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0001 // SPDX-License-Identifier: GPL-2.0-only
0002 /*
0003  * 32bit Socket syscall emulation. Based on arch/sparc64/kernel/sys_sparc32.c.
0004  *
0005  * Copyright (C) 2000       VA Linux Co
0006  * Copyright (C) 2000       Don Dugger <n0ano@valinux.com>
0007  * Copyright (C) 1999       Arun Sharma <arun.sharma@intel.com>
0008  * Copyright (C) 1997,1998  Jakub Jelinek (jj@sunsite.mff.cuni.cz)
0009  * Copyright (C) 1997       David S. Miller (davem@caip.rutgers.edu)
0010  * Copyright (C) 2000       Hewlett-Packard Co.
0011  * Copyright (C) 2000       David Mosberger-Tang <davidm@hpl.hp.com>
0012  * Copyright (C) 2000,2001  Andi Kleen, SuSE Labs
0013  */
0014 
0015 #include <linux/kernel.h>
0016 #include <linux/gfp.h>
0017 #include <linux/fs.h>
0018 #include <linux/types.h>
0019 #include <linux/file.h>
0020 #include <linux/icmpv6.h>
0021 #include <linux/socket.h>
0022 #include <linux/syscalls.h>
0023 #include <linux/filter.h>
0024 #include <linux/compat.h>
0025 #include <linux/security.h>
0026 #include <linux/audit.h>
0027 #include <linux/export.h>
0028 
0029 #include <net/scm.h>
0030 #include <net/sock.h>
0031 #include <net/ip.h>
0032 #include <net/ipv6.h>
0033 #include <linux/uaccess.h>
0034 #include <net/compat.h>
0035 
0036 int __get_compat_msghdr(struct msghdr *kmsg,
0037             struct compat_msghdr *msg,
0038             struct sockaddr __user **save_addr)
0039 {
0040     ssize_t err;
0041 
0042     kmsg->msg_flags = msg->msg_flags;
0043     kmsg->msg_namelen = msg->msg_namelen;
0044 
0045     if (!msg->msg_name)
0046         kmsg->msg_namelen = 0;
0047 
0048     if (kmsg->msg_namelen < 0)
0049         return -EINVAL;
0050 
0051     if (kmsg->msg_namelen > sizeof(struct sockaddr_storage))
0052         kmsg->msg_namelen = sizeof(struct sockaddr_storage);
0053 
0054     kmsg->msg_control_is_user = true;
0055     kmsg->msg_get_inq = 0;
0056     kmsg->msg_control_user = compat_ptr(msg->msg_control);
0057     kmsg->msg_controllen = msg->msg_controllen;
0058 
0059     if (save_addr)
0060         *save_addr = compat_ptr(msg->msg_name);
0061 
0062     if (msg->msg_name && kmsg->msg_namelen) {
0063         if (!save_addr) {
0064             err = move_addr_to_kernel(compat_ptr(msg->msg_name),
0065                           kmsg->msg_namelen,
0066                           kmsg->msg_name);
0067             if (err < 0)
0068                 return err;
0069         }
0070     } else {
0071         kmsg->msg_name = NULL;
0072         kmsg->msg_namelen = 0;
0073     }
0074 
0075     if (msg->msg_iovlen > UIO_MAXIOV)
0076         return -EMSGSIZE;
0077 
0078     kmsg->msg_iocb = NULL;
0079     kmsg->msg_ubuf = NULL;
0080     return 0;
0081 }
0082 
0083 int get_compat_msghdr(struct msghdr *kmsg,
0084               struct compat_msghdr __user *umsg,
0085               struct sockaddr __user **save_addr,
0086               struct iovec **iov)
0087 {
0088     struct compat_msghdr msg;
0089     ssize_t err;
0090 
0091     if (copy_from_user(&msg, umsg, sizeof(*umsg)))
0092         return -EFAULT;
0093 
0094     err = __get_compat_msghdr(kmsg, &msg, save_addr);
0095     if (err)
