From: Maxime Coquelin <maxime.coquelin@redhat.com>
To: dev@dpdk.org, david.marchand@redhat.com, chenbo.xia@intel.com
Subject: Re: [PATCH] vhost: improve truncated messages handling
Date: Fri, 27 Jan 2023 17:30:15 +0100 [thread overview]
Message-ID: <b13dbe7d-a511-6a12-cf0b-0fb1d5149ac5@redhat.com> (raw)
In-Reply-To: <20230127135731.22499-1-maxime.coquelin@redhat.com>
On 1/27/23 14:57, Maxime Coquelin wrote:
> This patch improves truncated messages logging to ease
> debugging.
>
> First, it differentiates between message's buffer
> truncation and control data truncation. Indeed, MSG_CTRUNC
> can happen even if enough room was provided, in case LSM
> detects access rights issue.
>
> Then, it does not return directly in case of truncation,
> but returns normally to let a chance to display request
> type in Vhost-user protocol layer logs.
>
> Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
> ---
> lib/vhost/socket.c | 8 +++++---
> 1 file changed, 5 insertions(+), 3 deletions(-)
Discussing with David, there was/is a possible FDs leak when
truncation happens, a V2 is coming to handle these properly.
> diff --git a/lib/vhost/socket.c b/lib/vhost/socket.c
> index 863a6f6d52..669c322e12 100644
> --- a/lib/vhost/socket.c
> +++ b/lib/vhost/socket.c
> @@ -129,10 +129,12 @@ read_fd_message(char *ifname, int sockfd, char *buf, int buflen, int *fds, int m
> return ret;
> }
>
> - if (msgh.msg_flags & (MSG_TRUNC | MSG_CTRUNC)) {
> + if (msgh.msg_flags & MSG_TRUNC)
> VHOST_LOG_CONFIG(ifname, ERR, "truncated msg (fd %d)\n", sockfd);
> - return -1;
> - }
> +
> + /* MSG_CTRUNC may be caused by LSM misconfiguration */
> + if (msgh.msg_flags & MSG_CTRUNC)
> + VHOST_LOG_CONFIG(ifname, ERR, "truncated control data (fd %d)\n", sockfd);
>
> for (cmsg = CMSG_FIRSTHDR(&msgh); cmsg != NULL;
> cmsg = CMSG_NXTHDR(&msgh, cmsg)) {
prev parent reply other threads:[~2023-01-27 16:30 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-27 13:57 Maxime Coquelin
2023-01-27 16:30 ` Maxime Coquelin [this message]
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