linux/net/compat.c
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   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
  36int __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
  88int 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
 127static 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 */
 141int 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
 220Einval:
 221        err = -EINVAL;
 222Efault:
 223        if (kcmsg_base != (struct cmsghdr *)stackbuf)
 224                sock_kfree_s(sk, kcmsg_base, kcmlen);
 225        return err;
 226}
 227
 228int 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
 284static 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
 291void 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))
 335static 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
 343static 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
 351COMPAT_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
 357static 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
 365COMPAT_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
 371static 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
 379COMPAT_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
 385static 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
 394COMPAT_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
 399COMPAT_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
 406COMPAT_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
 415COMPAT_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
 424COMPAT_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}
 521