0096         return err;
0097 
0098     err = import_iovec(save_addr ? READ : WRITE, compat_ptr(msg.msg_iov), msg.msg_iovlen,
0099                UIO_FASTIOV, iov, &kmsg->msg_iter);
0100     return err < 0 ? err : 0;
0101 }
0102 
0103 /* Bleech... */
0104 #define CMSG_COMPAT_ALIGN(len)  ALIGN((len), sizeof(s32))
0105 
0106 #define CMSG_COMPAT_DATA(cmsg)              \
0107     ((void __user *)((char __user *)(cmsg) + sizeof(struct compat_cmsghdr)))
0108 #define CMSG_COMPAT_SPACE(len)              \
0109     (sizeof(struct compat_cmsghdr) + CMSG_COMPAT_ALIGN(len))
0110 #define CMSG_COMPAT_LEN(len)                \
0111     (sizeof(struct compat_cmsghdr) + (len))
0112 
0113 #define CMSG_COMPAT_FIRSTHDR(msg)           \
0114     (((msg)->msg_controllen) >= sizeof(struct compat_cmsghdr) ? \
0115      (struct compat_cmsghdr __user *)((msg)->msg_control) :     \
0116      (struct compat_cmsghdr __user *)NULL)
0117 
0118 #define CMSG_COMPAT_OK(ucmlen, ucmsg, mhdr) \
0119     ((ucmlen) >= sizeof(struct compat_cmsghdr) && \
0120      (ucmlen) <= (unsigned long) \
0121      ((mhdr)->msg_controllen - \
0122       ((char __user *)(ucmsg) - (char __user *)(mhdr)->msg_control_user)))
0123 
0124 static inline struct compat_cmsghdr __user *cmsg_compat_nxthdr(struct msghdr *msg,
0125         struct compat_cmsghdr __user *cmsg, int cmsg_len)
0126 {
0127     char __user *ptr = (char __user *)cmsg + CMSG_COMPAT_ALIGN(cmsg_len);
0128     if ((unsigned long)(ptr + 1 - (char __user *)msg->msg_control) >
0129             msg->msg_controllen)
0130         return NULL;
0131     return (struct compat_cmsghdr __user *)ptr;
0132 }
0133 
0134 /* There is a lot of hair here because the alignment rules (and
0135  * thus placement) of cmsg headers and length are different for
0136  * 32-bit apps.  -DaveM
0137  */
0138 int cmsghdr_from_user_compat_to_kern(struct msghdr *kmsg, struct sock *sk,
0139                    unsigned char *stackbuf, int stackbuf_size)
0140 {
0141     struct compat_cmsghdr __user *ucmsg;
0142     struct cmsghdr *kcmsg, *kcmsg_base;
0143     compat_size_t ucmlen;
0144     __kernel_size_t kcmlen, tmp;
0145     int err = -EFAULT;
0146 
0147     BUILD_BUG_ON(sizeof(struct compat_cmsghdr) !=
0148              CMSG_COMPAT_ALIGN(sizeof(struct compat_cmsghdr)));
0149 
0150     kcmlen = 0;
0151     kcmsg_base = kcmsg = (struct cmsghdr *)stackbuf;
0152     ucmsg = CMSG_COMPAT_FIRSTHDR(kmsg);
0153     while (ucmsg != NULL) {
0154         if (get_user(ucmlen, &ucmsg->cmsg_len))
0155             return -EFAULT;
0156 
0157         /* Catch bogons. */
0158         if (!CMSG_COMPAT_OK(ucmlen, ucmsg, kmsg))
0159             return -EINVAL;
0160 
0161         tmp = ((ucmlen - sizeof(*ucmsg)) + sizeof(struct cmsghdr));
0162         tmp = CMSG_ALIGN(tmp);
0163         kcmlen += tmp;
0164         ucmsg = cmsg_compat_nxthdr(kmsg, ucmsg, ucmlen);
0165     }
0166     if (kcmlen == 0)
0167         return -EINVAL;
0168 
0169     /* The kcmlen holds the 64-bit version of the control length.
0170      * It may not be modified as we do not stick it into the kmsg
0171      * until we have successfully copied over all of the data
0172      * from the user.
