linux/security/lsm_audit.c
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   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 */
  42int 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 */
 111int 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
 186static 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
 196static 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 */
 210static void dump_common_audit_data(struct audit_buffer *ab,
 211                                   struct common_audit_data *a)
 212{
 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_NONE:
 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_PATH: {
 232                struct inode *inode;
 233
 234                audit_log_d_path(ab, "path=", &a->u.path);
 235
 236                inode = a->u.path.dentry->d_inode;
 237                if (inode)
 238                        audit_log_format(ab, " dev=%s ino=%lu",
 239                                        inode->i_sb->s_id,
 240                                        inode->i_ino);
 241                break;
 242        }
 243        case LSM_AUDIT_DATA_DENTRY: {
 244                struct inode *inode;
 245
 246                audit_log_format(ab, " name=");
 247                audit_log_untrustedstring(ab, a->u.dentry->d_name.name);
 248
 249                inode = a->u.dentry->d_inode;
 250                if (inode)
 251                        audit_log_format(ab, " dev=%s ino=%lu",
 252                                        inode->i_sb->s_id,
 253                                        inode->i_ino);
 254                break;
 255        }
 256        case LSM_AUDIT_DATA_INODE: {
 257                struct dentry *dentry;
 258                struct inode *inode;
 259
 260                inode = a->u.inode;
 261                dentry = d_find_alias(inode);
 262                if (dentry) {
 263                        audit_log_format(ab, " name=");
 264                        audit_log_untrustedstring(ab,
 265                                         dentry->d_name.name);
 266                        dput(dentry);
 267                }
 268                audit_log_format(ab, " dev=%s ino=%lu", inode->i_sb->s_id,
 269                                 inode->i_ino);
 270                break;
 271        }
 272        case LSM_AUDIT_DATA_TASK:
 273                tsk = a->u.tsk;
 274                if (tsk && tsk->pid) {
 275                        audit_log_format(ab, " pid=%d comm=", tsk->pid);
 276                        audit_log_untrustedstring(ab, tsk->comm);
 277                }
 278                break;
 279        case LSM_AUDIT_DATA_NET:
 280                if (a->u.net.sk) {
 281                        struct sock *sk = a->u.net.sk;
 282                        struct unix_sock *u;
 283                        int len = 0;
 284                        char *p = NULL;
 285
 286                        switch (sk->sk_family) {
 287                        case AF_INET: {
 288                                struct inet_sock *inet = inet_sk(sk);
 289
 290                                print_ipv4_addr(ab, inet->inet_rcv_saddr,
 291                                                inet->inet_sport,
 292                                                "laddr", "lport");
 293                                print_ipv4_addr(ab, inet->inet_daddr,
 294                                                inet->inet_dport,
 295                                                "faddr", "fport");
 296                                break;
 297                        }
 298                        case AF_INET6: {
 299                                struct inet_sock *inet = inet_sk(sk);
 300                                struct ipv6_pinfo *inet6 = inet6_sk(sk);
 301
 302                                print_ipv6_addr(ab, &inet6->rcv_saddr,
 303                                                inet->inet_sport,
 304                                                "laddr", "lport");
 305                                print_ipv6_addr(ab, &inet6->daddr,
 306                                                inet->inet_dport,
 307                                                "faddr", "fport");
 308                                break;
 309                        }
 310                        case AF_UNIX:
 311                                u = unix_sk(sk);
 312                                if (u->dentry) {
 313                                        struct path path = {
 314                                                .dentry = u->dentry,
 315                                                .mnt = u->mnt
 316                                        };
 317                                        audit_log_d_path(ab, "path=", &path);
 318                                        break;
 319                                }
 320                                if (!u->addr)
 321                                        break;
 322                                len = u->addr->len-sizeof(short);
 323                                p = &u->addr->name->sun_path[0];
 324                                audit_log_format(ab, " path=");
 325                                if (*p)
 326                                        audit_log_untrustedstring(ab, p);
 327                                else
 328                                        audit_log_n_hex(ab, p, len);
 329                                break;
 330                        }
 331                }
 332
 333                switch (a->u.net.family) {
 334                case AF_INET:
 335                        print_ipv4_addr(ab, a->u.net.v4info.saddr,
 336                                        a->u.net.sport,
 337                                        "saddr", "src");
 338                        print_ipv4_addr(ab, a->u.net.v4info.daddr,
 339                                        a->u.net.dport,
 340                                        "daddr", "dest");
 341                        break;
 342                case AF_INET6:
 343                        print_ipv6_addr(ab, &a->u.net.v6info.saddr,
 344                                        a->u.net.sport,
 345                                        "saddr", "src");
 346                        print_ipv6_addr(ab, &a->u.net.v6info.daddr,
 347                                        a->u.net.dport,
 348                                        "daddr", "dest");
 349                        break;
 350                }
 351                if (a->u.net.netif > 0) {
 352                        struct net_device *dev;
 353
 354                        /* NOTE: we always use init's namespace */
 355                        dev = dev_get_by_index(&init_net, a->u.net.netif);
 356                        if (dev) {
 357                                audit_log_format(ab, " netif=%s", dev->name);
 358                                dev_put(dev);
 359                        }
 360                }
 361                break;
 362#ifdef CONFIG_KEYS
 363        case LSM_AUDIT_DATA_KEY:
 364                audit_log_format(ab, " key_serial=%u", a->u.key_struct.key);
 365                if (a->u.key_struct.key_desc) {
 366                        audit_log_format(ab, " key_desc=");
 367                        audit_log_untrustedstring(ab, a->u.key_struct.key_desc);
 368                }
 369                break;
 370#endif
 371        case LSM_AUDIT_DATA_KMOD:
 372                audit_log_format(ab, " kmod=");
 373                audit_log_untrustedstring(ab, a->u.kmod_name);
 374                break;
 375        } /* switch (a->type) */
 376}
 377
 378/**
 379 * common_lsm_audit - generic LSM auditing function
 380 * @a:  auxiliary audit data
 381 *
 382 * setup the audit buffer for common security information
 383 * uses callback to print LSM specific information
 384 */
 385void common_lsm_audit(struct common_audit_data *a)
 386{
 387        struct audit_buffer *ab;
 388
 389        if (a == NULL)
 390                return;
 391        /* we use GFP_ATOMIC so we won't sleep */
 392        ab = audit_log_start(current->audit_context, GFP_ATOMIC, AUDIT_AVC);
 393
 394        if (ab == NULL)
 395                return;
 396
 397        if (a->lsm_pre_audit)
 398                a->lsm_pre_audit(ab, a);
 399
 400        dump_common_audit_data(ab, a);
 401
 402        if (a->lsm_post_audit)
 403                a->lsm_post_audit(ab, a);
 404
 405        audit_log_end(ab);
 406}
 407
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