net/compat.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * 32bit Socket syscall emulation. Based on arch/sparc64/kernel/sys_sparc32.c.
   4  *
   5  * Copyright (C) 2000           VA Linux Co
   6  * Copyright (C) 2000           Don Dugger <n0ano@valinux.com>
   7  * Copyright (C) 1999           Arun Sharma <arun.sharma@intel.com>
   8  * Copyright (C) 1997,1998      Jakub Jelinek (jj@sunsite.mff.cuni.cz)
   9  * Copyright (C) 1997           David S. Miller (davem@caip.rutgers.edu)
  10  * Copyright (C) 2000           Hewlett-Packard Co.
  11  * Copyright (C) 2000           David Mosberger-Tang <davidm@hpl.hp.com>
  12  * Copyright (C) 2000,2001      Andi Kleen, SuSE Labs
  13  */
  14
  15 #include <linux/kernel.h>
  16 #include <linux/gfp.h>
  17 #include <linux/fs.h>
  18 #include <linux/types.h>
  19 #include <linux/file.h>
  20 #include <linux/icmpv6.h>
  21 #include <linux/socket.h>
  22 #include <linux/syscalls.h>
  23 #include <linux/filter.h>
  24 #include <linux/compat.h>
  25 #include <linux/security.h>
  26 #include <linux/audit.h>
  27 #include <linux/export.h>
  28
  29 #include <net/scm.h>
  30 #include <net/sock.h>
  31 #include <net/ip.h>
  32 #include <net/ipv6.h>
  33 #include <linux/uaccess.h>
  34 #include <net/compat.h>
  35
  36 int __get_compat_msghdr(struct msghdr *kmsg,
  37                         struct compat_msghdr __user *umsg,
  38                         struct sockaddr __user **save_addr,
  39                         compat_uptr_t *ptr, compat_size_t *len)
  40 {
  41         struct compat_msghdr msg;
  42         ssize_t err;
  43
  44         if (copy_from_user(&msg, umsg, sizeof(*umsg)))
  45                 return -EFAULT;
  46
  47         kmsg->msg_flags = msg.msg_flags;
  48         kmsg->msg_namelen = msg.msg_namelen;
  49
  50         if (!msg.msg_name)
  51                 kmsg->msg_namelen = 0;
  52
  53         if (kmsg->msg_namelen < 0)
  54                 return -EINVAL;
  55
  56         if (kmsg->msg_namelen > sizeof(struct sockaddr_storage))
  57                 kmsg->msg_namelen = sizeof(struct sockaddr_storage);
  58
  59         kmsg->msg_control_is_user = true;
  60         kmsg->msg_control_user = compat_ptr(msg.msg_control);
  61         kmsg->msg_controllen = msg.msg_controllen;
  62
  63         if (save_addr)
  64                 *save_addr = compat_ptr(msg.msg_name);
  65
  66         if (msg.msg_name && kmsg->msg_namelen) {
  67                 if (!save_addr) {
  68                         err = move_addr_to_kernel(compat_ptr(msg.msg_name),
  69                                                   kmsg->msg_namelen,
  70                                                   kmsg->msg_name);
  71                         if (err < 0)
  72                                 return err;
  73                 }
  74         } else {
  75                 kmsg->msg_name = NULL;
  76                 kmsg->msg_namelen = 0;
  77         }
  78
  79         if (msg.msg_iovlen > UIO_MAXIOV)
  80                 return -EMSGSIZE;
  81
  82         kmsg->msg_iocb = NULL;
  83         *ptr = msg.msg_iov;
  84         *len = msg.msg_iovlen;
  85         return 0;
  86 }
  87
  88 int get_compat_msghdr(struct msghdr *kmsg,
  89                       struct compat_msghdr __user *umsg,
  90                       struct sockaddr __user **save_addr,
  91                       struct iovec **iov)
  92 {
  93         compat_uptr_t ptr;
  94         compat_size_t len;
  95         ssize_t err;
  96
  97         err = __get_compat_msghdr(kmsg, umsg, save_addr, &ptr, &len);
