Add helper API for finding auth file path

* src/util/virauth.c, src/util/virauth.h: Add virAuthGetConfigFilePath * include/libvirt/virterror.h, src/util/virterror.c: Add VIR_FROM_AUTH error domain Signed-off-by: N Daniel P. Berrange <berrange@redhat.com>

Add helper API for finding auth file path
* src/util/virauth.c, src/util/virauth.h: Add virAuthGetConfigFilePath * include/libvirt/virterror.h, src/util/virterror.c: Add VIR_FROM_AUTH error domain Signed-off-by: N Daniel P. Berrange <berrange@redhat.com>
a4fb88b5 · Daniel P. Berrange · 4262e34e · a4fb88b5 · a4fb88b5 · a4fb88b5
12 changed file
--- a/docs/auth.html.in
+++ b/docs/auth.html.in
 <?xml version="1.0"?>
 <html>
  <body>
-    <h1 >Access control</h1>
+    <h1 >Authentication &amp; access control</h1>
    <p>
      When connecting to libvirt, some connections may require client
      authentication before allowing use of the APIs. The set of possible
@@ -11,6 +11,122 @@

    <ul id="toc"></ul>

+    <h2><a name="Auth_client_config">Client configuration</a></h2>
+
+    <p>
+      When connecting to a remote hypervisor which requires authentication,
+most libvirt applications will prompt the user for the credentials. It is
+also possible to provide a client configuration file containing all the
+authentication credentials, avoiding any interaction. Libvirt will look
+for the authentication file using the following sequence:
+    </p>
+    <ol>
+      <li>The file path specified by the $LIBVIRT_AUTH_FILE environment
+        variable.</li>
+      <li>The file path specified by the "authfile=/some/file" URI
+        query parameter</li>
+      <li>The file $HOME/.libvirt/auth.conf</li>
+      <li>The file /etc/libvirt/auth.conf</li>
+    </ol>
+
+    <p>
+      The auth configuration file uses the traditional <code>".ini"</code>
+      style syntax. There are two types of groups that can be present in
+      the config. First there are one or more <strong>credential</strong>
+      sets, which provide the actual authentication credentials. The keys
+      within the group may be:
+    </p>
+
+    <ul>
+      <li><code>username</code>: the user login name to act as. This
+        is relevant for ESX, Xen, HyperV and SSH, but probably not
+        the one you want to libvirtd with SASL.</li>
+      <li><code>authname</code>: the name to authorize as. This is
+        what is commonly required for libvirtd with SASL.</li>
+      <li><code>password</code>: the secret password</li>
+      <li><code>realm</code>: the domain realm for SASL, mostly
+        unused</li>
+    </ul>
+
+    <p>
+      Each set of credentials has a name, which is part of the group
+      entry name. Overall the syntax is
+    </p>
+
+    <pre>
+[credentials-$NAME]
+credname1=value1
+credname2=value2</pre>
+
+    <p>
+      For example, to define two sets of credentials used for production
+      and test machines, using libvirtd, and a further ESX server for dev:
+    </p>
+<pre>
+[credentials-test]
+authname=fred
+password=123456
+
+[credentials-prod]
+authname=bar
+password=letmein
+
+[credentials-dev]
+username=joe
+password=hello</pre>
+
+    <p>
+      The second set of groups provide mappings of credentials to
+      specific machine services. The config file group names compromise
+      the service type and host:
+    </p>
+
+    <pre>
+[auth-$SERVICE-$HOSTNAME]
+credentials=$CREDENTIALS</pre>
+
+    <p>
+      For example, following the previous example, here is how to
+      list some machines
+    </p>
+
+    <pre>
+[auth-libvirt-test1.example.com]
+credentials=test
+
+[auth-libvirt-test2.example.com]
+credentials=test
+
+[auth-libvirt-demo3.example.com]
+credentials=test
+
+[auth-libvirt-prod1.example.com]
+credentials=prod
+
+[auth-esx-dev1.example.com]
+credentials=dev</pre>
+
+    <p>
+      The following service types are known to libvirt
+    </p>
+
+    <ol>
+      <li><code>libvirt</code> - used for connections to a libvirtd
+        server, which is configured with SASL auth</li>
+      <li><code>ssh</code> - used for connections to a Phyp server
+        over SSH</li>
+      <li><code>esx</code> - used for connections to an ESX or
+        VirtualCenter server</li>
+      <li><code>xen</code> - used for connections to a Xen Enterprise
+        sever using XenAPI</li>
+    </ol>
+
+    <p>
+      Applications using libvirt are free to use this same configuration
+      file for storing other credentials. For example, it can be used
+      to storage VNC or SPICE login credentials
+    </p>
+
    <h2><a name="ACL_server_config">Server configuration</a></h2>
    <p>
 The libvirt daemon allows the administrator to choose the authentication

