sys/kern/kern_jail.c

   1 /*
   2  * ----------------------------------------------------------------------------
   3  * "THE BEER-WARE LICENSE" (Revision 42):
   4  * <phk@FreeBSD.ORG> wrote this file.  As long as you retain this notice you
   5  * can do whatever you want with this stuff. If we meet some day, and you think
   6  * this stuff is worth it, you can buy me a beer in return.   Poul-Henning Kamp
   7  * ----------------------------------------------------------------------------
   8  *
   9  * $FreeBSD: src/sys/kern/kern_jail.c,v 1.6.2.3 2001/08/17 01:00:26 rwatson Exp $
  10  * $DragonFly: src/sys/kern/kern_jail.c,v 1.7 2005/01/31 22:29:59 joerg Exp $
  11  *
  12  */
  13
  14 #include <sys/param.h>
  15 #include <sys/types.h>
  16 #include <sys/kernel.h>
  17 #include <sys/kinfo.h>
  18 #include <sys/systm.h>
  19 #include <sys/errno.h>
  20 #include <sys/sysproto.h>
  21 #include <sys/malloc.h>
  22 #include <sys/nlookup.h>
  23 #include <sys/namecache.h>
  24 #include <sys/proc.h>
  25 #include <sys/jail.h>
  26 #include <sys/socket.h>
  27 #include <sys/sysctl.h>
  28 #include <sys/kern_syscall.h>
  29 #include <net/if.h>
  30 #include <netinet/in.h>
  31
  32 static struct prison    *prison_find(int);
  33
  34 MALLOC_DEFINE(M_PRISON, "prison", "Prison structures");
  35
  36 SYSCTL_NODE(, OID_AUTO, jail, CTLFLAG_RW, 0,
  37     "Jail rules");
  38
  39 int     jail_set_hostname_allowed = 1;
  40 SYSCTL_INT(_jail, OID_AUTO, set_hostname_allowed, CTLFLAG_RW,
  41     &jail_set_hostname_allowed, 0,
  42     "Processes in jail can set their hostnames");
  43
  44 int     jail_socket_unixiproute_only = 1;
  45 SYSCTL_INT(_jail, OID_AUTO, socket_unixiproute_only, CTLFLAG_RW,
  46     &jail_socket_unixiproute_only, 0,
  47     "Processes in jail are limited to creating UNIX/IPv4/route sockets only");
  48
  49 int     jail_sysvipc_allowed = 0;
  50 SYSCTL_INT(_jail, OID_AUTO, sysvipc_allowed, CTLFLAG_RW,
  51     &jail_sysvipc_allowed, 0,
  52     "Processes in jail can use System V IPC primitives");
  53
  54 int     lastprid = 0;
  55 int     prisoncount = 0;
  56
  57 LIST_HEAD(prisonlist, prison);
  58 struct  prisonlist allprison = LIST_HEAD_INITIALIZER(&allprison);
  59
  60 static int
  61 kern_jail_attach(int jid)
  62 {
  63         struct proc *p = curthread->td_proc;
  64         struct prison *pr;
  65         int error;
  66
  67         pr = prison_find(jid);
  68         if (pr == NULL)
  69                 return(EINVAL);
  70
  71         error = kern_chroot(pr->pr_root);
  72         if (error)
  73                 return(error);
  74
  75         prison_hold(pr);
  76         cratom(&p->p_ucred);
  77         p->p_ucred->cr_prison = pr;
  78         p->p_flag |= P_JAILED;
  79
  80         return(0);
  81 }
  82
  83 /*
  84  * jail()
  85  *
  86  * jail_args(syscallarg(struct jail *) jail)
  87  */
  88 int
  89 jail(struct jail_args *uap)
  90 {
  91         struct prison *pr, *tpr;
  92         struct jail j;
  93         struct thread *td = curthread;
  94         int error, tryprid;
  95         struct nlookupdata nd;
  96
  97         error = suser(td);
  98         if (error)
  99                 return(error);
 100         error = copyin(uap->jail, &j, sizeof j);
 101         if (error)
 102                 return(error);
 103         if (j.version != 0)
 104                 return(EINVAL);
 105         MALLOC(pr, struct prison *, sizeof *pr , M_PRISON, M_WAITOK | M_ZERO);
 106
 107         error = copyinstr(j.hostname, &pr->pr_host, sizeof pr->pr_host, 0);
 108         if (error)
 109                 goto bail;
 110         error = nlookup_init(&nd, j.path, UIO_USERSPACE, NLC_FOLLOW);
 111         if (error)
 112                 goto nlookup_init_clean;
 113         error = nlookup(&nd);
 114         if (error)
 115                 goto nlookup_init_clean;
 116         pr->pr_root = cache_hold(nd.nl_ncp);
 117
 118         pr->pr_ip = j.ip_number;