  98         if (err)
  99                 return err;
 100
 101         err = import_iovec(save_addr ? READ : WRITE, compat_ptr(ptr), len,
 102                            UIO_FASTIOV, iov, &kmsg->msg_iter);
 103         return err < 0 ? err : 0;
 104 }
 105
 106 /* Bleech... */
 107 #define CMSG_COMPAT_ALIGN(len)  ALIGN((len), sizeof(s32))
 108
 109 #define CMSG_COMPAT_DATA(cmsg)                          \
 110         ((void __user *)((char __user *)(cmsg) + sizeof(struct compat_cmsghdr)))
 111 #define CMSG_COMPAT_SPACE(len)                          \
 112         (sizeof(struct compat_cmsghdr) + CMSG_COMPAT_ALIGN(len))
 113 #define CMSG_COMPAT_LEN(len)                            \
 114         (sizeof(struct compat_cmsghdr) + (len))
 115
 116 #define CMSG_COMPAT_FIRSTHDR(msg)                       \
 117         (((msg)->msg_controllen) >= sizeof(struct compat_cmsghdr) ?     \
 118          (struct compat_cmsghdr __user *)((msg)->msg_control) :         \
 119          (struct compat_cmsghdr __user *)NULL)
 120
 121 #define CMSG_COMPAT_OK(ucmlen, ucmsg, mhdr) \
 122         ((ucmlen) >= sizeof(struct compat_cmsghdr) && \
 123          (ucmlen) <= (unsigned long) \
 124          ((mhdr)->msg_controllen - \
 125           ((char __user *)(ucmsg) - (char __user *)(mhdr)->msg_control_user)))
 126
 127 static inline struct compat_cmsghdr __user *cmsg_compat_nxthdr(struct msghdr *msg,
 128                 struct compat_cmsghdr __user *cmsg, int cmsg_len)
 129 {
 130         char __user *ptr = (char __user *)cmsg + CMSG_COMPAT_ALIGN(cmsg_len);
 131         if ((unsigned long)(ptr + 1 - (char __user *)msg->msg_control) >
 132                         msg->msg_controllen)
 133                 return NULL;
 134         return (struct compat_cmsghdr __user *)ptr;
 135 }
 136
 137 /* There is a lot of hair here because the alignment rules (and
 138  * thus placement) of cmsg headers and length are different for
 139  * 32-bit apps.  -DaveM
 140  */
 141 int cmsghdr_from_user_compat_to_kern(struct msghdr *kmsg, struct sock *sk,
 142                                unsigned char *stackbuf, int stackbuf_size)
 143 {
 144         struct compat_cmsghdr __user *ucmsg;
 145         struct cmsghdr *kcmsg, *kcmsg_base;
 146         compat_size_t ucmlen;
 147         __kernel_size_t kcmlen, tmp;
 148         int err = -EFAULT;
 149
 150         BUILD_BUG_ON(sizeof(struct compat_cmsghdr) !=
 151                      CMSG_COMPAT_ALIGN(sizeof(struct compat_cmsghdr)));
 152
 153         kcmlen = 0;
 154         kcmsg_base = kcmsg = (struct cmsghdr *)stackbuf;
 155         ucmsg = CMSG_COMPAT_FIRSTHDR(kmsg);
 156         while (ucmsg != NULL) {
 157                 if (get_user(ucmlen, &ucmsg->cmsg_len))
 158                         return -EFAULT;
 159
 160                 /* Catch bogons. */
 161                 if (!CMSG_COMPAT_OK(ucmlen, ucmsg, kmsg))
 162                         return -EINVAL;
 163
 164                 tmp = ((ucmlen - sizeof(*ucmsg)) + sizeof(struct cmsghdr));
 165                 tmp = CMSG_ALIGN(tmp);
 166                 kcmlen += tmp;
 167                 ucmsg = cmsg_compat_nxthdr(kmsg, ucmsg, ucmlen);
 168         }
 169         if (kcmlen == 0)
 170                 return -EINVAL;
 171
 172         /* The kcmlen holds the 64-bit version of the control length.
 173          * It may not be modified as we do not stick it into the kmsg
 174          * until we have successfully copied over all of the data
 175          * from the user.
