Merge remote-tracking branch 'remotes/berrange/tags/authz-core-pull-request' into staging

Add a standard authorization framework

The current network services now support encryption via TLS and in some
cases support authentication via SASL. In cases where SASL is not
available, x509 client certificates can be used as a crude authorization
scheme, but using a sub-CA and controlling who you give certs to. In
general this is not very flexible though, so this series introduces a
new standard authorization framework.

It comes with four initial authorization mechanisms

 - Simple - an exact username match. This is useful when there is
   exactly one user that is known to connect. For example when live
   migrating from one QEMU to another with TLS, libvirt would use
   the simple scheme to whitelist the TLS cert of the source QEMU.

 - List - an full access control list, with optional regex matching.
   This is more flexible and is used to provide 100% backcompat with
   the existing HMP ACL commands. The caveat is that we can't create
   these via the CLI -object arg yet.

 - ListFile - the same as List, but with the rules stored in JSON
   format in an external file. This avoids the -object limitation
   while also allowing the admin to change list entries on the file.
   QEMU uses inotify to notice these changes and auto-reload the
   file contents. This is likely a good default choice for most
   network services, if the "simple" mechanism isn't sufficient.

 - PAM - delegate the username lookup to a PAM module, which opens
   the door to many options including things like SQL/LDAP lookups.

# gpg: Signature made Tue 26 Feb 2019 15:33:46 GMT
# gpg:                using RSA key BE86EBB415104FDF
# gpg: Good signature from "Daniel P. Berrange <dan@berrange.com>" [full]
# gpg:                 aka "Daniel P. Berrange <berrange@redhat.com>" [full]
# Primary key fingerprint: DAF3 A6FD B26B 6291 2D0E  8E3F BE86 EBB4 1510 4FDF

* remotes/berrange/tags/authz-core-pull-request:
  authz: delete existing ACL implementation
  authz: add QAuthZPAM object type for authorizing using PAM
  authz: add QAuthZListFile object type for a file access control list
  authz: add QAuthZList object type for an access control list
  authz: add QAuthZSimple object type for easy whitelist auth checks
  authz: add QAuthZ object as an authorization base class
  hw/usb: switch MTP to use new inotify APIs
  hw/usb: fix const-ness for string params in MTP driver
  hw/usb: don't set IN_ISDIR for inotify watch in MTP driver
  qom: don't require user creatable objects to be registered
  util: add helper APIs for dealing with inotify in portable manner

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

2 files changed, 114 insertions, 169 deletions

diff --git a/hw/usb/dev-mtp.c b/hw/usb/dev-mtp.c
index f1d20fa1b9..4ee4fc5a89 100644
--- a/hw/usb/dev-mtp.c
+++ b/hw/usb/dev-mtp.c
@@ -11,17 +11,16 @@
 
 #include "qemu/osdep.h"
 #include "qapi/error.h"
+#include "qemu/error-report.h"
 #include <wchar.h>
 #include <dirent.h>
 
 #include <sys/statvfs.h>
-#ifdef CONFIG_INOTIFY1
-#include <sys/inotify.h>
-#include "qemu/main-loop.h"
-#endif
+
 
 #include "qemu-common.h"
 #include "qemu/iov.h"
+#include "qemu/filemonitor.h"
 #include "trace.h"
 #include "hw/usb.h"
 #include "desc.h"
@@ -132,7 +131,6 @@ enum {
     EP_EVENT,
 };
 
-#ifdef CONFIG_INOTIFY1
 typedef struct MTPMonEntry MTPMonEntry;
 
 struct MTPMonEntry {
@@ -141,7 +139,6 @@ struct MTPMonEntry {
 
     QTAILQ_ENTRY(MTPMonEntry) next;
 };
-#endif
 
 struct MTPControl {
     uint16_t     code;
@@ -172,10 +169,8 @@ struct MTPObject {
     char         *name;
     char         *path;
     struct stat  stat;
-#ifdef CONFIG_INOTIFY1
-    /* inotify watch cookie */
-    int          watchfd;
-#endif
+    /* file monitor watch id */
+    int          watchid;
     MTPObject    *parent;
     uint32_t     nchildren;
     QLIST_HEAD(, MTPObject) children;
@@ -198,11 +193,8 @@ struct MTPState {
     bool         readonly;
 
