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linux-next/net/compat.c
Kevin Brodsky 60daf8d40b net/compat: Update msg_control_is_user when setting a kernel pointer
cmsghdr_from_user_compat_to_kern() is an unusual case w.r.t. how
the kmsg->msg_control* fields are used. The input struct msghdr
holds a pointer to a user buffer, i.e. ksmg->msg_control_user is
active. However, upon success, a kernel pointer is stored in
kmsg->msg_control. kmsg->msg_control_is_user should therefore be
updated accordingly.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Eric Dumazet <edumazet@google.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: David S. Miller <davem@davemloft.net>
2023-04-14 11:09:27 +01:00

520 lines
14 KiB
C

// SPDX-License-Identifier: GPL-2.0-only
/*
* 32bit Socket syscall emulation. Based on arch/sparc64/kernel/sys_sparc32.c.
*
* Copyright (C) 2000 VA Linux Co
* Copyright (C) 2000 Don Dugger <n0ano@valinux.com>
* Copyright (C) 1999 Arun Sharma <arun.sharma@intel.com>
* Copyright (C) 1997,1998 Jakub Jelinek (jj@sunsite.mff.cuni.cz)
* Copyright (C) 1997 David S. Miller (davem@caip.rutgers.edu)
* Copyright (C) 2000 Hewlett-Packard Co.
* Copyright (C) 2000 David Mosberger-Tang <davidm@hpl.hp.com>
* Copyright (C) 2000,2001 Andi Kleen, SuSE Labs
*/
#include <linux/kernel.h>
#include <linux/gfp.h>
#include <linux/fs.h>
#include <linux/types.h>
#include <linux/file.h>
#include <linux/icmpv6.h>
#include <linux/socket.h>
#include <linux/syscalls.h>
#include <linux/filter.h>
#include <linux/compat.h>
#include <linux/security.h>
#include <linux/audit.h>
#include <linux/export.h>
#include <net/scm.h>
#include <net/sock.h>
#include <net/ip.h>
#include <net/ipv6.h>
#include <linux/uaccess.h>
#include <net/compat.h>
int __get_compat_msghdr(struct msghdr *kmsg,
struct compat_msghdr *msg,
struct sockaddr __user **save_addr)
{
ssize_t err;
kmsg->msg_flags = msg->msg_flags;
kmsg->msg_namelen = msg->msg_namelen;
if (!msg->msg_name)
kmsg->msg_namelen = 0;
if (kmsg->msg_namelen < 0)
return -EINVAL;
if (kmsg->msg_namelen > sizeof(struct sockaddr_storage))
kmsg->msg_namelen = sizeof(struct sockaddr_storage);
kmsg->msg_control_is_user = true;
kmsg->msg_get_inq = 0;
kmsg->msg_control_user = compat_ptr(msg->msg_control);
kmsg->msg_controllen = msg->msg_controllen;
if (save_addr)
*save_addr = compat_ptr(msg->msg_name);
if (msg->msg_name && kmsg->msg_namelen) {
if (!save_addr) {
err = move_addr_to_kernel(compat_ptr(msg->msg_name),
kmsg->msg_namelen,
kmsg->msg_name);
if (err < 0)
return err;
}
} else {
kmsg->msg_name = NULL;
kmsg->msg_namelen = 0;
}
if (msg->msg_iovlen > UIO_MAXIOV)
return -EMSGSIZE;
kmsg->msg_iocb = NULL;
kmsg->msg_ubuf = NULL;
return 0;
}
