hw/9pfs: File system helper process for qemu 9p proxy FS
Provide root privilege access to QEMU 9p proxy filesystem using socket communication. Proxy helper is started by root user as: ~ # virtfs-proxy-helper -f|--fd <socket descriptor> -p|--path <path-to-share> Signed-off-by: M. Mohan Kumar <mohan@in.ibm.com> Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
This commit is contained in:
M. Mohan Kumar
Aneesh Kumar K.V
parent
4c793dda22
commit
17bff52b62
3
Makefile
3
Makefile
|
|
@ -155,6 +155,9 @@ qemu-img$(EXESUF): qemu-img.o $(tools-obj-y) $(block-obj-y)
|
|||
qemu-nbd$(EXESUF): qemu-nbd.o $(tools-obj-y) $(block-obj-y)
|
||||
qemu-io$(EXESUF): qemu-io.o cmd.o $(tools-obj-y) $(block-obj-y)
|
||||
|
||||
fsdev/virtfs-proxy-helper$(EXESUF): fsdev/virtfs-proxy-helper.o fsdev/virtio-9p-marshal.o
|
||||
fsdev/virtfs-proxy-helper$(EXESUF): LIBS += -lcap
|
||||
|
||||
qemu-img-cmds.h: $(SRC_PATH)/qemu-img-cmds.hx
|
||||
$(call quiet-command,sh $(SRC_PATH)/scripts/hxtool -h < $< > $@," GEN $@")
|
||||
|
||||
|
|
|
|||
|
|
@ -1966,6 +1966,22 @@ else
|
|||
exit 1
|
||||
fi
|
||||
|
||||
##########################################
|
||||
# libcap probe
|
||||
|
||||
if test "$cap" != "no" ; then
|
||||
cat > $TMPC <<EOF
|
||||
#include <stdio.h>
|
||||
#include <sys/capability.h>
|
||||
int main(void) { cap_t caps; caps = cap_init(); }
|
||||
EOF
|
||||
if compile_prog "" "-lcap" ; then
|
||||
cap=yes
|
||||
else
|
||||
cap=no
|
||||
fi
|
||||
fi
|
||||
|
||||
##########################################
|
||||
# pthread probe
|
||||
PTHREADLIBS_LIST="-pthread -lpthread -lpthreadGC2"
|
||||
|
|
@ -2767,6 +2783,9 @@ confdir=$sysconfdir$confsuffix
|
|||
tools=
|
||||
if test "$softmmu" = yes ; then
|
||||
tools="qemu-img\$(EXESUF) qemu-io\$(EXESUF) $tools"
|
||||
if [ "$cap" = "yes" -a "$linux" = "yes" ] ; then
|
||||
tools="$tools fsdev/virtfs-proxy-helper\$(EXESUF)"
|
||||
fi
|
||||
if [ "$linux" = "yes" -o "$bsd" = "yes" -o "$solaris" = "yes" ] ; then
|
||||
tools="qemu-nbd\$(EXESUF) $tools"
|
||||
if [ "$guest_agent" = "yes" ]; then
|
||||
|
|
|
|||
|
|
@ -0,0 +1,300 @@
|
|||
/*
|
||||
* Helper for QEMU Proxy FS Driver
|
||||
* Copyright IBM, Corp. 2011
|
||||
*
|
||||
* Authors:
|
||||
* M. Mohan Kumar <mohan@in.ibm.com>
|
||||
*
|
||||
* This work is licensed under the terms of the GNU GPL, version 2. See
|
||||
* the COPYING file in the top-level directory.
|
||||
*/
|
||||
#include <stdio.h>
|
||||
#include <string.h>
|
||||
#include <sys/un.h>
|
||||
#include <limits.h>
|
||||
#include <signal.h>
|
||||
#include <errno.h>
|
||||
#include <stdlib.h>
|
||||
#include <sys/resource.h>
|
||||
#include <sys/stat.h>
|
||||
#include <getopt.h>
|
||||
#include <unistd.h>
|
||||
#include <syslog.h>
|
||||
#include <sys/capability.h>
|
||||
#include <sys/fsuid.h>
|
||||
#include <stdarg.h>
|
||||
#include <stdbool.h>
|
||||
#include "qemu-common.h"
|
||||
#include "virtio-9p-marshal.h"
|
||||
#include "hw/9pfs/virtio-9p-proxy.h"
|
||||
|
||||
#define PROGNAME "virtfs-proxy-helper"
|
||||
|
||||
static struct option helper_opts[] = {
|
||||
{"fd", required_argument, NULL, 'f'},
|
||||
{"path", required_argument, NULL, 'p'},
|
||||
{"nodaemon", no_argument, NULL, 'n'},
|
||||
};
|
||||
|
||||
static bool is_daemon;
|
||||
|
||||
static void do_log(int loglevel, const char *format, ...)