--- a/include/libvirt/virterror.h
+++ b/include/libvirt/virterror.h
@@ -86,6 +86,7 @@ typedef enum {
    VIR_FROM_HYPERV = 43,	/* Error from Hyper-V driver */
    VIR_FROM_CAPABILITIES = 44, /* Error from capabilities */
    VIR_FROM_URI = 45,          /* Error from URI handling */
+    VIR_FROM_AUTH = 46,         /* Error from auth handling */
 } virErrorDomain;



--- a/po/POTFILES.in
+++ b/po/POTFILES.in
@@ -125,6 +125,7 @@ src/util/sysinfo.c
 src/util/util.c
 src/util/viraudit.c
 src/util/virauth.c
+src/util/virauthconfig.c
 src/util/virfile.c
 src/util/virhash.c
 src/util/virkeyfile.c

--- a/src/Makefile.am
+++ b/src/Makefile.am
@@ -81,6 +81,7 @@ UTIL_SOURCES =							\
 		util/util.c util/util.h				\
 		util/viraudit.c util/viraudit.h			\
 		util/virauth.c util/virauth.h			\
+		util/virauthconfig.c util/virauthconfig.h	\
 		util/virfile.c util/virfile.h			\
 		util/virnodesuspend.c util/virnodesuspend.h	\
 		util/virpidfile.c util/virpidfile.h		\

--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1161,8 +1161,16 @@ virUUIDParse;


 # virauth.h
-virAuthGetUsername;
+virAuthGetConfigFilePath;
 virAuthGetPassword;
+virAuthGetUsername;
+
+
+# virauthconfig.h
+virAuthConfigFree;
+virAuthConfigLookup;
+virAuthConfigNew;
+virAuthConfigNewData;


 # viraudit.h

--- a/src/util/virauth.c
+++ b/src/util/virauth.c
@@ -21,9 +21,83 @@

 #include <config.h>

+#include <stdlib.h>
+
 #include "virauth.h"
 #include "util.h"
 #include "memory.h"
+#include "logging.h"
+#include "datatypes.h"
+#include "virterror_internal.h"
+#include "configmake.h"
+
+#define VIR_FROM_THIS VIR_FROM_AUTH
+
+
+int virAuthGetConfigFilePath(virConnectPtr conn,
+                             char **path)
+{
+    int ret = -1;
+    size_t i;
+    const char *authenv = getenv("LIBVIRT_AUTH_FILE");
+    char *userdir = NULL;
+
+    *path = NULL;
+
+    VIR_DEBUG("Determining auth config file path");
+
+    if (authenv) {
+        VIR_DEBUG("Using path from env '%s'", authenv);
+        if (!(*path = strdup(authenv)))
+            goto no_memory;
+        return 0;
+    }
+
+    for (i = 0 ; i < conn->uri->paramsCount ; i++) {
+        if (STREQ_NULLABLE(conn->uri->params[i].name, "authfile") &&
+            conn->uri->params[i].value) {
+            VIR_DEBUG("Using path from URI '%s'",
+                      conn->uri->params[i].value);
+            if (!(*path = strdup(conn->uri->params[i].value)))
+                goto no_memory;
+            return 0;
+        }
+    }
+
+    if (!(userdir = virGetUserDirectory(geteuid())))
+        goto cleanup;
+
+    if (virAsprintf(path, "%s/.libvirt/auth.conf", userdir) < 0)
+        goto no_memory;
+
+    VIR_DEBUG("Checking for readability of '%s'", *path);
+    if (access(*path, R_OK) == 0)
+        goto done;
+
+    VIR_FREE(*path);
+
+    if (!(*path = strdup(SYSCONFDIR "/libvirt/auth.conf")))
+        goto no_memory;
+
+    VIR_DEBUG("Checking for readability of '%s'", *path);
+    if (access(*path, R_OK) == 0)
+        goto done;
+
+    VIR_FREE(*path);
+
+done:
+    ret = 0;
+
+    VIR_DEBUG("Using auth file '%s'", NULLSTR(*path));
+cleanup:
+    VIR_FREE(userdir);
+
+    return ret;
+
+no_memory:
+    virReportOOMError();
+    goto cleanup;
+}


