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 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 #include <linux/security.h> 31 32 /** 33 * ipv4_skb_to_auditdata : fill auditdata from skb 34 * @skb : the skb 35 * @ad : the audit data to fill 36 * @proto : the layer 4 protocol 37 * 38 * return 0 on success 39 */ 40 int ipv4_skb_to_auditdata(struct sk_buff *skb, 41 struct common_audit_data *ad, u8 *proto) 42 { 43 int ret = 0; 44 struct iphdr *ih; 45 46 ih = ip_hdr(skb); 47 ad->u.net->v4info.saddr = ih->saddr; 48 ad->u.net->v4info.daddr = ih->daddr; 49 50 if (proto) 51 *proto = ih->protocol; 52 /* non initial fragment */ 53 if (ntohs(ih->frag_off) & IP_OFFSET) 54 return 0; 55 56 switch (ih->protocol) { 57 case IPPROTO_TCP: { 58 struct tcphdr *th = tcp_hdr(skb); 59 60 ad->u.net->sport = th->source; 61 ad->u.net->dport = th->dest; 62 break; 63 } 64 case IPPROTO_UDP: { 65 struct udphdr *uh = udp_hdr(skb); 66 67 ad->u.net->sport = uh->source; 68 ad->u.net->dport = uh->dest; 69 break; 70 } 71 case IPPROTO_DCCP: { 72 struct dccp_hdr *dh = dccp_hdr(skb); 73 74 ad->u.net->sport = dh->dccph_sport; 75 ad->u.net->dport = dh->dccph_dport; 76 break; 77 } 78 case IPPROTO_SCTP: { 79 struct sctphdr *sh = sctp_hdr(skb); 80 81 ad->u.net->sport = sh->source; 82 ad->u.net->dport = sh->dest; 83 break; 84 } 85 default: 86 ret = -EINVAL; 87 } 88 return ret; 89 } 90 #if IS_ENABLED(CONFIG_IPV6) 91 /** 92 * ipv6_skb_to_auditdata : fill auditdata from skb 93 * @skb : the skb 94 * @ad : the audit data to fill 95 * @proto : the layer 4 protocol 96 * 97 * return 0 on success 98 */ 99 int ipv6_skb_to_auditdata(struct sk_buff *skb, 100 struct common_audit_data *ad, u8 *proto) 101 { 102 int offset, ret = 0; 103 struct ipv6hdr *ip6; 104 u8 nexthdr; 105 __be16 frag_off; 106 107 ip6 = ipv6_hdr(skb); 108 ad->u.net->v6info.saddr = ip6->saddr; 109 ad->u.net->v6info.daddr = ip6->daddr; 110 /* IPv6 can have several extension header before the Transport header 111 * skip them */ 112 offset = skb_network_offset(skb); 113 offset += sizeof(*ip6); 114 nexthdr = ip6->nexthdr; 115 offset = ipv6_skip_exthdr(skb, offset, &nexthdr, &frag_off); 116 if (offset < 0) 117 return 0; 118 if (proto) 119 *proto = nexthdr; 120 switch (nexthdr) { 121 case IPPROTO_TCP: { 122 struct tcphdr _tcph, *th; 123 124 th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph); 125 if (th == NULL) 126 break; 127 128 ad->u.net->sport = th->source; 129 ad->u.net->dport = th->dest; 130 break; 131 } 132 case IPPROTO_UDP: { 133 struct udphdr _udph, *uh; 134 135 uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph); 136 if (uh == NULL) 137 break; 138 139 ad->u.net->sport = uh->source; 140 ad->u.net->dport = uh->dest; 141 break; 142 } 143 case IPPROTO_DCCP: { 144 struct dccp_hdr _dccph, *dh; 145 146 dh = skb_header_pointer(skb, offset, sizeof(_dccph), &_dccph); 147 if (dh == NULL) 148 break; 149 150 ad->u.net->sport = dh->dccph_sport; 