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 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 char *name1, 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, char *name1, 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 * dump_common_audit_data - helper to dump common audit data 193 * @ab : the audit buffer 194 * @a : common audit data 195 * 196 */ 197 static void dump_common_audit_data(struct audit_buffer *ab, 198 struct common_audit_data *a) 199 { 200 char comm[sizeof(current->comm)]; 201 202 /* 203 * To keep stack sizes in check force programmers to notice if they 204 * start making this union too large! See struct lsm_network_audit 205 * as an example of how to deal with large data. 206 */ 207 BUILD_BUG_ON(sizeof(a->u) > sizeof(void *)*2); 208 209 audit_log_format(ab, " pid=%d comm=", task_tgid_nr(current)); 210 audit_log_untrustedstring(ab, memcpy(comm, current->comm, sizeof(comm))); 211 212 switch (a->type) { 213 case LSM_AUDIT_DATA_NONE: 214 return; 215 case LSM_AUDIT_DATA_IPC: 216 audit_log_format(ab, " ipc_key=%d ", a->u.ipc_id); 217 break; 218 case LSM_AUDIT_DATA_CAP: 219 audit_log_format(ab, " capability=%d ", a->u.cap); 220 break; 221 case LSM_AUDIT_DATA_PATH: { 222 struct inode *inode; 223 224 audit_log_d_path(ab, " path=", &a->u.path); 225 226 inode = d_backing_inode(a->u.path.dentry); 227 if (inode) { 228 audit_log_format(ab, " dev="); 229 audit_log_untrustedstring(ab, inode->i_sb->s_id); 230 audit_log_format(ab, " ino=%lu", inode->i_ino); 231 } 232 break; 233 } 234 case LSM_AUDIT_DATA_FILE: { 235 struct inode *inode; 236 237 audit_log_d_path(ab, " path=", &a->u.file->f_path); 238 239 inode = file_inode(a->u.file); 240 if (inode) { 241 audit_log_format(ab, " dev="); 242 audit_log_untrustedstring(ab, inode->i_sb->s_id); 243 audit_log_format(ab, " ino=%lu", inode->i_ino); 244 } 245 break; 246 } 247 case LSM_AUDIT_DATA_IOCTL_OP: { 248 struct inode *inode; 249 250 audit_log_d_path(ab, " path=", &a->u.op->path); 251 252 inode = a->u.op->path.dentry->d_inode; 253 if (inode) { 254 audit_log_format(ab, " dev="); 255 audit_log_untrustedstring(ab, inode->i_sb->s_id); 256 audit_log_format(ab, " ino=%lu", inode->i_ino); 257 } 258 259 audit_log_format(ab, " ioctlcmd=0x%hx", a->u.op->cmd); 260 break; 261 } 262 case LSM_AUDIT_DATA_DENTRY: { 263 struct inode *inode; 264 265 audit_log_format(ab, " name="); 266 spin_lock(&a->u.dentry->d_lock); 267 audit_log_untrustedstring(ab, a->u.dentry->d_name.name); 268 spin_unlock(&a->u.dentry->d_lock); 269 270 inode = d_backing_inode(a->u.dentry); 271 if (inode) { 272 audit_log_format(ab, " dev="); 273 audit_log_untrustedstring(ab, inode->i_sb->s_id); 274 audit_log_format(ab, " ino=%lu", inode->i_ino); 275 } 276 break; 277 } 278 case LSM_AUDIT_DATA_INODE: { 279 struct dentry *dentry; 280 struct inode *inode; 281 282 rcu_read_lock(); 283 inode = a->u.inode; 284 dentry = d_find_alias_rcu(inode); 285 if (dentry) { 286 audit_log_format(ab, " name="); 287 spin_lock(&dentry->d_lock); 288 audit_log_untrustedstring(ab, dentry->d_name.name); 289 spin_unlock(&dentry->d_lock); 290 } 291 audit_log_format(ab, " dev="); 292 audit_log_untrustedstring(ab, inode->i_sb->s_id); 293 audit_log_format(ab, " ino=%lu", inode->i_ino); 294 rcu_read_unlock(); 295 break; 296 } 297 case LSM_AUDIT_DATA_TASK: { 298 struct task_struct *tsk = a->u.tsk; 299 if (tsk) { 300 pid_t