qemu/qga/commands-posix-ssh.c

512 lines
13 KiB
C

/*
* This work is licensed under the terms of the GNU GPL, version 2 or later.
* See the COPYING file in the top-level directory.
*/
#include "qemu/osdep.h"
#include <glib-unix.h>
#include <glib/gstdio.h>
#include <locale.h>
#include <pwd.h>
#include "qapi/error.h"
#include "qga-qapi-commands.h"
#ifdef QGA_BUILD_UNIT_TEST
static struct passwd *
test_get_passwd_entry(const gchar *user_name, GError **error)
{
struct passwd *p;
int ret;
if (!user_name || g_strcmp0(user_name, g_get_user_name())) {
g_set_error(error, G_UNIX_ERROR, 0, "Invalid user name");
return NULL;
}
p = g_new0(struct passwd, 1);
p->pw_dir = (char *)g_get_home_dir();
p->pw_uid = geteuid();
p->pw_gid = getegid();
ret = g_mkdir_with_parents(p->pw_dir, 0700);
g_assert(ret == 0);
return p;
}
#define g_unix_get_passwd_entry_qemu(username, err) \
test_get_passwd_entry(username, err)
#endif
static struct passwd *
get_passwd_entry(const char *username, Error **errp)
{
g_autoptr(GError) err = NULL;
struct passwd *p;
ERRP_GUARD();
p = g_unix_get_passwd_entry_qemu(username, &err);
if (p == NULL) {
error_setg(errp, "failed to lookup user '%s': %s",
username, err->message);
return NULL;
}
return p;
}
static bool
mkdir_for_user(const char *path, const struct passwd *p,
mode_t mode, Error **errp)
{
ERRP_GUARD();
if (g_mkdir(path, mode) == -1) {
error_setg(errp, "failed to create directory '%s': %s",
path, g_strerror(errno));
return false;
}
if (chown(path, p->pw_uid, p->pw_gid) == -1) {
error_setg(errp, "failed to set ownership of directory '%s': %s",
path, g_strerror(errno));
return false;
}
if (chmod(path, mode) == -1) {
error_setg(errp, "failed to set permissions of directory '%s': %s",
path, g_strerror(errno));
return false;
}
return true;
}
static bool
check_openssh_pub_key(const char *key, Error **errp)
{
ERRP_GUARD();
/* simple sanity-check, we may want more? */
if (!key || key[0] == '#' || strchr(key, '\n')) {
error_setg(errp, "invalid OpenSSH public key: '%s'", key);
return false;
}
return true;
}
static bool
check_openssh_pub_keys(strList *keys, size_t *nkeys, Error **errp)
{
size_t n = 0;
strList *k;
ERRP_GUARD();
for (k = keys; k != NULL; k = k->next) {
if (!check_openssh_pub_key(k->value, errp)) {
return false;
}
n++;
}
if (nkeys) {
*nkeys = n;
}
return true;
}
static bool
write_authkeys(const char *path, const GStrv keys,
const struct passwd *p, Error **errp)
{
g_autofree char *contents = NULL;
g_autoptr(GError) err = NULL;
ERRP_GUARD();
contents = g_strjoinv("\n", keys);
if (!g_file_set_contents(path, contents, -1, &err)) {
error_setg(errp, "failed to write to '%s': %s", path, err->message);
return false;
}
if (chown(path, p->pw_uid, p->pw_gid) == -1) {
error_setg(errp, "failed to set ownership of directory '%s': %s",
path, g_strerror(errno));
return false;
}
if (chmod(path, 0600) == -1) {
error_setg(errp, "failed to set permissions of '%s': %s",
path, g_strerror(errno));
return false;
}
return true;
}
static GStrv
read_authkeys(const char *path, Error **errp)
{
g_autoptr(GError) err = NULL;
g_autofree char *contents = NULL;
ERRP_GUARD();
if (!g_file_get_contents(path, &contents, NULL, &err)) {
error_setg(errp, "failed to read '%s': %s", path, err->message);
return NULL;
}
return g_strsplit(contents, "\n", -1);
}
void
qmp_guest_ssh_add_authorized_keys(const char *username, strList *keys,
bool has_reset, bool reset,
Error **errp)
{
g_autofree struct passwd *p = NULL;
g_autofree char *ssh_path = NULL;
g_autofree char *authkeys_path = NULL;
g_auto(GStrv) authkeys = NULL;
