drop privs when permissions are changed in /run/user/$UID

2 files changed, 43 insertions, 7 deletions

diff --git a/src/firejail/fs.c b/src/firejail/fs.c
index 24ff553d7..8db14d502 100644
--- a/src/firejail/fs.c
+++ b/src/firejail/fs.c
@@ -641,8 +641,26 @@ void fs_proc_sys_dev_boot(void) {
                         char *fnamegpg;
                         if (asprintf(&fnamegpg, "/run/user/%d/gnupg", getuid()) == -1)
                                 errExit("asprintf");
-                        if (stat(fnamegpg, &s) == -1)
-                            mkdir_attr(fnamegpg, 0700, getuid(), getgid());
+                        if (stat(fnamegpg, &s) == -1) {
+                                pid_t child = fork();
+                                if (child < 0)
+                                        errExit("fork");
+                                if (child == 0) {
+                                        // drop privileges
+                                        drop_privs(0);
+                                        if (mkdir(fnamegpg, 0700) == -1)
+                                                {;} // do nothing
+                                        if (set_perms(fnamegpg, -1, -1, 0700))
+                                                {;}
+#ifdef HAVE_GCOV
+                                        __gcov_flush();
+#endif
+                                        _exit(0);
+                                }
+                                // wait for the child to finish
+                                waitpid(child, NULL, 0);
+                                fs_logger2("create", fnamegpg);
+                        }
                         if (stat(fnamegpg, &s) == 0)
                                 disable_file(BLACKLIST_FILE, fnamegpg);
                         free(fnamegpg);
@@ -651,8 +669,26 @@ void fs_proc_sys_dev_boot(void) {
                         char *fnamesysd;
                         if (asprintf(&fnamesysd, "/run/user/%d/systemd", getuid()) == -1)
                                 errExit("asprintf");
-                        if (stat(fnamesysd, &s) == -1)
-                                mkdir_attr(fnamesysd, 0755, getuid(), getgid());
+                        if (stat(fnamesysd, &s) == -1) {
+                                pid_t child = fork();
+                                if (child < 0)
+                                        errExit("fork");
+                                if (child == 0) {
+                                        // drop privileges
+                                        drop_privs(0);
+                                        if (mkdir(fnamesysd, 0755) == -1)
+                                                {;} // do nothing
+                                        if (set_perms(fnamesysd, -1, -1, 0755))
+                                                {;}
+#ifdef HAVE_GCOV
+                                        __gcov_flush();
+#endif
+                                        _exit(0);
+                                }
+                                // wait for the child to finish
+                                waitpid(child, NULL, 0);
+                                fs_logger2("create", fnamesysd);
+                        }
                         if (stat(fnamesysd, &s) == 0)
                                 disable_file(BLACKLIST_FILE, fnamesysd);
                         free(fnamesysd);
diff --git a/src/firejail/util.c b/src/firejail/util.c
index c15e3b691..86faaf8b8 100644
--- a/src/firejail/util.c
+++ b/src/firejail/util.c
@@ -1053,7 +1053,7 @@ int safe_fd(const char *path, int flags) {
                 errExit("open");
 
         // traverse the path and return -1 if a symlink is encountered
-        int entered = 0;
+        int weird_pathname = 1;
         int fd = -1;
         char *tok = strtok(dup, "/");
         while (tok) {
@@ -1062,7 +1062,7 @@ int safe_fd(const char *path, int flags) {
                         tok = strtok(NULL, "/");
                         continue;
                 }
-                entered = 1;
+                weird_pathname = 0;
 
                 // open the directory
                 fd = openat(parentfd, tok, O_PATH|O_DIRECTORY|O_NOFOLLOW|O_CLOEXEC);
@@ -1077,7 +1077,7 @@ int safe_fd(const char *path, int flags) {
         }
         if (p != dup) {
                 // consistent flags for top level directories (////foo, /.///foo)
-                if (!entered)
+                if (weird_pathname)
                         flags = O_PATH|O_DIRECTORY|O_CLOEXEC;
                 // open last path segment
                 fd = openat(parentfd, p + 1, flags|O_NOFOLLOW);