|
||||
{
|
||||
va_list ap;
|
||||
|
||||
va_start(ap, format);
|
||||
if (is_daemon) {
|
||||
vsyslog(LOG_CRIT, format, ap);
|
||||
} else {
|
||||
vfprintf(stderr, format, ap);
|
||||
}
|
||||
va_end(ap);
|
||||
}
|
||||
|
||||
static void do_perror(const char *string)
|
||||
{
|
||||
if (is_daemon) {
|
||||
syslog(LOG_CRIT, "%s:%s", string, strerror(errno));
|
||||
} else {
|
||||
fprintf(stderr, "%s:%s\n", string, strerror(errno));
|
||||
}
|
||||
}
|
||||
|
||||
static int do_cap_set(cap_value_t *cap_value, int size, int reset)
|
||||
{
|
||||
cap_t caps;
|
||||
if (reset) {
|
||||
/*
|
||||
* Start with an empty set and set permitted and effective
|
||||
*/
|
||||
caps = cap_init();
|
||||
if (caps == NULL) {
|
||||
do_perror("cap_init");
|
||||
return -1;
|
||||
}
|
||||
if (cap_set_flag(caps, CAP_PERMITTED, size, cap_value, CAP_SET) < 0) {
|
||||
do_perror("cap_set_flag");
|
||||
goto error;
|
||||
}
|
||||
} else {
|
||||
caps = cap_get_proc();
|
||||
if (!caps) {
|
||||
do_perror("cap_get_proc");
|
||||
return -1;
|
||||
}
|
||||
}
|
||||
if (cap_set_flag(caps, CAP_EFFECTIVE, size, cap_value, CAP_SET) < 0) {
|
||||
do_perror("cap_set_flag");
|
||||
goto error;
|
||||
}
|
||||
if (cap_set_proc(caps) < 0) {
|
||||
do_perror("cap_set_proc");
|
||||
goto error;
|
||||
}
|
||||
cap_free(caps);
|
||||
return 0;
|
||||
|
||||
error:
|
||||
cap_free(caps);
|
||||
return -1;
|
||||
}
|
||||
|
||||
static int init_capabilities(void)
|
||||
{
|
||||
/* helper needs following capbabilities only */
|
||||
cap_value_t cap_list[] = {
|
||||
CAP_CHOWN,
|
||||
CAP_DAC_OVERRIDE,
|
||||
CAP_FOWNER,
|
||||
CAP_FSETID,
|
||||
CAP_SETGID,
|
||||
CAP_MKNOD,
|
||||
CAP_SETUID,
|
||||
};
|
||||
return do_cap_set(cap_list, ARRAY_SIZE(cap_list), 1);
|
||||
}
|
||||
|
||||
static int socket_read(int sockfd, void *buff, ssize_t size)
|
||||
{
|
||||
ssize_t retval, total = 0;
|
||||
|
||||
while (size) {
|
||||
retval = read(sockfd, buff, size);
|
||||
if (retval == 0) {
|
||||
return -EIO;
|
||||
}
|
||||
if (retval < 0) {
|
||||
if (errno == EINTR) {
|
||||
continue;
|
||||
}
|
||||
return -errno;
|
||||
}
|
||||
size -= retval;
|
||||
buff += retval;
|
||||
total += retval;
|
||||
}
|
||||
return total;
|
||||
}
|
||||
|
||||
static int socket_write(int sockfd, void *buff, ssize_t size)
|
||||
{
|
||||
ssize_t retval, total = 0;
|
||||
|
||||
while (size) {
|
||||
retval = write(sockfd, buff, size);
|
||||
if (retval < 0) {
|
||||
if (errno == EINTR) {
|
||||
continue;
|
||||
}
|
||||
return -errno;
|
||||
}
|
||||
size -= retval;
|
||||
buff += retval;
|
||||
total += retval;
|
||||
}
|
||||
return total;
|
||||
}
|
||||
|
||||
static int read_request(int sockfd, struct iovec *iovec, ProxyHeader *header)
|
||||
{
|
||||
int retval;
|
||||
|
||||
/*
|
||||
* read the request header.
|
||||
*/
|
||||
iovec->iov_len = 0;
|
||||
retval = socket_read(sockfd, iovec->iov_base, PROXY_HDR_SZ);
|
||||
if (retval < 0) {
|
||||
return retval;
|
||||
}
|
||||
iovec->iov_len = PROXY_HDR_SZ;
|
||||
retval = proxy_unmarshal(iovec, 0, "dd", &header->type, &header->size);
|
||||
if (retval < 0) {
|
||||
return retval;
|
||||
}
|
||||
/*
|
||||
* We can't process message.size > PROXY_MAX_IO_SZ.