int get_compat_msghdr(struct msghdr *kmsg,
struct compat_msghdr __user *umsg,
struct sockaddr __user **save_addr,
struct iovec **iov)
{
struct compat_msghdr msg;
ssize_t err;
if (copy_from_user(&msg, umsg, sizeof(*umsg)))
return -EFAULT;
err = __get_compat_msghdr(kmsg, &msg, save_addr);
if (err)
return err;
err = import_iovec(save_addr ? ITER_DEST : ITER_SOURCE,
compat_ptr(msg.msg_iov), msg.msg_iovlen,
UIO_FASTIOV, iov, &kmsg->msg_iter);
return err < 0 ? err : 0;
}
/* Bleech... */
#define CMSG_COMPAT_ALIGN(len) ALIGN((len), sizeof(s32))
#define CMSG_COMPAT_DATA(cmsg) \
((void __user *)((char __user *)(cmsg) + sizeof(struct compat_cmsghdr)))
#define CMSG_COMPAT_SPACE(len) \
(sizeof(struct compat_cmsghdr) + CMSG_COMPAT_ALIGN(len))
#define CMSG_COMPAT_LEN(len) \
(sizeof(struct compat_cmsghdr) + (len))
#define CMSG_COMPAT_FIRSTHDR(msg) \
(((msg)->msg_controllen) >= sizeof(struct compat_cmsghdr) ? \
(struct compat_cmsghdr __user *)((msg)->msg_control_user) : \
(struct compat_cmsghdr __user *)NULL)
#define CMSG_COMPAT_OK(ucmlen, ucmsg, mhdr) \
((ucmlen) >= sizeof(struct compat_cmsghdr) && \
(ucmlen) <= (unsigned long) \
((mhdr)->msg_controllen - \
((char __user *)(ucmsg) - (char __user *)(mhdr)->msg_control_user)))
static inline struct compat_cmsghdr __user *cmsg_compat_nxthdr(struct msghdr *msg,
struct compat_cmsghdr __user *cmsg, int cmsg_len)
{
char __user *ptr = (char __user *)cmsg + CMSG_COMPAT_ALIGN(cmsg_len);
if ((unsigned long)(ptr + 1 - (char __user *)msg->msg_control_user) >
msg->msg_controllen)
return NULL;
return (struct compat_cmsghdr __user *)ptr;
}
/* There is a lot of hair here because the alignment rules (and
* thus placement) of cmsg headers and length are different for
* 32-bit apps. -DaveM
*/
int cmsghdr_from_user_compat_to_kern(struct msghdr *kmsg, struct sock *sk,
unsigned char *stackbuf, int stackbuf_size)
{
struct compat_cmsghdr __user *ucmsg;
struct cmsghdr *kcmsg, *kcmsg_base;
compat_size_t ucmlen;
__kernel_size_t kcmlen, tmp;
int err = -EFAULT;
BUILD_BUG_ON(sizeof(struct compat_cmsghdr) !=
CMSG_COMPAT_ALIGN(sizeof(struct compat_cmsghdr)));
kcmlen = 0;
kcmsg_base = kcmsg = (struct cmsghdr *)stackbuf;
ucmsg = CMSG_COMPAT_FIRSTHDR(kmsg);
while (ucmsg != NULL) {
if (get_user(ucmlen, &ucmsg->cmsg_len))
return -EFAULT;
/* Catch bogons. */
if (!CMSG_COMPAT_OK(ucmlen, ucmsg, kmsg))
return -EINVAL;
tmp = ((ucmlen - sizeof(*ucmsg)) + sizeof(struct cmsghdr));
tmp = CMSG_ALIGN(tmp);
kcmlen += tmp;
ucmsg = cmsg_compat_nxthdr(kmsg, ucmsg, ucmlen);
}
if (kcmlen == 0)
return -EINVAL;
/* The kcmlen holds the 64-bit version of the control length.
* It may not be modified as we do not stick it into the kmsg
* until we have successfully copied over all of the data
* from the user.