     QTAILQ_HEAD(, MTPObject) objects;
-#ifdef CONFIG_INOTIFY1
-    /* inotify descriptor */
-    int          inotifyfd;
+    QFileMonitor *file_monitor;
     QTAILQ_HEAD(, MTPMonEntry) events;
-#endif
     /* Responder is expecting a write operation */
     bool write_pending;
     struct {
@@ -383,7 +375,7 @@ static const USBDesc desc = {
 /* ----------------------------------------------------------------------- */
 
 static MTPObject *usb_mtp_object_alloc(MTPState *s, uint32_t handle,
-                                       MTPObject *parent, char *name)
+                                       MTPObject *parent, const char *name)
 {
     MTPObject *o = g_new0(MTPObject, 1);
 
@@ -391,6 +383,7 @@ static MTPObject *usb_mtp_object_alloc(MTPState *s, uint32_t handle,
         goto ignore;
     }
 
+    o->watchid = -1;
     o->handle = handle;
     o->parent = parent;
     o->name = g_strdup(name);
@@ -437,6 +430,10 @@ static void usb_mtp_object_free(MTPState *s, MTPObject *o)
 
     trace_usb_mtp_object_free(s->dev.addr, o->handle, o->path);
 
+    if (o->watchid != -1 && s->file_monitor) {
+        qemu_file_monitor_remove_watch(s->file_monitor, o->path, o->watchid);
+    }
+
     QTAILQ_REMOVE(&s->objects, o, next);
     if (o->parent) {
         QLIST_REMOVE(o, list);
@@ -465,7 +462,7 @@ static MTPObject *usb_mtp_object_lookup(MTPState *s, uint32_t handle)
 }
 
 static MTPObject *usb_mtp_add_child(MTPState *s, MTPObject *o,
-                                    char *name)
+                                    const char *name)
 {
     MTPObject *child =
         usb_mtp_object_alloc(s, s->next_handle++, o, name);
@@ -484,10 +481,14 @@ static MTPObject *usb_mtp_add_child(MTPState *s, MTPObject *o,
 }
 
 static MTPObject *usb_mtp_object_lookup_name(MTPObject *parent,
-                                             char *name, int len)
+                                             const char *name, int len)
 {
     MTPObject *iter;
 
+    if (len == -1) {
+        len = strlen(name);
+    }
+
     QLIST_FOREACH(iter, &parent->children, list) {
         if (strncmp(iter->name, name, len) == 0) {
             return iter;
@@ -497,13 +498,12 @@ static MTPObject *usb_mtp_object_lookup_name(MTPObject *parent,
     return NULL;
 }
 
-#ifdef CONFIG_INOTIFY1
-static MTPObject *usb_mtp_object_lookup_wd(MTPState *s, int wd)
+static MTPObject *usb_mtp_object_lookup_id(MTPState *s, int id)
 {
     MTPObject *iter;
 
     QTAILQ_FOREACH(iter, &s->objects, next) {
-        if (iter->watchfd == wd) {
+        if (iter->watchid == id) {
             return iter;
         }
     }
@@ -511,160 +511,103 @@ static MTPObject *usb_mtp_object_lookup_wd(MTPState *s, int wd)
     return NULL;
 }
 
-static void inotify_watchfn(void *arg)
+static void file_monitor_event(int id,
+                               QFileMonitorEvent ev,
+                               const char *name,
+                               void *opaque)
 {
-    MTPState *s = arg;
-    ssize_t bytes;
-    /* From the man page: atleast one event can be read */
-    int pos;
-    char buf[sizeof(struct inotify_event) + NAME_MAX + 1];
-
-    for (;;) {
-        bytes = read(s->inotifyfd, buf, sizeof(buf));
-        pos = 0;
-
-        if (bytes <= 0) {
-            /* Better luck next time */
+    MTPState *s = opaque;
+    MTPObject *parent = usb_mtp_object_lookup_id(s, id);
+    MTPMonEntry *entry = NULL;
+    MTPObject *o;
+
+    if (!parent) {
+        return;
+    }
+
+    switch (ev) {
+    case QFILE_MONITOR_EVENT_CREATED:
+        if (usb_mtp_object_lookup_name(parent, name, -1)) {
+            /* Duplicate create event */
             return;
         }
+        entry = g_new0(MTPMonEntry, 1);
+        entry->handle = s->next_handle;
+        entry->event = EVT_OBJ_ADDED;
+        o = usb_mtp_add_child(s, parent, name);
+        if (!o) {
+            g_free(entry);
+            return;
+        }
+        trace_usb_mtp_file_monitor_event(s->dev.addr, name, "Obj Added");
+        break;
 