0173      */
0174     if (kcmlen > stackbuf_size)
0175         kcmsg_base = kcmsg = sock_kmalloc(sk, kcmlen, GFP_KERNEL);
0176     if (kcmsg == NULL)
0177         return -ENOMEM;
0178 
0179     /* Now copy them over neatly. */
0180     memset(kcmsg, 0, kcmlen);
0181     ucmsg = CMSG_COMPAT_FIRSTHDR(kmsg);
0182     while (ucmsg != NULL) {
0183         struct compat_cmsghdr cmsg;
0184         if (copy_from_user(&cmsg, ucmsg, sizeof(cmsg)))
0185             goto Efault;
0186         if (!CMSG_COMPAT_OK(cmsg.cmsg_len, ucmsg, kmsg))
0187             goto Einval;
0188         tmp = ((cmsg.cmsg_len - sizeof(*ucmsg)) + sizeof(struct cmsghdr));
0189         if ((char *)kcmsg_base + kcmlen - (char *)kcmsg < CMSG_ALIGN(tmp))
0190             goto Einval;
0191         kcmsg->cmsg_len = tmp;
0192         kcmsg->cmsg_level = cmsg.cmsg_level;
0193         kcmsg->cmsg_type = cmsg.cmsg_type;
0194         tmp = CMSG_ALIGN(tmp);
0195         if (copy_from_user(CMSG_DATA(kcmsg),
0196                    CMSG_COMPAT_DATA(ucmsg),
0197                    (cmsg.cmsg_len - sizeof(*ucmsg))))
0198             goto Efault;
0199 
0200         /* Advance. */
0201         kcmsg = (struct cmsghdr *)((char *)kcmsg + tmp);
0202         ucmsg = cmsg_compat_nxthdr(kmsg, ucmsg, cmsg.cmsg_len);
0203     }
0204 
0205     /*
0206      * check the length of messages copied in is the same as the
0207      * what we get from the first loop
0208      */
0209     if ((char *)kcmsg - (char *)kcmsg_base != kcmlen)
0210         goto Einval;
0211 
0212     /* Ok, looks like we made it.  Hook it up and return success. */
0213     kmsg->msg_control = kcmsg_base;
0214     kmsg->msg_controllen = kcmlen;
0215     return 0;
0216 
0217 Einval:
0218     err = -EINVAL;
0219 Efault:
0220     if (kcmsg_base != (struct cmsghdr *)stackbuf)
0221         sock_kfree_s(sk, kcmsg_base, kcmlen);
0222     return err;
0223 }
0224 
0225 int put_cmsg_compat(struct msghdr *kmsg, int level, int type, int len, void *data)
0226 {
0227     struct compat_cmsghdr __user *cm = (struct compat_cmsghdr __user *) kmsg->msg_control;
0228     struct compat_cmsghdr cmhdr;
0229     struct old_timeval32 ctv;
0230     struct old_timespec32 cts[3];
0231     int cmlen;
0232 
0233     if (cm == NULL || kmsg->msg_controllen < sizeof(*cm)) {
0234         kmsg->msg_flags |= MSG_CTRUNC;
0235         return 0; /* XXX: return error? check spec. */
0236     }
0237 
0238     if (!COMPAT_USE_64BIT_TIME) {
0239         if (level == SOL_SOCKET && type == SO_TIMESTAMP_OLD) {
0240             struct __kernel_old_timeval *tv = (struct __kernel_old_timeval *)data;
0241             ctv.tv_sec = tv->tv_sec;
0242             ctv.tv_usec = tv->tv_usec;
0243             data = &ctv;
0244             len = sizeof(ctv);
0245         }
0246         if (level == SOL_SOCKET &&
0247             (type == SO_TIMESTAMPNS_OLD || type == SO_TIMESTAMPING_OLD)) {
