From c60389e4f9ea88d7246dbb148d28791d577fe5b4 Mon Sep 17 00:00:00 2001 From: Stephen Hemminger Date: Thu, 13 Sep 2018 12:33:38 -0700 Subject: [PATCH] libnetlink: fix leak and using unused memory on error If an error happens in multi-segment message (tc only) then report the error and stop processing further responses. This also fixes refering to the buffer after free. The sequence check is not necessary here because the response message has already been validated to be in the window of the sequence number of the iov. Reported-by: Mahesh Bandewar Signed-off-by: Stephen Hemminger Acked-by: Mahesh Bandewar --- lib/libnetlink.c | 23 +++++++++-------------- 1 file changed, 9 insertions(+), 14 deletions(-) diff --git a/lib/libnetlink.c b/lib/libnetlink.c index 928de1dd..58680929 100644 --- a/lib/libnetlink.c +++ b/lib/libnetlink.c @@ -617,7 +617,6 @@ static int __rtnl_talk_iov(struct rtnl_handle *rtnl, struct iovec *iov, msg.msg_iovlen = 1; i = 0; while (1) { -next: status = rtnl_recvmsg(rtnl->fd, &msg, &buf); ++i; @@ -660,27 +659,23 @@ next: if (l < sizeof(struct nlmsgerr)) { fprintf(stderr, "ERROR truncated\n"); - } else if (!err->error) { + free(buf); + return -1; + } + + if (!err->error) /* check messages from kernel */ nl_dump_ext_ack(h, errfn); - if (answer) - *answer = (struct nlmsghdr *)buf; - else - free(buf); - if (h->nlmsg_seq == seq) - return 0; - else if (i < iovlen) - goto next; - return 0; - } - if (rtnl->proto != NETLINK_SOCK_DIAG && show_rtnl_err) rtnl_talk_error(h, err, errfn); errno = -err->error; - free(buf); + if (answer) + *answer = (struct nlmsghdr *)buf; + else + free(buf); return -i; }