pid = task_tgid_nr(tsk); 301 if (pid) { 302 char comm[sizeof(tsk->comm)]; 303 audit_log_format(ab, " opid=%d ocomm=", pid); 304 audit_log_untrustedstring(ab, 305 memcpy(comm, tsk->comm, sizeof(comm))); 306 } 307 } 308 break; 309 } 310 case LSM_AUDIT_DATA_NET: 311 if (a->u.net->sk) { 312 const struct sock *sk = a->u.net->sk; 313 const struct unix_sock *u; 314 struct unix_address *addr; 315 int len = 0; 316 char *p = NULL; 317 318 switch (sk->sk_family) { 319 case AF_INET: { 320 const struct inet_sock *inet = inet_sk(sk); 321 322 print_ipv4_addr(ab, inet->inet_rcv_saddr, 323 inet->inet_sport, 324 "laddr", "lport"); 325 print_ipv4_addr(ab, inet->inet_daddr, 326 inet->inet_dport, 327 "faddr", "fport"); 328 break; 329 } 330 #if IS_ENABLED(CONFIG_IPV6) 331 case AF_INET6: { 332 const struct inet_sock *inet = inet_sk(sk); 333 334 print_ipv6_addr(ab, &sk->sk_v6_rcv_saddr, 335 inet->inet_sport, 336 "laddr", "lport"); 337 print_ipv6_addr(ab, &sk->sk_v6_daddr, 338 inet->inet_dport, 339 "faddr", "fport"); 340 break; 341 } 342 #endif 343 case AF_UNIX: 344 u = unix_sk(sk); 345 addr = smp_load_acquire(&u->addr); 346 if (!addr) 347 break; 348 if (u->path.dentry) { 349 audit_log_d_path(ab, " path=", &u->path); 350 break; 351 } 352 len = addr->len-sizeof(short); 353 p = &addr->name->sun_path[0]; 354 audit_log_format(ab, " path="); 355 if (*p) 356 audit_log_untrustedstring(ab, p); 357 else 358 audit_log_n_hex(ab, p, len); 359 break; 360 } 361 } 362 363 switch (a->u.net->family) { 364 case AF_INET: 365 print_ipv4_addr(ab, a->u.net->v4info.saddr, 366 a->u.net->sport, 367 "saddr", "src"); 368 print_ipv4_addr(ab, a->u.net->v4info.daddr, 369 a->u.net->dport, 370 "daddr", "dest"); 371 break; 372 case AF_INET6: 373 print_ipv6_addr(ab, &a->u.net->v6info.saddr, 374 a->u.net->sport, 375 "saddr", "src"); 376 print_ipv6_addr(ab, &a->u.net->v6info.daddr, 377 a->u.net->dport, 378 "daddr", "dest"); 379 break; 380 } 381 if (a->u.net->netif > 0) { 382 struct net_device *dev; 383 384 /* NOTE: we always use init's namespace */ 385 dev = dev_get_by_index(&init_net, a->u.net->netif); 386 if (dev) { 387 audit_log_format(ab, " netif=%s", dev->name); 388 dev_put(dev); 389 } 390 } 391 break; 392 #ifdef CONFIG_KEYS 393 case LSM_AUDIT_DATA_KEY: 394 audit_log_format(ab, " key_serial=%u", a->u.key_struct.key); 395 if (a->u.key_struct.key_desc) { 396 audit_log_format(ab, " key_desc="); 397 audit_log_untrustedstring(ab, a->u.key_struct.key_desc); 398 } 399 break; 400 #endif 401 case LSM_AUDIT_DATA_KMOD: 402 audit_log_format(ab, " kmod="); 403 audit_log_untrustedstring(ab, a->u.kmod_name); 404 break; 405 case LSM_AUDIT_DATA_IBPKEY: { 406 struct in6_addr sbn_pfx; 407 408 memset(&sbn_pfx.s6_addr, 0, 409 sizeof(sbn_pfx.s6_addr)); 410 memcpy(&sbn_pfx.s6_addr, &a->u.ibpkey->subnet_prefix, 411 sizeof(a->u.ibpkey->subnet_prefix)); 412 audit_log_format(ab, " pkey=0x%x subnet_prefix=%pI6c", 413 a->u.ibpkey->pkey, &sbn_pfx); 414 break; 415 } 416 case LSM_AUDIT_DATA_IBENDPORT: 417 audit_log_format(ab, " device=%s port_num=%u", 418 a->u.ibendport->dev_name, 419 a->u.ibendport->port); 420 break; 421 case LSM_AUDIT_DATA_LOCKDOWN: 422 audit_log_format(ab, " lockdown_reason=\"%s\"", 423 lockdown_reasons[a->u.reason]); 424 break; 425 case LSM_AUDIT_DATA_ANONINODE: 426 audit_log_format(ab, " anonclass=%s", a->u.anonclass); 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