1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * common LSM auditing functions 4 * 5 * Based on code written for SELinux by : 6 * Stephen Smalley, <sds@tycho.nsa.gov> 7 * James Morris <jmorris@redhat.com> 8 * Author : Etienne Basset, <etienne.basset@ensta.org> 9 */ 10 11 #include <linux/types.h> 12 #include <linux/stddef.h> 13 #include <linux/kernel.h> 14 #include <linux/gfp.h> 15 #include <linux/fs.h> 16 #include <linux/init.h> 17 #include <net/sock.h> 18 #include <linux/un.h> 19 #include <net/af_unix.h> 20 #include <linux/audit.h> 21 #include <linux/ipv6.h> 22 #include <linux/ip.h> 23 #include <net/ip.h> 24 #include <net/ipv6.h> 25 #include <linux/tcp.h> 26 #include <linux/udp.h> 27 #include <linux/dccp.h> 28 #include <linux/sctp.h> 29 #include <linux/lsm_audit.h> 30 31 /** 32 * ipv4_skb_to_auditdata : fill auditdata from skb 33 * @skb : the skb 34 * @ad : the audit data to fill 35 * @proto : the layer 4 protocol 36 * 37 * return 0 on success 38 */ 39 int ipv4_skb_to_auditdata(struct sk_buff *skb, 40 struct common_audit_data *ad, u8 *proto) 41 { 42 int ret = 0; 43 struct iphdr *ih; 44 45 ih = ip_hdr(skb); 46 if (ih == NULL) 47 return -EINVAL; 48 49 ad->u.net->v4info.saddr = ih->saddr; 50 ad->u.net->v4info.daddr = ih->daddr; 51 52 if (proto) 53 *proto = ih->protocol; 54 /* non initial fragment */ 55 if (ntohs(ih->frag_off) & IP_OFFSET) 56 return 0; 57 58 switch (ih->protocol) { 59 case IPPROTO_TCP: { 60 struct tcphdr *th = tcp_hdr(skb); 61 if (th == NULL) 62 break; 63 64 ad->u.net->sport = th->source; 65 ad->u.net->dport = th->dest; 66 break; 67 } 68 case IPPROTO_UDP: { 69 struct udphdr *uh = udp_hdr(skb); 70 if (uh == NULL) 71 break; 72 73 ad->u.net->sport = uh->source; 74 ad->u.net->dport = uh->dest; 75 break; 76 } 77 case IPPROTO_DCCP: { 78 struct dccp_hdr *dh = dccp_hdr(skb); 79 if (dh == NULL) 80 break; 81 82 ad->u.net->sport = dh->dccph_sport; 83 ad->u.net->dport = dh->dccph_dport; 84 break; 85 } 86 case IPPROTO_SCTP: { 87 struct sctphdr *sh = sctp_hdr(skb); 88 if (sh == NULL) 89 break; 90 ad->u.net->sport = sh->source; 91 ad->u.net->dport = sh->dest; 92 break; 93 } 94 default: 95 ret = -EINVAL; 96 } 97 return ret; 98 } 99 #if IS_ENABLED(CONFIG_IPV6) 100 /** 101 * ipv6_skb_to_auditdata : fill auditdata from skb 102 * @skb : the skb 103 * @ad : the audit data to fill 104 * @proto : the layer 4 protocol 105 * 106 * return 0 on success 107 */ 108 int ipv6_skb_to_auditdata(struct sk_buff *skb, 109 struct common_audit_data *ad, u8 *proto) 110 { 111 int offset, ret = 0; 112 struct ipv6hdr *ip6; 113 u8 nexthdr; 114 __be16 frag_off; 115 116 ip6 = ipv6_hdr(skb); 117 if (ip6 == NULL) 118 return -EINVAL; 119 ad->u.net->v6info.saddr = ip6->saddr; 120 ad->u.net->v6info.daddr = ip6->daddr; 121 ret = 0; 122 /* IPv6 can have several extension header before the Transport header 123 * skip them */ 124 offset = skb_network_offset(skb); 125 offset += sizeof(*ip6); 126 