[lxc-devel] [PATCH] handle unprivileged user calls more gracefully

[S.Çağlar Onur]

Return an error if the function is not supposed to be called by an unprivileged user.
Otherwise those calls fail in the middle of their execution with different reasons.

Signed-off-by: S.Çağlar Onur <caglar at 10ur.org>
---
 src/lxc/lxccontainer.c | 33 ++++++++++++++++++++++++++++-----
 1 file changed, 28 insertions(+), 5 deletions(-)

diff --git a/src/lxc/lxccontainer.c b/src/lxc/lxccontainer.c
index 0bebdff..8d49e94 100644
--- a/src/lxc/lxccontainer.c
+++ b/src/lxc/lxccontainer.c
@@ -64,6 +64,10 @@
 
 lxc_log_define(lxc_container, lxc);
 
+static bool am_unpriv(struct lxc_container *c) {
+	return c->lxc_conf && geteuid() != 0 && !lxc_list_empty(&c->lxc_conf->id_map);
+}
+
 static bool file_exists(const char *f)
 {
 	struct stat statbuf;
@@ -1489,6 +1493,9 @@ static char** lxcapi_get_interfaces(struct lxc_container *c)
 	char **interfaces = NULL;
 	int old_netns = -1, new_netns = -1;
 
+	if (am_unpriv(c))
+		goto out;
+
 	if (!enter_to_ns(c, &old_netns, &new_netns))
 		goto out;
 
@@ -1538,6 +1545,9 @@ static char** lxcapi_get_ips(struct lxc_container *c, const char* interface, con
 	char *address = NULL;
 	int old_netns = -1, new_netns = -1;
 
+	if (am_unpriv(c))
+		goto out;
+
 	if (!enter_to_ns(c, &old_netns, &new_netns))
 		goto out;
 
@@ -1818,7 +1828,7 @@ static int lxc_rmdir_onedev_wrapper(void *data)
 static bool lxcapi_destroy(struct lxc_container *c)
 {
 	struct bdev *r = NULL;
-	bool bret = false, am_unpriv;
+	bool bret = false;
 	int ret;
 
 	if (!c || !lxcapi_is_defined(c))
@@ -1833,14 +1843,12 @@ static bool lxcapi_destroy(struct lxc_container *c)
 		goto out;
 	}
 
-	am_unpriv = c->lxc_conf && geteuid() != 0 && !lxc_list_empty(&c->lxc_conf->id_map);
-
 	if (c->lxc_conf && has_snapshots(c)) {
 		ERROR("container %s has dependent snapshots", c->name);
 		goto out;
 	}
 
-	if (!am_unpriv && c->lxc_conf->rootfs.path && c->lxc_conf->rootfs.mount) {
+	if (!am_unpriv(c) && c->lxc_conf->rootfs.path && c->lxc_conf->rootfs.mount) {
 		r = bdev_init(c->lxc_conf->rootfs.path, c->lxc_conf->rootfs.mount, NULL);
 		if (r) {
 			if (r->ops->destroy(r) < 0) {
@@ -1857,7 +1865,7 @@ static bool lxcapi_destroy(struct lxc_container *c)
 	const char *p1 = lxcapi_get_config_path(c);
 	char *path = alloca(strlen(p1) + strlen(c->name) + 2);
 	sprintf(path, "%s/%s", p1, c->name);
-	if (am_unpriv)
+	if (am_unpriv(c))
 		ret = userns_exec_1(c->lxc_conf, lxc_rmdir_onedev_wrapper, path);
 	else
 		ret = lxc_rmdir_onedev(path);
@@ -2406,6 +2414,9 @@ static struct lxc_container *lxcapi_clone(struct lxc_container *c, const char *n
 	if (!c || !c->is_defined(c))
 		return NULL;
 
+	if (am_unpriv(c))
+		return NULL;
+
 	if (container_mem_lock(c))
 		return NULL;
 
@@ -2587,6 +2598,9 @@ static int lxcapi_snapshot(struct lxc_container *c, const char *commentfile)
 	struct lxc_container *c2;
 	char snappath[MAXPATHLEN], newname[20];
 
+	if (am_unpriv(c))
+		return -1;
+
 	// /var/lib/lxc -> /var/lib/lxcsnaps \0
 	ret = snprintf(snappath, MAXPATHLEN, "%ssnaps/%s", c->config_path, c->name);
 	if (ret < 0 || ret >= MAXPATHLEN)
@@ -2802,6 +2816,9 @@ static bool lxcapi_snapshot_restore(struct lxc_container *c, const char *snapnam
 	if (!c || !c->name || !c->config_path)
 		return false;
 
+	if (am_unpriv(c))
+		return false;
+
 	bdev = bdev_init(c->lxc_conf->rootfs.path, c->lxc_conf->rootfs.mount, NULL);
 	if (!bdev) {
 		ERROR("Failed to find original backing store type");
@@ -2851,6 +2868,9 @@ static bool lxcapi_snapshot_destroy(struct lxc_container *c, const char *snapnam
 	if (!c || !c->name || !c->config_path)
 		return false;
 
+	if (am_unpriv(c))
+		return false;
+
 	ret = snprintf(clonelxcpath, MAXPATHLEN, "%ssnaps/%s", c->config_path, c->name);
 	if (ret < 0 || ret >= MAXPATHLEN)
 		goto err;
@@ -2888,6 +2908,9 @@ static bool add_remove_device_node(struct lxc_container *c, const char *src_path
 	char *directory_path = NULL;
 	const char *p;
 
+	if (am_unpriv(c))
+		goto out;
+
 	/* make sure container is running */
 	if (!c->is_running(c)) {
 		ERROR("container is not running");
-- 
1.8.3.2