 119         varsymset_init(&pr->pr_varsymset, NULL);
 120
 121         tryprid = lastprid + 1;
 122         if (tryprid == JAIL_MAX)
 123                 tryprid = 1;
 124 next:
 125         LIST_FOREACH(tpr, &allprison, pr_list) {
 126                 if (tpr->pr_id != tryprid)
 127                         continue;
 128                 tryprid++;
 129                 if (tryprid == JAIL_MAX) {
 130                         error = EAGAIN;
 131                         goto varsym_clean;
 132                 }
 133                 goto next;
 134         }
 135         pr->pr_id = lastprid = tryprid;
 136         LIST_INSERT_HEAD(&allprison, pr, pr_list);
 137         prisoncount++;
 138
 139         error = kern_jail_attach(pr->pr_id);
 140         if (error)
 141                 goto jail_attach_clean;
 142
 143         nlookup_done(&nd);
 144         return (0);
 145
 146 jail_attach_clean:
 147         LIST_REMOVE(pr, pr_list);
 148 varsym_clean:
 149         varsymset_clean(&pr->pr_varsymset);
 150 nlookup_init_clean:
 151         nlookup_done(&nd);
 152 bail:
 153         FREE(pr, M_PRISON);
 154         return(error);
 155 }
 156
 157 /*
 158  * int jail_attach(int jid);
 159  */
 160 int
 161 jail_attach(struct jail_attach_args *uap)
 162 {
 163         struct thread *td = curthread;
 164         int error;
 165
 166         error = suser(td);
 167         if (error)
 168                 return(error);
 169
 170         return(kern_jail_attach(uap->jid));
 171 }
 172
 173 int
 174 prison_ip(struct thread *td, int flag, u_int32_t *ip)
 175 {
 176         u_int32_t tmp;
 177         struct prison *pr;
 178
 179         if (td->td_proc == NULL)
 180                 return (0);
 181         if ((pr = td->td_proc->p_ucred->cr_prison) == NULL)
 182                 return (0);
 183         if (flag)
 184                 tmp = *ip;
 185         else
 186                 tmp = ntohl(*ip);
 187         if (tmp == INADDR_ANY) {
 188                 if (flag)
 189                         *ip = pr->pr_ip;
 190                 else
 191                         *ip = htonl(pr->pr_ip);
 192                 return (0);
 193         }
 194         if (tmp == INADDR_LOOPBACK) {
 195                 if (flag)
 196                         *ip = pr->pr_ip;
 197                 else
 198                         *ip = htonl(pr->pr_ip);
 199                 return (0);
 200         }
 201         if (pr->pr_ip != tmp)
 202                 return (1);
 203         return (0);
 204 }
 205
 206 void
 207 prison_remote_ip(struct thread *td, int flag, u_int32_t *ip)
 208 {
 209         u_int32_t tmp;
 210         struct prison *pr;
 211
 212         if (td == NULL || td->td_proc == NULL)
 213                 return;
 214         if ((pr = td->td_proc->p_ucred->cr_prison) == NULL)
 215                 return;
 216         if (flag)
 217                 tmp = *ip;
 218         else
 219                 tmp = ntohl(*ip);
 220         if (tmp == INADDR_LOOPBACK) {
 221                 if (flag)
 222                         *ip = pr->pr_ip;
 223                 else
 224                         *ip = htonl(pr->pr_ip);
 225         }
 226         return;
 227 }
 228
 229 int
 230 prison_if(struct thread *td, struct sockaddr *sa)
 231 {
 232         struct prison *pr;
 233         struct sockaddr_in *sai = (struct sockaddr_in*) sa;
 234         int ok;
 235
 236         if (td->td_proc == NULL)
 237                 return(0);
 238         pr = td->td_proc->p_ucred->cr_prison;
 239
 240         if ((sai->sin_family != AF_INET) && jail_socket_unixiproute_only)
 241                 ok = 1;
 242         else if (sai->sin_family != AF_INET)
 243                 ok = 0;
 244         else if (pr->pr_ip != ntohl(sai->sin_addr.s_addr))
 245                 ok = 1;
 246         else
 247                 ok = 0;
 248         return (ok);
 249 }
 250
 251 /*
 252  * Returns a prison instance, or NULL on failure.