 176          */
 177         if (kcmlen > stackbuf_size)
 178                 kcmsg_base = kcmsg = sock_kmalloc(sk, kcmlen, GFP_KERNEL);
 179         if (kcmsg == NULL)
 180                 return -ENOMEM;
 181
 182         /* Now copy them over neatly. */
 183         memset(kcmsg, 0, kcmlen);
 184         ucmsg = CMSG_COMPAT_FIRSTHDR(kmsg);
 185         while (ucmsg != NULL) {
 186                 struct compat_cmsghdr cmsg;
 187                 if (copy_from_user(&cmsg, ucmsg, sizeof(cmsg)))
 188                         goto Efault;
 189                 if (!CMSG_COMPAT_OK(cmsg.cmsg_len, ucmsg, kmsg))
 190                         goto Einval;
 191                 tmp = ((cmsg.cmsg_len - sizeof(*ucmsg)) + sizeof(struct cmsghdr));
 192                 if ((char *)kcmsg_base + kcmlen - (char *)kcmsg < CMSG_ALIGN(tmp))
 193                         goto Einval;
 194                 kcmsg->cmsg_len = tmp;
 195                 kcmsg->cmsg_level = cmsg.cmsg_level;
 196                 kcmsg->cmsg_type = cmsg.cmsg_type;
 197                 tmp = CMSG_ALIGN(tmp);
 198                 if (copy_from_user(CMSG_DATA(kcmsg),
 199                                    CMSG_COMPAT_DATA(ucmsg),
 200                                    (cmsg.cmsg_len - sizeof(*ucmsg))))
 201                         goto Efault;
 202
 203                 /* Advance. */
 204                 kcmsg = (struct cmsghdr *)((char *)kcmsg + tmp);
 205                 ucmsg = cmsg_compat_nxthdr(kmsg, ucmsg, cmsg.cmsg_len);
 206         }
 207
 208         /*
 209          * check the length of messages copied in is the same as the
 210          * what we get from the first loop
 211          */
 212         if ((char *)kcmsg - (char *)kcmsg_base != kcmlen)
 213                 goto Einval;
 214
 215         /* Ok, looks like we made it.  Hook it up and return success. */
 216         kmsg->msg_control = kcmsg_base;
 217         kmsg->msg_controllen = kcmlen;
 218         return 0;
 219
 220 Einval:
 221         err = -EINVAL;
 222 Efault:
 223         if (kcmsg_base != (struct cmsghdr *)stackbuf)
 224                 sock_kfree_s(sk, kcmsg_base, kcmlen);
 225         return err;
 226 }
 227
 228 int put_cmsg_compat(struct msghdr *kmsg, int level, int type, int len, void *data)
 229 {
 230         struct compat_cmsghdr __user *cm = (struct compat_cmsghdr __user *) kmsg->msg_control;
 231         struct compat_cmsghdr cmhdr;
 232         struct old_timeval32 ctv;
 233         struct old_timespec32 cts[3];
 234         int cmlen;
 235
 236         if (cm == NULL || kmsg->msg_controllen < sizeof(*cm)) {
 237                 kmsg->msg_flags |= MSG_CTRUNC;
 238                 return 0; /* XXX: return error? check spec. */
 239         }
 240
 241         if (!COMPAT_USE_64BIT_TIME) {
 242                 if (level == SOL_SOCKET && type == SO_TIMESTAMP_OLD) {
 243                         struct __kernel_old_timeval *tv = (struct __kernel_old_timeval *)data;
 244                         ctv.tv_sec = tv->tv_sec;
 245                         ctv.tv_usec = tv->tv_usec;
 246                         data = &ctv;
 247                         len = sizeof(ctv);
 248                 }
 249                 if (level == SOL_SOCKET &&
 250                     (type == SO_TIMESTAMPNS_OLD || type == SO_TIMESTAMPING_OLD)) {