*/
if (kcmlen > stackbuf_size)
kcmsg_base = kcmsg = sock_kmalloc(sk, kcmlen, GFP_KERNEL);
if (kcmsg == NULL)
return -ENOMEM;
/* Now copy them over neatly. */
memset(kcmsg, 0, kcmlen);
ucmsg = CMSG_COMPAT_FIRSTHDR(kmsg);
while (ucmsg != NULL) {
struct compat_cmsghdr cmsg;
if (copy_from_user(&cmsg, ucmsg, sizeof(cmsg)))
goto Efault;
if (!CMSG_COMPAT_OK(cmsg.cmsg_len, ucmsg, kmsg))
goto Einval;
tmp = ((cmsg.cmsg_len - sizeof(*ucmsg)) + sizeof(struct cmsghdr));
if ((char *)kcmsg_base + kcmlen - (char *)kcmsg < CMSG_ALIGN(tmp))
goto Einval;
kcmsg->cmsg_len = tmp;
kcmsg->cmsg_level = cmsg.cmsg_level;
kcmsg->cmsg_type = cmsg.cmsg_type;
tmp = CMSG_ALIGN(tmp);
if (copy_from_user(CMSG_DATA(kcmsg),
CMSG_COMPAT_DATA(ucmsg),
(cmsg.cmsg_len - sizeof(*ucmsg))))
goto Efault;
/* Advance. */
kcmsg = (struct cmsghdr *)((char *)kcmsg + tmp);
ucmsg = cmsg_compat_nxthdr(kmsg, ucmsg, cmsg.cmsg_len);
}
/*
* check the length of messages copied in is the same as the
* what we get from the first loop
*/
if ((char *)kcmsg - (char *)kcmsg_base != kcmlen)
goto Einval;
/* Ok, looks like we made it. Hook it up and return success. */
kmsg->msg_control_is_user = false;
kmsg->msg_control = kcmsg_base;
kmsg->msg_controllen = kcmlen;
return 0;
Einval:
err = -EINVAL;
Efault:
if (kcmsg_base != (struct cmsghdr *)stackbuf)
sock_kfree_s(sk, kcmsg_base, kcmlen);
return err;
}
int put_cmsg_compat(struct msghdr *kmsg, int level, int type, int len, void *data)
{
struct compat_cmsghdr __user *cm = (struct compat_cmsghdr __user *) kmsg->msg_control_user;
struct compat_cmsghdr cmhdr;
struct old_timeval32 ctv;
struct old_timespec32 cts[3];
int cmlen;
if (cm == NULL || kmsg->msg_controllen < sizeof(*cm)) {
kmsg->msg_flags |= MSG_CTRUNC;
return 0; /* XXX: return error? check spec. */
}
if (!COMPAT_USE_64BIT_TIME) {
if (level == SOL_SOCKET && type == SO_TIMESTAMP_OLD) {
struct __kernel_old_timeval *tv = (struct __kernel_old_timeval *)data;
ctv.tv_sec = tv->tv_sec;
ctv.tv_usec = tv->tv_usec;
data = &ctv;
len = sizeof(ctv);
}
if (level == SOL_SOCKET &&
(type == SO_TIMESTAMPNS_OLD || type == SO_TIMESTAMPING_OLD)) {
int count = type == SO_TIMESTAMPNS_OLD ? 1 : 3;
int i;
struct __kernel_old_timespec *ts = data;
for (i = 0; i < count; i++) {
cts[i].tv_sec = ts[i].tv_sec;
cts[i].tv_nsec = ts[i].tv_nsec;
}
data = &cts;
len = sizeof(cts[0]) * count;
}
}
cmlen = CMSG_COMPAT_LEN(len);
if (kmsg->msg_controllen < cmlen) {
kmsg->msg_flags |= MSG_CTRUNC;
cmlen = kmsg->msg_controllen;
}
cmhdr.cmsg_level = level;
cmhdr.cmsg_type = type;
cmhdr.cmsg_len = cmlen;
if (copy_to_user(cm, &cmhdr, sizeof cmhdr))
return -EFAULT;
if (copy_to_user(CMSG_COMPAT_DATA(cm), data, cmlen - sizeof(struct compat_cmsghdr)))
return -EFAULT;
cmlen = CMSG_COMPAT_SPACE(len);
if (kmsg->msg_controllen < cmlen)
cmlen = kmsg->msg_controllen;
kmsg->msg_control_user += cmlen;
kmsg->msg_controllen -= cmlen;
return 0;
}
static int scm_max_fds_compat(struct msghdr *msg)
{
if (msg->msg_controllen <= sizeof(struct compat_cmsghdr))
return 0;
return (msg->msg_controllen - sizeof(struct compat_cmsghdr)) / sizeof(int);
}
void scm_detach_fds_compat(struct msghdr *msg, struct scm_cookie *scm)
{
struct compat_cmsghdr __user *cm =
(struct compat_cmsghdr __user *)msg->msg_control_user;
unsigned int o_flags = (msg->msg_flags & MSG_CMSG_CLOEXEC) ? O_CLOEXEC : 0;
int fdmax = min_t(int, scm_max_fds_compat(msg), scm->fp->count);
int __user *cmsg_data = CMSG_COMPAT_DATA(cm);
int err = 0, i;
for (i = 0; i < fdmax; i++) {
err = receive_fd_user(scm->fp->fp[i], cmsg_data + i, o_flags);
if (err < 0)
break;
}
if (i > 0) {
int cmlen = CMSG_COMPAT_LEN(i * sizeof(int));
err = put_user(SOL_SOCKET, &cm->cmsg_level);
if (!err)
err = put_user(SCM_RIGHTS, &cm->cmsg_type);
if (!err)
err = put_user(cmlen, &cm->cmsg_len);
if (!err) {
cmlen = CMSG_COMPAT_SPACE(i * sizeof(int));
if (msg->msg_controllen < cmlen)
cmlen = msg->msg_controllen;
msg->msg_control_user += cmlen;
msg->msg_controllen -= cmlen;
}
}
if (i < scm->fp->count || (scm->fp->count && fdmax <= 0))
msg->msg_flags |= MSG_CTRUNC;
/*
* All of the files that fit in the message have had their usage counts
* incremented, so we just free the list.
