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/* Copyright (C) 2001-2018 Free Software Foundation, Inc.
This file is part of the GNU C Library.
The GNU C Library is free software; you can redistribute it and/or
modify it under the terms of the GNU Lesser General Public License as
published by the Free Software Foundation; either version 2.1 of the
License, or (at your option) any later version.
The GNU C Library is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
Lesser General Public License for more details.
You should have received a copy of the GNU Lesser General Public
License along with the GNU C Library; see the file COPYING.LIB. If
not, see <http://www.gnu.org/licenses/>. */
#include <errno.h>
#include <string.h>
#include <sys/socket.h>
#include <hurd.h>
#include <hurd/fd.h>
#include <hurd/socket.h>
static unsigned
contains_uid (unsigned int n, __uid_t uids[n], __uid_t uid)
{
unsigned i;
for (i = 0; i < n; i++)
if (uids[i] == uid)
return 1;
return 0;
}
static unsigned
contains_gid (unsigned int n, __gid_t gids[n], __gid_t gid)
{
unsigned i;
for (i = 0; i < n; i++)
if (gids[i] == gid)
return 1;
return 0;
}
/* Check the passed credentials. */
static error_t
check_auth (mach_port_t rendezvous,
__pid_t pid,
__uid_t uid, __uid_t euid,
__gid_t gid,
int ngroups, __gid_t groups[ngroups])
{
error_t err;
size_t neuids = CMGROUP_MAX, nauids = CMGROUP_MAX;
size_t negids = CMGROUP_MAX, nagids = CMGROUP_MAX;
__uid_t euids_buf[neuids], auids_buf[nauids];
__gid_t egids_buf[negids], agids_buf[nagids];
__uid_t *euids = euids_buf, *auids = auids_buf;
__gid_t *egids = egids_buf, *agids = agids_buf;
struct procinfo *pi = NULL;
mach_msg_type_number_t pi_size = 0;
int flags = PI_FETCH_TASKINFO;
char *tw = NULL;
size_t tw_size = 0;
unsigned i;
err = __mach_port_mod_refs (mach_task_self (), rendezvous,
MACH_PORT_RIGHT_SEND, 1);
if (err)
goto out;
do
err = __USEPORT
(AUTH, __auth_server_authenticate (port,
rendezvous, MACH_MSG_TYPE_COPY_SEND,
MACH_PORT_NULL, 0,
&euids, &neuids, &auids, &nauids,
&egids, &negids, &agids, &nagids));
while (err == EINTR);
if (err)
goto out;
/* Check whether this process indeed has these IDs */
if ( !contains_uid (neuids, euids, uid)
&& !contains_uid (nauids, auids, uid)
|| !contains_uid (neuids, euids, euid)
&& !contains_uid (nauids, auids, euid)
|| !contains_gid (negids, egids, gid)
&& !contains_gid (nagids, agids, gid)
)
{
err = EIO;
goto out;
}
/* Check groups */
for (i = 0; i < ngroups; i++)
if ( !contains_gid (negids, egids, groups[i])
&& !contains_gid (nagids, agids, groups[i]))
{
err = EIO;
goto out;
}
/* Check PID */
/* XXX: Using proc_getprocinfo until
proc_user_authenticate proc_server_authenticate is implemented
*/
/* Get procinfo to check the owner. Maybe he faked the pid, but at least we
check the owner. */
err = __USEPORT (PROC, __proc_getprocinfo (port, pid, &flags,
(procinfo_t *)&pi,
&pi_size, &tw, &tw_size));
if (err)
goto out;
if ( !contains_uid (neuids, euids, pi->owner)
&& !contains_uid (nauids, auids, pi->owner))
err = EIO;
out:
__mach_port_deallocate (__mach_task_self (), rendezvous);
if (euids != euids_buf)
__vm_deallocate (__mach_task_self(), (vm_address_t) euids, neuids * sizeof(uid_t));
if (auids != auids_buf)
__vm_deallocate (__mach_task_self(), (vm_address_t) auids, nauids * sizeof(uid_t));
if (egids != egids_buf)
__vm_deallocate (__mach_task_self(), (vm_address_t) egids, negids * sizeof(uid_t));
if (agids != agids_buf)
__vm_deallocate (__mach_task_self(), (vm_address_t) agids, nagids * sizeof(uid_t));
if (tw_size)
__vm_deallocate (__mach_task_self(), (vm_address_t) tw, tw_size);
if (pi_size)
__vm_deallocate (__mach_task_self(), (vm_address_t) pi, pi_size);
return err;
}
/* Receive a message as described by MESSAGE from socket FD.
