Commit 2a03d3e6 authored by Laurent Vivier's avatar Laurent Vivier
Browse files

linux-user: fix recvmsg()/recvfrom() with netlink and MSG_TRUNC 

If recvmsg()/recvfrom() are used with the MSG_TRUNC flag, they return the
real length even if it was longer than the passed buffer.
So when we translate the buffer we must check we don't go beyond the
end of the buffer.

Bug: https://github.com/vivier/qemu-m68k/issues/33


Reported-by: default avatarJohn Paul Adrian Glaubitz <glaubitz@physik.fu-berlin.de>
Signed-off-by: default avatarLaurent Vivier <laurent@vivier.eu>
Reviewed-by: default avatarPeter Maydell <peter.maydell@linaro.org>
Message-Id: <20180820171557.7734-2-laurent@vivier.eu>
parent 5b38d026

linux-user/syscall.c

+7 −2
Original line number Diff line number Diff line
@@ -3892,7 +3892,7 @@ static abi_long do_sendrecvmsg_locked(int fd, struct target_msghdr *msgp, 
            len = ret;

            if (fd_trans_host_to_target_data(fd)) {

                ret = fd_trans_host_to_target_data(fd)(msg.msg_iov->iov_base,

                                                       len);

                                               MIN(msg.msg_iov->iov_len, len));

            } else {

                ret = host_to_target_cmsg(msgp, &msg);

            }
@@ -4169,7 +4169,12 @@ static abi_long do_recvfrom(int fd, abi_ulong msg, size_t len, int flags, 
    }

    if (!is_error(ret)) {

        if (fd_trans_host_to_target_data(fd)) {

            ret = fd_trans_host_to_target_data(fd)(host_msg, ret);

            abi_long trans;

            trans = fd_trans_host_to_target_data(fd)(host_msg, MIN(ret, len));

            if (is_error(trans)) {

                ret = trans;

                goto fail;

            }

        }

        if (target_addr) {

            host_to_target_sockaddr(target_addr, addr, addrlen);