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