0248             int count = type == SO_TIMESTAMPNS_OLD ? 1 : 3;
0249             int i;
0250             struct __kernel_old_timespec *ts = data;
0251             for (i = 0; i < count; i++) {
0252                 cts[i].tv_sec = ts[i].tv_sec;
0253                 cts[i].tv_nsec = ts[i].tv_nsec;
0254             }
0255             data = &cts;
0256             len = sizeof(cts[0]) * count;
0257         }
0258     }
0259 
0260     cmlen = CMSG_COMPAT_LEN(len);
0261     if (kmsg->msg_controllen < cmlen) {
0262         kmsg->msg_flags |= MSG_CTRUNC;
0263         cmlen = kmsg->msg_controllen;
0264     }
0265     cmhdr.cmsg_level = level;
0266     cmhdr.cmsg_type = type;
0267     cmhdr.cmsg_len = cmlen;
0268 
0269     if (copy_to_user(cm, &cmhdr, sizeof cmhdr))
0270         return -EFAULT;
0271     if (copy_to_user(CMSG_COMPAT_DATA(cm), data, cmlen - sizeof(struct compat_cmsghdr)))
0272         return -EFAULT;
0273     cmlen = CMSG_COMPAT_SPACE(len);
0274     if (kmsg->msg_controllen < cmlen)
0275         cmlen = kmsg->msg_controllen;
0276     kmsg->msg_control += cmlen;
0277     kmsg->msg_controllen -= cmlen;
0278     return 0;
0279 }
0280 
0281 static int scm_max_fds_compat(struct msghdr *msg)
0282 {
0283     if (msg->msg_controllen <= sizeof(struct compat_cmsghdr))
0284         return 0;
0285     return (msg->msg_controllen - sizeof(struct compat_cmsghdr)) / sizeof(int);
0286 }
0287 
0288 void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm)
0289 {
0290     struct compat_cmsghdr __user *cm =
0291         (struct compat_cmsghdr __user *)msg->msg_control;
0292     unsigned int o_flags = (msg->msg_flags & MSG_CMSG_CLOEXEC) ? O_CLOEXEC : 0;
0293     int fdmax = min_t(int, scm_max_fds_compat(msg), scm->fp->count);
0294     int __user *cmsg_data = CMSG_COMPAT_DATA(cm);
0295     int err = 0, i;
0296 
0297     for (i = 0; i < fdmax; i++) {
0298         err = receive_fd_user(scm->fp->fp[i], cmsg_data + i, o_flags);
0299         if (err < 0)
0300             break;
0301     }
0302 
0303     if (i > 0) {
0304         int cmlen = CMSG_COMPAT_LEN(i * sizeof(int));
0305 
0306         err = put_user(SOL_SOCKET, &cm->cmsg_level);
0307         if (!err)
0308             err = put_user(SCM_RIGHTS, &cm->cmsg_type);
0309         if (!err)
0310             err = put_user(cmlen, &cm->cmsg_len);
0311         if (!err) {
0312             cmlen = CMSG_COMPAT_SPACE(i * sizeof(int));
0313             if (msg->msg_controllen < cmlen)
0314                 cmlen = msg->msg_controllen;
0315             msg->msg_control += cmlen;
0316             msg->msg_controllen -= cmlen;
0317         }
0318     }
0319 
0320     if (i < scm->fp->count || (scm->fp->count && fdmax <= 0))
0321         msg->msg_flags |= MSG_CTRUNC;
0322 
0323     /*
0324      * All of the files that fit in the message have had their usage counts
0325      * incremented, so we just free the list.