*/
__scm_destroy(scm);
}
/* Argument list sizes for compat_sys_socketcall */
#define AL(x) ((x) * sizeof(u32))
static unsigned char nas[21] = {
AL(0), AL(3), AL(3), AL(3), AL(2), AL(3),
AL(3), AL(3), AL(4), AL(4), AL(4), AL(6),
AL(6), AL(2), AL(5), AL(5), AL(3), AL(3),
AL(4), AL(5), AL(4)
};
#undef AL
static inline long __compat_sys_sendmsg(int fd,
struct compat_msghdr __user *msg,
unsigned int flags)
{
return __sys_sendmsg(fd, (struct user_msghdr __user *)msg,
flags | MSG_CMSG_COMPAT, false);
}
COMPAT_SYSCALL_DEFINE3(sendmsg, int, fd, struct compat_msghdr __user *, msg,
unsigned int, flags)
{
return __compat_sys_sendmsg(fd, msg, flags);
}
static inline long __compat_sys_sendmmsg(int fd,
struct compat_mmsghdr __user *mmsg,
unsigned int vlen, unsigned int flags)
{
return __sys_sendmmsg(fd, (struct mmsghdr __user *)mmsg, vlen,
flags | MSG_CMSG_COMPAT, false);
}
COMPAT_SYSCALL_DEFINE4(sendmmsg, int, fd, struct compat_mmsghdr __user *, mmsg,
unsigned int, vlen, unsigned int, flags)
{
return __compat_sys_sendmmsg(fd, mmsg, vlen, flags);
}
static inline long __compat_sys_recvmsg(int fd,
struct compat_msghdr __user *msg,
unsigned int flags)
{
return __sys_recvmsg(fd, (struct user_msghdr __user *)msg,
flags | MSG_CMSG_COMPAT, false);
}
COMPAT_SYSCALL_DEFINE3(recvmsg, int, fd, struct compat_msghdr __user *, msg,
unsigned int, flags)
{
return __compat_sys_recvmsg(fd, msg, flags);
}
static inline long __compat_sys_recvfrom(int fd, void __user *buf,
compat_size_t len, unsigned int flags,
struct sockaddr __user *addr,
int __user *addrlen)
{
return __sys_recvfrom(fd, buf, len, flags | MSG_CMSG_COMPAT, addr,
addrlen);
}
COMPAT_SYSCALL_DEFINE4(recv, int, fd, void __user *, buf, compat_size_t, len, unsigned int, flags)
{
return __compat_sys_recvfrom(fd, buf, len, flags, NULL, NULL);
}
COMPAT_SYSCALL_DEFINE6(recvfrom, int, fd, void __user *, buf, compat_size_t, len,
unsigned int, flags, struct sockaddr __user *, addr,
int __user *, addrlen)
{
return __compat_sys_recvfrom(fd, buf, len, flags, addr, addrlen);
}
COMPAT_SYSCALL_DEFINE5(recvmmsg_time64, int, fd, struct compat_mmsghdr __user *, mmsg,
unsigned int, vlen, unsigned int, flags,
struct __kernel_timespec __user *, timeout)
{
return __sys_recvmmsg(fd, (struct mmsghdr __user *)mmsg, vlen,
flags | MSG_CMSG_COMPAT, timeout, NULL);
}
#ifdef CONFIG_COMPAT_32BIT_TIME
COMPAT_SYSCALL_DEFINE5(recvmmsg_time32, int, fd, struct compat_mmsghdr __user *, mmsg,