nexthdr = ip6->nexthdr; 127 offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off); 128 if (offset < 0) 129 return 0; 130 if (proto) 131 *proto = nexthdr; 132 switch (nexthdr) { 133 case IPPROTO_TCP: { 134 struct tcphdr _tcph, *th; 135 136 th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph); 137 if (th == NULL) 138 break; 139 140 ad->u.net->sport = th->source; 141 ad->u.net->dport = th->dest; 142 break; 143 } 144 case IPPROTO_UDP: { 145 struct udphdr _udph, *uh; 146 147 uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph); 148 if (uh == NULL) 149 break; 150 151 ad->u.net->sport = uh->source; 152 ad->u.net->dport = uh->dest; 153 break; 154 } 155 case IPPROTO_DCCP: { 156 struct dccp_hdr _dccph, *dh; 157 158 dh = skb_header_pointer(skb, offset, sizeof(_dccph), &_dccph); 159 if (dh == NULL) 160 break; 161 162 ad->u.net->sport = dh->dccph_sport; 163 ad->u.net->dport = dh->dccph_dport; 164 break; 165 } 166 case IPPROTO_SCTP: { 167 struct sctphdr _sctph, *sh; 168 169 sh = skb_header_pointer(skb, offset, sizeof(_sctph), &_sctph); 170 if (sh == NULL) 171 break; 172 ad->u.net->sport = sh->source; 173 ad->u.net->dport = sh->dest; 174 break; 175 } 176 default: 177 ret = -EINVAL; 178 } 179 return ret; 180 } 181 #endif 182 183 184 static inline void print_ipv6_addr(struct audit_buffer *ab, 185 struct in6_addr *addr, __be16 port, 186 char *name1, char *name2) 187 { 188 if (!ipv6_addr_any(addr)) 189 audit_log_format(ab, " %s=%pI6c", name1, addr); 190 if (port) 191 audit_log_format(ab, " %s=%d", name2, ntohs(port)); 192 } 193 194 static inline void print_ipv4_addr(struct audit_buffer *ab, __be32 addr, 195 __be16 port, char *name1, char *name2) 196 { 197 if (addr) 198 audit_log_format(ab, " %s=%pI4", name1, &addr); 199 if (port) 200 audit_log_format(ab, " %s=%d", name2, ntohs(port)); 201 } 202 203 /** 204 * dump_common_audit_data - helper to dump common audit data 205 * @a : common audit data 206 * 207 */ 208 static void dump_common_audit_data(struct audit_buffer *ab, 209 struct common_audit_data *a) 210 { 211 char comm[sizeof(current->comm)]; 212 213 /* 214 * To keep stack sizes in check force programers to notice if they 215 * start making this union too large! See struct lsm_network_audit 216 * as an example of how to deal with large data. 217 */ 218 BUILD_BUG_ON(sizeof(a->u) > sizeof(void *)*2); 219 220 audit_log_format(ab, " pid=%d comm=", task_tgid_nr(current)); 221 audit_log_untrustedstring(ab, memcpy(comm, current->comm, sizeof(comm))); 222 223 switch (a->type) { 224 case LSM_AUDIT_DATA_NONE: 225 return; 226 case LSM_AUDIT_DATA_IPC: 227 audit_log_format(ab, " key=%d ", a->u.ipc_id); 228 break; 229 case LSM_AUDIT_DATA_CAP: 230 audit_log_format(ab, " capability=%d ", a->u.cap); 231 break; 232 case LSM_AUDIT_DATA_PATH: { 233 struct inode *inode; 234 235 audit_log_d_path(ab, " path=", &a->u.path); 236 237 inode = d_backing_inode(a->u.path.dentry); 238 if (inode) { 