 251                         int count = type == SO_TIMESTAMPNS_OLD ? 1 : 3;
 252                         int i;
 253                         struct __kernel_old_timespec *ts = data;
 254                         for (i = 0; i < count; i++) {
 255                                 cts[i].tv_sec = ts[i].tv_sec;
 256                                 cts[i].tv_nsec = ts[i].tv_nsec;
 257                         }
 258                         data = &cts;
 259                         len = sizeof(cts[0]) * count;
 260                 }
 261         }
 262
 263         cmlen = CMSG_COMPAT_LEN(len);
 264         if (kmsg->msg_controllen < cmlen) {
 265                 kmsg->msg_flags |= MSG_CTRUNC;
 266                 cmlen = kmsg->msg_controllen;
 267         }
 268         cmhdr.cmsg_level = level;
 269         cmhdr.cmsg_type = type;
 270         cmhdr.cmsg_len = cmlen;
 271
 272         if (copy_to_user(cm, &cmhdr, sizeof cmhdr))
 273                 return -EFAULT;
 274         if (copy_to_user(CMSG_COMPAT_DATA(cm), data, cmlen - sizeof(struct compat_cmsghdr)))
 275                 return -EFAULT;
 276         cmlen = CMSG_COMPAT_SPACE(len);
 277         if (kmsg->msg_controllen < cmlen)
 278                 cmlen = kmsg->msg_controllen;
 279         kmsg->msg_control += cmlen;
 280         kmsg->msg_controllen -= cmlen;
 281         return 0;
 282 }
 283
 284 static int scm_max_fds_compat(struct msghdr *msg)
 285 {
 286         if (msg->msg_controllen <= sizeof(struct compat_cmsghdr))
 287                 return 0;
 288         return (msg->msg_controllen - sizeof(struct compat_cmsghdr)) / sizeof(int);
 289 }
 290
 291 void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm)
 292 {
 293         struct compat_cmsghdr __user *cm =
 294                 (struct compat_cmsghdr __user *)msg->msg_control;
 295         unsigned int o_flags = (msg->msg_flags & MSG_CMSG_CLOEXEC) ? O_CLOEXEC : 0;
 296         int fdmax = min_t(int, scm_max_fds_compat(msg), scm->fp->count);
 297         int __user *cmsg_data = CMSG_COMPAT_DATA(cm);
 298         int err = 0, i;
 299
 300         for (i = 0; i < fdmax; i++) {
 301                 err = receive_fd_user(scm->fp->fp[i], cmsg_data + i, o_flags);
 302                 if (err < 0)
 303                         break;
 304         }
 305
 306         if (i > 0) {
 307                 int cmlen = CMSG_COMPAT_LEN(i * sizeof(int));
 308
 309                 err = put_user(SOL_SOCKET, &cm->cmsg_level);
 310                 if (!err)
 311                         err = put_user(SCM_RIGHTS, &cm->cmsg_type);
 312                 if (!err)
 313                         err = put_user(cmlen, &cm->cmsg_len);
 314                 if (!err) {
 315                         cmlen = CMSG_COMPAT_SPACE(i * sizeof(int));
 316                         if (msg->msg_controllen < cmlen)
 317                                 cmlen = msg->msg_controllen;
 318                         msg->msg_control += cmlen;
 319                         msg->msg_controllen -= cmlen;
 320                 }
 321         }
 322
 323         if (i < scm->fp->count || (scm->fp->count && fdmax <= 0))
 324                 msg->msg_flags |= MSG_CTRUNC;
 325
 326         /*
 327          * All of the files that fit in the message have had their usage counts
 328          * incremented, so we just free the list.