+    case QFILE_MONITOR_EVENT_DELETED:
         /*
-         * TODO: Ignore initiator initiated events.
-         * For now we are good because the store is RO
+         * The kernel issues a IN_IGNORED event
+         * when a dir containing a watchpoint is
+         * deleted, so we don't have to delete the
+         * watchpoint
          */
-        while (bytes > 0) {
-            char *p = buf + pos;
-            struct inotify_event *event = (struct inotify_event *)p;
-            int watchfd = 0;
-            uint32_t mask = event->mask & (IN_CREATE | IN_DELETE |
-                                           IN_MODIFY | IN_IGNORED);
-            MTPObject *parent = usb_mtp_object_lookup_wd(s, event->wd);
-            MTPMonEntry *entry = NULL;
-            MTPObject *o;
-
-            pos = pos + sizeof(struct inotify_event) + event->len;
-            bytes = bytes - pos;
-
-            if (!parent) {
-                continue;
-            }
-
-            switch (mask) {
-            case IN_CREATE:
-                if (usb_mtp_object_lookup_name
-                    (parent, event->name, event->len)) {
-                    /* Duplicate create event */
-                    continue;
-                }
-                entry = g_new0(MTPMonEntry, 1);
-                entry->handle = s->next_handle;
-                entry->event = EVT_OBJ_ADDED;
-                o = usb_mtp_add_child(s, parent, event->name);
-                if (!o) {
-                    g_free(entry);
-                    continue;
-                }
-                o->watchfd = watchfd;
-                trace_usb_mtp_inotify_event(s->dev.addr, event->name,
-                                            event->mask, "Obj Added");
-                break;
-
-            case IN_DELETE:
-                /*
-                 * The kernel issues a IN_IGNORED event
-                 * when a dir containing a watchpoint is
-                 * deleted, so we don't have to delete the
-                 * watchpoint
-                 */
-                o = usb_mtp_object_lookup_name(parent, event->name, event->len);
-                if (!o) {
-                    continue;
-                }
-                entry = g_new0(MTPMonEntry, 1);
-                entry->handle = o->handle;
-                entry->event = EVT_OBJ_REMOVED;
-                trace_usb_mtp_inotify_event(s->dev.addr, o->path,
-                                      event->mask, "Obj Deleted");
-                usb_mtp_object_free(s, o);
-                break;
-
-            case IN_MODIFY:
-                o = usb_mtp_object_lookup_name(parent, event->name, event->len);
-                if (!o) {
-                    continue;
-                }
-                entry = g_new0(MTPMonEntry, 1);
-                entry->handle = o->handle;
-                entry->event = EVT_OBJ_INFO_CHANGED;
-                trace_usb_mtp_inotify_event(s->dev.addr, o->path,
-                                      event->mask, "Obj Modified");
-                break;
-
-            case IN_IGNORED:
-                trace_usb_mtp_inotify_event(s->dev.addr, parent->path,
-                                      event->mask, "Obj parent dir ignored");
-                break;
-
-            default:
-                fprintf(stderr, "usb-mtp: failed to parse inotify event\n");
-                continue;
-            }
-
-            if (entry) {
-                QTAILQ_INSERT_HEAD(&s->events, entry, next);
-            }
+        o = usb_mtp_object_lookup_name(parent, name, -1);
+        if (!o) {
+            return;
         }
-    }
-}
+        entry = g_new0(MTPMonEntry, 1);
+        entry->handle = o->handle;
+        entry->event = EVT_OBJ_REMOVED;
+        trace_usb_mtp_file_monitor_event(s->dev.addr, o->path, "Obj Deleted");
+        usb_mtp_object_free(s, o);
+        break;
 
