From 2bc41ea3b3fd4c2f2473ec84f4ee3ef5ff21e49b Mon Sep 17 00:00:00 2001 From: Olaf Hering Date: Wed, 7 Aug 2013 15:07:21 +0200 Subject: [PATCH] Tools: hv: correct payload size in netlink_send netlink_send is supposed to send just the cn_msg+hv_kvp_msg via netlink. Currently it sets an incorrect iovec size, as reported by valgrind. In the case of registering with the kernel the allocated buffer is large enough to hold nlmsghdr+cn_msg+hv_kvp_msg, no overrun happens. In the case of responding to the kernel the cn_msg is located in the middle of recv_buffer, after the nlmsghdr. Currently the code in netlink_send adds also the size of nlmsghdr to the payload. But nlmsghdr is a separate iovec. This leads to an (harmless) out-of-bounds access when the kernel processes the iovec. Correct the iovec size of the cn_msg to be just cn_msg + its payload. Signed-off-by: Olaf Hering Signed-off-by: K. Y. Srinivasan Signed-off-by: Greg Kroah-Hartman --- tools/hv/hv_kvp_daemon.c | 2 +- tools/hv/hv_vss_daemon.c | 2 +- 2 files changed, 2 insertions(+), 2 deletions(-) diff --git a/tools/hv/hv_kvp_daemon.c b/tools/hv/hv_kvp_daemon.c index b96eccce48e3..dca06a26ee2a 100644 --- a/tools/hv/hv_kvp_daemon.c +++ b/tools/hv/hv_kvp_daemon.c @@ -1398,7 +1398,7 @@ netlink_send(int fd, struct cn_msg *msg) char buffer[64]; struct iovec iov[2]; - size = NLMSG_SPACE(sizeof(struct cn_msg) + msg->len); + size = sizeof(struct cn_msg) + msg->len; nlh = (struct nlmsghdr *)buffer; nlh->nlmsg_seq = 0; diff --git a/tools/hv/hv_vss_daemon.c b/tools/hv/hv_vss_daemon.c index 4213d0e3083f..7cd2544aa49b 100644 --- a/tools/hv/hv_vss_daemon.c +++ b/tools/hv/hv_vss_daemon.c @@ -111,7 +111,7 @@ static int netlink_send(int fd, struct cn_msg *msg) char buffer[64]; struct iovec iov[2]; - size = NLMSG_SPACE(sizeof(struct cn_msg) + msg->len); + size = sizeof(struct cn_msg) + msg->len; nlh = (struct nlmsghdr *)buffer; nlh->nlmsg_seq = 0; -- 2.39.5