0326      */
0327     __scm_destroy(scm);
0328 }
0329 
0330 /* Argument list sizes for compat_sys_socketcall */
0331 #define AL(x) ((x) * sizeof(u32))
0332 static unsigned char nas[21] = {
0333     AL(0), AL(3), AL(3), AL(3), AL(2), AL(3),
0334     AL(3), AL(3), AL(4), AL(4), AL(4), AL(6),
0335     AL(6), AL(2), AL(5), AL(5), AL(3), AL(3),
0336     AL(4), AL(5), AL(4)
0337 };
0338 #undef AL
0339 
0340 static inline long __compat_sys_sendmsg(int fd,
0341                     struct compat_msghdr __user *msg,
0342                     unsigned int flags)
0343 {
0344     return __sys_sendmsg(fd, (struct user_msghdr __user *)msg,
0345                  flags | MSG_CMSG_COMPAT, false);
0346 }
0347 
0348 COMPAT_SYSCALL_DEFINE3(sendmsg, int, fd, struct compat_msghdr __user *, msg,
0349                unsigned int, flags)
0350 {
0351     return __compat_sys_sendmsg(fd, msg, flags);
0352 }
0353 
0354 static inline long __compat_sys_sendmmsg(int fd,
0355                      struct compat_mmsghdr __user *mmsg,
0356                      unsigned int vlen, unsigned int flags)
0357 {
0358     return __sys_sendmmsg(fd, (struct mmsghdr __user *)mmsg, vlen,
0359                   flags | MSG_CMSG_COMPAT, false);
0360 }
0361 
0362 COMPAT_SYSCALL_DEFINE4(sendmmsg, int, fd, struct compat_mmsghdr __user *, mmsg,
0363                unsigned int, vlen, unsigned int, flags)
0364 {
0365     return __compat_sys_sendmmsg(fd, mmsg, vlen, flags);
0366 }
0367 
0368 static inline long __compat_sys_recvmsg(int fd,
0369                     struct compat_msghdr __user *msg,
0370                     unsigned int flags)
0371 {
0372     return __sys_recvmsg(fd, (struct user_msghdr __user *)msg,
0373                  flags | MSG_CMSG_COMPAT, false);
0374 }
0375 
0376 COMPAT_SYSCALL_DEFINE3(recvmsg, int, fd, struct compat_msghdr __user *, msg,
0377                unsigned int, flags)
0378 {
0379     return __compat_sys_recvmsg(fd, msg, flags);
0380 }
0381 
0382 static inline long __compat_sys_recvfrom(int fd, void __user *buf,
0383                      compat_size_t len, unsigned int flags,
0384                      struct sockaddr __user *addr,
0385                      int __user *addrlen)
0386 {
0387     return __sys_recvfrom(fd, buf, len, flags | MSG_CMSG_COMPAT, addr,
0388                   addrlen);
0389 }
0390 
0391 COMPAT_SYSCALL_DEFINE4(recv, int, fd, void __user *, buf, compat_size_t, len, unsigned int, flags)
0392 {
0393     return __compat_sys_recvfrom(fd, buf, len, flags, NULL, NULL);
0394 }
0395 
0396 COMPAT_SYSCALL_DEFINE6(recvfrom, int, fd, void __user *, buf, compat_size_t, len,
0397                unsigned int, flags, struct sockaddr __user *, addr,
0398                int __user *, addrlen)
0399 {
0400     return __compat_sys_recvfrom(fd, buf, len, flags, addr, addrlen);
0401 }
0402 
0403 COMPAT_SYSCALL_DEFINE5(recvmmsg_time64, int, fd, struct compat_mmsghdr __user *, mmsg,
0404                unsigned int, vlen, unsigned int, flags,
0405                struct __kernel_timespec __user *, timeout)
0406 {
0407     return __sys_recvmmsg(fd, (struct mmsghdr __user *)mmsg, vlen,
0408                   flags | MSG_CMSG_COMPAT, timeout, NULL);
0409 }
0410 
0411 #ifdef CONFIG_COMPAT_32BIT_TIME
0412 COMPAT_SYSCALL_DEFINE5(recvmmsg_time32, int, fd, struct compat_mmsghdr __user *, mmsg,
0413                unsigned int, vlen, unsigned int, flags,
0414                struct old_timespec32 __user *, timeout)
0415 {
0416     return __sys_recvmmsg(fd, (struct mmsghdr __user *)mmsg, vlen,