-static int usb_mtp_inotify_init(MTPState *s)
-{
-    int fd;
+    case QFILE_MONITOR_EVENT_MODIFIED:
+        o = usb_mtp_object_lookup_name(parent, name, -1);
+        if (!o) {
+            return;
+        }
+        entry = g_new0(MTPMonEntry, 1);
+        entry->handle = o->handle;
+        entry->event = EVT_OBJ_INFO_CHANGED;
+        trace_usb_mtp_file_monitor_event(s->dev.addr, o->path, "Obj Modified");
+        break;
 
-    fd = inotify_init1(IN_NONBLOCK);
-    if (fd == -1) {
-        return 1;
-    }
+    case QFILE_MONITOR_EVENT_IGNORED:
+        trace_usb_mtp_file_monitor_event(s->dev.addr, parent->path,
+                                    "Obj parent dir ignored");
+        break;
 
-    QTAILQ_INIT(&s->events);
-    s->inotifyfd = fd;
+    case QFILE_MONITOR_EVENT_ATTRIBUTES:
+        break;
 
-    qemu_set_fd_handler(fd, inotify_watchfn, NULL, s);
+    default:
+        g_assert_not_reached();
+    }
 
-    return 0;
+    if (entry) {
+        QTAILQ_INSERT_HEAD(&s->events, entry, next);
+    }
 }
 
-static void usb_mtp_inotify_cleanup(MTPState *s)
+static void usb_mtp_file_monitor_cleanup(MTPState *s)
 {
     MTPMonEntry *e, *p;
 
-    if (!s->inotifyfd) {
-        return;
-    }
-
-    qemu_set_fd_handler(s->inotifyfd, NULL, NULL, s);
-    close(s->inotifyfd);
-
     QTAILQ_FOREACH_SAFE(e, &s->events, next, p) {
         QTAILQ_REMOVE(&s->events, e, next);
         g_free(e);
     }
-}
 
-static int usb_mtp_add_watch(int inotifyfd, char *path)
-{
-    uint32_t mask = IN_CREATE | IN_DELETE | IN_MODIFY |
-        IN_ISDIR;
-
-    return inotify_add_watch(inotifyfd, path, mask);
+    qemu_file_monitor_free(s->file_monitor);
+    s->file_monitor = NULL;
 }
-#endif
+
 
 static void usb_mtp_object_readdir(MTPState *s, MTPObject *o)
 {
     struct dirent *entry;
     DIR *dir;
     int fd;
+    Error *err = NULL;
 
     if (o->have_children) {
         return;
@@ -680,16 +623,21 @@ static void usb_mtp_object_readdir(MTPState *s, MTPObject *o)
         close(fd);
         return;
     }
-#ifdef CONFIG_INOTIFY1
-    int watchfd = usb_mtp_add_watch(s->inotifyfd, o->path);
-    if (watchfd == -1) {
-        fprintf(stderr, "usb-mtp: failed to add watch for %s\n", o->path);
-    } else {
-        trace_usb_mtp_inotify_event(s->dev.addr, o->path,
-                                    0, "Watch Added");
-        o->watchfd = watchfd;
+
+    if (s->file_monitor) {
+        int id = qemu_file_monitor_add_watch(s->file_monitor, o->path, NULL,
+                                             file_monitor_event, s, &err);
+        if (id == -1) {
+            error_report("usb-mtp: failed to add watch for %s: %s", o->path,
+                         error_get_pretty(err));
+            error_free(err);
+        } else {
+            trace_usb_mtp_file_monitor_event(s->dev.addr, o->path,
+                                             "Watch Added");
+            o->watchid = id;
+        }
     }
-#endif
+
     while ((entry = readdir(dir)) != NULL) {
         usb_mtp_add_child(s, o, entry->d_name);
     }
@@ -1197,13 +1145,11 @@ enum {
 /* Assumes that children, if any, have been already freed */
 static void usb_mtp_object_free_one(MTPState *s, MTPObject *o)
 {
-#ifndef CONFIG_INOTIFY1
     assert(o->nchildren == 0);
     QTAILQ_REMOVE(&s->objects, o, next);
     g_free(o->name);
     g_free(o->path);
     g_free(o);
-#endif
 }
 
 static int usb_mtp_deletefn(MTPState *s, MTPObject *o, uint32_t trans)
@@ -1302,6 +1248,7 @@ static void usb_mtp_command(MTPState *s, MTPControl *c)
     MTPData *data_in = NULL;
     MTPObject *o = NULL;
     uint32_t nres = 0, res0 = 0;
+    Error *err = NULL;
 
