2 files changed, 50 insertions, 28 deletions

diff --git a/pkg/rootless/rootless_linux.c b/pkg/rootless/rootless_linux.c
index 041a161dc..6643bfbbf 100644
--- a/pkg/rootless/rootless_linux.c
+++ b/pkg/rootless/rootless_linux.c
@@ -58,7 +58,7 @@ static const char *_max_user_namespaces = "/proc/sys/user/max_user_namespaces";
 static const char *_unprivileged_user_namespaces = "/proc/sys/kernel/unprivileged_userns_clone";
 
 static int open_files_max_fd;
-fd_set open_files_set;
+static fd_set *open_files_set;
 static uid_t rootless_uid_init;
 static gid_t rootless_gid_init;
 
@@ -108,10 +108,9 @@ do_pause ()
 }
 
 static char **
-get_cmd_line_args (pid_t pid)
+get_cmd_line_args ()
 {
   int fd;
-  char path[PATH_MAX];
   char *buffer;
   size_t allocated;
   size_t used = 0;
@@ -119,11 +118,7 @@ get_cmd_line_args (pid_t pid)
   int i, argc = 0;
   char **argv;
 
-  if (pid)
-    sprintf (path, "/proc/%d/cmdline", pid);
-  else
-    strcpy (path, "/proc/self/cmdline");
-  fd = open (path, O_RDONLY);
+  fd = open ("/proc/self/cmdline", O_RDONLY);
   if (fd < 0)
     return NULL;
 
@@ -196,10 +191,13 @@ can_use_shortcut ()
   return false;
 #endif
 
-  argv = get_cmd_line_args (0);
+  argv = get_cmd_line_args ();
   if (argv == NULL)
     return false;
 
+  if (strstr (argv[0], "podman") == NULL)
+    return false;
+
   for (argc = 0; argv[argc]; argc++)
     {
       if (argc == 0 || argv[argc][0] == '-')
@@ -237,17 +235,39 @@ static void __attribute__((constructor)) init()
   if (d)
     {
       struct dirent *ent;
+      size_t size = 0;
 
-      FD_ZERO (&open_files_set);
       for (ent = readdir (d); ent; ent = readdir (d))
         {
-          int fd = atoi (ent->d_name);
-          if (fd != dirfd (d))
+          int fd;
+
+          if (ent->d_name[0] == '.')
+            continue;
+
+          fd = atoi (ent->d_name);
+          if (fd == dirfd (d))
+            continue;
+
+          if (fd >= size * FD_SETSIZE)
             {
-              if (fd > open_files_max_fd)
-                open_files_max_fd = fd;
-              FD_SET (fd, &open_files_set);
+              int i;
+              size_t new_size;
+
+              new_size = (fd / FD_SETSIZE) + 1;
+              open_files_set = realloc (open_files_set, new_size * sizeof (fd_set));
+              if (open_files_set == NULL)
+                _exit (EXIT_FAILURE);
+
+              for (i = size; i < new_size; i++)
+                FD_ZERO (&(open_files_set[i]));
+
+              size = new_size;
             }
+
+          if (fd > open_files_max_fd)
+            open_files_max_fd = fd;
+
+          FD_SET (fd % FD_SETSIZE, &(open_files_set[fd / FD_SETSIZE]));
         }
       closedir (d);
     }
@@ -517,7 +537,6 @@ create_pause_process (const char *pause_pid_file_path, char **argv)
 int
 reexec_userns_join (int userns, int mountns, char *pause_pid_file_path)
 {
-  pid_t ppid = getpid ();
   char uid[16];
   char gid[16];
   char **argv;
@@ -534,7 +553,7 @@ reexec_userns_join (int userns, int mountns, char *pause_pid_file_path)
   sprintf (uid, "%d", geteuid ());
   sprintf (gid, "%d", getegid ());
 
-  argv = get_cmd_line_args (ppid);
+  argv = get_cmd_line_args ();
   if (argv == NULL)
     {
       fprintf (stderr, "cannot read argv: %s\n", strerror (errno));
@@ -550,10 +569,8 @@ reexec_userns_join (int userns, int mountns, char *pause_pid_file_path)
       /* We passed down these fds, close them.  */
       int f;
       for (f = 3; f < open_files_max_fd; f++)
-        {
-          if (FD_ISSET (f, &open_files_set))
-            close (f);
-        }
+        if (open_files_set == NULL || FD_ISSET (f % FD_SETSIZE, &(open_files_set[f / FD_SETSIZE])))
+          close (f);
       return pid;
     }
 
@@ -701,7 +718,6 @@ reexec_in_user_namespace (int ready, char *pause_pid_file_path, char *file_to_re
   int ret;
   pid_t pid;
   char b;
-  pid_t ppid = getpid ();
   char **argv;
   char uid[16];
   char gid[16];
@@ -744,10 +760,11 @@ reexec_in_user_namespace (int ready, char *pause_pid_file_path, char *file_to_re
           num_fds = strtol (listen_fds, NULL, 10);
           if (num_fds != LONG_MIN && num_fds != LONG_MAX)
             {
-              long i;
-              for (i = 3; i < num_fds + 3; i++)
-                if (FD_ISSET (i, &open_files_set))
-                  close (i);
+              int f;
+
+              for (f = 3; f < num_fds + 3; f++)
+                if (open_files_set == NULL || FD_ISSET (f % FD_SETSIZE, &(open_files_set[f / FD_SETSIZE])))
+                  close (f);
             }
           unsetenv ("LISTEN_PID");
           unsetenv ("LISTEN_FDS");
@@ -777,7 +794,7 @@ reexec_in_user_namespace (int ready, char *pause_pid_file_path, char *file_to_re
       _exit (EXIT_FAILURE);
     }
 
-  argv = get_cmd_line_args (ppid);
+  argv = get_cmd_line_args ();
   if (argv == NULL)
     {
       fprintf (stderr, "cannot read argv: %s\n", strerror (errno));
diff --git a/pkg/rootless/rootless_linux.go b/pkg/rootless/rootless_linux.go
index 182a39f6b..5ddfab7ad 100644
--- a/pkg/rootless/rootless_linux.go
+++ b/pkg/rootless/rootless_linux.go
@@ -452,6 +452,7 @@ func TryJoinFromFilePaths(pausePidPath string, needNewNamespace bool, paths []st
 
 	var lastErr error
 	var pausePid int
+	foundProcess := false
 
 	for _, path := range paths {
 		if !needNewNamespace {
@@ -502,12 +503,16 @@ func TryJoinFromFilePaths(pausePidPath string, needNewNamespace bool, paths []st
 			}
 
 			pausePid, err = strconv.Atoi(string(b[:n]))
-			if err == nil {
+			if err == nil && unix.Kill(pausePid, 0) == nil {
+				foundProcess = true
 				lastErr = nil
 				break
 			}
 		}
 	}
+	if !foundProcess && pausePidPath != "" {
+		return BecomeRootInUserNS(pausePidPath)
+	}
 	if lastErr != nil {
 		return false, 0, lastErr
 	}