 253  */
 254 static struct prison *
 255 prison_find(int prid)
 256 {
 257         struct prison *pr;
 258
 259         LIST_FOREACH(pr, &allprison, pr_list) {
 260                 if (pr->pr_id == prid)
 261                         break;
 262         }
 263         return(pr);
 264 }
 265
 266 static int
 267 sysctl_jail_list(SYSCTL_HANDLER_ARGS)
 268 {
 269         struct proc *p;
 270         struct kinfo_prison *xp, *sxp;
 271         struct prison *pr;
 272         int count, error;
 273
 274         p = curthread->td_proc;
 275
 276         if (jailed(p->p_ucred))
 277                 return (0);
 278 retry:
 279         count = prisoncount;
 280
 281         if (count == 0)
 282                 return(0);
 283
 284         sxp = xp = malloc(sizeof(*xp) * count, M_TEMP, M_WAITOK | M_ZERO);
 285         if (count < prisoncount) {
 286                 free(sxp, M_TEMP);
 287                 goto retry;
 288         }
 289         count = prisoncount;
 290
 291         LIST_FOREACH(pr, &allprison, pr_list) {
 292                 char *fullpath, *freepath;
 293                 xp->pr_version = KINFO_PRISON_VERSION;
 294                 xp->pr_id = pr->pr_id;
 295                 error = cache_fullpath(p, pr->pr_root, &fullpath, &freepath);
 296                 if (error == 0) {
 297                         strlcpy(xp->pr_path, fullpath, sizeof(xp->pr_path));
 298                         free(freepath, M_TEMP);
 299                 } else {
 300                         bzero(xp->pr_path, sizeof(xp->pr_path));
 301                 }
 302                 strlcpy(xp->pr_host, pr->pr_host, sizeof(xp->pr_host));
 303                 xp->pr_ip = pr->pr_ip;
 304                 xp++;
 305         }
 306
 307         error = SYSCTL_OUT(req, sxp, sizeof(*sxp) * count);
 308         free(sxp, M_TEMP);
 309         return(error);
 310 }
 311
 312 SYSCTL_OID(_jail, OID_AUTO, list, CTLTYPE_STRUCT | CTLFLAG_RD, NULL, 0,
 313            sysctl_jail_list, "S", "List of active jails");
 314
 315 void
 316 prison_hold(struct prison *pr)
 317 {
 318         pr->pr_ref++;
 319 }
 320
 321 void
 322 prison_free(struct prison *pr)
 323 {
 324         KKASSERT(pr->pr_ref >= 1);
 325
 326         if (--pr->pr_ref > 0)
 327                 return;
 328
 329         LIST_REMOVE(pr, pr_list);
 330         prisoncount--;
 331
 332         if (pr->pr_linux != NULL)
 333                 free(pr->pr_linux, M_PRISON);
 334         varsymset_clean(&pr->pr_varsymset);
 335         cache_drop(pr->pr_root);
 336         free(pr, M_PRISON);
 337 }