Returns the number of bytes read or -1 for errors. */
ssize_t
__libc_recvmsg (int fd, struct msghdr *message, int flags)
{
error_t err;
addr_port_t aport;
char *data = NULL;
mach_msg_type_number_t len = 0;
mach_port_t *ports, *newports = NULL;
mach_msg_type_number_t nports = 0;
struct cmsghdr *cmsg;
char *cdata = NULL;
mach_msg_type_number_t clen = 0;
size_t amount;
char *buf;
int nfds, *opened_fds = NULL;
int i, ii, j;
int newfds;
error_t reauthenticate (mach_port_t port, mach_port_t *result)
{
error_t err;
mach_port_t ref;
ref = __mach_reply_port ();
do
err = __io_reauthenticate (port, ref, MACH_MSG_TYPE_MAKE_SEND);
while (err == EINTR);
if (!err)
do
err = __USEPORT (AUTH, __auth_user_authenticate (port,
ref, MACH_MSG_TYPE_MAKE_SEND,
result));
while (err == EINTR);
__mach_port_destroy (__mach_task_self (), ref);
return err;
}
/* Find the total number of bytes to be read. */
amount = 0;
for (i = 0; i < message->msg_iovlen; i++)
{
amount += message->msg_iov[i].iov_len;
/* As an optimization, we set the initial values of DATA and LEN
from the first non-empty iovec. This kicks-in in the case
where the whole packet fits into that iovec buffer. */
if (data == NULL && message->msg_iov[i].iov_len > 0)
{
data = message->msg_iov[i].iov_base;
len = message->msg_iov[i].iov_len;
}
}
buf = data;
if (err = HURD_DPORT_USE (fd, __socket_recv (port, &aport,
flags, &data, &len,
&ports, &nports,
&cdata, &clen,
&message->msg_flags, amount)))
return __hurd_sockfail (fd, flags, err);
if (message->msg_name != NULL && aport != MACH_PORT_NULL)
{
char *buf = message->msg_name;
mach_msg_type_number_t buflen = message->msg_namelen;
int type;
err = __socket_whatis_address (aport, &type, &buf, &buflen);
if (err == EOPNOTSUPP)
/* If the protocol server can't tell us the address, just return a
zero-length one. */
{
buf = message->msg_name;
buflen = 0;
err = 0;
}
if (err)
{
__mach_port_deallocate (__mach_task_self (), aport);
return __hurd_sockfail (fd, flags, err);
}
if (message->msg_namelen > buflen)
message->msg_namelen = buflen;
if (buf != message->msg_name)
{
memcpy (message->msg_name, buf, message->msg_namelen);
__vm_deallocate (__mach_task_self (), (vm_address_t) buf, buflen);
}
if (buflen > 0)
((struct sockaddr *) message->msg_name)->sa_family = type;
}
else if (message->msg_name != NULL)
message->msg_namelen = 0;
__mach_port_deallocate (__mach_task_self (), aport);
if (buf == data)
buf += len;
else
{
/* Copy the data into MSG. */
if (len > amount)
message->msg_flags |= MSG_TRUNC;
else
amount = len;
buf = data;
for (i = 0; i < message->msg_iovlen; i++)
{
#define min(a, b) ((a) > (b) ? (b) : (a))
size_t copy = min (message->msg_iov[i].iov_len, amount);
memcpy (message->msg_iov[i].iov_base, buf, copy);
buf += copy;
amount -= copy;
if (len == 0)
break;
}
__vm_deallocate (__mach_task_self (), (vm_address_t) data, len);
}
/* Copy the control message into MSG. */
if (clen > message->msg_controllen)
message->msg_flags |= MSG_CTRUNC;
else
message->msg_controllen = clen;
memcpy (message->msg_control, cdata, message->msg_controllen);
if (nports > 0)
{
newports = __alloca (nports * sizeof (mach_port_t));
opened_fds = __alloca (nports * sizeof (int));
}
/* This counts how many ports we processed completely. */
i = 0;
/* This counts how many new fds we create. */
newfds = 0;
for (cmsg = CMSG_FIRSTHDR (message);
cmsg;
cmsg = CMSG_NXTHDR (message, cmsg))
{
if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS)
{
/* SCM_RIGHTS support. */
/* The fd's flags are passed in the control data. */
int *fds = (int *) CMSG_DATA (cmsg);
nfds = (cmsg->cmsg_len - CMSG_ALIGN (sizeof (struct cmsghdr)))
/ sizeof (int);
for (j = 0; j < nfds; j++)
{
err = reauthenticate (ports[i], &newports[newfds]);
if (err)
goto cleanup;
fds[j] = opened_fds[newfds] = _hurd_intern_fd (newports[newfds],
fds[j], 0);
if (fds[j] == -1)
{
err = errno;
__mach_port_deallocate (__mach_task_self (), newports[newfds]);
goto cleanup;
}
i++;
newfds++;
}
}
else if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_CREDS)
{
/* SCM_CREDS support. */
/* Check received credentials */
struct cmsgcred *ucredp = (struct cmsgcred *) CMSG_DATA(cmsg);
err = check_auth (ports[i],
ucredp->cmcred_pid,
ucredp->cmcred_uid, ucredp->cmcred_euid,
ucredp->cmcred_gid,
ucredp->cmcred_ngroups, ucredp->cmcred_groups);
if (err)
goto cleanup;
i++;
}
}
for (i = 0; i < nports; i++)
__mach_port_deallocate (mach_task_self (), ports[i]);
__vm_deallocate (__mach_task_self (), (vm_address_t) cdata, clen);
return (buf - data);
cleanup:
/* Clean up all the file descriptors from port 0 to i-1. */
if (nports > 0)
{
ii = 0;
newfds = 0;
for (cmsg = CMSG_FIRSTHDR (message);
cmsg;
cmsg = CMSG_NXTHDR (message, cmsg))
{
if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS)
{
nfds = (cmsg->cmsg_len - CMSG_ALIGN (sizeof (struct cmsghdr)))
/ sizeof (int);
for (j = 0; j < nfds && ii < i; j++, ii++, newfds++)
{
_hurd_fd_close (_hurd_fd_get (opened_fds[newfds]));
__mach_port_deallocate (__mach_task_self (), newports[newfds]);
__mach_port_deallocate (__mach_task_self (), ports[ii]);
}
}
else if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_CREDS)
{
__mach_port_deallocate (__mach_task_self (), ports[ii]);
ii++;
}
}
}
__vm_deallocate (__mach_task_self (), (vm_address_t) cdata, clen);
return __hurd_fail (err);
}
weak_alias (__libc_recvmsg, recvmsg)
weak_alias (__libc_recvmsg, __recvmsg)
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