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 * @a : common audit data 194 * 195 */ 196 static void dump_common_audit_data(struct audit_buffer *ab, 197 struct common_audit_data *a) 198 { 199 char comm[sizeof(current->comm)]; 200 201 /* 202 * To keep stack sizes in check force programers to notice if they 203 * start making this union too large! See struct lsm_network_audit 204 * as an example of how to deal with large data. 205 */ 206 BUILD_BUG_ON(sizeof(a->u) > sizeof(void *)*2); 207 208 audit_log_format(ab, " pid=%d comm=", task_tgid_nr(current)); 209 audit_log_untrustedstring(ab, memcpy(comm, current->comm, sizeof(comm))); 210 211 switch (a->type) { 212 case LSM_AUDIT_DATA_NONE: 213 return; 214 case LSM_AUDIT_DATA_IPC: 215 audit_log_format(ab, " ipc_key=%d ", a->u.ipc_id); 216 break; 217 case LSM_AUDIT_DATA_CAP: 218 audit_log_format(ab, " capability=%d ", a->u.cap); 219 break; 220 case LSM_AUDIT_DATA_PATH: { 221 struct inode *inode; 222 223 audit_log_d_path(ab, " path=", &a->u.path); 224 225 inode = d_backing_inode(a->u.path.dentry); 226 if (inode) { 227 audit_log_format(ab, " dev="); 228 audit_log_untrustedstring(ab, inode->i_sb->s_id); 229 audit_log_format(ab, " ino=%lu", inode->i_ino); 230 } 231 break; 232 } 233 case LSM_AUDIT_DATA_FILE: { 234 struct inode *inode; 235 236 audit_log_d_path(ab, " path=", &a->u.file->f_path); 237 238 inode = file_inode(a->u.file); 239 if (inode) { 240 audit_log_format(ab, " dev="); 241 audit_log_untrustedstring(ab, inode->i_sb->s_id); 242 audit_log_format(ab, " ino=%lu", inode->i_ino); 243 } 244 break; 245 } 246 case LSM_AUDIT_DATA_IOCTL_OP: { 247 struct inode *inode; 248 249 audit_log_d_path(ab, " path=", &a->u.op->path); 250 251 inode = a->u.op->path.dentry->d_inode; 252 if (inode) { 253 audit_log_format(ab, " dev="); 254 audit_log_untrustedstring(ab, inode->i_sb->s_id); 255 audit_log_format(ab, " ino=%lu", inode->i_ino); 256 } 257 258 audit_log_format(ab, " ioctlcmd=0x%hx", a->u.op->cmd); 259 break; 260 } 261 case LSM_AUDIT_DATA_DENTRY: { 262 struct inode *inode; 263 264 audit_log_format(ab, " name="); 265 spin_lock(&a->u.dentry->d_lock); 266 audit_log_untrustedstring(ab, a->u.dentry->d_name.name); 267 spin_unlock(&a->u.dentry->d_lock); 268 269 inode = d_backing_inode(a->u.dentry); 270 if (inode) { 271 audit_log_format(ab, " dev="); 272 audit_log_untrustedstring(ab, inode->i_sb->s_id); 273 audit_log_format(ab, " ino=%lu", inode->i_ino); 274 } 275 break; 276 } 277 case LSM_AUDIT_DATA_INODE: { 278 struct dentry *dentry; 279 struct inode *inode; 280 281 rcu_read_lock(); 282 inode = a->u.inode; 283 dentry = d_find_alias_rcu(inode); 284 if (dentry) { 285 audit_log_format(ab, " name="); 286 spin_lock(&dentry->d_lock); 287 audit_log_untrustedstring(ab, dentry->d_name.name); 288 spin_unlock(&dentry->d_lock); 289 } 290 audit_log_format(ab, " dev="); 291 audit_log_untrustedstring(ab, inode->i_sb->s_id); 292 audit_log_format(ab, " ino=%lu", inode->i_ino); 293 rcu_read_unlock(); 294 break; 295 } 296 case LSM_AUDIT_DATA_TASK: { 297 struct task_struct *tsk = a->u.tsk; 298 if (tsk) { 299 pid_t pid = task_tgid_nr(tsk); 300 if (pid) { 301 char comm[sizeof(tsk->comm)]; 302 audit_log_format(ab, " opid=%d ocomm=", pid); 303 audit_log_untrustedstring(ab, 304 memcpy(comm, tsk->comm, sizeof(comm))); 305 } 306 } 307 break; 308 } 309 case LSM_AUDIT_DATA_NET: 310 if (a->u.net->sk) { 311 const struct sock *sk = a->u.net->sk; 312 struct unix_sock *u; 313 struct unix_address *addr; 314 int len = 0; 315 char *p = NULL; 316 317 switch (sk->sk_family) { 318 case AF_INET: { 319 struct inet_sock *inet = inet_sk(sk); 320 321 print_ipv4_addr(ab, inet->inet_rcv_saddr, 322 inet->inet_sport, 