strList *k;
size_t nkeys, nauthkeys;
ERRP_GUARD();
reset = has_reset && reset;
if (!check_openssh_pub_keys(keys, &nkeys, errp)) {
return;
}
p = get_passwd_entry(username, errp);
if (p == NULL) {
return;
}
ssh_path = g_build_filename(p->pw_dir, ".ssh", NULL);
authkeys_path = g_build_filename(ssh_path, "authorized_keys", NULL);
if (!reset) {
authkeys = read_authkeys(authkeys_path, NULL);
}
if (authkeys == NULL) {
if (!g_file_test(ssh_path, G_FILE_TEST_IS_DIR) &&
!mkdir_for_user(ssh_path, p, 0700, errp)) {
return;
}
}
nauthkeys = authkeys ? g_strv_length(authkeys) : 0;
authkeys = g_realloc_n(authkeys, nauthkeys + nkeys + 1, sizeof(char *));
memset(authkeys + nauthkeys, 0, (nkeys + 1) * sizeof(char *));
for (k = keys; k != NULL; k = k->next) {
if (g_strv_contains((const gchar * const *)authkeys, k->value)) {
continue;
}
authkeys[nauthkeys++] = g_strdup(k->value);
}
write_authkeys(authkeys_path, authkeys, p, errp);
}
void
qmp_guest_ssh_remove_authorized_keys(const char *username, strList *keys,
Error **errp)
{
g_autofree struct passwd *p = NULL;
g_autofree char *authkeys_path = NULL;
g_autofree GStrv new_keys = NULL; /* do not own the strings */
g_auto(GStrv) authkeys = NULL;
GStrv a;
size_t nkeys = 0;
ERRP_GUARD();
if (!check_openssh_pub_keys(keys, NULL, errp)) {
return;
}
p = get_passwd_entry(username, errp);
if (p == NULL) {
return;
}
authkeys_path = g_build_filename(p->pw_dir, ".ssh",
"authorized_keys", NULL);
if (!g_file_test(authkeys_path, G_FILE_TEST_EXISTS)) {
return;
}
authkeys = read_authkeys(authkeys_path, errp);
if (authkeys == NULL) {
return;
}
new_keys = g_new0(char *, g_strv_length(authkeys) + 1);
for (a = authkeys; *a != NULL; a++) {
strList *k;
for (k = keys; k != NULL; k = k->next) {
if (g_str_equal(k->value, *a)) {
break;
}
}
if (k != NULL) {
continue;
}
new_keys[nkeys++] = *a;
}
write_authkeys(authkeys_path, new_keys, p, errp);
}
GuestAuthorizedKeys *
qmp_guest_ssh_get_authorized_keys(const char *username, Error **errp)
{
g_autofree struct passwd *p = NULL;
g_autofree char *authkeys_path = NULL;
g_auto(GStrv) authkeys = NULL;
g_autoptr(GuestAuthorizedKeys) ret = NULL;
int i;
ERRP_GUARD();
p = get_passwd_entry(username, errp);
if (p == NULL) {
return NULL;
}
authkeys_path = g_build_filename(p->pw_dir, ".ssh",
"authorized_keys", NULL);
authkeys = read_authkeys(authkeys_path, errp);
if (authkeys == NULL) {
return NULL;
}
ret = g_new0(GuestAuthorizedKeys, 1);
for (i = 0; authkeys[i] != NULL; i++) {
g_strstrip(authkeys[i]);
if (!authkeys[i][0] || authkeys[i][0] == '#') {
continue;
}
QAPI_LIST_PREPEND(ret->keys, g_strdup(authkeys[i]));
}
return g_steal_pointer(&ret);
}
#ifdef QGA_BUILD_UNIT_TEST
#if GLIB_CHECK_VERSION(2, 60, 0)
static const strList test_key2 = {
.value = (char *)"algo key2 comments"
};
static const strList test_key1_2 = {
.value = (char *)"algo key1 comments",
.next = (strList *)&test_key2,
};
static char *
test_get_authorized_keys_path(void)
{
return g_build_filename(g_get_home_dir(), ".ssh", "authorized_keys", NULL);
}
static void
test_authorized_keys_set(const char *contents)
{
g_autoptr(GError) err = NULL;
g_autofree char *path = NULL;
int ret;
path = g_build_filename(g_get_home_dir(), ".ssh", NULL);
ret = g_mkdir_with_parents(path, 0700);
g_assert(ret == 0);
g_free(path);
path = test_get_authorized_keys_path();
g_file_set_contents(path, contents, -1, &err);
g_assert(err == NULL);
}
static void
test_authorized_keys_equal(const char *expected)
{
g_autoptr(GError) err = NULL;
g_autofree char *path = NULL;
g_autofree char *contents = NULL;
