From 1e01430bdfcb63c9f8027ddbb204a224cb179576 Mon Sep 17 00:00:00 2001
From: smitsohu <smitsohu@gmail.com>
Date: Wed, 22 Aug 2018 11:03:17 +0200
Subject: drop privs when permissions are changed in /run/user/$UID

---
 src/firejail/fs.c   | 44 ++++++++++++++++++++++++++++++++++++++++----
 src/firejail/util.c |  6 +++---
 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);
-- 
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