libmount: idmap: fix sock write to child

The current code writes to sock_fds[0], which is set to -1 on line 227, instead of the correct sock_fds[1].
As a cause, a simple `mount` command which uses idmapping and doesn't specify a user ns hangs indefinitely.

diff --git a/libmount/src/hook_idmap.c b/libmount/src/hook_idmap.c
index 7e7c9e742fd2eb4181573fcc751061737d73943d..9306e5d9711f857e0acf3b0fe99075a8f5d3d20e 100644 (file)
--- a/libmount/src/hook_idmap.c
+++ b/libmount/src/hook_idmap.c
@@ -240,7 +240,7 @@ static int get_userns_fd_from_idmap(struct list_head *idmap)
        fd_userns = open(path, O_RDONLY | O_CLOEXEC | O_NOCTTY);
 
        /* Let child know we've persisted its namespace. */
-       (void)write_all(sock_fds[0], &c, 1);
+       (void)write_all(sock_fds[1], &c, 1);
 
 err_wait:
        rc = wait_for_pid(pid);