151 ad->u.net->dport = dh->dccph_dport; 152 break; 153 } 154 case IPPROTO_SCTP: { 155 struct sctphdr _sctph, *sh; 156 157 sh = skb_header_pointer(skb, offset, sizeof(_sctph), &_sctph); 158 if (sh == NULL) 159 break; 160 ad->u.net->sport = sh->source; 161 ad->u.net->dport = sh->dest; 162 break; 163 } 164 default: 165 ret = -EINVAL; 166 } 167 return ret; 168 } 169 #endif 170 171 172 static inline void print_ipv6_addr(struct audit_buffer *ab, 173 const struct in6_addr *addr, __be16 port, 174 const char *name1, const char *name2) 175 { 176 if (!ipv6_addr_any(addr)) 177 audit_log_format(ab, " %s=%pI6c", name1, addr); 178 if (port) 179 audit_log_format(ab, " %s=%d", name2, ntohs(port)); 180 } 181 182 static inline void print_ipv4_addr(struct audit_buffer *ab, __be32 addr, 183 __be16 port, const char *name1, const char *name2) 184 { 185 if (addr) 186 audit_log_format(ab, " %s=%pI4", name1, &addr); 187 if (port) 188 audit_log_format(ab, " %s=%d", name2, ntohs(port)); 189 } 190 191 /** 192 * audit_log_lsm_data - helper to log common LSM audit data 193 * @ab : the audit buffer 194 * @a : common audit data 195 */ 196 void audit_log_lsm_data(struct audit_buffer *ab, 197 const struct common_audit_data *a) 198 { 199 /* 200 * To keep stack sizes in check force programmers to notice if they 201 * start making this union too large! See struct lsm_network_audit 202 * as an example of how to deal with large data. 203 */ 204 BUILD_BUG_ON(sizeof(a->u) > sizeof(void *)*2); 205 206 switch (a->type) { 207 case LSM_AUDIT_DATA_NONE: 208 return; 209 case LSM_AUDIT_DATA_IPC: 210 audit_log_format(ab, " ipc_key=%d ", a->u.ipc_id); 211 break; 212 case LSM_AUDIT_DATA_CAP: 213 audit_log_format(ab, " capability=%d ", a->u.cap); 214 break; 215 case LSM_AUDIT_DATA_PATH: { 216 struct inode *inode; 217 218 audit_log_d_path(ab, " path=", &a->u.path); 219 220 inode = d_backing_inode(a->u.path.dentry); 221 if (inode) { 222 audit_log_format(ab, " dev="); 223 audit_log_untrustedstring(ab, inode->i_sb->s_id); 224 audit_log_format(ab, " ino=%lu", inode->i_ino); 225 } 226 break; 227 } 228 case LSM_AUDIT_DATA_FILE: { 229 struct inode *inode; 230 231 audit_log_d_path(ab, " path=", &a->u.file->f_path); 232 233 inode = file_inode(a->u.file); 234 if (inode) { 235 audit_log_format(ab, " dev="); 236 audit_log_untrustedstring(ab, inode->i_sb->s_id); 237 audit_log_format(ab, " ino=%lu", inode->i_ino); 238 } 239 break; 240 } 241 case LSM_AUDIT_DATA_IOCTL_OP: { 242 struct inode *inode; 243 244 audit_log_d_path(ab, " path=", &a->u.op->path); 245 246 inode = a->u.op->path.dentry->d_inode; 247 if (inode) { 248 audit_log_format(ab, " dev="); 249 audit_log_untrustedstring(ab, inode->i_sb->s_id); 250 audit_log_format(ab, " ino=%lu", inode->i_ino); 251 } 252 253 audit_log_format(ab, " ioctlcmd=0x%hx", a->u.op->cmd); 254 break; 255 } 256 case LSM_AUDIT_DATA_DENTRY: { 257 struct inode *inode; 258 259 audit_log_format(ab, " name="); 