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; 117 118 ip6 = ipv6_hdr(skb); 119 if (ip6 == NULL) 120 return -EINVAL; 121 ipv6_addr_copy(&ad->u.net.v6info.saddr, &ip6->saddr); 122 ipv6_addr_copy(&ad->u.net.v6info.daddr, &ip6->daddr); 123 ret = 0; 124 /* IPv6 can have several extension header before the Transport header 125 * skip them */ 126 offset = skb_network_offset(skb); 127 offset += sizeof(*ip6); 128 nexthdr = ip6->nexthdr; 129 offset = ipv6_skip_exthdr(skb, offset, &nexthdr); 130 if (offset < 0) 131 return 0; 132 if (proto) 133 *proto = nexthdr; 134 switch (nexthdr) { 135 case IPPROTO_TCP: { 136 struct tcphdr _tcph, *th; 137 138 th = skb_header_pointer(skb, offset, sizeof(_tcph), &_tcph); 139 if (th == NULL) 140 break; 141 142 ad->u.net.sport = th->source; 143 ad->u.net.dport = th->dest; 144 break; 145 } 146 case IPPROTO_UDP: { 147 struct udphdr _udph, *uh; 148 149 uh = skb_header_pointer(skb, offset, sizeof(_udph), &_udph); 150 if (uh == NULL) 151 break; 152 153 ad->u.net.sport = uh->source; 154 ad->u.net.dport = uh->dest; 155 break; 156 } 157 case IPPROTO_DCCP: { 158 struct dccp_hdr _dccph, *dh; 159 160 dh = skb_header_pointer(skb, offset, sizeof(_dccph), &_dccph); 161 if (dh == NULL) 162 break; 163 164 ad->u.net.sport = dh->dccph_sport; 165 ad->u.net.dport = dh->dccph_dport; 166 break; 167 } 168 case IPPROTO_SCTP: { 169 struct sctphdr _sctph, *sh; 170 171 sh = skb_header_pointer(skb, offset, sizeof(_sctph), &_sctph); 172 if (sh == NULL) 173 break; 174 ad->u.net.sport = sh->source; 175 ad->u.net.dport = sh->dest; 176 break; 177 } 178 default: 179 ret = -EINVAL; 180 } 181 return ret; 182 } 183 #endif 184 185 186 static inline void print_ipv6_addr(struct audit_buffer *ab, 187 struct in6_addr *addr, __be16 port, 188 char *name1, char *name2) 189 { 190 if (!ipv6_addr_any(addr)) 191 audit_log_format(ab, " %s=%pI6c", name1, addr); 192 if (port) 193 audit_log_format(ab, " %s=%d", name2, ntohs(port)); 194 } 195 196 static inline void print_ipv4_addr(struct audit_buffer *ab, __be32 addr, 197 __be16 port, char *name1, char *name2) 198 { 199 if (addr) 200 audit_log_format(ab, " %s=%pI4", name1, &addr); 201 if (port) 202 audit_log_format(ab, " %s=%d", name2, ntohs(port)); 203 } 204 205 /** 206 * dump_common_audit_data - helper to dump common audit data 207 * @a : common audit data 208 * 209 */ 210 static void dump_common_audit_data(struct audit_buffer *ab, 211 struct common_audit_data *a) 212 { 213 struct inode *inode = NULL; 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_NO_AUDIT: 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_FS: 233 if (a->u.fs.path.dentry) { 234 struct dentry *dentry = a->u.fs.path.dentry; 235 if (a->u.fs.path.mnt) { 236 audit_log_d_path(ab, "path=", &a->u.fs.path); 237 } else { 238 audit_log_format(ab, " name="); 239 audit_log_untrustedstring(ab, 240 dentry->d_name.name); 241 } 242 inode = dentry->d_inode; 243 } else if (a->u.fs.inode) { 244 struct dentry *dentry; 245 inode = a->u.fs.inode; 246 dentry = d_find_alias(inode); 247 if (dentry) { 248 audit_log_format(ab, " name="); 249 audit_log_untrustedstring(ab, 250 dentry->d_name.name); 251 dput(dentry); 252 } 253 } 254 if (inode) 255 audit_log_format(ab, " dev=%s ino=%lu", 256 inode->i_sb->s_id, 257 inode->i_ino); 258 