0417                   flags | MSG_CMSG_COMPAT, NULL, timeout);
0418 }
0419 #endif
0420 
0421 COMPAT_SYSCALL_DEFINE2(socketcall, int, call, u32 __user *, args)
0422 {
0423     u32 a[AUDITSC_ARGS];
0424     unsigned int len;
0425     u32 a0, a1;
0426     int ret;
0427 
0428     if (call < SYS_SOCKET || call > SYS_SENDMMSG)
0429         return -EINVAL;
0430     len = nas[call];
0431     if (len > sizeof(a))
0432         return -EINVAL;
0433 
0434     if (copy_from_user(a, args, len))
0435         return -EFAULT;
0436 
0437     ret = audit_socketcall_compat(len / sizeof(a[0]), a);
0438     if (ret)
0439         return ret;
0440 
0441     a0 = a[0];
0442     a1 = a[1];
0443 
0444     switch (call) {
0445     case SYS_SOCKET:
0446         ret = __sys_socket(a0, a1, a[2]);
0447         break;
0448     case SYS_BIND:
0449         ret = __sys_bind(a0, compat_ptr(a1), a[2]);
0450         break;
0451     case SYS_CONNECT:
0452         ret = __sys_connect(a0, compat_ptr(a1), a[2]);
0453         break;
0454     case SYS_LISTEN:
0455         ret = __sys_listen(a0, a1);
0456         break;
0457     case SYS_ACCEPT:
0458         ret = __sys_accept4(a0, compat_ptr(a1), compat_ptr(a[2]), 0);
0459         break;
0460     case SYS_GETSOCKNAME:
0461         ret = __sys_getsockname(a0, compat_ptr(a1), compat_ptr(a[2]));
0462         break;
0463     case SYS_GETPEERNAME:
0464         ret = __sys_getpeername(a0, compat_ptr(a1), compat_ptr(a[2]));
0465         break;
0466     case SYS_SOCKETPAIR:
0467         ret = __sys_socketpair(a0, a1, a[2], compat_ptr(a[3]));
0468         break;
0469     case SYS_SEND:
0470         ret = __sys_sendto(a0, compat_ptr(a1), a[2], a[3], NULL, 0);
0471         break;
0472     case SYS_SENDTO:
0473         ret = __sys_sendto(a0, compat_ptr(a1), a[2], a[3],
0474                    compat_ptr(a[4]), a[5]);
0475         break;
0476     case SYS_RECV:
0477         ret = __compat_sys_recvfrom(a0, compat_ptr(a1), a[2], a[3],
0478                         NULL, NULL);
0479         break;
0480     case SYS_RECVFROM:
0481         ret = __compat_sys_recvfrom(a0, compat_ptr(a1), a[2], a[3],
0482                         compat_ptr(a[4]),
0483                         compat_ptr(a[5]));
0484         break;
0485     case SYS_SHUTDOWN:
0486         ret = __sys_shutdown(a0, a1);
0487         break;
0488     case SYS_SETSOCKOPT:
0489         ret = __sys_setsockopt(a0, a1, a[2], compat_ptr(a[3]), a[4]);
0490         break;
0491     case SYS_GETSOCKOPT:
0492         ret = __sys_getsockopt(a0, a1, a[2], compat_ptr(a[3]),
0493                        compat_ptr(a[4]));
0494         break;
0495     case SYS_SENDMSG:
0496         ret = __compat_sys_sendmsg(a0, compat_ptr(a1), a[2]);
0497         break;
0498     case SYS_SENDMMSG:
0499         ret = __compat_sys_sendmmsg(a0, compat_ptr(a1), a[2], a[3]);
0500         break;
0501     case SYS_RECVMSG:
0502         ret = __compat_sys_recvmsg(a0, compat_ptr(a1), a[2]);
0503         break;
0504     case SYS_RECVMMSG:
0505         ret = __sys_recvmmsg(a0, compat_ptr(a1), a[2],
0506                      a[3] | MSG_CMSG_COMPAT, NULL,
0507                      compat_ptr(a[4]));
0508         break;
0509     case SYS_ACCEPT4:
0510         ret = __sys_accept4(a0, compat_ptr(a1), compat_ptr(a[2]), a[3]);
0511         break;
0512     default:
0513         ret = -EINVAL;
0514         break;
0515     }
0516     return ret;
0517 }
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