 char *

--- a/src/util/virauth.h
+++ b/src/util/virauth.h
@@ -24,6 +24,9 @@

 # include "internal.h"

+int virAuthGetConfigFilePath(virConnectPtr conn,
+                             char **path);
+
 char *virAuthGetUsername(virConnectAuthPtr auth, const char *defaultUsername,
                         const char *hostname);
 char *virAuthGetPassword(virConnectAuthPtr auth, const char *username,

--- a/src/util/virauthconfig.c
+++ b/src/util/virauthconfig.c
+/*
+ * virauthconfig.c: authentication config handling
+ *
+ * Copyright (C) 2012 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
+ *
+ * Author: Daniel P. Berrange <berrange@redhat.com>
+ */
+
+#include <config.h>
+
+#include "virauthconfig.h"
+
+#include "virkeyfile.h"
+#include "memory.h"
+#include "util.h"
+#include "logging.h"
+#include "virterror_internal.h"
+
+
+struct _virAuthConfig {
+    virKeyFilePtr keyfile;
+    char *path;
+};
+
+#define VIR_FROM_THIS VIR_FROM_NONE
+
+#define virAuthReportError(code, ...)                                   \
+    virReportErrorHelper(VIR_FROM_THIS, code, __FILE__,                 \
+                         __FUNCTION__, __LINE__, __VA_ARGS__)
+
+
+virAuthConfigPtr virAuthConfigNew(const char *path)
+{
+    virAuthConfigPtr auth;
+
+    if (VIR_ALLOC(auth) < 0) {
+        virReportOOMError();
+        goto error;
+    }
+
+    if (!(auth->path = strdup(path))) {
+        virReportOOMError();
+        goto error;
+    }
+
+    if (!(auth->keyfile = virKeyFileNew()))
+        goto error;
+
+    if (virKeyFileLoadFile(auth->keyfile, path) < 0)
+        goto error;
+
+    return auth;
+
+error:
+    virAuthConfigFree(auth);
+    return NULL;
+}
+
+
+virAuthConfigPtr virAuthConfigNewData(const char *path,
+                                      const char *data,
+                                      size_t len)
+{
+    virAuthConfigPtr auth;
+
+    if (VIR_ALLOC(auth) < 0) {
+        virReportOOMError();
+        goto error;
+    }
+
+    if (!(auth->path = strdup(path))) {
+        virReportOOMError();
+        goto error;
+    }
+
+    if (!(auth->keyfile = virKeyFileNew()))
+        goto error;
+
+    if (virKeyFileLoadData(auth->keyfile, path, data, len) < 0)
+        goto error;
+
+    return auth;
+
+error:
+    virAuthConfigFree(auth);
+    return NULL;
+}
+
+
+void virAuthConfigFree(virAuthConfigPtr auth)
+{
+    if (!auth)
+        return;
+
+    virKeyFileFree(auth->keyfile);
+    VIR_FREE(auth->path);
+    VIR_FREE(auth);
+}
+
+
+int virAuthConfigLookup(virAuthConfigPtr auth,
+                        const char *service,
+                        const char *hostname,
+                        const char *credname,
+                        const char **value)
+{
+    char *authgroup = NULL;
+    char *credgroup = NULL;
+    const char *authcred;
+    int ret = -1;
+
+    *value = NULL;
+
+    VIR_DEBUG("Lookup '%s' '%s' '%s'", service, NULLSTR(hostname), credname);
+
+    if (!hostname)
+        hostname = "localhost";
+
+    if (virAsprintf(&authgroup, "auth-%s-%s", service, hostname) < 0) {
+        virReportOOMError();
+        goto cleanup;
+    }
+
+    if (!virKeyFileHasGroup(auth->keyfile, authgroup)) {
+        ret = 0;
+        goto cleanup;
+    }
+
+    if (!(authcred = virKeyFileGetValueString(auth->keyfile, authgroup, "credentials"))) {
+        virAuthReportError(VIR_ERR_CONF_SYNTAX,
+                           _("Missing item 'credentials' in group '%s' in '%s'"),
+                           authgroup, auth->path);
+        goto cleanup;
+    }
+
+    if (virAsprintf(&credgroup, "credentials-%s", authcred) < 0) {
+        virReportOOMError();
+        goto cleanup;
+    }
+
+    if (!virKeyFileHasGroup(auth->keyfile, credgroup)) {
+        virAuthReportError(VIR_ERR_CONF_SYNTAX,
+                           _("Missing group 'credentials-%s' referenced from group '%s' in '%s'"),
+                           authcred, authgroup, auth->path);
+        goto cleanup;
+    }
+
+    if (!virKeyFileHasValue(auth->keyfile, credgroup, credname)) {
+        ret = 0;
+        goto cleanup;
+    }
+
+    *value = virKeyFileGetValueString(auth->keyfile, credgroup, credname);
+
+    ret = 0;
+
+cleanup:
+    VIR_FREE(authgroup);
+    VIR_FREE(credgroup);
+    return ret;
+}
--- a/src/util/virauthconfig.h
+++ b/src/util/virauthconfig.h
+/*
+ * virauthconfig.h: authentication config handling
+ *
+ * Copyright (C) 2012 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
+ *
+ * Author: Daniel P. Berrange <berrange@redhat.com>
+ */
+
+#ifndef __VIR_AUTHCONFIG_H__
+# define __VIR_AUTHCONFIG_H__
+
+# include "internal.h"
+
+typedef struct _virAuthConfig virAuthConfig;
+typedef virAuthConfig *virAuthConfigPtr;
+
+
+virAuthConfigPtr virAuthConfigNew(const char *path);
+virAuthConfigPtr virAuthConfigNewData(const char *path,
+                                      const char *data,
+                                      size_t len);
+
+void virAuthConfigFree(virAuthConfigPtr auth);
+
+int virAuthConfigLookup(virAuthConfigPtr auth,
+                        const char *service,
+                        const char *hostname,
+                        const char *credname,
+                        const char **value);
+
+#endif /* __VIR_AUTHCONFIG_H__ */
--- a/src/util/virterror.c
+++ b/src/util/virterror.c
@@ -181,6 +181,9 @@ static const char *virErrorDomainName(virErrorDomain domain) {
        case VIR_FROM_URI:
            dom = "URI ";
            break;
+        case VIR_FROM_AUTH:
+            dom = "Auth ";
+            break;
    }
    return(dom);
 }

