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=%pI6", 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_DATA_IPC: 224 audit_log_format(ab, " key=%d ", a->u.ipc_id); 225 break; 226 case LSM_AUDIT_DATA_CAP: 227 audit_log_format(ab, " capability=%d ", a->u.cap); 228 break; 229 case LSM_AUDIT_DATA_FS: 230 if (a->u.fs.path.dentry) { 231 struct dentry *dentry = a->u.fs.path.dentry; 232 if (a->u.fs.path.mnt) { 233 audit_log_d_path(ab, "path=", &a->u.fs.path); 234 } else { 235 audit_log_format(ab, " name="); 236 audit_log_untrustedstring(ab, 237 dentry->d_name.name); 238 } 239 inode = dentry->d_inode; 240 } else if (a->u.fs.inode) { 241 struct dentry *dentry; 242 inode = a->u.fs.inode; 243 dentry = d_find_alias(inode); 244 if (dentry) { 245 audit_log_format(ab, " name="); 246 audit_log_untrustedstring(ab, 247 dentry->d_name.name); 248 dput(dentry); 249 } 250 } 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 case LSM_AUDIT_DATA_TASK: 257 tsk = a->u.tsk; 258 if (tsk && tsk->pid) { 259 audit_log_format(ab, " pid=%d comm=", tsk->pid); 260 audit_log_untrustedstring(ab, tsk->comm); 261 } 262 break; 263 case LSM_AUDIT_DATA_NET: 264 if (a->u.net.sk) { 265 struct sock *sk = a->u.net.sk; 266 struct unix_sock *u; 267 int len = 0; 268 char *p = NULL; 269 270 switch (sk->sk_family) { 271 case AF_INET: { 272 struct inet_sock *inet = inet_sk(sk); 273 274 print_ipv4_addr(ab, inet->rcv_saddr, 275 inet->sport, 276 "laddr", "lport"); 277 print_ipv4_addr(ab, inet->daddr, 278 inet->dport, 279 "faddr", "fport"); 280 break; 281 } 282 case AF_INET6: { 283 struct inet_sock *inet = inet_sk(sk); 284 struct ipv6_pinfo *inet6 = inet6_sk(sk); 285 286 print_ipv6_addr(ab, &inet6->rcv_saddr, 287 inet->sport, 288 "laddr", "lport"); 289 print_ipv6_addr(ab, &inet6->daddr, 290 inet->dport, 291 "faddr", "fport"); 292 break; 293 } 294 case AF_UNIX: 295 u = unix_sk(sk); 296 if (u->dentry) { 297 struct path path = { 298 .dentry = u->dentry, 299 .mnt = u->mnt 300 }; 301 audit_log_d_path(ab, "path=", &path); 302 break; 303 } 304 if (!u->addr) 305 break; 306 len = u->addr->len-sizeof(short); 307 p = &u->addr->name->sun_path[0]; 308 audit_log_format(ab, " path="); 309 if (*p) 310 audit_log_untrustedstring(ab, p); 311 else 312 audit_log_n_hex(ab, p, len); 313 break; 314 } 315 } 316 317 switch (a->u.net.family) { 318 case AF_INET: 319 print_ipv4_addr(ab, a->u.net.v4info.saddr, 320 a->u.net.sport, 321 "saddr", "src"); 322 print_ipv4_addr(ab, a->u.net.v4info.daddr, 323 a->u.net.dport, 324 "daddr", "dest"); 325 break; 326 case AF_INET6: 327 print_ipv6_addr(ab, &a->u.net.v6info.saddr, 328 a->u.net.sport, 329 "saddr", "src"); 330 print_ipv6_addr(ab, &a->u.net.v6info.daddr, 331 a->u.net.dport, 332 "daddr", "dest"); 333 break; 334 } 335 if (a->u.net.netif > 0) { 336 struct net_device *dev; 337 338 /* NOTE: we always use init's namespace */ 339 dev = dev_get_by_index(&init_net, a->u.net.netif); 340 if (dev) { 341 audit_log_format(ab, " netif=%s", dev->name); 342 dev_put(dev); 343 } 344 } 345 break; 346 #ifdef CONFIG_KEYS 347 case LSM_AUDIT_DATA_KEY: 348 audit_log_format(ab, " key_serial=%u", a->u.key_struct.key); 349 if (a->u.key_struct.key_desc) { 350 audit_log_format(ab, " key_desc="); 351 audit_log_untrustedstring(ab, a->u.key_struct.key_desc); 352 } 353 break; 354 #endif 355 } /* switch (a->type) */ 356 } 357 358 /** 359 * common_lsm_audit - generic LSM auditing function 360 * @a: auxiliary audit data 361 * 362 * setup the audit buffer for common security information 363 * uses callback to print LSM specific information 364 */ 365 void common_lsm_audit(struct common_audit_data *a) 366 { 367 struct audit_buffer *ab; 368 369 if (a == NULL) 370 return; 371 /* we use GFP_ATOMIC so we won't sleep */ 372 ab = audit_log_start(current->audit_context, GFP_ATOMIC, AUDIT_AVC); 373 374 if (ab == NULL) 375 return; 376 377 if (a->lsm_pre_audit) 378 a->lsm_pre_audit(ab, a); 379 380 dump_common_audit_data(ab, a); 381 382 if (a->lsm_post_audit) 383 a->lsm_post_audit(ab, a); 384 385 audit_log_end(ab); 386 } 387