From: Icenowy Zheng <[email protected]> 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 <[email protected]> Reviewed-by: Laurent Vivier <[email protected]> Message-Id: <[email protected]> Signed-off-by: Laurent Vivier <[email protected]> --- 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 8b18adfba894..24b25759beab 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -3353,7 +3353,8 @@ 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)) { -- 2.37.3
