From df447a3b4a4b961c9979b4b3ffb74317394b9b40 Mon Sep 17 00:00:00 2001 From: Tiwei Bie Date: Mon, 1 Sep 2025 08:27:15 +0800 Subject: [PATCH] um: Fix FD copy size in os_rcv_fd_msg() When copying FDs, the copy size should not include the control message header (cmsghdr). Fix it. Fixes: 5cde6096a4dd ("um: generalize os_rcv_fd") Signed-off-by: Tiwei Bie Signed-off-by: Johannes Berg --- arch/um/os-Linux/file.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/arch/um/os-Linux/file.c b/arch/um/os-Linux/file.c index 617886d1fb1e..21f0e50fb1df 100644 --- a/arch/um/os-Linux/file.c +++ b/arch/um/os-Linux/file.c @@ -535,7 +535,7 @@ ssize_t os_rcv_fd_msg(int fd, int *fds, unsigned int n_fds, cmsg->cmsg_type != SCM_RIGHTS) return n; - memcpy(fds, CMSG_DATA(cmsg), cmsg->cmsg_len); + memcpy(fds, CMSG_DATA(cmsg), cmsg->cmsg_len - CMSG_LEN(0)); return n; }