Le 28/10/2022 à 10:12, Icenowy Zheng a écrit :
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 <u...@icenowy.me> --- 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 8402c1399d..029a4e8b42 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -3346,7 +3346,8 @@ 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)) {
Applied to my linux-user-for-7.2 branch. Thanks, Laurent
