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 defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) 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 struct task_struct *tsk = current; 215 216 if (a->tsk) 217 tsk = a->tsk; 218 if (tsk && tsk->pid) { 219 audit_log_format(ab, " pid=%d comm=", tsk->pid); 220 audit_log_untrustedstring(ab, tsk->comm); 221 } 222 223 switch (a->type) { 224 case LSM_AUDIT_DATA_NONE: 225 return; 226 case LSM_AUDIT_DATA_IPC: 227 audit_log_format(ab, " 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 = a->u.path.dentry->d_inode; 238 if (inode) 239 audit_log_format(ab, " dev=%s ino=%lu", 240 inode->i_sb->s_id, 241 inode->i_ino); 242 break; 243 } 244 case LSM_AUDIT_DATA_DENTRY: { 245 struct inode *inode; 246 247 audit_log_format(ab, " name="); 248 audit_log_untrustedstring(ab, a->u.dentry->d_name.name); 249 250 inode = a->u.dentry->d_inode; 251 if (inode) 252 audit_log_format(ab, " dev=%s ino=%lu", 253 inode->i_sb->s_id, 254 inode->i_ino); 255 break; 256 } 257 case LSM_AUDIT_DATA_INODE: { 258 struct dentry *dentry; 259 struct inode *inode; 260 261 inode = a->u.inode; 262 dentry = d_find_alias(inode); 263 if (dentry) { 264 audit_log_format(ab, " name="); 265 audit_log_untrustedstring(ab, 266 dentry->d_name.name); 267 dput(dentry); 268 } 269 audit_log_format(ab, " dev=%s ino=%lu", inode->i_sb->s_id, 270 inode->i_ino); 271 break; 272 } 273 case LSM_AUDIT_DATA_TASK: 274 tsk = a->u.tsk; 275 if (tsk && tsk->pid) { 276 audit_log_format(ab, " pid=%d comm=", tsk->pid); 277 audit_log_untrustedstring(ab, tsk->comm); 278 } 279 break; 280 case LSM_AUDIT_DATA_NET: 281 if (a->u.net.sk) { 282 struct sock *sk = a->u.net.sk; 283 struct unix_sock *u; 284 int len = 0; 285 char *p = NULL; 286 287 switch (sk->sk_family) { 288 case AF_INET: { 289 struct inet_sock *inet = inet_sk(sk); 290 291 print_ipv4_addr(ab, inet->inet_rcv_saddr, 292 inet->inet_sport, 293 "laddr", "lport"); 294 print_ipv4_addr(ab, inet->inet_daddr, 295 inet->inet_dport, 296 "faddr", "fport"); 297 break; 298 } 299 case AF_INET6: { 300 struct inet_sock *inet = inet_sk(sk); 301 struct ipv6_pinfo *inet6 = inet6_sk(sk); 302 303 print_ipv6_addr(ab, &inet6->rcv_saddr, 304 inet->inet_sport, 305 "laddr", "lport"); 306 print_ipv6_addr(ab, &inet6->daddr, 307 inet->inet_dport, 308 "faddr", "fport"); 309 break; 310 } 311 case AF_UNIX: 312 u = unix_sk(sk); 313 if (u->dentry) { 314 struct path path = { 315 .dentry = u->dentry, 316 .mnt = u->mnt 317 }; 318 audit_log_d_path(ab, "path=", &path); 319 break; 320 } 321 if (!u->addr) 322 break; 323 len = u->addr->len-sizeof(short); 324 p = &u->addr->name->sun_path[0]; 325 audit_log_format(ab, " path="); 326 if (*p) 327 audit_log_untrustedstring(ab, p); 328 else 329 audit_log_n_hex(ab, p, len); 330 break; 331 } 332 } 333 334 switch (a->u.net.family) { 335 case AF_INET: 336 print_ipv4_addr(ab, a->u.net.v4info.saddr, 337 a->u.net.sport, 338 "saddr", "src"); 339 print_ipv4_addr(ab, a->u.net.v4info.daddr, 340 a->u.net.dport, 341 "daddr", "dest"); 342 break; 343 case AF_INET6: 344 print_ipv6_addr(ab, &a->u.net.v6info.saddr, 345 a->u.net.sport, 346 "saddr", "src"); 347 print_ipv6_addr(ab, &a->u.net.v6info.daddr, 348 a->u.net.dport, 349 "daddr", "dest"); 350 break; 351 } 352 if (a->u.net.netif > 0) { 353 struct net_device *dev; 354 355 /* NOTE: we always use init's namespace */ 356 dev = dev_get_by_index(&init_net, a->u.net.netif); 357 if (dev) { 358 audit_log_format(ab, " netif=%s", dev->name); 359 dev_put(dev); 360 } 361 } 362 break; 363 #ifdef CONFIG_KEYS 364 case LSM_AUDIT_DATA_KEY: 365 audit_log_format(ab, " key_serial=%u", a->u.key_struct.key); 366 if (a->u.key_struct.key_desc) { 367 audit_log_format(ab, " key_desc="); 368 audit_log_untrustedstring(ab, a->u.key_struct.key_desc); 369 } 370 break; 371 #endif 372 case LSM_AUDIT_DATA_KMOD: 373 audit_log_format(ab, " kmod="); 374 audit_log_untrustedstring(ab, a->u.kmod_name); 375 break; 376 } /* switch (a->type) */ 377 } 378 379 /** 380 * common_lsm_audit - generic LSM auditing function 381 * @a: auxiliary audit data 382 * 383 * setup the audit buffer for common security information 384 * uses callback to print LSM specific information 385 */ 386 void common_lsm_audit(struct common_audit_data *a) 387 { 388 struct audit_buffer *ab; 389 390 if (a == NULL) 391 return; 392 /* we use GFP_ATOMIC so we won't sleep */ 393 ab = audit_log_start(current->audit_context, GFP_ATOMIC, AUDIT_AVC); 394 395 if (ab == NULL) 396 return; 397 398 if (a->lsm_pre_audit) 399 a->lsm_pre_audit(ab, a); 400 401 dump_common_audit_data(ab, a); 402 403 if (a->lsm_post_audit) 404 a->lsm_post_audit(ab, a); 405 406 audit_log_end(ab); 407 } 408