qemu: ensure sane umask for qemu process

Add umask to _virCommand, allow user to set umask to command.
Set umask(002) to qemu process to overwrite the default umask
of 022 set by many distros, so that unix sockets created for
virtio-serial has expected permissions.

Fix problem reported here:
https://sourceware.org/bugzilla/show_bug.cgi?id=13078#c11
https://bugzilla.novell.com/show_bug.cgi?id=888166

To use virtio-serial device, unix socket created for chardev with
default umask(022) has insufficient permissions.
e.g.:
-device virtio-serial \
-chardev socket,path=/tmp/foo,server,nowait,id=foo \
-device virtserialport,chardev=foo,name=org.fedoraproject.port.0

srwxr-xr-x 1 qemu qemu 0 21. Jul 14:19 /tmp/somefile.sock

Other users in the same group (like real user, test engines, etc)
cannot write to this socket.

Signed-off-by: Chunyan Liu <cyliu@suse.com>
Signed-off-by: Eric Blake <eblake@redhat.com>

diff --git a/src/libvirt_private.syms b/src/libvirt_private.syms
index 71fc0638c39d510f2725ee5f0854c30a2ee4ed57..f136d244b1b5e3ff7bda5b36e90be1e1b75447e0 100644 (file)
--- a/src/libvirt_private.syms
+++ b/src/libvirt_private.syms
@@ -1171,6 +1171,7 @@ virCommandSetPidFile;
 virCommandSetPreExecHook;
 virCommandSetSELinuxLabel;
 virCommandSetUID;
+virCommandSetUmask;
 virCommandSetWorkingDirectory;
 virCommandToString;
 virCommandWait;

diff --git a/src/qemu/qemu_process.c b/src/qemu/qemu_process.c
index f68dfbee52aad02e2ac7fcd5568c69709fa4d2f2..f76aa5a3b6114790f52fdb64c0a79cd6f01fdfd4 100644 (file)
--- a/src/qemu/qemu_process.c
+++ b/src/qemu/qemu_process.c
@@ -4141,6 +4141,7 @@ int qemuProcessStart(virConnectPtr conn,
     virCommandSetPreExecHook(cmd, qemuProcessHook, &hookData);
     virCommandSetMaxProcesses(cmd, cfg->maxProcesses);
     virCommandSetMaxFiles(cmd, cfg->maxFiles);
+    virCommandSetUmask(cmd, 0x002);
 
     VIR_DEBUG("Setting up security labelling");
     if (virSecurityManagerSetChildProcessLabel(driver->securityManager,

diff --git a/src/util/vircommand.c b/src/util/vircommand.c
index 1d6dbd91d2b1e01134c43605d08dda95cd60134d..efb5f69e01963f8b4aefd9bdd94bba5299a005e1 100644 (file)
--- a/src/util/vircommand.c
+++ b/src/util/vircommand.c
@@ -133,6 +133,7 @@ struct _virCommand {
 #if defined(WITH_SECDRIVER_APPARMOR)
     char *appArmorProfile;
 #endif
+    int umask;
 };
 
 /* See virCommandSetDryRun for description for this variable */
@@ -582,6 +583,8 @@ virExec(virCommandPtr cmd)
 
     /* child */
 
+    if (cmd->umask)
+        umask(cmd->umask);
     ret = EXIT_CANCELED;
     openmax = sysconf(_SC_OPEN_MAX);
     if (openmax < 0) {
@@ -1082,6 +1085,14 @@ virCommandSetMaxFiles(virCommandPtr cmd, unsigned int files)
     cmd->maxFiles = files;
 }
 
+void virCommandSetUmask(virCommandPtr cmd, int umask)
+{
+    if (!cmd || cmd->has_error)
+        return;
+
+    cmd->umask = umask;
+}
+
 /**
  * virCommandClearCaps:
  * @cmd: the command to modify

diff --git a/src/util/vircommand.h b/src/util/vircommand.h
index d3b286de835d300789e4f492a4c77d412267146a..bf65de4ff97ac01c33c8e757ca2c90d9560066c2 100644 (file)
--- a/src/util/vircommand.h
+++ b/src/util/vircommand.h
@@ -72,6 +72,7 @@ void virCommandSetUID(virCommandPtr cmd, uid_t uid);
 void virCommandSetMaxMemLock(virCommandPtr cmd, unsigned long long bytes);
 void virCommandSetMaxProcesses(virCommandPtr cmd, unsigned int procs);
 void virCommandSetMaxFiles(virCommandPtr cmd, unsigned int files);
+void virCommandSetUmask(virCommandPtr cmd, int umask);
 
 void virCommandClearCaps(virCommandPtr cmd);