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071488983c
libvirt/tools/virt-login-shell.c
Erik Skultety 5165ff0971 src: More cleanup of some system headers already contained in internal.h 
All of the ones being removed are pulled in by internal.h. The only
exception is sanlock which expects the application to include <stdint.h>
before sanlock's headers, because sanlock prototypes use fixed width
int, but they don't include stdint.h themselves, so we have to leave
that one in place.

Signed-off-by: Erik Skultety <eskultet@redhat.com>
Acked-by: Michal Privoznik <mprivozn@redhat.com>
2018-09-20 10:16:39 +02:00

412 lines
11 KiB
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/*
* virt-login-shell.c: a shell to connect to a container
*
* Copyright (C) 2013-2014 Red Hat, Inc.
*
* This 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.
*
* This 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 this library. If not, see
* <http://www.gnu.org/licenses/>.
*
* Daniel Walsh <dwalsh@redhat.com>
*/
#include <config.h>
#include <fnmatch.h>
#include <getopt.h>
#include <signal.h>
#include <stdarg.h>
#include <unistd.h>
#include "internal.h"
#include "virerror.h"
#include "virconf.h"
#include "virutil.h"
#include "virfile.h"
#include "virprocess.h"
#include "configmake.h"
#include "virstring.h"
#include "viralloc.h"
#include "vircommand.h"
#include "virgettext.h"
#define VIR_FROM_THIS VIR_FROM_NONE
static const char *conf_file = SYSCONFDIR "/libvirt/virt-login-shell.conf";
static int virLoginShellAllowedUser(virConfPtr conf,
const char *name,
gid_t *groups,
size_t ngroups)
{
int ret = -1;
size_t i;
char *gname = NULL;
char **users = NULL, **entries;
if (virConfGetValueStringList(conf, "allowed_users", false, &users) < 0)
goto cleanup;
for (entries = users; *entries; entries++) {
char *entry = *entries;
/*
If string begins with a % this indicates a linux group.
Check to see if the user is in the Linux Group.
*/
if (entry[0] == '%') {
entry++;
if (!*entry)
continue;
for (i = 0; i < ngroups; i++) {
if (!(gname = virGetGroupName(groups[i])))
continue;
if (fnmatch(entry, gname, 0) == 0) {
ret = 0;
goto cleanup;
}
VIR_FREE(gname);
}
} else {
if (fnmatch(entry, name, 0) == 0) {
ret = 0;
goto cleanup;
}
}
}
virReportSystemError(EPERM,
_("%s not matched against 'allowed_users' in %s"),
name, conf_file);
cleanup:
VIR_FREE(gname);
virStringListFree(users);
return ret;
}
static int virLoginShellGetShellArgv(virConfPtr conf,
char ***shargv,
size_t *shargvlen)
{
int rv;
if ((rv = virConfGetValueStringList(conf, "shell", true, shargv)) < 0)
return -1;
if (rv == 0) {
if (VIR_ALLOC_N(*shargv, 2) < 0)
return -1;
if (VIR_STRDUP((*shargv)[0], "/bin/sh") < 0) {
VIR_FREE(*shargv);
return -1;
}
*shargvlen = 1;
} else {
*shargvlen = virStringListLength((const char *const *)shargv);
}
return 0;
}
static char *progname;
/*
* Print usage
*/
static void
usage(void)
{
fprintf(stdout,
_("\n"
"Usage:\n"
" %s [option]\n\n"
"Options:\n"
" -h | --help Display program help\n"
" -V | --version Display program version\n"
" -c CMD Run CMD via shell\n"
"\n"
"libvirt login shell\n"),
progname);
return;
}
/* Display version information. */
static void
show_version(void)
{
printf("%s (%s) %s\n", progname, PACKAGE_NAME, PACKAGE_VERSION);
}
int
main(int argc, char **argv)
{
virConfPtr conf = NULL;
const char *login_shell_path = conf_file;
pid_t cpid = -1;
int ret = EXIT_CANCELED;
int status;
uid_t uid = getuid();
gid_t gid = getgid();
char *name = NULL;
char **shargv = NULL;
size_t shargvlen = 0;
char *shcmd = NULL;
virSecurityModelPtr secmodel = NULL;
virSecurityLabelPtr seclabel = NULL;
virDomainPtr dom = NULL;
virConnectPtr conn = NULL;
char *homedir = NULL;
int arg;
int longindex = -1;
int ngroups;
gid_t *groups = NULL;
ssize_t nfdlist = 0;
int *fdlist = NULL;
int openmax;
size_t i;
const char *cmdstr = NULL;
char *tmp;
char *term = NULL;
virErrorPtr saved_err = NULL;
bool autoshell = false;
struct option opt[] = {
{"help", no_argument, NULL, 'h'},
{"version", optional_argument, NULL, 'V'},
{NULL, 0, NULL, 0}
};
if (virInitialize() < 0) {
fprintf(stderr, _("Failed to initialize libvirt error handling"));
return EXIT_CANCELED;
}
virSetErrorFunc(NULL, NULL);
virSetErrorLogPriorityFunc(NULL);
progname = argv[0];
if (virGettextInitialize() < 0)
return ret;
while ((arg = getopt_long(argc, argv, "hVc:", opt, &longindex)) != -1) {
switch (arg) {
case 'h':
usage();
exit(EXIT_SUCCESS);
case 'V':
show_version();
