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 B4CC35A0272 for ; Thu, 9 Mar 2023 05:49:11 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1678337350; 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=noZ4NokHaL7wbYJq+XDt6uUH4Iro2sQnM0yYE6TpbFo=; b=c0vYUE8YFxmYGnCCiKMOKlVsfoyJCuMD92crZlYLJdmQGQ6Bv6cU9vEm6EBftXDtlMkQmo jeI6h/UNKmy+dY9FU+N8x3iETFYi93MuEaiWxM58XzU5wu6pRr38LIrFcuwKNuNqZVrPoX GpXtZiBu2qBxYgx5eRBekuBe+kBxTew= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-299-F-m1mIeyPqGoU7_NAbNs5A-1; Wed, 08 Mar 2023 23:49:09 -0500 X-MC-Unique: F-m1mIeyPqGoU7_NAbNs5A-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 270B429DD985 for ; Thu, 9 Mar 2023 04:49:09 +0000 (UTC) Received: from vhost3.router.laine.org (unknown [10.2.16.63]) by smtp.corp.redhat.com (Postfix) with ESMTP id 0A50CC15BA0; Thu, 9 Mar 2023 04:49:08 +0000 (UTC) From: Laine Stump To: libvir-list@redhat.com Subject: [libvirt PATCH 3/4] security: make it possible to set SELinux label of child process from its binary Date: Wed, 8 Mar 2023 23:49:07 -0500 Message-Id: <20230309044908.29316-4-laine@redhat.com> In-Reply-To: <20230309044908.29316-1-laine@redhat.com> References: <20230309044908.29316-1-laine@redhat.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 3.1 on 10.11.54.8 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset="US-ASCII"; x-default=true Message-ID-Hash: 2L4KQJBAB3GDU6M7SHI522K7LI7CH3AE X-Message-ID-Hash: 2L4KQJBAB3GDU6M7SHI522K7LI7CH3AE X-MailFrom: laine@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: 3.3.8 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: Normally when a child process is started by libvirt, the SELinux label of that process is set to virtd_t (plus an MCS range). In at least one case (passt) we need for the SELinux label of a child process label to match the label that the binary would have transitioned to automatically if it had been run standalone (in the case of passt, that label is passt_t). This patch modifies virSecuritySELinuxSetChildProcessLabel() (and all the functions above it in the call chain) so that the toplevel function can set a new argument "useBinarySpecificLabel" to true. If it is true, then virSecuritySELinuxSetChildProcessLabel() will call the new function virSecuritySELinuxContextSetFromFile(), which uses the selinux library function security_compute_create() to determine what would be the label of the new process if it had been run standalone (rather than being run by libvirt) - the MCS range from the normally-used label is added to this newly derived label, and that is what is used for the new process rather than whatever is in the domain's security label (which will usually be virtd_t). In order to easily verify that nothing was broken by these changes to the call chain, all callers currently set useBinarySpecificPath = false, so all behavior should be completely unchanged. (The next patch will set it to true only for the case of running passt.) https://bugzilla.redhat.com/2172267 Signed-off-by: Laine Stump --- src/qemu/qemu_dbus.c | 2 +- src/qemu/qemu_passt.c | 2 +- src/qemu/qemu_process.c | 2 +- src/qemu/qemu_security.c | 5 ++- src/qemu/qemu_security.h | 1 + src/qemu/qemu_slirp.c | 2 +- src/qemu/qemu_tpm.c | 3 +- src/qemu/qemu_vhost_user_gpu.c | 2 +- src/security/security_apparmor.c | 1 + src/security/security_dac.c | 1 + src/security/security_driver.h | 1 + src/security/security_manager.c | 8 +++- src/security/security_manager.h | 1 + src/security/security_nop.c | 1 + src/security/security_selinux.c | 73 +++++++++++++++++++++++++++++++- src/security/security_stack.c | 5 ++- 16 files