unsigned int, vlen, unsigned int, flags,
struct old_timespec32 __user *, timeout)
{
return __sys_recvmmsg(fd, (struct mmsghdr __user *)mmsg, vlen,
flags | MSG_CMSG_COMPAT, NULL, timeout);
}
#endif
COMPAT_SYSCALL_DEFINE2(socketcall, int, call, u32 __user *, args)
{
u32 a[AUDITSC_ARGS];
unsigned int len;
u32 a0, a1;
int ret;
if (call < SYS_SOCKET || call > SYS_SENDMMSG)
return -EINVAL;
len = nas[call];
if (len > sizeof(a))
return -EINVAL;
if (copy_from_user(a, args, len))
return -EFAULT;
ret = audit_socketcall_compat(len / sizeof(a[0]), a);
if (ret)
return ret;
a0 = a[0];
a1 = a[1];
switch (call) {
case SYS_SOCKET:
ret = __sys_socket(a0, a1, a[2]);
break;
case SYS_BIND:
ret = __sys_bind(a0, compat_ptr(a1), a[2]);
break;
case SYS_CONNECT:
ret = __sys_connect(a0, compat_ptr(a1), a[2]);
break;
case SYS_LISTEN:
ret = __sys_listen(a0, a1);
break;
case SYS_ACCEPT:
ret = __sys_accept4(a0, compat_ptr(a1), compat_ptr(a[2]), 0);
break;
case SYS_GETSOCKNAME:
ret = __sys_getsockname(a0, compat_ptr(a1), compat_ptr(a[2]));
break;
case SYS_GETPEERNAME:
ret = __sys_getpeername(a0, compat_ptr(a1), compat_ptr(a[2]));
break;
case SYS_SOCKETPAIR:
ret = __sys_socketpair(a0, a1, a[2], compat_ptr(a[3]));
break;
case SYS_SEND:
ret = __sys_sendto(a0, compat_ptr(a1), a[2], a[3], NULL, 0);
break;
case SYS_SENDTO:
ret = __sys_sendto(a0, compat_ptr(a1), a[2], a[3],
compat_ptr(a[4]), a[5]);
break;
case SYS_RECV:
ret = __compat_sys_recvfrom(a0, compat_ptr(a1), a[2], a[3],
NULL, NULL);
break;
case SYS_RECVFROM:
ret = __compat_sys_recvfrom(a0, compat_ptr(a1), a[2], a[3],
compat_ptr(a[4]),
compat_ptr(a[5]));
break;
case SYS_SHUTDOWN:
ret = __sys_shutdown(a0, a1);
break;
case SYS_SETSOCKOPT:
ret = __sys_setsockopt(a0, a1, a[2], compat_ptr(a[3]), a[4]);
break;
case SYS_GETSOCKOPT:
ret = __sys_getsockopt(a0, a1, a[2], compat_ptr(a[3]),
compat_ptr(a[4]));
break;
case SYS_SENDMSG:
ret = __compat_sys_sendmsg(a0, compat_ptr(a1), a[2]);
break;
case SYS_SENDMMSG:
ret = __compat_sys_sendmmsg(a0, compat_ptr(a1), a[2], a[3]);
break;
case SYS_RECVMSG:
ret = __compat_sys_recvmsg(a0, compat_ptr(a1), a[2]);
break;
case SYS_RECVMMSG:
ret = __sys_recvmmsg(a0, compat_ptr(a1), a[2],
a[3] | MSG_CMSG_COMPAT, NULL,
compat_ptr(a[4]));
break;
case SYS_ACCEPT4:
ret = __sys_accept4(a0, compat_ptr(a1), compat_ptr(a[2]), a[3]);
break;
default:
ret = -EINVAL;
break;
}
return ret;
}