260 spin_lock(&a->u.dentry->d_lock); 261 audit_log_untrustedstring(ab, a->u.dentry->d_name.name); 262 spin_unlock(&a->u.dentry->d_lock); 263 264 inode = d_backing_inode(a->u.dentry); 265 if (inode) { 266 audit_log_format(ab, " dev="); 267 audit_log_untrustedstring(ab, inode->i_sb->s_id); 268 audit_log_format(ab, " ino=%lu", inode->i_ino); 269 } 270 break; 271 } 272 case LSM_AUDIT_DATA_INODE: { 273 struct dentry *dentry; 274 struct inode *inode; 275 276 rcu_read_lock(); 277 inode = a->u.inode; 278 dentry = d_find_alias_rcu(inode); 279 if (dentry) { 280 audit_log_format(ab, " name="); 281 spin_lock(&dentry->d_lock); 282 audit_log_untrustedstring(ab, dentry->d_name.name); 283 spin_unlock(&dentry->d_lock); 284 } 285 audit_log_format(ab, " dev="); 286 audit_log_untrustedstring(ab, inode->i_sb->s_id); 287 audit_log_format(ab, " ino=%lu", inode->i_ino); 288 rcu_read_unlock(); 289 break; 290 } 291 case LSM_AUDIT_DATA_TASK: { 292 struct task_struct *tsk = a->u.tsk; 293 if (tsk) { 294 pid_t pid = task_tgid_nr(tsk); 295 if (pid) { 296 char tskcomm[sizeof(tsk->comm)]; 297 audit_log_format(ab, " opid=%d ocomm=", pid); 298 audit_log_untrustedstring(ab, 299 get_task_comm(tskcomm, tsk)); 300 } 301 } 302 break; 303 } 304 case LSM_AUDIT_DATA_NET: 305 if (a->u.net->sk) { 306 const struct sock *sk = a->u.net->sk; 307 const struct unix_sock *u; 308 struct unix_address *addr; 309 int len = 0; 310 char *p = NULL; 311 312 switch (sk->sk_family) { 313 case AF_INET: { 314 const struct inet_sock *inet = inet_sk(sk); 315 316 print_ipv4_addr(ab, inet->inet_rcv_saddr, 317 inet->inet_sport, 318 "laddr", "lport"); 319 print_ipv4_addr(ab, inet->inet_daddr, 320 inet->inet_dport, 321 "faddr", "fport"); 322 break; 323 } 324 #if IS_ENABLED(CONFIG_IPV6) 325 case AF_INET6: { 326 const struct inet_sock *inet = inet_sk(sk); 327 328 print_ipv6_addr(ab, &sk->sk_v6_rcv_saddr, 329 inet->inet_sport, 330 "laddr", "lport"); 331 print_ipv6_addr(ab, &sk->sk_v6_daddr, 332 inet->inet_dport, 333 "faddr", "fport"); 334 break; 335 } 336 #endif 337 case AF_UNIX: 338 u = unix_sk(sk); 339 addr = smp_load_acquire(&u->addr); 340 if (!addr) 341 break; 342 if (u->path.dentry) { 343 audit_log_d_path(ab, " path=", &u->path); 344 break; 345 } 346 len = addr->len-sizeof(short); 347 p = &addr->name->sun_path[0]; 348 audit_log_format(ab, " path="); 349 if (*p) 350 audit_log_untrustedstring(ab, p); 351 else 352 audit_log_n_hex(ab, p, len); 353 break; 354 } 355 } 356 357 switch (a->u.net->family) { 358 case AF_INET: 359 print_ipv4_addr(ab, a->u.net->v4info.saddr, 360 a->u.net->sport, 361 "saddr", "src"); 362 print_ipv4_addr(ab, a->u.net->v4info.daddr, 363 a->u.net->dport, 364 "daddr", "dest"); 365 break; 366 case AF_INET6: 367 print_ipv6_addr(ab, &a->u.net->v6info.saddr, 368 a->u.net->sport, 369 "saddr", "src"); 370 print_ipv6_addr(ab, &a->u.net->v6info.daddr, 371 a->u.net->dport, 372 "daddr", "dest"); 373 break; 374 } 375 if (a->u.net->netif > 0) { 376 struct net_device *dev; 377 378 /* NOTE: we always use init's namespace */ 379 dev = dev_get_by_index(&init_net, a->u.net->netif); 380 if (dev) { 381 audit_log_format(ab, " netif=%s", dev->name); 382 dev_put(dev); 383 } 384 } 385 break; 386 #ifdef CONFIG_KEYS 387 case LSM_AUDIT_DATA_KEY: 388 audit_log_format(ab, " key_serial=%u", a->u.key_struct.key); 389 if (a->u.key_struct.key_desc) { 390 audit_log_format(ab, " key_desc="); 391 audit_log_untrustedstring(ab, a->u.key_struct.key_desc); 392 } 393 break; 394 #endif 395 case LSM_AUDIT_DATA_KMOD: 396 audit_log_format(ab, " kmod="); 397 audit_log_untrustedstring(ab, a->u.kmod_name); 398 break; 399 case LSM_AUDIT_DATA_IBPKEY: { 400 struct in6_addr sbn_pfx; 401 402 memset(&sbn_pfx.s6_addr, 0, 403 sizeof(sbn_pfx.s6_addr)); 404 memcpy(&sbn_pfx.s6_addr, &a->u.ibpkey->subnet_prefix, 405 sizeof(a->u.ibpkey->subnet_prefix)); 406 audit_log_format(ab, " pkey=0x%x subnet_prefix=%pI6c", 407 a->u.ibpkey->pkey, &sbn_pfx); 408 break; 409 } 410 case LSM_AUDIT_DATA_IBENDPORT: 411 audit_log_format(ab, " device=%s port_num=%u", 412 a->u.ibendport->dev_name, 413 a->u.ibendport->port); 414 break; 415 case LSM_AUDIT_DATA_LOCKDOWN: 416 audit_log_format(ab, " lockdown_reason=\"%s\"", 417 lockdown_reasons[a->u.reason]); 418 break; 419 case LSM_AUDIT_DATA_ANONINODE: 420 audit_log_format(ab, " anonclass=%s", a->u.anonclass); 421 break; 422 case LSM_AUDIT_DATA_NLMSGTYPE: 423 audit_log_format(ab, " nl-msgtype=%hu", a->u.nlmsg_type); 424 break; 425 } /* switch (a->type) */ 426 } 427 428 /** 429 * dump_common_audit_data - helper to dump common audit data 430 * @ab : the audit buffer 431 * @a : common audit data 432 */ 433 static void dump_common_audit_data(struct audit_buffer *ab, 434 const struct common_audit_data *a) 435 { 436 char comm[sizeof(current->comm)]; 437 438 audit_log_format(ab, " pid=%d comm=", task_tgid_nr(current)); 439 audit_log_untrustedstring(ab, get_task_comm(comm, current)); 440 audit_log_lsm_data(ab, a); 441 } 442 443 /** 444 * common_lsm_audit - generic LSM auditing function 445 * @a: auxiliary audit data 446 * @pre_audit: lsm-specific pre-audit callback 447 * @post_audit: lsm-specific post-audit callback 448 * 449 * setup the audit buffer for common security information 450 * uses callback to print LSM specific information 451 */ 452 void common_lsm_audit(struct common_audit_data *a, 453 void (*pre_audit)(struct audit_buffer *, void *), 454 void (*post_audit)(struct audit_buffer *, void *)) 455 { 456 struct audit_buffer *ab; 457 458 if (a == NULL) 459 return; 460 /* we use GFP_ATOMIC so we won't sleep */ 461 ab = audit_log_start(audit_context(), GFP_ATOMIC | __GFP_NOWARN, 462 AUDIT_AVC); 463 464 if (ab == NULL) 465 return; 466 467 if (pre_audit) 468 pre_audit(ab, a); 469 470 dump_common_audit_data(ab, a); 471 472 if (post_audit) 473 post_audit(ab, a); 474 475 audit_log_end(ab); 476 } 477