changed, 99 insertions(+), 11 deletions(-) diff --git a/src/qemu/qemu_dbus.c b/src/qemu/qemu_dbus.c index a6dc802637..2e4067e704 100644 --- a/src/qemu/qemu_dbus.c +++ b/src/qemu/qemu_dbus.c @@ -217,7 +217,7 @@ qemuDBusStart(virQEMUDriver *driver, virCommandDaemonize(cmd); virCommandAddArgFormat(cmd, "--config-file=%s", configfile); - if (qemuSecurityCommandRun(driver, vm, cmd, -1, -1, NULL) < 0) + if (qemuSecurityCommandRun(driver, vm, cmd, -1, -1, false, NULL) < 0) goto cleanup; if (virPidFileReadPath(pidfile, &cpid) < 0) { diff --git a/src/qemu/qemu_passt.c b/src/qemu/qemu_passt.c index 0afa8bdb3a..fd0076077e 100644 --- a/src/qemu/qemu_passt.c +++ b/src/qemu/qemu_passt.c @@ -281,7 +281,7 @@ qemuPasstStart(virDomainObj *vm, if (qemuExtDeviceLogCommand(driver, vm, cmd, "passt") < 0) return -1; - if (qemuSecurityCommandRun(driver, vm, cmd, -1, -1, NULL) < 0) + if (qemuSecurityCommandRun(driver, vm, cmd, -1, -1, false, NULL) < 0) goto error; return 0; diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c index deebd03717..be418ad8e6 100644 --- a/src/qemu/qemu_process.c +++ b/src/qemu/qemu_process.c @@ -7747,7 +7747,7 @@ qemuProcessLaunch(virConnectPtr conn, VIR_DEBUG("Setting up security labelling"); if (qemuSecuritySetChildProcessLabel(driver->securityManager, - vm->def, cmd) < 0) + vm->def, false, cmd) < 0) goto cleanup; virCommandSetOutputFD(cmd, &logfile); diff --git a/src/qemu/qemu_security.c b/src/qemu/qemu_security.c index ee03e2225e..8bcef14d08 100644 --- a/src/qemu/qemu_security.c +++ b/src/qemu/qemu_security.c @@ -636,6 +636,7 @@ qemuSecurityCommandRun(virQEMUDriver *driver, virCommand *cmd, uid_t uid, gid_t gid, + bool useBinarySpecificLabel, int *exitstatus) { g_autoptr(virQEMUDriverConfig) cfg = virQEMUDriverGetConfig(driver); @@ -643,8 +644,10 @@ qemuSecurityCommandRun(virQEMUDriver *driver, int ret = -1; if (virSecurityManagerSetChildProcessLabel(driver->securityManager, - vm->def, cmd) < 0) + vm->def, useBinarySpecificLabel, + cmd) < 0) { return -1; + } if (uid != (uid_t) -1) virCommandSetUID(cmd, uid); diff --git a/src/qemu/qemu_security.h b/src/qemu/qemu_security.h index dc8e67cc81..10f11771b4 100644 --- a/src/qemu/qemu_security.h +++ b/src/qemu/qemu_security.h @@ -115,6 +115,7 @@ int qemuSecurityCommandRun(virQEMUDriver *driver, virCommand *cmd, uid_t uid, gid_t gid, + bool useBinarySpecificLabel, int *exitstatus); /* Please note that for these APIs there is no wrapper yet. Do NOT blindly add diff --git a/src/qemu/qemu_slirp.c b/src/qemu/qemu_slirp.c index 9697542cd3..fdf0823d03 100644 --- a/src/qemu/qemu_slirp.c +++ b/src/qemu/qemu_slirp.c @@ -325,7 +325,7 @@ qemuSlirpStart(virDomainObj *vm, if (qemuExtDeviceLogCommand(driver, vm, cmd, "slirp") < 0) goto error; - if (qemuSecurityCommandRun(driver, vm, cmd, -1, -1, NULL) < 0) + if (qemuSecurityCommandRun(driver, vm, cmd, -1, -1, false, NULL) < 0) goto error; rc = virPidFileReadPath(pidfile, &pid); diff --git a/src/qemu/qemu_tpm.c b/src/qemu/qemu_tpm.c index 982e5f13b6..abe0ba7429 100644 --- a/src/qemu/qemu_tpm.c +++ b/src/qemu/qemu_tpm.c @@ -962,8 +962,9 @@ qemuTPMEmulatorStart(virQEMUDriver *driver, return -1; if (qemuSecurityCommandRun(driver, vm, cmd, cfg->swtpm_user, - cfg->swtpm_group, NULL) < 0) + cfg->swtpm_group, false, NULL) < 0) { goto error; + } if (virPidFileReadPath(pidfile, &pid) < 0) { virReportError(VIR_ERR_INTERNAL_ERROR, "%s", diff --git a/src/qemu/qemu_vhost_user_gpu.c b/src/qemu/qemu_vhost_user_gpu.c index 5b49ef4e28..ced41b0466 100644 --- a/src/qemu/qemu_vhost_user_gpu.c +++ b/src/qemu/qemu_vhost_user_gpu.c @@ -152,7 +152,7 @@ int qemuExtVhostUserGPUStart(virQEMUDriver *driver, virCommandAddArgFormat(cmd, "--render-node=%s", video->accel->rendernode); } - if (qemuSecurityCommandRun(driver, vm, cmd, -1, -1, NULL) < 0) + if (qemuSecurityCommandRun(driver, vm, cmd, -1, -1, false, NULL) < 0) goto error; rc = virPidFileReadPath(pidfile, &pid); diff --git a/src/security/security_apparmor.c b/src/security/security_apparmor.c index b63b248975..b5642c9a28 100644 --- a/src/security/security_apparmor.c +++ b/src/security/security_apparmor.c @@ -570,6 +570,7 @@ AppArmorSetSecurityProcessLabel(virSecurityManager *mgr G_GNUC_UNUSED, static int AppArmorSetSecurityChildProcessLabel(virSecurityManager *mgr G_GNUC_UNUSED, virDomainDef *def, + bool useBinarySpecificLabel G_GNUC_UNUSED, virCommand *cmd) { g_autofree char *profile_name = NULL; diff --git a/src/security/security_dac.c b/src/security/security_dac.c index 9be8f458d1..ca3f4d2dc5 100644 --- a/src/security/security_dac.c +++ b/src/security/security_dac.c @@ -2273,6 +2273,7 @@ virSecurityDACSetProcessLabel(virSecurityManager *mgr, static int virSecurityDACSetChildProcessLabel(virSecurityManager *mgr, virDomainDef *def, + bool useBinarySpecificLabel G_GNUC_UNUSED, virCommand *cmd) { virSecurityDACData *priv = virSecurityManagerGetPrivateData(mgr); diff --git a/src/security/security_driver.h b/src/security/security_driver.h index fe6982ceca..aa1fb2125d 100644 --- a/src/security/security_driver.h +++ b/src/security/security_driver.h @@ -96,6 +96,7 @@ typedef int (*virSecurityDomainSetProcessLabel) (virSecurityManager *mgr, virDomainDef *def); typedef int (*virSecurityDomainSetChildProcessLabel) (virSecurityManager *mgr, virDomainDef *def, + bool useBinarySpecificLabel, virCommand *cmd); typedef int (*virSecurityDomainSecurityVerify) (virSecurityManager *mgr, virDomainDef *def); diff --git a/src/security/security_manager.c b/src/security/security_manager.c index 2f8e89cb04..b0578d7209 100644 --- a/src/security/security_manager.c +++ b/src/security/security_manager.c @@ -885,10 +885,14 @@ virSecurityManagerSetProcessLabel(virSecurityManager *mgr, int virSecurityManagerSetChildProcessLabel(virSecurityManager *mgr, virDomainDef *vm, + bool useBinarySpecificLabel, virCommand *cmd) { - if (mgr->drv->domainSetSecurityChildProcessLabel) - return mgr->drv->domainSetSecurityChildProcessLabel(mgr, vm, cmd); + if (mgr->drv->domainSetSecurityChildProcessLabel) { + return mgr->drv->domainSetSecurityChildProcessLabel(mgr, vm, + useBinarySpecificLabel, + cmd); + } virReportUnsupportedError(); return -1; diff --git a/src/security/security_manager.h b/src/security/security_manager.h index 4afdcc167b..97add3294d 100644 --- a/src/security/security_manager.h +++ b/src/security/security_manager.h @@ -145,6 +145,7 @@ int virSecurityManagerSetProcessLabel(virSecurityManager *mgr, virDomainDef *def); int virSecurityManagerSetChildProcessLabel(virSecurityManager *mgr, virDomainDef *def, + bool useBinarySpecificLabel, virCommand *cmd); int virSecurityManagerVerify(virSecurityManager *mgr, virDomainDef *def); diff --git a/src/security/security_nop.c b/src/security/security_nop.c index 0dbc547feb..1413f43d57 100644 --- a/src/security/security_nop.c +++ b/src/security/security_nop.c @@ -152,6 +152,7 @@ virSecurityDomainSetProcessLabelNop(virSecurityManager *mgr G_GNUC_UNUSED, static int virSecurityDomainSetChildProcessLabelNop(virSecurityManager *mgr G_GNUC_UNUSED, virDomainDef *vm G_GNUC_UNUSED, + bool useBinarySpecificLabel G_GNUC_UNUSED, virCommand *cmd G_GNUC_UNUSED) { return 0; diff --git a/src/security/security_selinux.c b/src/security/security_selinux.c index cd1d9d14f7..7f409af525 100644 --- a/src/security/security_selinux.c +++ b/src/security/security_selinux.c @@ -560,6 +560,52 @@ virSecuritySELinuxContextAddRange(const char *src, return ret; } + +static char * +virSecuritySELinuxContextSetFromFile(const char *origLabel, + const char *binaryPath) +{ + g_autofree char *currentCon = NULL; + g_autofree char *binaryCon = NULL; + g_autofree char *naturalLabel = NULL; + g_autofree char *updatedLabel = NULL; + + /* First learn what would be the context set + * if binaryPath was exec'ed from this process. + */ + if (getcon(¤tCon) < 0) { + virReportSystemError(errno, "%s", + _("unable to get SELinux context for current process")); + return NULL; + } + + if (getfilecon(binaryPath, &binaryCon) < 0) { + virReportSystemError(errno, _("unable to get SELinux context for '%s'"), + binaryPath); + return NULL; + } + + if (security_compute_create(currentCon, binaryCon, + string_to_security_class("process"), + &naturalLabel) < 0) { + virReportSystemError(errno, + _("unable create new SELinux label based on label '%s' and file '%s'"), + origLabel, binaryPath); + return NULL; + } + + /* now get the type from the original label + * (which already has proper MCS set) and add it to + * the new label + */ + updatedLabel = virSecuritySELinuxContextAddRange(origLabel, naturalLabel); + + VIR_DEBUG("original label: '%s' binary: '%s' binary-specific label: '%s'", + origLabel, binaryPath, NULLSTR(updatedLabel)); + return g_steal_pointer(&updatedLabel); +} + + static char * virSecuritySELinuxGenNewContext(const char *basecontext, const char *mcs, @@ -2986,10 +3032,13 @@ virSecuritySELinuxSetProcessLabel(virSecurityManager *mgr G_GNUC_UNUSED, static int virSecuritySELinuxSetChildProcessLabel(virSecurityManager *mgr G_GNUC_UNUSED, virDomainDef *def, + bool useBinarySpecificLabel G_GNUC_UNUSED, virCommand *cmd) { /* TODO: verify DOI */ virSecurityLabelDef *secdef; + g_autofree char *tmpLabel = NULL; + const char *label = NULL; secdef = virDomainDefGetSecurityLabelDef(def, SECURITY_SELINUX_NAME); if (!secdef || !secdef->label) @@ -3006,8 +3055,30 @@ virSecuritySELinuxSetChildProcessLabel(virSecurityManager *mgr G_GNUC_UNUSED, return -1; } + /* pick either the common label used by most binaries exec'ed by + * libvirt, or the specific label of this binary. + */ + if (useBinarySpecificLabel) { + const char *binaryPath = virCommandGetBinaryPath(cmd); + + if (!binaryPath) + return -1; /* error was already logged */ + + tmpLabel = virSecuritySELinuxContextSetFromFile(secdef->label, + binaryPath); + if (!tmpLabel) + return -1; + + label = tmpLabel; + + } else { + + label = secdef->label; + + } + /* save in cmd to be set after fork/before child process is exec'ed */ - virCommandSetSELinuxLabel(cmd, secdef->label); + virCommandSetSELinuxLabel(cmd, label); return 0; } diff --git a/src/security/security_stack.c b/src/security/security_stack.c index 560f797030..369b5dd3a6 100644 --- a/src/security/security_stack.c +++ b/src/security/security_stack.c @@ -458,6 +458,7 @@ virSecurityStackSetProcessLabel(virSecurityManager *mgr, static int virSecurityStackSetChildProcessLabel(virSecurityManager *mgr, virDomainDef *vm, + bool useBinarySpecificLabel, virCommand *cmd) { virSecurityStackData *priv = virSecurityManagerGetPrivateData(mgr); @@ -465,8 +466,10 @@ virSecurityStackSetChildProcessLabel(virSecurityManager *mgr, int rc = 0; for (; item; item = item->next) { - if (virSecurityManagerSetChildProcessLabel(item->securityManager, vm, cmd) < 0) + if (virSecurityManagerSetChildProcessLabel(item->securityManager, vm, + useBinarySpecificLabel, cmd) < 0) { rc = -1; + } } return rc; -- 2.39.2