From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from gandalf.ozlabs.org (gandalf.ozlabs.org [150.107.74.76]) by passt.top (Postfix) with ESMTPS id 3AB4C5A026D for ; Wed, 23 Aug 2023 09:03:46 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gibson.dropbear.id.au; s=201602; t=1692774220; bh=G0yPpNwc1zTj9IAL8SECVpvWsXd+JwGEco7asZshkj0=; h=From:To:Cc:Subject:Date:From; b=aednXQcs7TcmazB3uEdjeGxdFYeNEILULQPtbIphWfFSp915uJEyjWeOALe4Xbo/V 8SXwQ5IFmGoPaHMbNwYGA/hOwNYA4zMTZzhqfSvRRMQr1WOmV0uxE6G1eA5EkKAdxJ l7IiuWTXrLMw9voVZ+jGMgvc2qmFBi+qqdLwGYag= Received: by gandalf.ozlabs.org (Postfix, from userid 1007) id 4RVxyN3nv5z4wb0; Wed, 23 Aug 2023 17:03:40 +1000 (AEST) From: David Gibson To: Stefano Brivio , passt-dev@passt.top Subject: [PATCH] pasta: Strip RTA_PREFSRC when copying routes to the namespace Date: Wed, 23 Aug 2023 17:03:38 +1000 Message-ID: <20230823070338.1546174-1-david@gibson.dropbear.id.au> X-Mailer: git-send-email 2.41.0 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Message-ID-Hash: Z7SE5AIRVIHU3E5GZEX2ILMQ2FP2MGZL X-Message-ID-Hash: Z7SE5AIRVIHU3E5GZEX2ILMQ2FP2MGZL X-MailFrom: dgibson@gandalf.ozlabs.org X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: David Gibson X-Mailman-Version: 3.3.8 Precedence: list List-Id: Development discussion and patches for passt Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: Host routes can include a preferred source address (RTA_PREFSRC), which must be one of the host's addresses. However when using pasta with -a the namespace might be given a different address, not on the host. This seems to occur pretty routinely depending on the network configuration systems in place on the host. With --config-net we will try to copy host routes to the namespace. If one of those includes an RTA_PREFSRC, but the namespace doesn't have the host address, this will fail with -EINVAL, causing pasta to fail. Fix this by stripping off RTA_PREFSRC attributes from routes as we copy them to the namespace. This is by no means infallible, bit it should at least handle common cases for the time being. Link: https://bugs.passt.top/show_bug.cgi?id=71 Link: https://github.com/containers/podman/pull/19699#issuecomment-1688769287 Signed-off-by: David Gibson --- netlink.c | 15 ++++++++++++++- 1 file changed, 14 insertions(+), 1 deletion(-) diff --git a/netlink.c b/netlink.c index f55f2c3..98f08e7 100644 --- a/netlink.c +++ b/netlink.c @@ -462,8 +462,21 @@ int nl_route_dup(int s_src, unsigned int ifi_src, for (rta = RTM_RTA(rtm), na = RTM_PAYLOAD(nh); RTA_OK(rta, na); rta = RTA_NEXT(rta, na)) { - if (rta->rta_type == RTA_OIF) + if (rta->rta_type == RTA_OIF) { + /* The host obviously list's the host interface + * id here, we need to change it to the + * namespace's interface id + */ *(unsigned int *)RTA_DATA(rta) = ifi_dst; + } else if (rta->rta_type == RTA_PREFSRC) { + /* Host routes might include a preferred source + * address, which must be one of the host's + * addresses. However, with -a pasta will use a + * different namespace address, making such a + * route invalid in the namespace. Strip off + * RTA_PREFSRC attributes to avoid that. */ + rta->rta_type = RTA_UNSPEC; + } } } -- 2.41.0