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#ifndef _GNU_SOURCE
#define _GNU_SOURCE 1
#endif
#include <errno.h>
#include <fcntl.h>
#include <grp.h>
#include <limits.h>
#include <poll.h>
#include <pty.h>
#include <pwd.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/stat.h>
#include <sys/socket.h>
#include <sys/types.h>
#include <sys/un.h>
#include "unixfd.h"
#include "../../shared/cgo/memory_utils.h"
int lxc_abstract_unix_send_fds(int fd, int *sendfds, int num_sendfds,
void *data, size_t size)
{
__do_free char *cmsgbuf = NULL;
struct msghdr msg;
struct iovec iov;
struct cmsghdr *cmsg = NULL;
char buf[1] = {0};
size_t cmsgbufsize = CMSG_SPACE(num_sendfds * sizeof(int));
memset(&msg, 0, sizeof(msg));
memset(&iov, 0, sizeof(iov));
cmsgbuf = malloc(cmsgbufsize);
if (!cmsgbuf)
return -1;
msg.msg_control = cmsgbuf;
msg.msg_controllen = cmsgbufsize;
cmsg = CMSG_FIRSTHDR(&msg);
cmsg->cmsg_level = SOL_SOCKET;
cmsg->cmsg_type = SCM_RIGHTS;
cmsg->cmsg_len = CMSG_LEN(num_sendfds * sizeof(int));
msg.msg_controllen = cmsg->cmsg_len;
memcpy(CMSG_DATA(cmsg), sendfds, num_sendfds * sizeof(int));
iov.iov_base = data ? data : buf;
iov.iov_len = data ? size : sizeof(buf);
msg.msg_iov = &iov;
msg.msg_iovlen = 1;
return sendmsg(fd, &msg, MSG_NOSIGNAL);
}
ssize_t lxc_abstract_unix_recv_fds_iov(int fd, struct unix_fds *ret_fds,
struct iovec *ret_iov, size_t size_ret_iov)
{
__do_free char *cmsgbuf = NULL;
ssize_t ret;
struct msghdr msg = {};
struct cmsghdr *cmsg = NULL;
size_t cmsgbufsize = CMSG_SPACE(sizeof(struct ucred)) +
CMSG_SPACE(ret_fds->fd_count_max * sizeof(int));
if (ret_fds->flags & ~UNIX_FDS_ACCEPT_MASK)
return ret_errno(EINVAL);
if (hweight32((ret_fds->flags & ~UNIX_FDS_ACCEPT_NONE)) > 1)
return ret_errno(EINVAL);
if (ret_fds->fd_count_max >= KERNEL_SCM_MAX_FD)
return ret_errno(EINVAL);
if (ret_fds->fd_count_ret != 0)
return ret_errno(EINVAL);
cmsgbuf = zalloc(cmsgbufsize);
if (!cmsgbuf)
return ret_errno(ENOMEM);
msg.msg_control = cmsgbuf;
msg.msg_controllen = cmsgbufsize;
msg.msg_iov = ret_iov;
msg.msg_iovlen = size_ret_iov;
again:
ret = recvmsg(fd, &msg, MSG_CMSG_CLOEXEC);
if (ret < 0) {
if (errno == EINTR)
goto again;
return -errno;
}
if (ret == 0)
return 0;
/* If SO_PASSCRED is set we will always get a ucred message. */
for (cmsg = CMSG_FIRSTHDR(&msg); cmsg; cmsg = CMSG_NXTHDR(&msg, cmsg)) {
if (cmsg->cmsg_level == SOL_SOCKET && cmsg->cmsg_type == SCM_RIGHTS) {
__u32 idx;
/*
* This causes some compilers to complain about
* increased alignment requirements but I haven't found
* a better way to deal with this yet. Suggestions
* welcome!
*/
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wcast-align"
int *fds_raw = (int *)CMSG_DATA(cmsg);
#pragma GCC diagnostic pop
__u32 num_raw = (cmsg->cmsg_len - CMSG_LEN(0)) / sizeof(int);
/*
* We received an insane amount of file descriptors
* which exceeds the kernel limit we know about so
* close them and return an error.
*/
if (num_raw >= KERNEL_SCM_MAX_FD) {
for (idx = 0; idx < num_raw; idx++)
close(fds_raw[idx]);
return -EFBIG;
}
if (msg.msg_flags & MSG_CTRUNC) {
for (idx = 0; idx < num_raw; idx++)
close(fds_raw[idx]);
return -EFBIG;
}
if (ret_fds->fd_count_max > num_raw) {
if (!(ret_fds->flags & UNIX_FDS_ACCEPT_LESS)) {
for (idx = 0; idx < num_raw; idx++)
close(fds_raw[idx]);
return -EINVAL;
}
/*
* Make sure any excess entries in the fd array
* are set to -EBADF so our cleanup functions
* can safely be called.
*/
for (idx = num_raw; idx < ret_fds->fd_count_max; idx++)
ret_fds->fd[idx] = -EBADF;
ret_fds->flags |= UNIX_FDS_RECEIVED_LESS;
} else if (ret_fds->fd_count_max < num_raw) {
if (!(ret_fds->flags & UNIX_FDS_ACCEPT_MORE)) {
for (idx = 0; idx < num_raw; idx++)
close(fds_raw[idx]);
return -EINVAL;
}
/* Make sure we close any excess fds we received. */
for (idx = ret_fds->fd_count_max; idx < num_raw; idx++)
close(fds_raw[idx]);
/* Cap the number of received file descriptors. */
num_raw = ret_fds->fd_count_max;
ret_fds->flags |= UNIX_FDS_RECEIVED_MORE;
} else {
ret_fds->flags |= UNIX_FDS_RECEIVED_EXACT;
}
if (hweight32((ret_fds->flags & ~UNIX_FDS_ACCEPT_MASK)) > 1) {
for (idx = 0; idx < num_raw; idx++)
close(fds_raw[idx]);
return -EINVAL;
}
memcpy(ret_fds->fd, CMSG_DATA(cmsg), num_raw * sizeof(int));
ret_fds->fd_count_ret = num_raw;
break;
}
}
if (ret_fds->fd_count_ret == 0) {
ret_fds->flags |= UNIX_FDS_RECEIVED_NONE;
/* We expected to receive file descriptors. */
if ((ret_fds->flags & UNIX_FDS_ACCEPT_MASK) &&
!(ret_fds->flags & UNIX_FDS_ACCEPT_NONE))
return -EINVAL;
}
return ret;
}
ssize_t lxc_abstract_unix_recv_fds(int fd, struct unix_fds *ret_fds,
void *ret_data, size_t size_ret_data)
{
char buf[1] = {};
struct iovec iov = {
.iov_base = ret_data ? ret_data : buf,
.iov_len = ret_data ? size_ret_data : sizeof(buf),
};
ssize_t ret;
ret = lxc_abstract_unix_recv_fds_iov(fd, ret_fds, &iov, 1);
if (ret < 0)
return ret;
return ret;
}
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