     /* sanity checks */
     if (c->code >= CMD_CLOSE_SESSION && s->session == 0) {
@@ -1329,19 +1276,21 @@ static void usb_mtp_command(MTPState *s, MTPControl *c)
         trace_usb_mtp_op_open_session(s->dev.addr);
         s->session = c->argv[0];
         usb_mtp_object_alloc(s, s->next_handle++, NULL, s->root);
-#ifdef CONFIG_INOTIFY1
-        if (usb_mtp_inotify_init(s)) {
-            fprintf(stderr, "usb-mtp: file monitoring init failed\n");
+
+        s->file_monitor = qemu_file_monitor_new(&err);
+        if (err) {
+            error_report("usb-mtp: file monitoring init failed: %s",
+                         error_get_pretty(err));
+            error_free(err);
+        } else {
+            QTAILQ_INIT(&s->events);
         }
-#endif
         break;
     case CMD_CLOSE_SESSION:
         trace_usb_mtp_op_close_session(s->dev.addr);
         s->session = 0;
         s->next_handle = 0;
-#ifdef CONFIG_INOTIFY1
-        usb_mtp_inotify_cleanup(s);
-#endif
+        usb_mtp_file_monitor_cleanup(s);
         usb_mtp_object_free(s, QTAILQ_FIRST(&s->objects));
         assert(QTAILQ_EMPTY(&s->objects));
         break;
@@ -1554,9 +1503,7 @@ static void usb_mtp_handle_reset(USBDevice *dev)
 
     trace_usb_mtp_reset(s->dev.addr);
 
-#ifdef CONFIG_INOTIFY1
-    usb_mtp_inotify_cleanup(s);
-#endif
+    usb_mtp_file_monitor_cleanup(s);
     usb_mtp_object_free(s, QTAILQ_FIRST(&s->objects));
     s->session = 0;
     usb_mtp_data_free(s->data_in);
@@ -2027,7 +1974,6 @@ static void usb_mtp_handle_data(USBDevice *dev, USBPacket *p)
         }
         break;
     case EP_EVENT:
-#ifdef CONFIG_INOTIFY1
         if (!QTAILQ_EMPTY(&s->events)) {
             struct MTPMonEntry *e = QTAILQ_LAST(&s->events);
             uint32_t handle;
@@ -2051,7 +1997,6 @@ static void usb_mtp_handle_data(USBDevice *dev, USBPacket *p)
             g_free(e);
             return;
         }
-#endif
         p->status = USB_RET_NAK;
         return;
     default:
diff --git a/hw/usb/trace-events b/hw/usb/trace-events
index 2c18770ca5..99b1e8b8ce 100644
--- a/hw/usb/trace-events
+++ b/hw/usb/trace-events
@@ -237,7 +237,7 @@ usb_mtp_op_unknown(int dev, uint32_t code) "dev %d, command code 0x%x"
 usb_mtp_object_alloc(int dev, uint32_t handle, const char *path) "dev %d, handle 0x%x, path %s"
 usb_mtp_object_free(int dev, uint32_t handle, const char *path) "dev %d, handle 0x%x, path %s"
 usb_mtp_add_child(int dev, uint32_t handle, const char *path) "dev %d, handle 0x%x, path %s"
-usb_mtp_inotify_event(int dev, const char *path, uint32_t mask, const char *s) "dev %d, path %s mask 0x%x event %s"
+usb_mtp_file_monitor_event(int dev, const char *path, const char *s) "dev %d, path %s event %s"
 
 # hw/usb/host-libusb.c
 usb_host_open_started(int bus, int addr) "dev %d:%d"