--- a/tests/Makefile.am
+++ b/tests/Makefile.am
@@ -96,7 +96,8 @@ check_PROGRAMS = virshtest conftest sockettest \
 	commandtest commandhelper seclabeltest \
 	virhashtest virnetmessagetest virnetsockettest ssh \
 	utiltest virnettlscontexttest shunloadtest \
-	virtimetest viruritest virkeyfiletest
+	virtimetest viruritest virkeyfiletest \
+	virauthconfigtest

 check_LTLIBRARIES = libshunload.la

@@ -221,6 +222,7 @@ TESTS = virshtest \
 	virtimetest \
 	viruritest \
 	virkeyfiletest \
+	virauthconfigtest \
 	shunloadtest \
 	utiltest \
 	$(test_scripts)
@@ -518,6 +520,11 @@ virkeyfiletest_SOURCES = \
 virkeyfiletest_CFLAGS = -Dabs_builddir="\"$(abs_builddir)\"" $(AM_CFLAGS)
 virkeyfiletest_LDADD = ../src/libvirt-net-rpc.la $(LDADDS)

+virauthconfigtest_SOURCES = \
+	virauthconfigtest.c testutils.h testutils.c
+virauthconfigtest_CFLAGS = -Dabs_builddir="\"$(abs_builddir)\"" $(AM_CFLAGS)
+virauthconfigtest_LDADD = ../src/libvirt-net-rpc.la $(LDADDS)
+
 seclabeltest_SOURCES = \
 	seclabeltest.c
 seclabeltest_LDADD = ../src/libvirt_driver_security.la $(LDADDS)

