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-rw-r--r--pkg/rootless/rootless_linux.c113
-rw-r--r--pkg/rootless/rootless_linux.go112
-rw-r--r--pkg/rootless/rootless_unsupported.go12
3 files changed, 197 insertions, 40 deletions
diff --git a/pkg/rootless/rootless_linux.c b/pkg/rootless/rootless_linux.c
index b08a27fec..2356882e7 100644
--- a/pkg/rootless/rootless_linux.c
+++ b/pkg/rootless/rootless_linux.c
@@ -346,6 +346,26 @@ syscall_clone (unsigned long flags, void *child_stack)
#endif
}
+int
+reexec_in_user_namespace_wait (int pid, int options)
+{
+ pid_t p;
+ int status;
+
+ do
+ p = waitpid (pid, &status, 0);
+ while (p < 0 && errno == EINTR);
+
+ if (p < 0)
+ return -1;
+
+ if (WIFEXITED (status))
+ return WEXITSTATUS (status);
+ if (WIFSIGNALED (status))
+ return 128 + WTERMSIG (status);
+ return -1;
+}
+
static int
create_pause_process (const char *pause_pid_file_path, char **argv)
{
@@ -369,6 +389,8 @@ create_pause_process (const char *pause_pid_file_path, char **argv)
while (r < 0 && errno == EINTR);
close (p[0]);
+ reexec_in_user_namespace_wait(r, 0);
+
return r == 1 && b == '0' ? 0 : -1;
}
else
@@ -573,8 +595,51 @@ check_proc_sys_userns_file (const char *path)
}
}
+static int
+copy_file_to_fd (const char *file_to_read, int outfd)
+{
+ char buf[512];
+ int fd;
+
+ fd = open (file_to_read, O_RDONLY);
+ if (fd < 0)
+ return fd;
+
+ for (;;)
+ {
+ ssize_t r, w, t = 0;
+
+ do
+ r = read (fd, buf, sizeof buf);
+ while (r < 0 && errno == EINTR);
+ if (r < 0)
+ {
+ close (fd);
+ return r;
+ }
+
+ if (r == 0)
+ break;
+
+ while (t < r)
+ {
+ do
+ w = write (outfd, &buf[t], r - t);
+ while (w < 0 && errno == EINTR);
+ if (w < 0)
+ {
+ close (fd);
+ return w;
+ }
+ t += w;
+ }
+ }
+ close (fd);
+ return 0;
+}
+
int
-reexec_in_user_namespace (int ready, char *pause_pid_file_path)
+reexec_in_user_namespace (int ready, char *pause_pid_file_path, char *file_to_read, int outputfd)
{
int ret;
pid_t pid;
@@ -598,11 +663,11 @@ reexec_in_user_namespace (int ready, char *pause_pid_file_path)
listen_pid = getenv("LISTEN_PID");
listen_fds = getenv("LISTEN_FDS");
- if (listen_pid != NULL && listen_fds != NULL) {
- if (strtol(listen_pid, NULL, 10) == getpid()) {
- do_socket_activation = true;
+ if (listen_pid != NULL && listen_fds != NULL)
+ {
+ if (strtol(listen_pid, NULL, 10) == getpid())
+ do_socket_activation = true;
}
- }
sprintf (uid, "%d", geteuid ());
sprintf (gid, "%d", getegid ());
@@ -658,11 +723,12 @@ reexec_in_user_namespace (int ready, char *pause_pid_file_path)
_exit (EXIT_FAILURE);
}
- if (do_socket_activation) {
- char s[32];
- sprintf (s, "%d", getpid());
- setenv ("LISTEN_PID", s, true);
- }
+ if (do_socket_activation)
+ {
+ char s[32];
+ sprintf (s, "%d", getpid());
+ setenv ("LISTEN_PID", s, true);
+ }
setenv ("_CONTAINERS_USERNS_CONFIGURED", "init", 1);
setenv ("_CONTAINERS_ROOTLESS_UID", uid, 1);
@@ -721,27 +787,14 @@ reexec_in_user_namespace (int ready, char *pause_pid_file_path)
_exit (EXIT_FAILURE);
}
+ if (file_to_read && file_to_read[0])
+ {
+ ret = copy_file_to_fd (file_to_read, outputfd);
+ close (outputfd);
+ _exit (ret == 0 ? EXIT_SUCCESS : EXIT_FAILURE);
+ }
+
execvp (argv[0], argv);