 329          */
 330         __scm_destroy(scm);
 331 }
 332
 333 /* Argument list sizes for compat_sys_socketcall */
 334 #define AL(x) ((x) * sizeof(u32))
 335 static unsigned char nas[21] = {
 336         AL(0), AL(3), AL(3), AL(3), AL(2), AL(3),
 337         AL(3), AL(3), AL(4), AL(4), AL(4), AL(6),
 338         AL(6), AL(2), AL(5), AL(5), AL(3), AL(3),
 339         AL(4), AL(5), AL(4)
 340 };
 341 #undef AL
 342
 343 static inline long __compat_sys_sendmsg(int fd,
 344                                         struct compat_msghdr __user *msg,
 345                                         unsigned int flags)
 346 {
 347         return __sys_sendmsg(fd, (struct user_msghdr __user *)msg,
 348                              flags | MSG_CMSG_COMPAT, false);
 349 }
 350
 351 COMPAT_SYSCALL_DEFINE3(sendmsg, int, fd, struct compat_msghdr __user *, msg,
 352                        unsigned int, flags)
 353 {
 354         return __compat_sys_sendmsg(fd, msg, flags);
 355 }
 356
 357 static inline long __compat_sys_sendmmsg(int fd,
 358                                          struct compat_mmsghdr __user *mmsg,
 359                                          unsigned int vlen, unsigned int flags)
 360 {
 361         return __sys_sendmmsg(fd, (struct mmsghdr __user *)mmsg, vlen,
 362                               flags | MSG_CMSG_COMPAT, false);
 363 }
 364
 365 COMPAT_SYSCALL_DEFINE4(sendmmsg, int, fd, struct compat_mmsghdr __user *, mmsg,
 366                        unsigned int, vlen, unsigned int, flags)
 367 {
 368         return __compat_sys_sendmmsg(fd, mmsg, vlen, flags);
 369 }
 370
 371 static inline long __compat_sys_recvmsg(int fd,
 372                                         struct compat_msghdr __user *msg,
 373                                         unsigned int flags)
 374 {
 375         return __sys_recvmsg(fd, (struct user_msghdr __user *)msg,
 376                              flags | MSG_CMSG_COMPAT, false);
 377 }
 378
 379 COMPAT_SYSCALL_DEFINE3(recvmsg, int, fd, struct compat_msghdr __user *, msg,
 380                        unsigned int, flags)
 381 {
 382         return __compat_sys_recvmsg(fd, msg, flags);
 383 }
 384
 385 static inline long __compat_sys_recvfrom(int fd, void __user *buf,
 386                                          compat_size_t len, unsigned int flags,
 387                                          struct sockaddr __user *addr,
 388                                          int __user *addrlen)
 389 {
 390         return __sys_recvfrom(fd, buf, len, flags | MSG_CMSG_COMPAT, addr,
 391                               addrlen);
 392 }
 393
 394 COMPAT_SYSCALL_DEFINE4(recv, int, fd, void __user *, buf, compat_size_t, len, unsigned int, flags)
 395 {
 396         return __compat_sys_recvfrom(fd, buf, len, flags, NULL, NULL);
 397 }
 398
 399 COMPAT_SYSCALL_DEFINE6(recvfrom, int, fd, void __user *, buf, compat_size_t, len,
 400                        unsigned int, flags, struct sockaddr __user *, addr,
 401                        int __user *, addrlen)
 402 {
 403         return __compat_sys_recvfrom(fd, buf, len, flags, addr, addrlen);
 404 }
 405
 406 COMPAT_SYSCALL_DEFINE5(recvmmsg_time64, int, fd, struct compat_mmsghdr __user *, mmsg,
 407                        unsigned int, vlen, unsigned int, flags,
 408                        struct __kernel_timespec __user *, timeout)
 409 {
 410         return __sys_recvmmsg(fd, (struct mmsghdr __user *)mmsg, vlen,
 411                               flags | MSG_CMSG_COMPAT, timeout, NULL);
 412 }
 413
 414 #ifdef CONFIG_COMPAT_32BIT_TIME
 415 COMPAT_SYSCALL_DEFINE5(recvmmsg_time32, int, fd, struct compat_mmsghdr __user *, mmsg,
 416                        unsigned int, vlen, unsigned int, flags,
 417                        struct old_timespec32 __user *, timeout)
 418 {
 419         return __sys_recvmmsg(fd, (struct mmsghdr __user *)mmsg, vlen,
 420                               flags | MSG_CMSG_COMPAT, NULL, timeout);
 421 }
