1 /* 2 * Privilege Separation for dhcpcd 3 * SPDX-License-Identifier: BSD-2-Clause 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_CONTROL 0x0019 56 #define PS_CTL_READ 0x0020 57 #define PS_LOGREOPEN 0x0021 58 #define PS_STOPPROCS 0x0022 59 #define PS_DAEMONISED 0x0023 60 #define PS_USER_INGROUP 0x0024 61 62 /* Domains */ 63 #define PS_ROOT 0x0101 64 #define PS_INET 0x0102 65 #define PS_CONTROL 0x0103 66 67 /* BSD Commands */ 68 #define PS_IOCTLLINK 0x0201 69 #define PS_IOCTL6 0x0202 70 #define PS_IOCTLINDIRECT 0x0203 71 #define PS_IP6FORWARDING 0x0204 72 #define PS_GETIFADDRS 0x0205 73 #define PS_IFIGNOREGRP 0x0206 74 #define PS_SYSCTL 0x0207 75 #define PS_GETHOSTNAME 0x0208 76 77 /* Dev Commands */ 78 #define PS_DEV_LISTENING 0x1001 79 #define PS_DEV_INITTED 0x1002 80 #define PS_DEV_IFCMD 0x1003 81 82 /* Dev Interface Commands (via flags) */ 83 #define PS_DEV_IFADDED 0x0001 84 #define PS_DEV_IFREMOVED 0x0002 85 #define PS_DEV_IFUPDATED 0x0003 86 87 /* Sysctl Needs (via flags) */ 88 #define PS_SYSCTL_OLEN 0x0001 89 #define PS_SYSCTL_ODATA 0x0002 90 91 /* Process commands */ 92 #define PS_START 0x4000 93 #define PS_STOP 0x8000 94 95 #define PSP_NAMESIZE 16 + INET_MAX_ADDRSTRLEN 96 97 /* Handy macro to work out if in the privsep engine or not. */ 98 #define IN_PRIVSEP(ctx) ((ctx)->options & DHCPCD_PRIVSEP) 99 #define IN_PRIVSEP_SE(ctx) \ 100 (((ctx)->options & (DHCPCD_PRIVSEP | DHCPCD_FORKED)) == DHCPCD_PRIVSEP) 101 102 #define PS_PROCESS_TIMEOUT 5 /* seconds to stop all processes */ 103 104 #ifdef PRIVSEP 105 #ifdef HAVE_CAPSICUM 106 #define PRIVSEP_RIGHTS 107 #endif 108 /* Pledge and Capsicum deny nearly all sysctls. 109 * Linux needs directory access to sysctls. */ 110 #if defined(HAVE_CAPSICUM) || defined(HAVE_PLEDGE) || defined(__linux__) 111 #define PRIVSEP_SYSCTL 112 #endif 113 #endif 114 115 #define PS_ROOT_FD(ctx) ((ctx)->ps_root ? (ctx)->ps_root->psp_fd : -1) 116 117 #if !defined(DISABLE_SECCOMP) && defined(__linux__) 118 #include <linux/version.h> 119 #if LINUX_VERSION_CODE >= KERNEL_VERSION(3, 5, 0) 120 #define HAVE_SECCOMP 121 #endif 122 #endif 123 124 #include "config.h" 125 #include "arp.h" 126 #include "dhcp.h" 127 #include "dhcpcd.h" 128 129 struct ps_addr { 130 sa_family_t psa_family; 131 uint8_t psa_pad[4 - sizeof(sa_family_t)]; 132 union { 133 struct in_addr psau_in_addr; 134 struct in6_addr psau_in6_addr; 135 } psa_u; 136 #define psa_in_addr psa_u.psau_in_addr 137 #define psa_in6_addr psa_u.psau_in6_addr 138 }; 139 140 /* Uniquely identify a process */ 141 struct ps_id { 142 struct ps_addr psi_addr; 143 unsigned int psi_ifindex; 144 uint16_t psi_cmd; 145 uint8_t psi_pad[2]; 146 }; 147 148 struct ps_msghdr { 149 uint16_t ps_cmd; 150 uint8_t ps_pad[sizeof(unsigned long) - sizeof(uint16_t)]; 151 unsigned long ps_flags; 152 struct ps_id ps_id; 153 socklen_t ps_namelen; 154 socklen_t ps_controllen; 155 uint8_t ps_pad2[sizeof(size_t) - sizeof(socklen_t)]; 156 size_t ps_datalen; 157 }; 158 159 struct bpf; 160 161 struct ps_process { 162 TAILQ_ENTRY(ps_process) next; 163 