core-agent-linux/qubes-rpc/qopen-in-vm.c
Marek Marczykowski-Górecki b5a9d9bf8e
Add build-time assert for filename buffer size
Suggested by @cfcs
2018-05-28 22:45:39 +02:00

137 lines
3.4 KiB
C

#define _GNU_SOURCE
#include <dirent.h>
#include <stdio.h>
#include <string.h>
#include <sys/stat.h>
#include <signal.h>
#include <fcntl.h>
#include <malloc.h>
#include <stdlib.h>
#include <libqubes-rpc-filecopy.h>
#include <unistd.h>
#include <getopt.h>
#include <gui-fatal.h>
#include "dvm2.h"
void send_file(const char *fname, int view_only)
{
const char *base;
char sendbuf[DVM_FILENAME_SIZE] = {0};
size_t sendbuf_size = DVM_FILENAME_SIZE;
int fd = open(fname, O_RDONLY);
if (fd < 0)
gui_fatal("open %s", fname);
_Static_assert(DVM_FILENAME_SIZE > sizeof(DVM_VIEW_ONLY_PREFIX),
"DVM_FILENAME_SIZE > sizeof(DVM_VIEW_ONLY_PREFIX)");
if (view_only) {
strncpy(sendbuf, DVM_VIEW_ONLY_PREFIX, sendbuf_size);
sendbuf_size -= strlen(DVM_VIEW_ONLY_PREFIX);
}
base = rindex(fname, '/');
if (!base)
base = fname;
else
base++;
if (strlen(base) >= sendbuf_size)
base += strlen(base) - sendbuf_size + 1;
strncat(sendbuf,base,sendbuf_size - 1); /* fills out with NULs */
sendbuf[DVM_FILENAME_SIZE - 1] = '\0';
if (!write_all(1, sendbuf, DVM_FILENAME_SIZE))
gui_fatal("send filename to dispVM");
if (!copy_fd_all(1, fd))
gui_fatal("send file to dispVM");
close(1);
close(fd);
}
int copy_and_return_nonemptiness(int tmpfd)
{
struct stat st;
if (!copy_fd_all(tmpfd, 0))
gui_fatal("receiving file from dispVM");
if (fstat(tmpfd, &st))
gui_fatal("fstat");
close(tmpfd);
return st.st_size > 0;
}
void recv_file_nowrite(const char *fname)
{
char *tempfile;
char *errmsg;
int tmpfd = -1;
if (asprintf(&tempfile, "/tmp/file_edited_in_dvm.XXXXXX") != -1)
tmpfd = mkstemp(tempfile);
if (tmpfd < 0)
gui_fatal("unable to create any temporary file, aborting");
if (!copy_and_return_nonemptiness(tmpfd)) {
unlink(tempfile);
return;
}
if (asprintf(&errmsg,
"The file %s has been edited in Disposable VM and the modified content has been received, "
"but this file is in nonwritable directory and thus cannot be modified safely. The edited file has been "
"saved to %s", fname, tempfile) != -1)
gui_nonfatal(errmsg);
}
void actually_recv_file(const char *fname, const char *tempfile, int tmpfd)
{
if (!copy_and_return_nonemptiness(tmpfd)) {
unlink(tempfile);
return;
}
if (rename(tempfile, fname))
gui_fatal("rename");
}
void recv_file(const char *fname)
{
int tmpfd = -1;
char *tempfile;
if (asprintf(&tempfile, "%s.XXXXXX", fname) != -1) {
tmpfd = mkstemp(tempfile);
}
if (tmpfd < 0)
recv_file_nowrite(fname);
else
actually_recv_file(fname, tempfile, tmpfd);
}
int main(int argc, char ** argv)
{
char *fname;
int view_only = 0;
int ret;
const struct option opts[] = {
{"view-only", no_argument, &view_only, 1},
{0}
};
while ((ret=getopt_long(argc, argv, "", opts, NULL)) != -1) {
if (ret == '?') {
exit(2);
}
}
signal(SIGPIPE, SIG_IGN);
if (optind >= argc)
gui_fatal("OpenInVM - no file given?");
fname = argv[optind];
send_file(fname, view_only);
if (!view_only) {
recv_file(fname);
} else {
/* discard received data */
int null_fd = open("/dev/null", O_WRONLY);
copy_fd_all(null_fd, 0);
close(null_fd);
}
return 0;
}