From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by passt.top (Postfix) with ESMTP id A0FF35A0265 for ; Thu, 13 Oct 2022 06:01:49 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1665633708; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=usXMceqhLgACV+J3bWSDvDNBg76uFt5FEe0ubJJ3JBs=; b=URFx/Qz7XIhD3XauAAKZl435WzdX1SZU/Npa8iZ7vJPDt76OaoXoOBL4HcEfU0DpMJfAU5 Y04XVHucG+4iI5PmcQI2aZpEw4mwuSd/hDkuZW84pLvBvJRDi6FhWc5TogxmHGtWuOJ34S Fso0cOqj1A6IjA/go9VwJe9SgGsA91g= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-41-bRkUPXdWM3KGXVXM02o5vA-1; Thu, 13 Oct 2022 00:01:47 -0400 X-MC-Unique: bRkUPXdWM3KGXVXM02o5vA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 76630185A78B; Thu, 13 Oct 2022 04:01:46 +0000 (UTC) Received: from maya.cloud.tilaa.com (ovpn-208-3.brq.redhat.com [10.40.208.3]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 069A620899E0; Thu, 13 Oct 2022 04:01:42 +0000 (UTC) Date: Thu, 13 Oct 2022 06:01:19 +0200 From: Stefano Brivio To: David Gibson Subject: Re: [PATCH 07/10] isolation: Replace drop_caps() with a version that actually does something Message-ID: <20221013060119.48d51493@elisabeth> In-Reply-To: <20221011054018.1449506-8-david@gibson.dropbear.id.au> References: <20221011054018.1449506-1-david@gibson.dropbear.id.au> <20221011054018.1449506-8-david@gibson.dropbear.id.au> Organization: Red Hat MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Message-ID-Hash: HGBYVEJTWA5KN7VM56UDZ3HGWP7VREZ6 X-Message-ID-Hash: HGBYVEJTWA5KN7VM56UDZ3HGWP7VREZ6 X-MailFrom: sbrivio@redhat.com 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: passt-dev@passt.top X-Mailman-Version: 3.3.3 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: On Tue, 11 Oct 2022 16:40:15 +1100 David Gibson wrote: > @@ -251,7 +275,19 @@ int isolate_prefork(struct ctx *c) > return -errno; > } > > - drop_caps(); /* Relative to the new user namespace this time. */ > + /* Drop capabilites in our new userns */ > + if (c->mode == MODE_PASTA) { > + /* Keep CAP_SYS_ADMIN, so that we can setns() to the > + * netns when we need to act upon it > + */ > + ns_caps |= 1UL << CAP_SYS_ADMIN; > + /* Keep CAP_NET_BIND_SERVICE, so we can splice > + * outbound connections to low port numbers > + */ > + ns_caps |= 1UL << CAP_NET_BIND_SERVICE; > + } > + > + drop_caps_ep_except(ns_caps); Hmm, I didn't really look into this yet, but there seems to be an issue with filesystem-bound network namespaces now. Running something like: pasta --config-net --netns /run/user/1000/netns/netns-6466ff4b-1efc-2b58-685b-cbc12feb9ccc (from Podman), this happens: readlink("/proc/self/exe", "/usr/local/bin/passt.avx2", 4095) = 25 capget({version=_LINUX_CAPABILITY_VERSION_3, pid=0}, {effective=1< [pid 1763223] setns(7, CLONE_NEWNET) = -1 EPERM (Operation not permitted) [pid 1763223] exit(0) = ? [pid 1763222] <... clone resumed>) = 1763223 [pid 1763223] +++ exited with 0 +++ --- SIGCHLD {si_signo=SIGCHLD, si_code=CLD_EXITED, si_pid=1763223, si_uid=0, si_status=0, si_utime=0, si_stime=0} --- waitid(P_ALL, 0, NULL, WNOHANG|WEXITED, NULL) = 0 waitid(P_ALL, 0, NULL, WNOHANG|WEXITED, NULL) = -1 ECHILD (No child processes) rt_sigreturn({mask=[]}) = 1763223 sendto(5, "<3> Couldn't switch to pasta nam"..., 40, 0, NULL, 0) = 40 write(2, "Couldn't switch to pasta namespa"..., 35Couldn't switch to pasta namespaces) = 35 write(2, "\n", 1 -- Stefano