struct dhcpcd_ctx *psp_ctx; 164 struct ps_id psp_id; 165 pid_t psp_pid; 166 int psp_fd; 167 int psp_work_fd; 168 unsigned int psp_ifindex; 169 char psp_ifname[IF_NAMESIZE]; 170 char psp_name[PSP_NAMESIZE]; 171 uint16_t psp_proto; 172 const char *psp_protostr; 173 bool psp_started; 174 175 #ifdef INET 176 int (*psp_filter)(const struct bpf *, const struct in_addr *); 177 struct interface psp_ifp; /* Move BPF gubbins elsewhere */ 178 struct bpf *psp_bpf; 179 #endif 180 181 #ifdef HAVE_CAPSICUM 182 int psp_pfd; 183 #endif 184 }; 185 TAILQ_HEAD(ps_process_head, ps_process); 186 187 #include "privsep-control.h" 188 #include "privsep-inet.h" 189 #include "privsep-root.h" 190 #ifdef INET 191 #include "privsep-bpf.h" 192 #endif 193 194 int ps_bufalloc(struct dhcpcd_ctx *, size_t); 195 int ps_init(struct dhcpcd_ctx *); 196 int ps_start(struct dhcpcd_ctx *); 197 int ps_stop(struct dhcpcd_ctx *); 198 int ps_stopwait(struct dhcpcd_ctx *); 199 int ps_entersandbox(const char *, const char **); 200 int ps_managersandbox(struct dhcpcd_ctx *, const char *); 201 ssize_t ps_daemonised(struct dhcpcd_ctx *); 202 203 int ps_unrollmsg(struct msghdr *, struct ps_msghdr *, const void *, size_t); 204 ssize_t ps_sendpsmmsg(struct dhcpcd_ctx *, int, struct ps_msghdr *, 205 const struct msghdr *); 206 ssize_t ps_sendpsmdata(struct dhcpcd_ctx *, int, struct ps_msghdr *, 207 const void *, size_t); 208 ssize_t ps_sendmsg(struct dhcpcd_ctx *, int, uint16_t, unsigned long, 209 const struct msghdr *); 210 ssize_t ps_sendcmd(struct dhcpcd_ctx *, int, uint16_t, unsigned long, 211 const void *data, size_t len); 212 ssize_t ps_sendcmdmsg(struct dhcpcd_ctx *, int fd, uint16_t cmd, 213 unsigned long flags, const struct msghdr *msg); 214 ssize_t ps_recvmsg(int, unsigned short, uint16_t, int); 215 ssize_t ps_recvpsmsg(struct dhcpcd_ctx *, int, unsigned short, 216 ssize_t (*callback)(void *, struct ps_msghdr *, struct msghdr *), void *); 217 218 #ifdef PRIVSEP_RIGHTS 219 int ps_rights_limit_ioctl(int); 220 int ps_rights_limit_fd_getsockopt(int); 221 int ps_rights_limit_fd_fctnl(int); 222 int ps_rights_limit_fd_rdonly(int); 223 int ps_rights_limit_fd_sockopt(int); 224 int ps_rights_limit_fd(int); 225 int ps_rights_limit_fdpair(int[]); 226 #endif 227 228 #ifdef HAVE_SECCOMP 229 int ps_seccomp_enter(void); 230 #endif 231 232 pid_t ps_startprocess(struct ps_process *, 233 void (*recv_msg)(void *, unsigned short), 234 void (*recv_unpriv_msg)(void *, unsigned short), 235 int (*callback)(struct ps_process *), unsigned int); 236 int ps_stopprocess(struct ps_process *); 237 struct ps_process *ps_findprocess(struct dhcpcd_ctx *, struct ps_id *); 238 struct ps_process *ps_findprocesspid(struct dhcpcd_ctx *, pid_t); 239 struct ps_process *ps_newprocess(struct dhcpcd_ctx *, struct ps_id *); 240 bool ps_waitforprocs(struct dhcpcd_ctx *ctx); 241 void ps_process_timeout(void *); 242 void ps_freeprocess(struct ps_process *); 243 void ps_freeprocesses(struct dhcpcd_ctx *, struct ps_process *); 244 #endif 245
Indexes created Tue Sep 01 00:24:37 UTC 2026