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/fs.h> 18 #include <linux/init.h> 19 #include <net/sock.h> 20 #include <linux/un.h> 21 #include <net/af_unix.h> 22 #include <linux/audit.h> 23 #include <linux/ipv6.h> 24 #include <linux/ip.h> 25 #include <net/ip.h> 26 #include <net/ipv6.h> 27 #include <linux/tcp.h> 28 #include <linux/udp.h> 29 #include <linux/dccp.h> 30 #include <linux/sctp.h> 31 #include <linux/lsm_audit.h> 32 33 /** 34 * ipv4_skb_to_auditdata : fill auditdata from skb 35 * @skb : the skb 36 * @ad : the audit data to fill 37 * @proto : the layer 4 protocol 38 * 39 * return 0 on success 40 */ 41 int ipv4_skb_to_auditdata(struct sk_buff *skb, 42 struct common_audit_data *ad, u8 *proto) 43 { 44 int ret = 0; 45 struct iphdr *ih; 46 47 ih = ip_hdr(skb); 48 if (ih == NULL) 49 return -EINVAL; 50 51 ad->u.net.v4info.saddr = ih->saddr; 52 ad->u.net.v4info.daddr = ih->daddr; 53 54 if (proto) 55 *proto = ih->protocol; 56 /* non initial fragment */ 57 if (ntohs(ih->frag_off) & IP_OFFSET) 58 return 0; 59 60 switch (ih->protocol) { 61 case IPPROTO_TCP: { 62 struct tcphdr *th = tcp_hdr(skb); 63 if (th == NULL) 64 break; 65 66 ad->u.net.sport = th->source; 67 ad->u.net.dport = th->dest; 68 break; 69 } 70 case IPPROTO_UDP: { 71 struct udphdr *uh = udp_hdr(skb); 72 if (uh == NULL) 73 break; 74 75 ad->u.net.sport = uh->source; 76 ad->u.net.dport = uh->dest; 77 break; 78 } 79 case IPPROTO_DCCP: { 80 struct dccp_hdr *dh = dccp_hdr(skb); 81 if (dh == NULL) 82 break; 83 84 ad->u.net.sport = dh->dccph_sport; 85 ad->u.net.dport = dh->dccph_dport; 86 break; 87 } 88 case IPPROTO_SCTP: { 89 struct sctphdr *sh = sctp_hdr(skb); 90 if (sh == NULL) 91 break; 92 ad->u.net.sport = sh->source; 93 ad->u.net.dport = sh->dest; 94 break; 95 } 96 default: 97 ret = -EINVAL; 98 } 99 return ret; 100 } 101 #if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) 102 /** 103 * ipv6_skb_to_auditdata : fill auditdata from skb 104 * @skb : the skb 105 * @ad : the audit data to fill 106 * @proto : the layer 4 protocol 107 * 108 * return 0 on success 109 */ 110 int ipv6_skb_to_auditdata(struct sk_buff *skb, 111 struct common_audit_data *ad, u8 *proto) 112 { 113 int offset, ret = 0; 114 struct ipv6hdr *ip6; 115 u8 nexthdr; 116 117 ip6 = ipv6_hdr(skb); 118 if (ip6 == NULL) 119 return -EINVAL; 120 ipv6_addr_copy(&ad->u.net.v6info.saddr, &ip6->saddr); 121 ipv6_addr_copy(&ad->u.net.v6info.daddr, &ip6->daddr); 122 ret = 0; 123 /* IPv6 can have several extension header before the Transport header 124 * skip them */ 125 offset = skb_network_offset(skb); 126 offset += sizeof(*ip6); 127 nexthdr = ip6->nexthdr; 128 offset = ipv6_skip_exthdr(skb, offset, &nexthdr); 129 if (offset < 0) 130 return 0; 131 if (proto) 132 *proto = nexthdr; 133 switch (nexthdr) { 134 case IPPROTO_TCP: { 135 struct tcphdr _tcph, *th; 136 137 th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph); 138 if (th == NULL) 139 break; 140 141 ad->u.net.sport = th->source; 142 ad->u.net.dport = th->dest; 143 break; 144 } 145 case IPPROTO_UDP: { 146 struct udphdr _udph, *uh; 147 148 uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph); 149 if (uh == NULL) 150 break; 151 152 ad->u.net.sport = uh->source; 153 ad->u.net.dport = uh->dest; 154 break; 155 } 156 case IPPROTO_DCCP: { 157 struct dccp_hdr _dccph, *dh; 158 159 dh = skb_header_pointer(skb, offset, sizeof(_dccph), &_dccph); 160 if (dh == NULL) 161 break; 162 163 ad->u.net.sport = dh->dccph_sport; 164 ad->u.net.dport = dh->dccph_dport; 165 break; 166 } 167 case IPPROTO_SCTP: { 168 struct sctphdr _sctph, *sh; 169 170 sh = skb_header_pointer(skb, offset, sizeof(_sctph), &_sctph); 171 if (sh == NULL) 172 break; 173 ad->u.net.sport = sh->source; 174 ad->u.net.dport = sh->dest; 175 break; 176 } 177 default: 178 ret = -EINVAL; 179 } 180 return ret; 181 } 182 #endif 183 184 185 static inline void print_ipv6_addr(struct audit_buffer *ab, 186 struct in6_addr *addr, __be16 port, 187 char *name1, char *name2) 188 { 189 if (!ipv6_addr_any(addr)) 190 audit_log_format(ab, " %s=%pI6c", name1, addr); 191 if (port) 192 audit_log_format(ab, " %s=%d", name2, ntohs(port)); 193 } 194 195 static inline void print_ipv4_addr(struct audit_buffer *ab, __be32 addr, 196 __be16 port, char *name1, char *name2) 197 { 198 if (addr) 199 audit_log_format(ab, " %s=%pI4", name1, &addr); 200 if (port) 201 audit_log_format(ab, " %s=%d", name2, ntohs(port)); 202 } 203 204 /** 205 * dump_common_audit_data - helper to dump common audit data 206 * @a : common audit data 207 * 208 */ 209 static void dump_common_audit_data(struct audit_buffer *ab, 210 struct common_audit_data *a) 211 { 212 struct inode *inode = NULL; 213 struct task_struct *tsk = current; 214 215 if (a->tsk) 216 tsk = a->tsk; 217 if (tsk && tsk->pid) { 218 audit_log_format(ab, " pid=%d comm=", tsk->pid); 219 audit_log_untrustedstring(ab, tsk->comm); 220 } 221 222 switch (a->type) { 223 case LSM_AUDIT_NO_AUDIT: 224 return; 225 case LSM_AUDIT_DATA_IPC: 226 audit_log_format(ab, " key=%d ", a->u.ipc_id); 227 break; 228 case LSM_AUDIT_DATA_CAP: 229 audit_log_format(ab, " capability=%d ", a->u.cap); 230 break; 231 case LSM_AUDIT_DATA_FS: 232 if (a->u.fs.path.dentry) { 233 struct dentry *dentry = a->u.fs.path.dentry; 234 if (a->u.fs.path.mnt) { 235 audit_log_d_path(ab, "path=", &a->u.fs.path); 236 } else { 237 audit_log_format(ab, " name="); 238 audit_log_untrustedstring(ab, 239 dentry->d_name.name); 240 } 241 inode = dentry->d_inode; 242 } else if (a->u.fs.inode) { 243 struct dentry *dentry; 244 inode = a->u.fs.inode; 245 dentry = d_find_alias(inode); 246 if (dentry) { 247 audit_log_format(ab, " name="); 248 audit_log_untrustedstring(ab, 249 dentry->d_name.name); 250 dput(dentry); 251 } 252 } 253 if (inode) 254 audit_log_format(ab, " dev=%s ino=%lu", 255 inode->i_sb->s_id, 256 inode->i_ino); 257 break; 258 case LSM_AUDIT_DATA_TASK: 259 tsk = a->u.tsk; 260 if (tsk && tsk->pid) { 261 audit_log_format(ab, " pid=%d comm=", tsk->pid); 