239 audit_log_format(ab, " dev="); 240 audit_log_untrustedstring(ab, inode->i_sb->s_id); 241 audit_log_format(ab, " ino=%lu", inode->i_ino); 242 } 243 break; 244 } 245 case LSM_AUDIT_DATA_FILE: { 246 struct inode *inode; 247 248 audit_log_d_path(ab, " path=", &a->u.file->f_path); 249 250 inode = file_inode(a->u.file); 251 if (inode) { 252 audit_log_format(ab, " dev="); 253 audit_log_untrustedstring(ab, inode->i_sb->s_id); 254 audit_log_format(ab, " ino=%lu", inode->i_ino); 255 } 256 break; 257 } 258 case LSM_AUDIT_DATA_IOCTL_OP: { 259 struct inode *inode; 260 261 audit_log_d_path(ab, " path=", &a->u.op->path); 262 263 inode = a->u.op->path.dentry->d_inode; 264 if (inode) { 265 audit_log_format(ab, " dev="); 266 audit_log_untrustedstring(ab, inode->i_sb->s_id); 267 audit_log_format(ab, " ino=%lu", inode->i_ino); 268 } 269 270 audit_log_format(ab, " ioctlcmd=0x%hx", a->u.op->cmd); 271 break; 272 } 273 case LSM_AUDIT_DATA_DENTRY: { 274 struct inode *inode; 275 276 audit_log_format(ab, " name="); 277 audit_log_untrustedstring(ab, a->u.dentry->d_name.name); 278 279 inode = d_backing_inode(a->u.dentry); 280 if (inode) { 281 audit_log_format(ab, " dev="); 282 audit_log_untrustedstring(ab, inode->i_sb->s_id); 283 audit_log_format(ab, " ino=%lu", inode->i_ino); 284 } 285 break; 286 } 287 case LSM_AUDIT_DATA_INODE: { 288 struct dentry *dentry; 289 struct inode *inode; 290 291 inode = a->u.inode; 292 dentry = d_find_alias(inode); 293 if (dentry) { 294 audit_log_format(ab, " name="); 295 audit_log_untrustedstring(ab, 296 dentry->d_name.name); 297 dput(dentry); 298 } 299 audit_log_format(ab, " dev="); 300 audit_log_untrustedstring(ab, inode->i_sb->s_id); 301 audit_log_format(ab, " ino=%lu", inode->i_ino); 302 break; 303 } 304 case LSM_AUDIT_DATA_TASK: { 305 struct task_struct *tsk = a->u.tsk; 306 if (tsk) { 307 pid_t pid = task_tgid_nr(tsk); 308 if (pid) { 309 char comm[sizeof(tsk->comm)]; 310 audit_log_format(ab, " opid=%d ocomm=", pid); 311 audit_log_untrustedstring(ab, 312 memcpy(comm, tsk->comm, sizeof(comm))); 313 } 314 } 315 break; 316 } 317 case LSM_AUDIT_DATA_NET: 318 if (a->u.net->sk) { 319 struct sock *sk = a->u.net->sk; 320 struct unix_sock *u; 321 struct unix_address *addr; 322 int len = 0; 323 char *p = NULL; 324 325 switch (sk->sk_family) { 326 case AF_INET: { 327 struct inet_sock *inet = inet_sk(sk); 328 329 print_ipv4_addr(ab, inet->inet_rcv_saddr, 330 inet->inet_sport, 331 "laddr", "lport"); 332 print_ipv4_addr(ab, inet->inet_daddr, 333 inet->inet_dport, 334 "faddr", "fport"); 335 break; 336 } 337 #if IS_ENABLED(CONFIG_IPV6) 338 case AF_INET6: { 339 struct inet_sock *inet = inet_sk(sk); 340 341 print_ipv6_addr(ab, &sk->sk_v6_rcv_saddr, 342 inet->inet_sport, 343 "laddr", "lport"); 344 print_ipv6_addr(ab, &sk->sk_v6_daddr, 345 inet->inet_dport, 346 "faddr", "fport"); 347 break; 348 } 349 #endif 350 case AF_UNIX: 351 u = unix_sk(sk); 352 addr = smp_load_acquire(&u->addr); 