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 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_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_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 */
 372void 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
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