262 audit_log_untrustedstring(ab, tsk->comm); 263 } 264 break; 265 case LSM_AUDIT_DATA_NET: 266 if (a->u.net.sk) { 267 struct sock *sk = a->u.net.sk; 268 struct unix_sock *u; 269 int len = 0; 270 char *p = NULL; 271 272 switch (sk->sk_family) { 273 case AF_INET: { 274 struct inet_sock *inet = inet_sk(sk); 275 276 print_ipv4_addr(ab, inet->rcv_saddr, 277 inet->sport, 278 "laddr", "lport"); 279 print_ipv4_addr(ab, inet->daddr, 280 inet->dport, 281 "faddr", "fport"); 282 break; 283 } 284 case AF_INET6: { 285 struct inet_sock *inet = inet_sk(sk); 286 struct ipv6_pinfo *inet6 = inet6_sk(sk); 287 288 print_ipv6_addr(ab, &inet6->rcv_saddr, 289 inet->sport, 290 "laddr", "lport"); 291 print_ipv6_addr(ab, &inet6->daddr, 292 inet->dport, 293 "faddr", "fport"); 294 break; 295 } 296 case AF_UNIX: 297 u = unix_sk(sk); 298 if (u->dentry) { 299 struct path path = { 300 .dentry = u->dentry, 301 .mnt = u->mnt 302 }; 303 audit_log_d_path(ab, "path=", &path); 304 break; 305 } 306 if (!u->addr) 307 break; 308 len = u->addr->len-sizeof(short); 309 p = &u->addr->name->sun_path[0]; 310 audit_log_format(ab, " path="); 311 if (*p) 312 audit_log_untrustedstring(ab, p); 313 else 314 audit_log_n_hex(ab, p, len); 315 break; 316 } 317 } 318 319 switch (a->u.net.family) { 320 case AF_INET: 321 print_ipv4_addr(ab, a->u.net.v4info.saddr, 322 a->u.net.sport, 323 "saddr", "src"); 324 print_ipv4_addr(ab, a->u.net.v4info.daddr, 325 a->u.net.dport, 326 "daddr", "dest"); 327 break; 328 case AF_INET6: 329 print_ipv6_addr(ab, &a->u.net.v6info.saddr, 330 a->u.net.sport, 331 "saddr", "src"); 332 print_ipv6_addr(ab, &a->u.net.v6info.daddr, 333 a->u.net.dport, 334 "daddr", "dest"); 335 break; 336 } 337 if (a->u.net.netif > 0) { 338 struct net_device *dev; 339 340 /* NOTE: we always use init's namespace */ 341 dev = dev_get_by_index(&init_net, a->u.net.netif); 342 if (dev) { 343 audit_log_format(ab, " netif=%s", dev->name); 344 dev_put(dev); 345 } 346 } 347 break; 348 #ifdef CONFIG_KEYS 349 case LSM_AUDIT_DATA_KEY: 350 audit_log_format(ab, " key_serial=%u", a->u.key_struct.key); 351 if (a->u.key_struct.key_desc) { 352 audit_log_format(ab, " key_desc="); 353 audit_log_untrustedstring(ab, a->u.key_struct.key_desc); 354 } 355 break; 356 #endif 357 } /* switch (a->type) */ 358 } 359 360 /** 361 * common_lsm_audit - generic LSM auditing function 362 * @a: auxiliary audit data 363 * 364 * setup the audit buffer for common security information 365 * uses callback to print LSM specific information 366 */ 367 void common_lsm_audit(struct common_audit_data *a) 368 { 369 struct audit_buffer *ab; 370 371 if (a == NULL) 372 return; 373 /* we use GFP_ATOMIC so we won't sleep */ 374 ab = audit_log_start(current->audit_context, GFP_ATOMIC, AUDIT_AVC); 375 376 if (ab == NULL) 377 return; 378 379 if (a->lsm_pre_audit) 380 a->lsm_pre_audit(ab, a); 381 382 dump_common_audit_data(ab, a); 383 384 if (a->lsm_post_audit) 385 a->lsm_post_audit(ab, a); 386 387 audit_log_end(ab); 388 } 389