353 if (!addr) 354 break; 355 if (u->path.dentry) { 356 audit_log_d_path(ab, " path=", &u->path); 357 break; 358 } 359 len = addr->len-sizeof(short); 360 p = &addr->name->sun_path[0]; 361 audit_log_format(ab, " path="); 362 if (*p) 363 audit_log_untrustedstring(ab, p); 364 else 365 audit_log_n_hex(ab, p, len); 366 break; 367 } 368 } 369 370 switch (a->u.net->family) { 371 case AF_INET: 372 print_ipv4_addr(ab, a->u.net->v4info.saddr, 373 a->u.net->sport, 374 "saddr", "src"); 375 print_ipv4_addr(ab, a->u.net->v4info.daddr, 376 a->u.net->dport, 377 "daddr", "dest"); 378 break; 379 case AF_INET6: 380 print_ipv6_addr(ab, &a->u.net->v6info.saddr, 381 a->u.net->sport, 382 "saddr", "src"); 383 print_ipv6_addr(ab, &a->u.net->v6info.daddr, 384 a->u.net->dport, 385 "daddr", "dest"); 386 break; 387 } 388 if (a->u.net->netif > 0) { 389 struct net_device *dev; 390 391 /* NOTE: we always use init's namespace */ 392 dev = dev_get_by_index(&init_net, a->u.net->netif); 393 if (dev) { 394 audit_log_format(ab, " netif=%s", dev->name); 395 dev_put(dev); 396 } 397 } 398 break; 399 #ifdef CONFIG_KEYS 400 case LSM_AUDIT_DATA_KEY: 401 audit_log_format(ab, " key_serial=%u", a->u.key_struct.key); 402 if (a->u.key_struct.key_desc) { 403 audit_log_format(ab, " key_desc="); 404 audit_log_untrustedstring(ab, a->u.key_struct.key_desc); 405 } 406 break; 407 #endif 408 case LSM_AUDIT_DATA_KMOD: 409 audit_log_format(ab, " kmod="); 410 audit_log_untrustedstring(ab, a->u.kmod_name); 411 break; 412 case LSM_AUDIT_DATA_IBPKEY: { 413 struct in6_addr sbn_pfx; 414 415 memset(&sbn_pfx.s6_addr, 0, 416 sizeof(sbn_pfx.s6_addr)); 417 memcpy(&sbn_pfx.s6_addr, &a->u.ibpkey->subnet_prefix, 418 sizeof(a->u.ibpkey->subnet_prefix)); 419 audit_log_format(ab, " pkey=0x%x subnet_prefix=%pI6c", 420 a->u.ibpkey->pkey, &sbn_pfx); 421 break; 422 } 423 case LSM_AUDIT_DATA_IBENDPORT: 424 audit_log_format(ab, " device=%s port_num=%u", 425 a->u.ibendport->dev_name, 426 a->u.ibendport->port); 427 break; 428 } /* switch (a->type) */ 429 } 430 431 /** 432 * common_lsm_audit - generic LSM auditing function 433 * @a: auxiliary audit data 434 * @pre_audit: lsm-specific pre-audit callback 435 * @post_audit: lsm-specific post-audit callback 436 * 437 * setup the audit buffer for common security information 438 * uses callback to print LSM specific information 439 */ 440 void common_lsm_audit(struct common_audit_data *a, 441 void (*pre_audit)(struct audit_buffer *, void *), 442 void (*post_audit)(struct audit_buffer *, void *)) 443 { 444 struct audit_buffer *ab; 445 446 if (a == NULL) 447 return; 448 /* we use GFP_ATOMIC so we won't sleep */ 449 ab = audit_log_start(audit_context(), GFP_ATOMIC | __GFP_NOWARN, 450 AUDIT_AVC); 451 452 if (ab == NULL) 453 return; 454 455 if (pre_audit) 456 pre_audit(ab, a); 457 458 dump_common_audit_data(ab, a); 459 460 if (post_audit) 461 post_audit(ab, a); 462 463 audit_log_end(ab); 464 } 465