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Diffstat (limited to 'src/basic/util.c')
-rw-r--r--src/basic/util.c45
1 files changed, 38 insertions, 7 deletions
diff --git a/src/basic/util.c b/src/basic/util.c
index d4d3d3c83a..3811460895 100644
--- a/src/basic/util.c
+++ b/src/basic/util.c
@@ -4950,8 +4950,8 @@ int container_get_leader(const char *machine, pid_t *pid) {
return 0;
}
-int namespace_open(pid_t pid, int *pidns_fd, int *mntns_fd, int *netns_fd, int *root_fd) {
- _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, netnsfd = -1;
+int namespace_open(pid_t pid, int *pidns_fd, int *mntns_fd, int *netns_fd, int *userns_fd, int *root_fd) {
+ _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, netnsfd = -1, usernsfd = -1;
int rfd = -1;
assert(pid >= 0);
@@ -4983,6 +4983,15 @@ int namespace_open(pid_t pid, int *pidns_fd, int *mntns_fd, int *netns_fd, int *
return -errno;
}
+ if (userns_fd) {
+ const char *userns;
+
+ userns = procfs_file_alloca(pid, "ns/user");
+ usernsfd = open(userns, O_RDONLY|O_NOCTTY|O_CLOEXEC);
+ if (usernsfd < 0 && errno != ENOENT)
+ return -errno;
+ }
+
if (root_fd) {
const char *root;
@@ -5001,15 +5010,33 @@ int namespace_open(pid_t pid, int *pidns_fd, int *mntns_fd, int *netns_fd, int *
if (netns_fd)
*netns_fd = netnsfd;
+ if (userns_fd)
+ *userns_fd = usernsfd;
+
if (root_fd)
*root_fd = rfd;
- pidnsfd = mntnsfd = netnsfd = -1;
+ pidnsfd = mntnsfd = netnsfd = usernsfd = -1;
return 0;
}
-int namespace_enter(int pidns_fd, int mntns_fd, int netns_fd, int root_fd) {
+int namespace_enter(int pidns_fd, int mntns_fd, int netns_fd, int userns_fd, int root_fd) {
+ if (userns_fd >= 0) {
+ /* Can't setns to your own userns, since then you could
+ * escalate from non-root to root in your own namespace, so
+ * check if namespaces equal before attempting to enter. */
+ _cleanup_free_ char *userns_fd_path = NULL;
+ int r;
+ if (asprintf(&userns_fd_path, "/proc/self/fd/%d", userns_fd) < 0)
+ return -ENOMEM;
+
+ r = files_same(userns_fd_path, "/proc/self/ns/user");
+ if (r < 0)
+ return r;
+ if (r)
+ userns_fd = -1;
+ }
if (pidns_fd >= 0)
if (setns(pidns_fd, CLONE_NEWPID) < 0)
@@ -5023,6 +5050,10 @@ int namespace_enter(int pidns_fd, int mntns_fd, int netns_fd, int root_fd) {
if (setns(netns_fd, CLONE_NEWNET) < 0)
return -errno;
+ if (userns_fd >= 0)
+ if (setns(userns_fd, CLONE_NEWUSER) < 0)
+ return -errno;
+
if (root_fd >= 0) {
if (fchdir(root_fd) < 0)
return -errno;
@@ -6012,7 +6043,7 @@ int ptsname_malloc(int fd, char **ret) {
}
int openpt_in_namespace(pid_t pid, int flags) {
- _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, rootfd = -1;
+ _cleanup_close_ int pidnsfd = -1, mntnsfd = -1, usernsfd = -1, rootfd = -1;
_cleanup_close_pair_ int pair[2] = { -1, -1 };
union {
struct cmsghdr cmsghdr;
@@ -6029,7 +6060,7 @@ int openpt_in_namespace(pid_t pid, int flags) {
assert(pid > 0);
- r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &rootfd);
+ r = namespace_open(pid, &pidnsfd, &mntnsfd, NULL, &usernsfd, &rootfd);
if (r < 0)
return r;
@@ -6045,7 +6076,7 @@ int openpt_in_namespace(pid_t pid, int flags) {
pair[0] = safe_close(pair[0]);
- r = namespace_enter(pidnsfd, mntnsfd, -1, rootfd);
+ r = namespace_enter(pidnsfd, mntnsfd, -1, usernsfd, rootfd);
if (r < 0)
_exit(EXIT_FAILURE);