHOUT_CAPSICUM 47 #include <capsicum_helpers.h> 48 #endif 49 #include <err.h> 50 #include <errno.h> 51 #include <fcntl.h> 52 #include <stdio.h> 53 #include <stdlib.h> 54 #include <string.h> 55 #include <unistd.h> 56 #include <assert.h> 57 #include <pthread.h> 58 #include <sysexits.h> 59 60 #include "bhyverun.h" 61 #include "debug.h" 62 #include "pci_emul.h" 63 #include "virtio.h" 64 65 #define VTRND_RINGSZ 64 66 67 68 static int pci_vtrnd_debug; 69 #define DPRINTF(params) if (pci_vtrnd_debug) PRINTLN params 70 #define WPRINTF(params) PRINTLN params 71 72 /* 73 * Per-device softc 74 */ 75 struct pci_vtrnd_softc { 76 struct virtio_softc vrsc_vs; 77 struct vqueue_info vrsc_vq; 78 pthread_mutex_t vrsc_mtx; 79 uint64_t vrsc_cfg; 80 int vrsc_fd; 81 }; 82 83 static void pci_vtrnd_reset(void *); 84 static void pci_vtrnd_notify(void *, struct vqueue_info *); 85 86 static struct virtio_consts vtrnd_vi_consts = { 87 "vtrnd", /* our name */ 88 1, /* we support 1 virtqueue */ 89 0, /* config reg size */ 90 pci_vtrnd_reset, /* reset */ 91 pci_vtrnd_notify, /* device-wide qnotify */ 92 NULL, /* read virtio config */ 93 NULL, /* write virtio config */ 94 NULL, /* apply negotiated features */ 95 0, /* our capabilities */ 96 }; 97 98 99 static void 100 pci_vtrnd_reset(void *vsc) 101 { 102 struct pci_vtrnd_softc *sc; 103 104 sc = vsc; 105 106 DPRINTF(("vtrnd: device reset requested !")); 107 vi_reset_dev(&sc->vrsc_vs); 108 } 109 110 111 static void 112 pci_vtrnd_notify(void *vsc, struct vqueue_info *vq) 113 { 114 struct iovec iov; 115 struct pci_vtrnd_softc *sc; 116 struct vi_req req; 117 int len, n; 118 119 sc = vsc; 120 121 if (sc->vrsc_fd < 0) { 122 vq_endchains(vq, 0); 123 return; 124 } 125 126 while (vq_has_descs(vq)) { 127 n = vq_getchain(vq, &iov, 1, &req); 128 assert(n == 1); 129 130 len = read(sc->vrsc_fd, iov.iov_base, iov.iov_len); 131 132 DPRINTF(("vtrnd: vtrnd_notify(): %d", len)); 133 134 /* Catastrophe if unable to read from /dev/random */ 135 assert(len > 0); 136 137 /* 138 * Release this chain and handle more 139 */ 140 vq_relchain(vq, req.idx, len); 141 } 142 vq_endchains(vq, 1); /* Generate interrupt if appropriate. */ 143 } 144 145 146 static int 147 pci_vtrnd_init(struct vmctx *ctx, struct pci_devinst *pi, nvlist_t *nvl) 148 { 149 struct pci_vtrnd_softc *sc; 150 int fd; 151 int len; 152 uint8_t v; 153 #ifndef WITHOUT_CAPSICUM 154 cap_rights_t rights; 155 #endif 156 157 /* 158 * Should always be able to open /dev/random. 159 */ 160 fd = open("/dev/random", O_RDONLY | O_NONBLOCK); 161 162 assert(fd >= 0); 163 164 #ifndef WITHOUT_CAPSICUM 165 cap_rights_init(&rights, CAP_READ); 166 if (caph_rights_limit(fd, &rights) == -1) 167 errx(EX_OSERR, "Unable to apply rights for sandbox"); 168 #endif 169 170 /* 171 * Check that device is seeded and non-blocking. 172 */ 173 len = read(fd, &v, sizeof(v)); 174 if (len <= 0) { 175 WPRINTF(("vtrnd: /dev/random not ready, read(): %d", len)); 176 close(fd); 177 return (1); 178 } 179 180 sc = calloc(1, sizeof(struct pci_vtrnd_softc)); 181 182 pthread_mutex_init(&sc->vrsc_mtx, NULL); 183 184 vi_softc_linkup(&sc->vrsc_vs, &vtrnd_vi_consts, sc, pi, &sc->vrsc_vq); 185 sc->vrsc_vs.vs_mtx = &sc->vrsc_mtx; 186 187 sc->vrsc_vq.vq_qsize = VTRND_RINGSZ; 188 189 /* keep /dev/random opened while emulating */ 190 sc->vrsc_fd = fd; 191 192 /* initialize config space */ 193 pci_set_cfgdata16(pi, PCIR_DEVICE, VIRTIO_DEV_RANDOM); 194 pci_set_cfgdata16(pi, PCIR_VENDOR, VIRTIO_VENDOR); 195 pci_set_cfgdata8(pi, PCIR_CLASS, PCIC_CRYPTO); 196 pci_set_cfgdata16(pi, PCIR_SUBDEV_0, VIRTIO_ID_ENTROPY); 197 pci_set_cfgdata16(pi, PCIR_SUBVEND_0, VIRTIO_VENDOR); 198 199 if (vi_intr_init(&sc->vrsc_vs, 1, fbsdrun_virtio_msix())) 200 return (1); 201 vi_set_io_bar(&sc->vrsc_vs, 0); 202 203 return (0); 204 } 205 206 207 static const struct pci_devemu pci_de_vrnd = { 208 .pe_emu = "virtio-rnd", 209 .pe_init = pci_vtrnd_init, 210 .pe_barwrite = vi_pci_write, 211 .pe_barread = vi_pci_read, 212 }; 213 PCI_EMUL_SET(pci_de_vrnd); 214