_exit (EXIT_FAILURE);
}
-
-int
-reexec_in_user_namespace_wait (int pid)
-{
- pid_t p;
- int status;
-
- do
- p = waitpid (pid, &status, 0);
- while (p < 0 && errno == EINTR);
-
- if (p < 0)
- return -1;
-
- if (WIFEXITED (status))
- return WEXITSTATUS (status);
- if (WIFSIGNALED (status))
- return 128 + WTERMSIG (status);
- return -1;
-}
diff --git a/pkg/rootless/rootless_linux.go b/pkg/rootless/rootless_linux.go
index 9132c0fe5..27d64d1fc 100644
--- a/pkg/rootless/rootless_linux.go
+++ b/pkg/rootless/rootless_linux.go
@@ -26,8 +26,8 @@ import (
#include <stdlib.h>
extern uid_t rootless_uid();
extern uid_t rootless_gid();
-extern int reexec_in_user_namespace(int ready, char *pause_pid_file_path);
-extern int reexec_in_user_namespace_wait(int pid);
+extern int reexec_in_user_namespace(int ready, char *pause_pid_file_path, char *file_to_read, int fd);
+extern int reexec_in_user_namespace_wait(int pid, int options);
extern int reexec_userns_join(int userns, int mountns, char *pause_pid_file_path);
*/
import "C"
@@ -226,7 +226,7 @@ func JoinUserAndMountNS(pid uint, pausePid string) (bool, int, error) {
return false, -1, errors.Errorf("cannot re-exec process")
}
- ret := C.reexec_in_user_namespace_wait(pidC)
+ ret := C.reexec_in_user_namespace_wait(pidC, 0)
if ret < 0 {
return false, -1, errors.New("error waiting for the re-exec process")
}
@@ -234,11 +234,7 @@ func JoinUserAndMountNS(pid uint, pausePid string) (bool, int, error) {
return true, int(ret), nil
}
-// BecomeRootInUserNS re-exec podman in a new userNS. It returns whether podman was re-executed
-// into a new user namespace and the return code from the re-executed podman process.
-// If podman was re-executed the caller needs to propagate the error code returned by the child
-// process.
-func BecomeRootInUserNS(pausePid string) (bool, int, error) {
+func becomeRootInUserNS(pausePid, fileToRead string, fileOutput *os.File) (bool, int, error) {
if os.Geteuid() == 0 || os.Getenv("_CONTAINERS_USERNS_CONFIGURED") != "" {
if os.Getenv("_CONTAINERS_USERNS_CONFIGURED") == "init" {
return false, 0, runInUser()
@@ -249,6 +245,13 @@ func BecomeRootInUserNS(pausePid string) (bool, int, error) {
cPausePid := C.CString(pausePid)
defer C.free(unsafe.Pointer(cPausePid))
+ cFileToRead := C.CString(fileToRead)
+ defer C.free(unsafe.Pointer(cFileToRead))
+ var fileOutputFD C.int
+ if fileOutput != nil {
+ fileOutputFD = C.int(fileOutput.Fd())
+ }
+
runtime.LockOSThread()
defer runtime.UnlockOSThread()
@@ -262,7 +265,7 @@ func BecomeRootInUserNS(pausePid string) (bool, int, error) {
defer w.Close()
defer w.Write([]byte("0"))
- pidC := C.reexec_in_user_namespace(C.int(r.Fd()), cPausePid)
+ pidC := C.reexec_in_user_namespace(C.int(r.Fd()), cPausePid, cFileToRead, fileOutputFD)
pid := int(pidC)
if pid < 0 {
return false, -1, errors.Errorf("cannot re-exec process")
@@ -328,6 +331,10 @@ func BecomeRootInUserNS(pausePid string) (bool, int, error) {
return false, -1, errors.Wrapf(err, "read from sync pipe")
}
+ if fileOutput != nil {
+ return true, 0, nil
+ }
+
if b[0] == '2' {
// We have lost the race for writing the PID file, as probably another
// process created a namespace and wrote the PID.
