1 /* SPDX-License-Identifier: BSD-2-Clause */ 2 /* 3 * Privilege Separation for dhcpcd 4 * Copyright (c) 2006-2020 Roy Marples <roy@marples.name> 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 * 2. Redistributions in binary form must reproduce the above copyright 13 * notice, this list of conditions and the following disclaimer in the 14 * documentation and/or other materials provided with the distribution. 15 * 16 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 17 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19 * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 20 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26 * SUCH DAMAGE. 27 */ 28 29 #ifndef PRIVSEP_H 30 #define PRIVSEP_H 31 32 //#define PRIVSEP_DEBUG 33 34 /* Start flags */ 35 #define PSF_DROPPRIVS 0x01 36 37 /* Protocols */ 38 #define PS_BOOTP 0x0001 39 #define PS_ND 0x0002 40 #define PS_DHCP6 0x0003 41 #define PS_BPF_BOOTP 0x0004 42 #define PS_BPF_ARP 0x0005 43 44 /* Generic commands */ 45 #define PS_IOCTL 0x0010 46 #define PS_ROUTE 0x0011 /* Also used for NETLINK */ 47 #define PS_SCRIPT 0x0012 48 #define PS_UNLINK 0x0013 49 #define PS_READFILE 0x0014 50 #define PS_WRITEFILE 0x0015 51 #define PS_FILEMTIME 0x0016 52 53 /* BSD Commands */ 54 #define PS_IOCTLLINK 0x0101 55 #define PS_IOCTL6 0x0102 56 #define PS_IOCTLINDIRECT 0x0103 57 #define PS_IP6FORWARDING 0x0104 58 #define PS_GETIFADDRS 0x0105 59 60 /* Dev Commands */ 61 #define PS_DEV_LISTENING 0x0201 62 #define PS_DEV_INITTED 0x0202 63 #define PS_DEV_IFCMD 0x0203 64 65 /* Dev Interface Commands (via flags) */ 66 #define PS_DEV_IFADDED 0x0001 67 #define PS_DEV_IFREMOVED 0x0002 68 #define PS_DEV_IFUPDATED 0x0003 69 70 /* Process commands */ 71 #define PS_START 0x4000 72 #define PS_STOP 0x8000 73 74 /* Max INET message size + meta data for IPC */ 75 #define PS_BUFLEN ((64 * 1024) + \ 76 sizeof(struct ps_msghdr) + \ 77 sizeof(struct msghdr) + \ 78 CMSG_SPACE(sizeof(struct in6_pktinfo) + \ 79 sizeof(int))) 80 81 /* Handy macro to work out if in the privsep engine or not. */ 82 #define IN_PRIVSEP(ctx) \ 83 ((ctx)->options & DHCPCD_PRIVSEP) 84 #define IN_PRIVSEP_SE(ctx) \ 85 (((ctx)->options & (DHCPCD_PRIVSEP | DHCPCD_FORKED)) == DHCPCD_PRIVSEP) 86 87 #include "config.h" 88 #include "arp.h" 89 #include "dhcp.h" 90 #include "dhcpcd.h" 91 92 struct ps_addr { 93 sa_family_t psa_family; 94 uint8_t psa_pad[4 - sizeof(sa_family_t)]; 95 union { 96 struct in_addr psau_in_addr; 97 struct in6_addr psau_in6_addr; 98 } psa_u; 99 #define psa_in_addr psa_u.psau_in_addr 100 #define psa_in6_addr psa_u.psau_in6_addr 101 }; 102 103 /* Uniquely identify a process */ 104 struct ps_id { 105 struct ps_addr psi_addr; 106 unsigned int psi_ifindex; 107 uint16_t psi_cmd; 108 uint8_t psi_pad[2]; 109 }; 110 111 struct ps_msghdr { 112 uint16_t ps_cmd; 113 uint8_t ps_pad[sizeof(unsigned long) - sizeof(uint16_t)]; 114 unsigned long ps_flags; 115 struct ps_id ps_id; 116 socklen_t ps_namelen; 117 socklen_t ps_controllen; 118 uint8_t ps_pad2[sizeof(size_t) - sizeof(socklen_t)]; 119 size_t ps_datalen; 120 }; 121 122 struct ps_msg { 123 struct ps_msghdr psm_hdr; 124 uint8_t psm_data[PS_BUFLEN]; 125 }; 126 127 struct bpf; 128 struct ps_process { 129 TAILQ_ENTRY(ps_process) next; 130 struct dhcpcd_ctx *psp_ctx; 131 struct ps_id psp_id; 132 pid_t psp_pid; 133 int psp_fd; 134 int psp_work_fd; 135 unsigned int psp_ifindex; 136 char psp_ifname[IF_NAMESIZE]; 137 uint16_t psp_proto; 138 const char *psp_protostr; 139 140 #ifdef INET 141 int (*psp_filter)(const struct bpf *, const struct in_addr *); 142 struct interface psp_ifp; /* Move BPF gubbins elsewhere */ 143 struct bpf *psp_bpf; 144 #endif 145 }; 146 TAILQ_HEAD(ps_process_head, ps_process); 147 148 #include "privsep-inet.h" 149 #include "privsep-root.h" 150 #ifdef INET 151 #include "privsep-bpf.h" 152 #endif 153 154 int ps_init(struct dhcpcd_ctx *); 155 int ps_dropprivs(struct dhcpcd_ctx *); 156 int ps_start(struct dhcpcd_ctx *); 157 int ps_stop(struct dhcpcd_ctx *); 158 159 int ps_unrollmsg(struct msghdr *, struct ps_msghdr *, const void *, size_t); 160 ssize_t ps_sendpsmmsg(struct dhcpcd_ctx *, int, 161 struct ps_msghdr *, const struct msghdr *); 162 ssize_t ps_sendpsmdata(struct dhcpcd_ctx *, int, 163 struct ps_msghdr *, const void *, size_t); 164 ssize_t ps_sendmsg(struct dhcpcd_ctx *, int, uint16_t, unsigned long, 165 const struct msghdr *); 166 ssize_t ps_sendcmd(struct dhcpcd_ctx *, int, uint16_t, unsigned long, 167 const void *data, size_t len); 168 ssize_t ps_recvmsg(struct dhcpcd_ctx *, int, uint16_t, int); 169 ssize_t ps_recvpsmsg(struct dhcpcd_ctx *, int, 170 ssize_t (*callback)(void *, struct ps_msghdr *, struct msghdr *), void *); 171 172 /* Internal privsep functions. */ 173 pid_t ps_dostart(struct dhcpcd_ctx * ctx, 174 pid_t *priv_pid, int *priv_fd, 175 void (*recv_msg)(void *), void (*recv_unpriv_msg), 176 void *recv_ctx, int (*callback)(void *), void (*)(int, void *), 177 unsigned int); 178 int ps_dostop(struct dhcpcd_ctx *ctx, pid_t *pid, int *fd); 179 180 struct ps_process *ps_findprocess(struct dhcpcd_ctx *, struct ps_id *); 181 struct ps_process *ps_newprocess(struct dhcpcd_ctx *, struct ps_id *); 182 void ps_freeprocess(struct ps_process *); 183 void ps_freeprocesses(struct dhcpcd_ctx *, struct ps_process *); 184 #endif 185