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