323 "laddr", "lport"); 324 print_ipv4_addr(ab, inet->inet_daddr, 325 inet->inet_dport, 326 "faddr", "fport"); 327 break; 328 } 329 #if IS_ENABLED(CONFIG_IPV6) 330 case AF_INET6: { 331 struct inet_sock *inet = inet_sk(sk); 332 333 print_ipv6_addr(ab, &sk->sk_v6_rcv_saddr, 334 inet->inet_sport, 335 "laddr", "lport"); 336 print_ipv6_addr(ab, &sk->sk_v6_daddr, 337 inet->inet_dport, 338 "faddr", "fport"); 339 break; 340 } 341 #endif 342 case AF_UNIX: 343 u = unix_sk(sk); 344 addr = smp_load_acquire(&u->addr); 345 if (!addr) 346 break; 347 if (u->path.dentry) { 348 audit_log_d_path(ab, " path=", &u->path); 349 break; 350 } 351 len = addr->len-sizeof(short); 352 p = &addr->name->sun_path[0]; 353 audit_log_format(ab, " path="); 354 if (*p) 355 audit_log_untrustedstring(ab, p); 356 else 357 audit_log_n_hex(ab, p, len); 358 break; 359 } 360 } 361 362 switch (a->u.net->family) { 363 case AF_INET: 364 print_ipv4_addr(ab, a->u.net->v4info.saddr, 365 a->u.net->sport, 366 "saddr", "src"); 367 print_ipv4_addr(ab, a->u.net->v4info.daddr, 368 a->u.net->dport, 369 "daddr", "dest"); 370 break; 371 case AF_INET6: 372 print_ipv6_addr(ab, &a->u.net->v6info.saddr, 373 a->u.net->sport, 374 "saddr", "src"); 375 print_ipv6_addr(ab, &a->u.net->v6info.daddr, 376 a->u.net->dport, 377 "daddr", "dest"); 378 break; 379 } 380 if (a->u.net->netif > 0) { 381 struct net_device *dev; 382 383 /* NOTE: we always use init's namespace */ 384 dev = dev_get_by_index(&init_net, a->u.net->netif); 385 if (dev) { 386 audit_log_format(ab, " netif=%s", dev->name); 387 dev_put(dev); 388 } 389 } 390 break; 391 #ifdef CONFIG_KEYS 392 case LSM_AUDIT_DATA_KEY: 393 audit_log_format(ab, " key_serial=%u", a->u.key_struct.key); 394 if (a->u.key_struct.key_desc) { 395 audit_log_format(ab, " key_desc="); 396 audit_log_untrustedstring(ab, a->u.key_struct.key_desc); 397 } 398 break; 399 #endif 400 case LSM_AUDIT_DATA_KMOD: 401 audit_log_format(ab, " kmod="); 402 audit_log_untrustedstring(ab, a->u.kmod_name); 403 break; 404 case LSM_AUDIT_DATA_IBPKEY: { 405 struct in6_addr sbn_pfx; 406 407 memset(&sbn_pfx.s6_addr, 0, 408 sizeof(sbn_pfx.s6_addr)); 409 memcpy(&sbn_pfx.s6_addr, &a->u.ibpkey->subnet_prefix, 410 sizeof(a->u.ibpkey->subnet_prefix)); 411 audit_log_format(ab, " pkey=0x%x subnet_prefix=%pI6c", 412 a->u.ibpkey->pkey, &sbn_pfx); 413 break; 414 } 415 case LSM_AUDIT_DATA_IBENDPORT: 416 audit_log_format(ab, " device=%s port_num=%u", 417 a->u.ibendport->dev_name, 418 a->u.ibendport->port); 419 break; 420 case LSM_AUDIT_DATA_LOCKDOWN: 421 audit_log_format(ab, " lockdown_reason=\"%s\"", 422 lockdown_reasons[a->u.reason]); 423 break; 424 case LSM_AUDIT_DATA_ANONINODE: 425 audit_log_format(ab, " anonclass=%s", a->u.anonclass); 426 break; 427 } /* switch (a->type) */ 428 } 429 430 /** 431 * common_lsm_audit - generic LSM auditing function 432 * @a: auxiliary audit data 433 * @pre_audit: lsm-specific pre-audit callback 434 * @post_audit: lsm-specific post-audit callback 435 * 436 * setup the audit buffer for common security information 437 * uses callback to print LSM specific information 438 */ 439 void common_lsm_audit(struct common_audit_data *a, 440 void (*pre_audit)(struct audit_buffer *, void *), 441 void (*post_audit)(struct audit_buffer *, void *)) 442 { 443 struct audit_buffer *ab; 444 445 if (a == NULL) 446 return; 447 /* we use GFP_ATOMIC so we won't sleep */ 448 ab = audit_log_start(audit_context(), GFP_ATOMIC | __GFP_NOWARN, 449 AUDIT_AVC); 450 451 if (ab == NULL) 452 return; 453 454 if (pre_audit) 455 pre_audit(ab, a); 456 457 dump_common_audit_data(ab, a); 458 459 if (post_audit) 460 post_audit(ab, a); 461 462 audit_log_end(ab); 463 } 464