utils: harden __safe_mount_beneath_at()

Signed-off-by: Christian Brauner <christian.brauner@ubuntu.com>

diff --git a/src/lxc/utils.c b/src/lxc/utils.c
index 12735f589683ebe5cfaac09dd77b0bd643cbe4fc..e947650860f33ad2bfa81feb6688dcc999753702 100644 (file)
--- a/src/lxc/utils.c
+++ b/src/lxc/utils.c
@@ -1081,8 +1081,8 @@ int __safe_mount_beneath_at(int beneath_fd, const char *src, const char *dst, co
 {
        __do_close int source_fd = -EBADF, target_fd = -EBADF;
        struct lxc_open_how how = {
-               .flags          = O_RDONLY | O_CLOEXEC | O_PATH,
-               .resolve        = RESOLVE_NO_SYMLINKS | RESOLVE_NO_MAGICLINKS | RESOLVE_BENEATH,
+               .flags          = PROTECT_OPATH_DIRECTORY,
+               .resolve        = PROTECT_LOOKUP_BENEATH_WITH_MAGICLINKS,
        };
        int ret;
        char src_buf[LXC_PROC_PID_FD_LEN], tgt_buf[LXC_PROC_PID_FD_LEN];
@@ -1122,7 +1122,7 @@ int safe_mount_beneath(const char *beneath, const char *src, const char *dst, co
        __do_close int beneath_fd = -EBADF;
        const char *path = beneath ? beneath : "/";
 
-       beneath_fd = openat(-1, path, O_RDONLY | O_CLOEXEC | O_DIRECTORY | O_PATH);
+       beneath_fd = openat(-1, path, PROTECT_OPATH_DIRECTORY);
        if (beneath_fd < 0)
                return log_error_errno(-errno, errno, "Failed to open %s", path);