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 #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 if (ih == NULL) 48 return -EINVAL; 49 50 ad->u.net->v4info.saddr = ih->saddr; 51 ad->u.net->v4info.daddr = ih->daddr; 52 53 if (proto) 54 *proto = ih->protocol; 55 /* non initial fragment */ 56 if (ntohs(ih->frag_off) & IP_OFFSET) 57 return 0; 58 59 switch (ih->protocol) { 60 case IPPROTO_TCP: { 61 struct tcphdr *th = tcp_hdr(skb); 62 if (th == NULL) 63 break; 64 65 ad->u.net->sport = th->source; 66 ad->u.net->dport = th->dest; 67 break; 68 } 69 case IPPROTO_UDP: { 70 struct udphdr *uh = udp_hdr(skb); 71 if (uh == NULL) 72 break; 73 74 ad->u.net->sport = uh->source; 75 ad->u.net->dport = uh->dest; 76 break; 77 } 78 case IPPROTO_DCCP: { 79 struct dccp_hdr *dh = dccp_hdr(skb); 80 if (dh == NULL) 81 break; 82 83 ad->u.net->sport = dh->dccph_sport; 84 ad->u.net->dport = dh->dccph_dport; 85 break; 86 } 87 case IPPROTO_SCTP: { 88 struct sctphdr *sh = sctp_hdr(skb); 89 if (sh == NULL) 90 break; 91 ad->u.net->sport = sh->source; 92 ad->u.net->dport = sh->dest; 93 break; 94 } 95 default: 96 ret = -EINVAL; 97 } 98 return ret; 99 } 100 #if IS_ENABLED(CONFIG_IPV6) 101 /** 102 * ipv6_skb_to_auditdata : fill auditdata from skb 103 * @skb : the skb 104 * @ad : the audit data to fill 105 * @proto : the layer 4 protocol 106 * 107 * return 0 on success 108 */ 109 int ipv6_skb_to_auditdata(struct sk_buff *skb, 110 struct common_audit_data *ad, u8 *proto) 111 { 112 int offset, ret = 0; 113 struct ipv6hdr *ip6; 114 u8 nexthdr; 115 __be16 frag_off; 116 117 ip6 = ipv6_hdr(skb); 118 if (ip6 == NULL) 119 return -EINVAL; 120 ad->u.net->v6info.saddr = ip6->saddr; 121 ad->u.net->v6info.daddr = ip6->daddr; 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 const 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, " ipc_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 spin_lock(&a->u.dentry->d_lock); 278 audit_log_untrustedstring(ab, a->u.dentry->d_name.name); 279 spin_unlock(&a->u.dentry->d_lock); 280 281 inode = d_backing_inode(a->u.dentry); 282 if (inode) { 283 audit_log_format(ab, " dev="); 284 audit_log_untrustedstring(ab, inode->i_sb->s_id); 285 audit_log_format(ab, " ino=%lu", inode->i_ino); 286 } 287 break; 288 } 289 case LSM_AUDIT_DATA_INODE: { 290 struct dentry *dentry; 291 struct inode *inode; 292 293 rcu_read_lock(); 294 inode = a->u.inode; 295 dentry = d_find_alias_rcu(inode); 296 if (dentry) { 297 audit_log_format(ab, " name="); 298 spin_lock(&dentry->d_lock); 299 audit_log_untrustedstring(ab, dentry->d_name.name); 300 spin_unlock(&dentry->d_lock); 301 } 302 audit_log_format(ab, " dev="); 303 audit_log_untrustedstring(ab, inode->i_sb->s_id); 304 audit_log_format(ab, " ino=%lu", inode->i_ino); 305 rcu_read_unlock(); 306 break; 307 } 308 case LSM_AUDIT_DATA_TASK: { 309 struct task_struct *tsk = a->u.tsk; 310 if (tsk) { 311 pid_t pid = task_tgid_nr(tsk); 312 if (pid) { 313 char comm[sizeof(tsk->comm)]; 314 audit_log_format(ab, " opid=%d ocomm=", pid); 315 audit_log_untrustedstring(ab, 316 memcpy(comm, tsk->comm, sizeof(comm))); 317 } 318 } 319 break; 320 } 321 case LSM_AUDIT_DATA_NET: 322 if (a->u.net->sk) { 323 const struct sock *sk = a->u.net->sk; 324 struct unix_sock *u; 325 struct unix_address *addr; 326 int len = 0; 327 char *p = NULL; 328 329 switch (sk->sk_family) { 330 case AF_INET: { 331 struct inet_sock *inet = inet_sk(sk); 332 333 print_ipv4_addr(ab, inet->inet_rcv_saddr, 334 inet->inet_sport, 335 "laddr", "lport"); 336 