From eb2a5f2f73e4cfaf20246fb3d3fb1b8bd5716606 Mon Sep 17 00:00:00 2001 From: jianchunfu Date: Tue, 22 Nov 2022 17:10:35 +0800 Subject: [PATCH 03/29] linux-user: always translate cmsg when recvmsg It's possible that a message contains both normal payload and ancillary data in the same message, and even if no ancillary data is available this information should be passed to the target, otherwise the target cmsghdr will be left uninitialized and the target is going to access uninitialized memory if it expects cmsg. Always call the function that translate cmsg when recvmsg, because that function should be empty-cmsg-safe(it creates an empty cmsg in the target). Signed-off-by: Icenowy Zheng Signed-off-by: jianchunfu --- linux-user/syscall.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/linux-user/syscall.c b/linux-user/syscall.c index f1cfcc8104..fce2c03259 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -3296,7 +3296,8 @@ static abi_long do_sendrecvmsg_locked(int fd, struct target_msghdr *msgp, if (fd_trans_host_to_target_data(fd)) { ret = fd_trans_host_to_target_data(fd)(msg.msg_iov->iov_base, MIN(msg.msg_iov->iov_len, len)); - } else { + } + if (!is_error(ret)) { ret = host_to_target_cmsg(msgp, &msg); } if (!is_error(ret)) { -- 2.27.0