From 2a03d3e6ae1b1ca86199a0c36a35e8ac847905f6 Mon Sep 17 00:00:00 2001 From: Laurent Vivier Date: Mon, 20 Aug 2018 19:15:54 +0200 Subject: [PATCH] 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: John Paul Adrian Glaubitz Signed-off-by: Laurent Vivier Reviewed-by: Peter Maydell Message-Id: <20180820171557.7734-2-laurent@vivier.eu> --- linux-user/syscall.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/linux-user/syscall.c b/linux-user/syscall.c index 1806b33b02..e66faf1c62 100644 --- a/linux-user/syscall.c +++ b/linux-user/syscall.c @@ -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);