path = test_get_authorized_keys_path();
g_file_get_contents(path, &contents, NULL, &err);
g_assert(err == NULL);
g_assert(g_strcmp0(contents, expected) == 0);
}
static void
test_invalid_user(void)
{
Error *err = NULL;
qmp_guest_ssh_add_authorized_keys("", NULL, FALSE, FALSE, &err);
error_free_or_abort(&err);
qmp_guest_ssh_remove_authorized_keys("", NULL, &err);
error_free_or_abort(&err);
}
static void
test_invalid_key(void)
{
strList key = {
.value = (char *)"not a valid\nkey"
};
Error *err = NULL;
qmp_guest_ssh_add_authorized_keys(g_get_user_name(), &key,
FALSE, FALSE, &err);
error_free_or_abort(&err);
qmp_guest_ssh_remove_authorized_keys(g_get_user_name(), &key, &err);
error_free_or_abort(&err);
}
static void
test_add_keys(void)
{
Error *err = NULL;
qmp_guest_ssh_add_authorized_keys(g_get_user_name(),
(strList *)&test_key2,
FALSE, FALSE,
&err);
g_assert(err == NULL);
test_authorized_keys_equal("algo key2 comments");
qmp_guest_ssh_add_authorized_keys(g_get_user_name(),
(strList *)&test_key1_2,
FALSE, FALSE,
&err);
g_assert(err == NULL);
/* key2 came first, and should'nt be duplicated */
test_authorized_keys_equal("algo key2 comments\n"
"algo key1 comments");
}
static void
test_add_reset_keys(void)
{
Error *err = NULL;
qmp_guest_ssh_add_authorized_keys(g_get_user_name(),
(strList *)&test_key1_2,
FALSE, FALSE,
&err);
g_assert(err == NULL);
/* reset with key2 only */
test_authorized_keys_equal("algo key1 comments\n"
"algo key2 comments");
qmp_guest_ssh_add_authorized_keys(g_get_user_name(),
(strList *)&test_key2,
TRUE, TRUE,
&err);
g_assert(err == NULL);
test_authorized_keys_equal("algo key2 comments");
/* empty should clear file */
qmp_guest_ssh_add_authorized_keys(g_get_user_name(),
(strList *)NULL,
TRUE, TRUE,
&err);
g_assert(err == NULL);
test_authorized_keys_equal("");
}
static void
test_remove_keys(void)
{
Error *err = NULL;
static const char *authkeys =
"algo key1 comments\n"
/* originally duplicated */
"algo key1 comments\n"
"# a commented line\n"
"algo some-key another\n";
test_authorized_keys_set(authkeys);
qmp_guest_ssh_remove_authorized_keys(g_get_user_name(),
(strList *)&test_key2, &err);
g_assert(err == NULL);
test_authorized_keys_equal(authkeys);
qmp_guest_ssh_remove_authorized_keys(g_get_user_name(),
(strList *)&test_key1_2, &err);
g_assert(err == NULL);
test_authorized_keys_equal("# a commented line\n"
"algo some-key another\n");
}
static void
test_get_keys(void)
{
Error *err = NULL;
static const char *authkeys =
"algo key1 comments\n"
"# a commented line\n"
"algo some-key another\n";
g_autoptr(GuestAuthorizedKeys) ret = NULL;
strList *k;
size_t len = 0;
test_authorized_keys_set(authkeys);
ret = qmp_guest_ssh_get_authorized_keys(g_get_user_name(), &err);
g_assert(err == NULL);
for (len = 0, k = ret->keys; k != NULL; k = k->next) {
g_assert(g_str_has_prefix(k->value, "algo "));
len++;
}
g_assert(len == 2);
}
int main(int argc, char *argv[])
{
setlocale(LC_ALL, "");
g_test_init(&argc, &argv, G_TEST_OPTION_ISOLATE_DIRS, NULL);
g_test_add_func("/qga/ssh/invalid_user", test_invalid_user);
g_test_add_func("/qga/ssh/invalid_key", test_invalid_key);
g_test_add_func("/qga/ssh/add_keys", test_add_keys);
g_test_add_func("/qga/ssh/add_reset_keys", test_add_reset_keys);
g_test_add_func("/qga/ssh/remove_keys", test_remove_keys);
g_test_add_func("/qga/ssh/get_keys", test_get_keys);
return g_test_run();
}
#else
int main(int argc, char *argv[])
{
g_test_message("test skipped, needs glib >= 2.60");
return 0;
}
#endif /* GLIB_2_60 */
#endif /* BUILD_UNIT_TEST */