 422 #endif
 423
 424 COMPAT_SYSCALL_DEFINE2(socketcall, int, call, u32 __user *, args)
 425 {
 426         u32 a[AUDITSC_ARGS];
 427         unsigned int len;
 428         u32 a0, a1;
 429         int ret;
 430
 431         if (call < SYS_SOCKET || call > SYS_SENDMMSG)
 432                 return -EINVAL;
 433         len = nas[call];
 434         if (len > sizeof(a))
 435                 return -EINVAL;
 436
 437         if (copy_from_user(a, args, len))
 438                 return -EFAULT;
 439
 440         ret = audit_socketcall_compat(len / sizeof(a[0]), a);
 441         if (ret)
 442                 return ret;
 443
 444         a0 = a[0];
 445         a1 = a[1];
 446
 447         switch (call) {
 448         case SYS_SOCKET:
 449                 ret = __sys_socket(a0, a1, a[2]);
 450                 break;
 451         case SYS_BIND:
 452                 ret = __sys_bind(a0, compat_ptr(a1), a[2]);
 453                 break;
 454         case SYS_CONNECT:
 455                 ret = __sys_connect(a0, compat_ptr(a1), a[2]);
 456                 break;
 457         case SYS_LISTEN:
 458                 ret = __sys_listen(a0, a1);
 459                 break;
 460         case SYS_ACCEPT:
 461                 ret = __sys_accept4(a0, compat_ptr(a1), compat_ptr(a[2]), 0);
 462                 break;
 463         case SYS_GETSOCKNAME:
 464                 ret = __sys_getsockname(a0, compat_ptr(a1), compat_ptr(a[2]));
 465                 break;
 466         case SYS_GETPEERNAME:
 467                 ret = __sys_getpeername(a0, compat_ptr(a1), compat_ptr(a[2]));
 468                 break;
 469         case SYS_SOCKETPAIR:
 470                 ret = __sys_socketpair(a0, a1, a[2], compat_ptr(a[3]));
 471                 break;
 472         case SYS_SEND:
 473                 ret = __sys_sendto(a0, compat_ptr(a1), a[2], a[3], NULL, 0);
 474                 break;
 475         case SYS_SENDTO:
 476                 ret = __sys_sendto(a0, compat_ptr(a1), a[2], a[3],
 477                                    compat_ptr(a[4]), a[5]);
 478                 break;
 479         case SYS_RECV:
 480                 ret = __compat_sys_recvfrom(a0, compat_ptr(a1), a[2], a[3],
 481                                             NULL, NULL);
 482                 break;
 483         case SYS_RECVFROM:
 484                 ret = __compat_sys_recvfrom(a0, compat_ptr(a1), a[2], a[3],
 485                                             compat_ptr(a[4]),
 486                                             compat_ptr(a[5]));
 487                 break;
 488         case SYS_SHUTDOWN:
 489                 ret = __sys_shutdown(a0, a1);
 490                 break;
 491         case SYS_SETSOCKOPT:
 492                 ret = __sys_setsockopt(a0, a1, a[2], compat_ptr(a[3]), a[4]);
 493                 break;
 494         case SYS_GETSOCKOPT:
 495                 ret = __sys_getsockopt(a0, a1, a[2], compat_ptr(a[3]),
 496                                        compat_ptr(a[4]));
 497                 break;
 498         case SYS_SENDMSG:
 499                 ret = __compat_sys_sendmsg(a0, compat_ptr(a1), a[2]);
 500                 break;
 501         case SYS_SENDMMSG:
 502                 ret = __compat_sys_sendmmsg(a0, compat_ptr(a1), a[2], a[3]);
 503                 break;
 504         case SYS_RECVMSG:
 505                 ret = __compat_sys_recvmsg(a0, compat_ptr(a1), a[2]);
 506                 break;
 507         case SYS_RECVMMSG:
 508                 ret = __sys_recvmmsg(a0, compat_ptr(a1), a[2],
 509                                      a[3] | MSG_CMSG_COMPAT, NULL,
 510                                      compat_ptr(a[4]));
 511                 break;
 512         case SYS_ACCEPT4:
 513                 ret = __sys_accept4(a0, compat_ptr(a1), compat_ptr(a[2]), a[3]);
 514                 break;
 515         default:
 516                 ret = -EINVAL;
 517                 break;
 518         }
 519         return ret;
 520 }