1 /* SPDX-License-Identifier: BSD-2-Clause */ 2 /* 3 * Privilege Separation for dhcpcd 4 * Copyright (c) 2006-2025 Roy Marples <roy (at) 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 #define PSF_ELOOP 0x02 37 38 /* Protocols */ 39 #define PS_BOOTP 0x0001 40 #define PS_ND 0x0002 41 #define PS_DHCP6 0x0003 42 #define PS_BPF_BOOTP 0x0004 43 #define PS_BPF_ARP 0x0005 44 45 /* Generic commands */ 46 #define PS_IOCTL 0x0010 47 #define PS_ROUTE 0x0011 /* Also used for NETLINK */ 48 #define PS_SCRIPT 0x0012 49 #define PS_UNLINK 0x0013 50 #define PS_READFILE 0x0014 51 #define PS_WRITEFILE 0x0015 52 #define PS_FILEMTIME 0x0016 53 #define PS_AUTH_MONORDM 0x0017 54 #define PS_CTL 0x0018 55 #define PS_CTL_EOF 0x0019 56 #define PS_LOGREOPEN 0x0020 57 #define PS_STOPPROCS 0x0021 58 #define PS_DAEMONISED 0x0022 59 60 /* Domains */ 61 #define PS_ROOT 0x0101 62 #define PS_INET 0x0102 63 #define PS_CONTROL 0x0103 64 65 /* BSD Commands */ 66 #define PS_IOCTLLINK 0x0201 67 #define PS_IOCTL6 0x0202 68 #define PS_IOCTLINDIRECT 0x0203 69 #define PS_IP6FORWARDING 0x0204 70 #define PS_GETIFADDRS 0x0205 71 #define PS_IFIGNOREGRP 0x0206 72 #define PS_SYSCTL 0x0207 73 74 /* Dev Commands */ 75 #define PS_DEV_LISTENING 0x1001 76 #define PS_DEV_INITTED 0x1002 77 #define PS_DEV_IFCMD 0x1003 78 79 /* Dev Interface Commands (via flags) */ 80 #define PS_DEV_IFADDED 0x0001 81 #define PS_DEV_IFREMOVED 0x0002 82 #define PS_DEV_IFUPDATED 0x0003 83 84 /* Control Type (via flags) */ 85 #define PS_CTL_PRIV 0x0004 86 #define PS_CTL_UNPRIV 0x0005 87 88 /* Sysctl Needs (via flags) */ 89 #define PS_SYSCTL_OLEN 0x0001 90 #define PS_SYSCTL_ODATA 0x0002 91 92 /* Process commands */ 93 #define PS_START 0x4000 94 #define PS_STOP 0x8000 95 96 /* Max INET message size + meta data for IPC */ 97 #define PS_BUFLEN ((64 * 1024) + \ 98 sizeof(struct ps_msghdr) + \ 99 sizeof(struct msghdr) + \ 100 CMSG_SPACE(sizeof(struct in6_pktinfo) + \ 101 sizeof(int))) 102 103 #define PSP_NAMESIZE 16 + INET_MAX_ADDRSTRLEN 104 105 /* Handy macro to work out if in the privsep engine or not. */ 106 #define IN_PRIVSEP(ctx) \ 107 ((ctx)->options & DHCPCD_PRIVSEP) 108 #define IN_PRIVSEP_SE(ctx) \ 109 (((ctx)->options & (DHCPCD_PRIVSEP | DHCPCD_FORKED)) == DHCPCD_PRIVSEP) 110 111 #define PS_PROCESS_TIMEOUT 5 /* seconds to stop all processes */ 112 113 #ifdef PRIVSEP 114 # ifdef HAVE_CAPSICUM 115 # define PRIVSEP_RIGHTS 116 # endif 117 /* Pledge and Capsicum deny nearly all sysctls. 118 * Linux needs directory access to sysctls. */ 119 # if defined(HAVE_CAPSICUM) ||defined(HAVE_PLEDGE) || defined(__linux__) 120 # define PRIVSEP_SYSCTL 121 # endif 122 #endif 123 124 #define PS_ROOT_FD(ctx) ((ctx)->ps_root ? (ctx)->ps_root->psp_fd : -1) 125 126 #if !defined(DISABLE_SECCOMP) && defined(__linux__) 127 # include <linux/version.h> 128 # if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 5, 0) 129 # define HAVE_SECCOMP 130 # endif 131 #endif 132 133 #include "config.h" 134 #include "arp.h" 135 #include "dhcp.h" 136 #include "dhcpcd.h" 137 138 struct ps_addr { 139 sa_family_t psa_family; 140 uint8_t psa_pad[4 - sizeof(sa_family_t)]; 141 union { 142 struct in_addr psau_in_addr; 143 struct in6_addr psau_in6_addr; 144 } psa_u; 145 #define psa_in_addr psa_u.psau_in_addr 146 #define psa_in6_addr psa_u.psau_in6_addr 147 }; 148 149 /* Uniquely identify a process */ 150 struct ps_id { 151 struct ps_addr psi_addr; 152 unsigned int psi_ifindex; 153 uint16_t psi_cmd; 154 uint8_t psi_pad[2]; 155 }; 156 157 struct ps_msghdr { 158 uint16_t ps_cmd; 159 uint8_t ps_pad[sizeof(unsigned long) - sizeof(uint16_t)]; 160 unsigned long ps_flags; 161 struct ps_id ps_id; 162 socklen_t ps_namelen; 163 socklen_t ps_controllen; 164 uint8_t ps_pad2[sizeof(size_t) - sizeof(socklen_t)]; 165 size_t ps_datalen; 166 }; 167 168 struct ps_msg { 169 struct ps_msghdr psm_hdr; 170 uint8_t psm_data[PS_BUFLEN]; 171 }; 172 173 struct bpf; 174 175 struct ps_process { 176 TAILQ_ENTRY(ps_process) next; 177 struct dhcpcd_ctx *psp_ctx; 178 struct ps_id psp_id; 179 pid_t psp_pid; 180 int psp_fd; 181 int psp_work_fd; 182 unsigned int psp_ifindex; 183 char psp_ifname[IF_NAMESIZE]; 184 char psp_name[PSP_NAMESIZE]; 185 uint16_t psp_proto; 186 const char *psp_protostr; 187 bool psp_started; 188 189 #ifdef INET 190 int (*psp_filter)(const struct bpf *, const struct in_addr *); 191 struct interface psp_ifp; /* Move BPF gubbins elsewhere */ 192 struct bpf *psp_bpf; 193 #endif 194 195 #ifdef HAVE_CAPSICUM 196 int psp_pfd; 197 #endif 198 }; 199 TAILQ_HEAD(ps_process_head, ps_process); 200 201 #include "privsep-control.h" 202 #include "privsep-inet.h" 203 #include "privsep-root.h" 204 #ifdef INET 205 #include "privsep-bpf.h" 206 #endif 207 208 int ps_init(struct dhcpcd_ctx *); 209 int ps_start(struct dhcpcd_ctx *); 210 int ps_stop(struct dhcpcd_ctx *); 211 int ps_stopwait(struct dhcpcd_ctx *); 212 int ps_entersandbox(const char *, const char **); 213 int ps_managersandbox(struct dhcpcd_ctx *, const char *); 214 ssize_t ps_daemonised(struct dhcpcd_ctx *); 215 216 int ps_unrollmsg(struct msghdr *, struct ps_msghdr *, const void *, size_t); 217 ssize_t ps_sendpsmmsg(struct dhcpcd_ctx *, int, 218 struct ps_msghdr *, const struct msghdr *); 219 ssize_t ps_sendpsmdata(struct dhcpcd_ctx *, int, 220 struct ps_msghdr *, const void *, size_t); 221 ssize_t ps_sendmsg(struct dhcpcd_ctx *, int, uint16_t, unsigned long, 222 const struct msghdr *); 223 ssize_t ps_sendcmd(struct dhcpcd_ctx *, int, uint16_t, unsigned long, 224 const void *data, size_t len); 225 ssize_t ps_sendcmdmsg(struct dhcpcd_ctx *, int fd, uint16_t cmd, 226 unsigned long flags, const struct msghdr *msg); 227 ssize_t ps_recvmsg(int, unsigned short, uint16_t, int); 228 ssize_t ps_recvpsmsg(struct dhcpcd_ctx *, int, unsigned short, 229 ssize_t (*callback)(void *, struct ps_msghdr *, struct msghdr *), void *); 230 231 /* Internal privsep functions. */ 232 int ps_setbuf_fdpair(int []); 233 234 #ifdef PRIVSEP_RIGHTS 235 int ps_rights_limit_ioctl(int); 236 int ps_rights_limit_fd_fctnl(int); 237 int ps_rights_limit_fd_rdonly(int); 238 int ps_rights_limit_fd_sockopt(int); 239 int ps_rights_limit_fd(int); 240 int ps_rights_limit_fdpair(int []); 241 #endif 242 243 #ifdef HAVE_SECCOMP 244 int ps_seccomp_enter(void); 245 #endif 246 247 pid_t ps_startprocess(struct ps_process *, 248 void (*recv_msg)(void *, unsigned short), 249 void (*recv_unpriv_msg)(void *, unsigned short), 250 int (*callback)(struct ps_process *), 251 unsigned int); 252 int ps_stopprocess(struct ps_process *); 253 struct ps_process *ps_findprocess(struct dhcpcd_ctx *, struct ps_id *); 254 struct ps_process *ps_findprocesspid(struct dhcpcd_ctx *, pid_t); 255 struct ps_process *ps_newprocess(struct dhcpcd_ctx *, struct ps_id *); 256 bool ps_waitforprocs(struct dhcpcd_ctx *ctx); 257 void ps_process_timeout(void *); 258 void ps_freeprocess(struct ps_process *); 259 void ps_freeprocesses(struct dhcpcd_ctx *, struct ps_process *); 260 #endif 261
Indexes created Mon May 25 00:24:39 UTC 2026