|
||||
* Treat it as fatal error
|
||||
*/
|
||||
if (header->size > PROXY_MAX_IO_SZ) {
|
||||
return -ENOBUFS;
|
||||
}
|
||||
retval = socket_read(sockfd, iovec->iov_base + PROXY_HDR_SZ, header->size);
|
||||
if (retval < 0) {
|
||||
return retval;
|
||||
}
|
||||
iovec->iov_len += header->size;
|
||||
return 0;
|
||||
}
|
||||
|
||||
static void usage(char *prog)
|
||||
{
|
||||
fprintf(stderr, "usage: %s\n"
|
||||
" -p|--path <path> 9p path to export\n"
|
||||
" {-f|--fd <socket-descriptor>} socket file descriptor to be used\n"
|
||||
" [-n|--nodaemon] Run as a normal program\n",
|
||||
basename(prog));
|
||||
}
|
||||
|
||||
static int process_requests(int sock)
|
||||
{
|
||||
int retval;
|
||||
ProxyHeader header;
|
||||
struct iovec in_iovec;
|
||||
|
||||
in_iovec.iov_base = g_malloc(PROXY_MAX_IO_SZ + PROXY_HDR_SZ);
|
||||
in_iovec.iov_len = PROXY_MAX_IO_SZ + PROXY_HDR_SZ;
|
||||
while (1) {
|
||||
retval = read_request(sock, &in_iovec, &header);
|
||||
if (retval < 0) {
|
||||
goto error;
|
||||
}
|
||||
}
|
||||
(void)socket_write;
|
||||
error:
|
||||
g_free(in_iovec.iov_base);
|
||||
return -1;
|
||||
}
|
||||
|
||||
int main(int argc, char **argv)
|
||||
{
|
||||
int sock;
|
||||
char *rpath = NULL;
|
||||
struct stat stbuf;
|
||||
int c, option_index;
|
||||
|
||||
is_daemon = true;
|
||||
sock = -1;
|
||||
while (1) {
|
||||
option_index = 0;
|
||||
c = getopt_long(argc, argv, "p:nh?f:", helper_opts,
|
||||
&option_index);
|
||||
if (c == -1) {
|
||||
break;
|
||||
}
|
||||
switch (c) {
|
||||
case 'p':
|
||||
rpath = strdup(optarg);
|
||||
break;
|
||||
case 'n':
|
||||
is_daemon = false;
|
||||
break;
|
||||
case 'f':
|
||||
sock = atoi(optarg);
|
||||
break;
|
||||
case '?':
|
||||
case 'h':
|
||||
default:
|
||||
usage(argv[0]);
|
||||
exit(EXIT_FAILURE);
|
||||
}
|
||||
}
|
||||
|
||||
/* Parameter validation */
|
||||
if (sock == -1 || rpath == NULL) {
|
||||
fprintf(stderr, "socket descriptor or path not specified\n");
|
||||
usage(argv[0]);
|
||||
exit(EXIT_FAILURE);
|
||||
}
|
||||
|
||||
if (lstat(rpath, &stbuf) < 0) {
|
||||
fprintf(stderr, "invalid path \"%s\" specified, %s\n",
|
||||
rpath, strerror(errno));
|
||||
exit(EXIT_FAILURE);
|
||||
}
|
||||
|
||||
if (!S_ISDIR(stbuf.st_mode)) {
|
||||
fprintf(stderr, "specified path \"%s\" is not directory\n", rpath);
|
||||
exit(EXIT_FAILURE);
|
||||
}
|
||||
|
||||
if (is_daemon) {
|
||||
if (daemon(0, 0) < 0) {
|
||||
fprintf(stderr, "daemon call failed\n");
|
||||
exit(EXIT_FAILURE);
|
||||
}
|
||||
openlog(PROGNAME, LOG_PID, LOG_DAEMON);
|
||||
}
|
||||
|
||||
do_log(LOG_INFO, "Started\n");
|
||||
|
||||
if (chdir("/") < 0) {
|
||||
do_perror("chdir");
|
||||
goto error;
|
||||
}
|
||||
if (chroot(rpath) < 0) {
|
||||
do_perror("chroot");
|
||||
goto error;
|
||||
}
|
||||
umask(0);
|
||||
|
||||
if (init_capabilities() < 0) {
|
||||
goto error;
|
||||
}
|
||||
|
||||
process_requests(sock);
|
||||
error:
|
||||
do_log(LOG_INFO, "Done\n");
|
||||
closelog();
|
||||
return 0;
|
||||
}
|
||||
|
|
@ -14,6 +14,15 @@
|
|||
|
||||
#define PROXY_MAX_IO_SZ (64 * 1024)
|
||||
|
||||
/*
|
||||
* proxy iovec only support one element and
|
||||
* marsha/unmarshal doesn't do little endian conversion.
|
||||
*/
|
||||
#define proxy_unmarshal(in_sg, offset, fmt, args...) \
|
||||
v9fs_unmarshal(in_sg, 1, offset, 0, fmt, ##args)
|
||||
#define proxy_marshal(out_sg, offset, fmt, args...) \
|
||||
v9fs_marshal(out_sg, 1, offset, 0, fmt, ##args)
|
||||
|
||||
typedef struct {
|
||||
uint32_t type;
|
||||
uint32_t size;
|
||||
|
|
|
|||
Loading…
Reference in New Issue