exit(EXIT_SUCCESS);
case 'c':
cmdstr = optarg;
break;
case '?':
default:
usage();
exit(EXIT_CANCELED);
}
}
if (argc > optind) {
virReportSystemError(EINVAL, _("%s takes no options"), progname);
goto cleanup;
}
if (uid == 0) {
virReportSystemError(EPERM, _("%s must be run by non root users"),
progname);
goto cleanup;
}
name = virGetUserName(uid);
if (!name)
goto cleanup;
homedir = virGetUserDirectoryByUID(uid);
if (!homedir)
goto cleanup;
if (!(conf = virConfReadFile(login_shell_path, 0)))
goto cleanup;
if ((ngroups = virGetGroupList(uid, gid, &groups)) < 0)
goto cleanup;
if (virLoginShellAllowedUser(conf, name, groups, ngroups) < 0)
goto cleanup;
if (virLoginShellGetShellArgv(conf, &shargv, &shargvlen) < 0)
goto cleanup;
if (virConfGetValueBool(conf, "auto_shell", &autoshell) < 0)
goto cleanup;
conn = virConnectOpen("lxc:///system");
if (!conn)
goto cleanup;
dom = virDomainLookupByName(conn, name);
if (!dom)
goto cleanup;
if (!virDomainIsActive(dom) && virDomainCreate(dom) < 0) {
virErrorPtr last_error;
last_error = virGetLastError();
if (last_error->code != VIR_ERR_OPERATION_INVALID) {
virReportSystemError(last_error->code,
_("Can't create %s container: %s"),
name, last_error->message);
goto cleanup;
}
}
openmax = sysconf(_SC_OPEN_MAX);
if (openmax < 0) {
virReportSystemError(errno, "%s",
_("sysconf(_SC_OPEN_MAX) failed"));
goto cleanup;
}
if ((nfdlist = virDomainLxcOpenNamespace(dom, &fdlist, 0)) < 0)
goto cleanup;
if (VIR_ALLOC(secmodel) < 0)
goto cleanup;
if (VIR_ALLOC(seclabel) < 0)
goto cleanup;
if (virNodeGetSecurityModel(conn, secmodel) < 0)
goto cleanup;
if (virDomainGetSecurityLabel(dom, seclabel) < 0)
goto cleanup;
if (virSetUIDGID(0, 0, NULL, 0) < 0)
goto cleanup;
if (virDomainLxcEnterSecurityLabel(secmodel, seclabel, NULL, 0) < 0)
goto cleanup;
if (virDomainLxcEnterCGroup(dom, 0) < 0)
goto cleanup;
if (nfdlist > 0 &&
virDomainLxcEnterNamespace(dom, nfdlist, fdlist, NULL, NULL, 0) < 0)
goto cleanup;
if (virSetUIDGID(uid, gid, groups, ngroups) < 0)
goto cleanup;
if (chdir(homedir) < 0) {
virReportSystemError(errno, _("Unable to chdir(%s)"), homedir);
goto cleanup;
}
if (autoshell) {
tmp = virGetUserShell(uid);
if (tmp) {
virStringListFree(shargv);
shargvlen = 1;
if (VIR_ALLOC_N(shargv[0], shargvlen + 1) < 0) {
VIR_FREE(tmp);
goto cleanup;
}
shargv[0] = tmp;
shargv[1] = NULL;
}
}
if (cmdstr) {
if (VIR_REALLOC_N(shargv, shargvlen + 3) < 0)
goto cleanup;
if (VIR_STRDUP(shargv[shargvlen++], "-c") < 0)
goto cleanup;
if (VIR_STRDUP(shargv[shargvlen++], cmdstr) < 0)
goto cleanup;
shargv[shargvlen] = NULL;
}
/* We need to modify the first elementin shargv
* so that it has the relative filename and has
* a leading '-' to indicate it is a login shell
*/
shcmd = shargv[0];
if (shcmd[0] != '/') {
virReportSystemError(errno,
_("Shell '%s' should have absolute path"),
shcmd);
goto cleanup;
}
tmp = strrchr(shcmd, '/');
if (VIR_STRDUP(shargv[0], tmp) < 0)
goto cleanup;
shargv[0][0] = '-';
/* We're duping the string because the clearenv()
* call will shortly release the pointer we get
* back from virGetEnvAllowSUID() right here */
if (VIR_STRDUP(term, virGetEnvAllowSUID("TERM")) < 0)
goto cleanup;
/* A fork is required to create new process in correct pid namespace. */
if ((cpid = virFork()) < 0)
goto cleanup;
if (cpid == 0) {
int tmpfd;
for (i = 3; i < openmax; i++) {
tmpfd = i;
VIR_MASS_CLOSE(tmpfd);
}
clearenv();
setenv("PATH", "/bin:/usr/bin", 1);
setenv("SHELL", shcmd, 1);
setenv("USER", name, 1);
setenv("LOGNAME", name, 1);
setenv("HOME", homedir, 1);
if (term)
setenv("TERM", term, 1);
if (execv(shcmd, (char *const*) shargv) < 0) {
virReportSystemError(errno, _("Unable to exec shell %s"),
shcmd);
virDispatchError(NULL);
return errno == ENOENT ? EXIT_ENOENT : EXIT_CANNOT_INVOKE;
}
}
/* At this point, the parent is now waiting for the child to exit,
* but as that may take a long time, we release resources now. */
cleanup:
saved_err = virSaveLastError();
if (nfdlist > 0)
for (i = 0; i < nfdlist; i++)
VIR_FORCE_CLOSE(fdlist[i]);
VIR_FREE(fdlist);
virConfFree(conf);
if (dom)
virDomainFree(dom);
if (conn)
virConnectClose(conn);
virStringListFree(shargv);
VIR_FREE(shcmd);
VIR_FREE(term);
VIR_FREE(name);
VIR_FREE(homedir);
VIR_FREE(seclabel);
VIR_FREE(secmodel);
VIR_FREE(groups);
if (virProcessWait(cpid, &status, true) == 0)
virProcessExitWithStatus(status);
if (saved_err) {
virSetError(saved_err);
virDispatchError(NULL);
}
return ret;
}
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