@@ -368,10 +375,95 @@ func BecomeRootInUserNS(pausePid string) (bool, int, error) {
}
}()
- ret := C.reexec_in_user_namespace_wait(pidC)
+ ret := C.reexec_in_user_namespace_wait(pidC, 0)
if ret < 0 {
return false, -1, errors.New("error waiting for the re-exec process")
}
return true, int(ret), nil
}
+
+// BecomeRootInUserNS re-exec podman in a new userNS. It returns whether podman was re-executed
+// into a new user namespace and the return code from the re-executed podman process.
+// If podman was re-executed the caller needs to propagate the error code returned by the child
+// process.
+func BecomeRootInUserNS(pausePid string) (bool, int, error) {
+ return becomeRootInUserNS(pausePid, "", nil)
+}
+
+// TryJoinFromFilePaths attempts to join the namespaces of the pid files in paths.
+// This is useful when there are already running containers and we
+// don't have a pause process yet. We can use the paths to the conmon
+// processes to attempt joining their namespaces.
+// If needNewNamespace is set, the file is read from a temporary user
+// namespace, this is useful for containers that are running with a
+// different uidmap and the unprivileged user has no way to read the
+// file owned by the root in the container.
+func TryJoinFromFilePaths(pausePidPath string, needNewNamespace bool, paths []string) (bool, int, error) {
+ if len(paths) == 0 {
+ return BecomeRootInUserNS(pausePidPath)
+ }
+
+ var lastErr error
+ var pausePid int
+
+ for _, path := range paths {
+ if !needNewNamespace {
+ data, err := ioutil.ReadFile(path)
+ if err != nil {
+ lastErr = err
+ continue
+ }
+
+ pausePid, err = strconv.Atoi(string(data))
+ if err != nil {
+ lastErr = errors.Wrapf(err, "cannot parse file %s", path)
+ continue
+ }
+
+ lastErr = nil
+ break
+ } else {
+ fds, err := syscall.Socketpair(syscall.AF_UNIX, syscall.SOCK_DGRAM, 0)
+ if err != nil {
+ lastErr = err
+ continue
+ }
+
+ r, w := os.NewFile(uintptr(fds[0]), "read file"), os.NewFile(uintptr(fds[1]), "write file")
+
+ defer w.Close()
+ defer r.Close()
+
+ if _, _, err := becomeRootInUserNS("", path, w); err != nil {
+ lastErr = err
+ continue
+ }
+
+ w.Close()
+ defer func() {
+ r.Close()
+ C.reexec_in_user_namespace_wait(-1, 0)
+ }()
+
+ b := make([]byte, 32)
+
+ n, err := r.Read(b)
+ if err != nil {
+ lastErr = errors.Wrapf(err, "cannot read %s\n", path)
+ continue
+ }
+
+ pausePid, err = strconv.Atoi(string(b[:n]))
+ if err == nil {
+ lastErr = nil
+ break
+ }
+ }
+ }
+ if lastErr != nil {
+ return false, 0, lastErr
+ }
+
+ return JoinUserAndMountNS(uint(pausePid), pausePidPath)
+}
diff --git a/pkg/rootless/rootless_unsupported.go b/pkg/rootless/rootless_unsupported.go
index 221baff97..06781e6ce 100644
--- a/pkg/rootless/rootless_unsupported.go
+++ b/pkg/rootless/rootless_unsupported.go
@@ -36,3 +36,15 @@ func GetRootlessGID() int {
func JoinUserAndMountNS(pid uint, pausePid string) (bool, int, error) {
return false, -1, errors.New("this function is not supported on this os")
}
+
+// TryJoinFromFilePaths attempts to join the namespaces of the pid files in paths.
+// This is useful when there are already running containers and we
+// don't have a pause process yet. We can use the paths to the conmon
+// processes to attempt joining their namespaces.
+// If needNewNamespace is set, the file is read from a temporary user
+// namespace, this is useful for containers that are running with a
+// different uidmap and the unprivileged user has no way to read the
+// file owned by the root in the container.
+func TryJoinFromFilePaths(pausePidPath string, needNewNamespace bool, paths []string) (bool, int, error) {
+ return false, -1, errors.New("this function is not supported on this os")
+}
generated by cgit v1.2.3-54-g00ecf (git 2.39.0) at 2024-11-06 07:38:10 +0000