--- a/tests/virauthconfigtest.c
+++ b/tests/virauthconfigtest.c
+/*
+ * Copyright (C) 2012 Red Hat, Inc.
+ *
+ * This library is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * This library is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with this library; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307  USA
+ *
+ * Author: Daniel P. Berrange <berrange@redhat.com>
+ */
+
+#include <config.h>
+
+#include <stdlib.h>
+#include <signal.h>
+
+#include "testutils.h"
+#include "util.h"
+#include "virterror_internal.h"
+#include "memory.h"
+#include "logging.h"
+
+#include "virauthconfig.h"
+
+#define VIR_FROM_THIS VIR_FROM_RPC
+
+struct ConfigLookupData {
+    virAuthConfigPtr config;
+    const char *hostname;
+    const char *service;
+    const char *credname;
+    const char *expect;
+};
+
+static int testAuthLookup(const void *args)
+{
+    int ret = -1;
+    const struct ConfigLookupData *data = args;
+    const char *actual = NULL;
+    int rv;
+
+    rv = virAuthConfigLookup(data->config,
+                             data->service,
+                             data->hostname,
+                             data->credname,
+                             &actual);
+
+    if (rv < 0)
+        goto cleanup;
+
+    if (data->expect) {
+        if (!actual ||
+            !STREQ(actual, data->expect)) {
+            VIR_WARN("Expected value '%s' for '%s' '%s' '%s', but got '%s'",
+                     data->expect, data->hostname,
+                     data->service, data->credname,
+                     NULLSTR(actual));
+            goto cleanup;
+        }
+    } else {
+        if (actual) {
+            VIR_WARN("Did not expect a value for '%s' '%s' '%s', but got '%s'",
+                     data->hostname,
+                     data->service, data->credname,
+                     actual);
+            goto cleanup;
+        }
+    }
+
+    ret = 0;
+cleanup:
+    return ret;
+}
+
+
+static int
+mymain(void)
+{
+    int ret = 0;
+
+    virAuthConfigPtr config;
+
+    signal(SIGPIPE, SIG_IGN);
+
+#define TEST_LOOKUP(config, hostname, service, credname, expect)        \
+    do  {                                                               \
+        const struct ConfigLookupData data = {                          \
+            config, hostname, service, credname, expect                 \
+        };                                                              \
+        if (virtTestRun("Test Lookup " hostname "-" service "-" credname, \
+                        1, testAuthLookup, &data) < 0)                   \
+            ret = -1;                                                   \
+    } while (0)
+
+    const char *confdata =
+        "[credentials-test]\n"
+        "username=fred\n"
+        "password=123456\n"
+        "\n"
+        "[credentials-prod]\n"
+        "username=bar\n"
+        "password=letmein\n"
+        "\n"
+        "[auth-libvirt-test1.example.com]\n"
+        "credentials=test\n"
+        "\n"
+        "[auth-libvirt-test2.example.com]\n"
+        "credentials=test\n"
+        "\n"
+        "[auth-libvirt-demo3.example.com]\n"
+        "credentials=test\n"
+        "\n"
+        "[auth-libvirt-prod1.example.com]\n"
+        "credentials=prod\n";
+
+    if (!(config = virAuthConfigNewData("auth.conf", confdata, strlen(confdata))))
+        return EXIT_FAILURE;
+
+    TEST_LOOKUP(config, "test1.example.com", "libvirt", "username", "fred");
+    TEST_LOOKUP(config, "test1.example.com", "vnc", "username", NULL);
+    TEST_LOOKUP(config, "test1.example.com", "libvirt", "realm", NULL);
+    TEST_LOOKUP(config, "test66.example.com", "libvirt", "username", NULL);
+    TEST_LOOKUP(config, "prod1.example.com", "libvirt", "username", "bar");
+    TEST_LOOKUP(config, "prod1.example.com", "libvirt", "password", "letmein");
+
+    virAuthConfigFree(config);
+
+    return (ret==0 ? EXIT_SUCCESS : EXIT_FAILURE);
+}
+
+VIRT_TEST_MAIN(mymain)