print_ipv4_addr(ab, inet->inet_daddr, 337 inet->inet_dport, 338 "faddr", "fport"); 339 break; 340 } 341 #if IS_ENABLED(CONFIG_IPV6) 342 case AF_INET6: { 343 struct inet_sock *inet = inet_sk(sk); 344 345 print_ipv6_addr(ab, &sk->sk_v6_rcv_saddr, 346 inet->inet_sport, 347 "laddr", "lport"); 348 print_ipv6_addr(ab, &sk->sk_v6_daddr, 349 inet->inet_dport, 350 "faddr", "fport"); 351 break; 352 } 353 #endif 354 case AF_UNIX: 355 u = unix_sk(sk); 356 addr = smp_load_acquire(&u->addr); 357 if (!addr) 358 break; 359 if (u->path.dentry) { 360 audit_log_d_path(ab, " path=", &u->path); 361 break; 362 } 363 len = addr->len-sizeof(short); 364 p = &addr->name->sun_path[0]; 365 audit_log_format(ab, " path="); 366 if (*p) 367 audit_log_untrustedstring(ab, p); 368 else 369 audit_log_n_hex(ab, p, len); 370 break; 371 } 372 } 373 374 switch (a->u.net->family) { 375 case AF_INET: 376 print_ipv4_addr(ab, a->u.net->v4info.saddr, 377 a->u.net->sport, 378 "saddr", "src"); 379 print_ipv4_addr(ab, a->u.net->v4info.daddr, 380 a->u.net->dport, 381 "daddr", "dest"); 382 break; 383 case AF_INET6: 384 print_ipv6_addr(ab, &a->u.net->v6info.saddr, 385 a->u.net->sport, 386 "saddr", "src"); 387 print_ipv6_addr(ab, &a->u.net->v6info.daddr, 388 a->u.net->dport, 389 "daddr", "dest"); 390 break; 391 } 392 if (a->u.net->netif > 0) { 393 struct net_device *dev; 394 395 /* NOTE: we always use init's namespace */ 396 dev = dev_get_by_index(&init_net, a->u.net->netif); 397 if (dev) { 398 audit_log_format(ab, " netif=%s", dev->name); 399 dev_put(dev); 400 } 401 } 402 break; 403 #ifdef CONFIG_KEYS 404 case LSM_AUDIT_DATA_KEY: 405 audit_log_format(ab, " key_serial=%u", a->u.key_struct.key); 406 if (a->u.key_struct.key_desc) { 407 audit_log_format(ab, " key_desc="); 408 audit_log_untrustedstring(ab, a->u.key_struct.key_desc); 409 } 410 break; 411 #endif 412 case LSM_AUDIT_DATA_KMOD: 413 audit_log_format(ab, " kmod="); 414 audit_log_untrustedstring(ab, a->u.kmod_name); 415 break; 416 case LSM_AUDIT_DATA_IBPKEY: { 417 struct in6_addr sbn_pfx; 418 419 memset(&sbn_pfx.s6_addr, 0, 420 sizeof(sbn_pfx.s6_addr)); 421 memcpy(&sbn_pfx.s6_addr, &a->u.ibpkey->subnet_prefix, 422 sizeof(a->u.ibpkey->subnet_prefix)); 423 audit_log_format(ab, " pkey=0x%x subnet_prefix=%pI6c", 424 a->u.ibpkey->pkey, &sbn_pfx); 425 break; 426 } 427 case LSM_AUDIT_DATA_IBENDPORT: 428 audit_log_format(ab, " device=%s port_num=%u", 429 a->u.ibendport->dev_name, 430 a->u.ibendport->port); 431 break; 432 case LSM_AUDIT_DATA_LOCKDOWN: 433 audit_log_format(ab, " lockdown_reason=\"%s\"", 434 lockdown_reasons[a->u.reason]); 435 break; 436 } /* switch (a->type) */ 437 } 438 439 /** 440 * common_lsm_audit - generic LSM auditing function 441 * @a: auxiliary audit data 442 * @pre_audit: lsm-specific pre-audit callback 443 * @post_audit: lsm-specific post-audit callback 444 * 445 * setup the audit buffer for common security information 446 * uses callback to print LSM specific information 447 */ 448 void common_lsm_audit(struct common_audit_data *a, 449 void (*pre_audit)(struct audit_buffer *, void *), 450 void (*post_audit)(struct audit_buffer *, void *)) 451 { 452 struct audit_buffer *ab; 453 454 if (a == NULL) 455 return; 456 /* we use GFP_ATOMIC so we won't sleep */ 457 ab = audit_log_start(audit_context(), GFP_ATOMIC | __GFP_NOWARN, 458 AUDIT_AVC); 459 460 if (ab == NULL) 461 return; 462 463 if (pre_audit) 464 pre_audit(ab, a); 465 466 dump_common_audit_data(ab, a); 467 468 if (post_audit) 469 post_audit(ab, a); 470 471 audit_log_end(ab); 472 } 473