break; 259 case LSM_AUDIT_DATA_TASK: 260 tsk = a->u.tsk; 261 if (tsk && tsk->pid) { 262 audit_log_format(ab, " pid=%d comm=", tsk->pid); 263 audit_log_untrustedstring(ab, tsk->comm); 264 } 265 break; 266 case LSM_AUDIT_DATA_NET: 267 if (a->u.net.sk) { 268 struct sock *sk = a->u.net.sk; 269 struct unix_sock *u; 270 int len = 0; 271 char *p = NULL; 272 273 switch (sk->sk_family) { 274 case AF_INET: { 275 struct inet_sock *inet = inet_sk(sk); 276 277 print_ipv4_addr(ab, inet->inet_rcv_saddr, 278 inet->inet_sport, 279 "laddr", "lport"); 280 print_ipv4_addr(ab, inet->inet_daddr, 281 inet->inet_dport, 282 "faddr", "fport"); 283 break; 284 } 285 case AF_INET6: { 286 struct inet_sock *inet = inet_sk(sk); 287 struct ipv6_pinfo *inet6 = inet6_sk(sk); 288 289 print_ipv6_addr(ab, &inet6->rcv_saddr, 290 inet->inet_sport, 291 "laddr", "lport"); 292 print_ipv6_addr(ab, &inet6->daddr, 293 inet->inet_dport, 294 "faddr", "fport"); 295 break; 296 } 297 case AF_UNIX: 298 u = unix_sk(sk); 299 if (u->dentry) { 300 struct path path = { 301 .dentry = u->dentry, 302 .mnt = u->mnt 303 }; 304 audit_log_d_path(ab, "path=", &path); 305 break; 306 } 307 if (!u->addr) 308 break; 309 len = u->addr->len-sizeof(short); 310 p = &u->addr->name->sun_path[0]; 311 audit_log_format(ab, " path="); 312 if (*p) 313 audit_log_untrustedstring(ab, p); 314 else 315 audit_log_n_hex(ab, p, len); 316 break; 317 } 318 } 319 320 switch (a->u.net.family) { 321 case AF_INET: 322 print_ipv4_addr(ab, a->u.net.v4info.saddr, 323 a->u.net.sport, 324 "saddr", "src"); 325 print_ipv4_addr(ab, a->u.net.v4info.daddr, 326 a->u.net.dport, 327 "daddr", "dest"); 328 break; 329 case AF_INET6: 330 print_ipv6_addr(ab, &a->u.net.v6info.saddr, 331 a->u.net.sport, 332 "saddr", "src"); 333 print_ipv6_addr(ab, &a->u.net.v6info.daddr, 334 a->u.net.dport, 335 "daddr", "dest"); 336 break; 337 } 338 if (a->u.net.netif > 0) { 339 struct net_device *dev; 340 341 /* NOTE: we always use init's namespace */ 342 dev = dev_get_by_index(&init_net, a->u.net.netif); 343 if (dev) { 344 audit_log_format(ab, " netif=%s", dev->name); 345 dev_put(dev); 346 } 347 } 348 break; 349 #ifdef CONFIG_KEYS 350 case LSM_AUDIT_DATA_KEY: 351 audit_log_format(ab, " key_serial=%u", a->u.key_struct.key); 352 if (a->u.key_struct.key_desc) { 353 audit_log_format(ab, " key_desc="); 354 audit_log_untrustedstring(ab, a->u.key_struct.key_desc); 355 } 356 break; 357 #endif 358 case LSM_AUDIT_DATA_KMOD: 359 audit_log_format(ab, " kmod="); 360 audit_log_untrustedstring(ab, a->u.kmod_name); 361 break; 362 } /* switch (a->type) */ 363 } 364 365 /** 366 * common_lsm_audit - generic LSM auditing function 367 * @a: auxiliary audit data 368 * 369 * setup the audit buffer for common security information 370 * uses callback to print LSM specific information 371 */ 372 void common_lsm_audit(struct common_audit_data *a) 373 { 374 struct audit_buffer *ab; 375 376 if (a == NULL) 377 return; 378 /* we use GFP_ATOMIC so we won't sleep */ 379 ab = audit_log_start(current->audit_context, GFP_ATOMIC, AUDIT_AVC); 380 381 if (ab == NULL) 382 return; 383 384 if (a->lsm_pre_audit) 385 a->lsm_pre_audit(ab, a); 386 387 dump_common_audit_data(ab, a); 388 389 if (a->lsm_post_audit) 390 a->lsm_post_audit(ab, a); 391 392 audit_log_end(ab); 393 } 394