[PATCH 2/2] Revert "qemu_passt: Precreate passt logfile"

[Michal Privoznik <mprivozn@xxxxxxxxxx>]

This reverts commit 8511b96a319836700b4829816cdae27c3630060d.

Turns out, we need to do a bit more than just plain
qemuSecurityDomainSetPathLabel() which sets svirt_image_t. Passt
has its own SELinux policy and as a part of that they invent
passt_log_t for log files. Right now, I don't know how libvirt
could query that and even if I did, passt SELinux policy would
need to permit relabelling from svirt_t to passt_log_t, which it
doesn't [1].

Until these problems are addressed we shouldn't be pre-creating
the file as it puts users into way worse position - even
scenarios that used to work don't work. But then again - using
log file for passt is usually valuable for developers only and
not regular users.

1: https://bugzilla.redhat.com/show_bug.cgi?id=2209191#c10
Signed-off-by: Michal Privoznik <mprivozn@xxxxxxxxxx>
---
 src/qemu/qemu_passt.c | 40 +++++-----------------------------------
 1 file changed, 5 insertions(+), 35 deletions(-)

diff --git a/src/qemu/qemu_passt.c b/src/qemu/qemu_passt.c
index 25b22d8ad9..99636a3a49 100644
--- a/src/qemu/qemu_passt.c
+++ b/src/qemu/qemu_passt.c
@@ -20,8 +20,6 @@
 
 #include <config.h>
 
-#include <fcntl.h>
-
 #include "qemu_dbus.h"
 #include "qemu_extdevice.h"
 #include "qemu_security.h"
@@ -138,13 +136,9 @@ void
 qemuPasstStop(virDomainObj *vm,
               virDomainNetDef *net)
 {
-    qemuDomainObjPrivate *priv = vm->privateData;
-    virQEMUDriver *driver = priv->driver;
     g_autofree char *pidfile = qemuPasstCreatePidFilename(vm, net);
     g_autofree char *passtSocketName = qemuPasstCreateSocketPath(vm, net);
 
-    qemuSecurityDomainRestorePathLabel(driver, vm, net->backend.logFile);
-
     qemuPasstKill(pidfile, passtSocketName);
 }
 
@@ -172,12 +166,10 @@ qemuPasstStart(virDomainObj *vm,
 {
     qemuDomainObjPrivate *priv = vm->privateData;
     virQEMUDriver *driver = priv->driver;
-    g_autoptr(virQEMUDriverConfig) cfg = virQEMUDriverGetConfig(driver);
     g_autofree char *passtSocketName = qemuPasstCreateSocketPath(vm, net);
     g_autoptr(virCommand) cmd = NULL;
     g_autofree char *pidfile = qemuPasstCreatePidFilename(vm, net);
     char macaddr[VIR_MAC_STRING_BUFLEN];
-    bool needUnlink = false;
     size_t i;
 
     cmd = virCommandNew(PASST);
@@ -199,25 +191,8 @@ qemuPasstStart(virDomainObj *vm,
     if (net->sourceDev)
         virCommandAddArgList(cmd, "--interface", net->sourceDev, NULL);
 
-    if (net->backend.logFile) {
-        VIR_AUTOCLOSE logfd = -1;
-        /* The logFile location is not restricted to a per-domain directory. It
-         * can be anywhere. Pre-create it as passt may not have enough perms to
-         * do so. */
-        if (qemuDomainOpenFile(cfg, vm->def, net->backend.logFile,
-                               O_CREAT | O_TRUNC | O_APPEND | O_RDWR,
-                               &needUnlink) < 0) {
-            return -1;
-        }
-
-        if (qemuSecurityDomainSetPathLabel(driver, vm,
-                                           net->backend.logFile, false) < 0) {
-            goto error;
-        }
-
-        /* Worse, passt deliberately doesn't support FD passing. */
+    if (net->backend.logFile)
         virCommandAddArgList(cmd, "--log-file", net->backend.logFile, NULL);
-    }
 
     /* Add IP address info */
     for (i = 0; i < net->guestIP.nips; i++) {
@@ -228,7 +203,7 @@ qemuPasstStart(virDomainObj *vm,
          * a single IPv4 and single IPv6 address
          */
         if (!(addr = virSocketAddrFormat(&ip->address)))
-            goto error;
+            return -1;
 
         virCommandAddArgList(cmd, "--address", addr, NULL);
 
@@ -256,14 +231,14 @@ qemuPasstStart(virDomainObj *vm,
             /* validation guarantees this will never happen */
             virReportError(VIR_ERR_INTERNAL_ERROR,
                            _("Invalid portForward proto value %1$u"), pf->proto);
-            goto error;
+            return -1;
         }
 
         if (VIR_SOCKET_ADDR_VALID(&pf->address)) {
             g_autofree char *addr = NULL;
 
             if (!(addr = virSocketAddrFormat(&pf->address)))
-                goto error;
+                return -1;
 
             virBufferAddStr(&buf, addr);
             emitsep = true;
@@ -309,7 +284,7 @@ qemuPasstStart(virDomainObj *vm,
 
 
     if (qemuExtDeviceLogCommand(driver, vm, cmd, "passt") < 0)
-        goto error;
+        return -1;
 
     if (qemuSecurityCommandRun(driver, vm, cmd, -1, -1, true, NULL) < 0)
         goto error;
@@ -317,11 +292,6 @@ qemuPasstStart(virDomainObj *vm,
     return 0;
 
  error:
-    if (needUnlink && unlink(net->backend.logFile) < 0) {
-        VIR_WARN("Unable to unlink '%s': %s",
-                 net->backend.logFile, g_strerror(errno));
-    }
-
     qemuPasstKill(pidfile, passtSocketName);
     return -1;
 }
-- 
2.41.0