[libvirt] [PATCH 5/6] Fix error handling in virSecurityManagerGetMountOptions

[Daniel P. Berrange]

From: "Daniel P. Berrange" <berrange at redhat.com>

The impls of virSecurityManagerGetMountOptions had no way to
return errors, since the code was treating 'NULL' as a success
value. This is somewhat pointless, since the calling code did
not want NULL in the first place and has to translate it into
the empty string "". So change the code so that the impls can
return "" directly, allowing use of NULL for error reporting
once again

Signed-off-by: Daniel P. Berrange <berrange at redhat.com>
---
 src/lxc/lxc_container.c          | 10 ++++++----
 src/security/security_apparmor.c | 17 +++++++++++++++++
 src/security/security_manager.c  |  5 +----
 src/security/security_nop.c      | 15 +++++++++++++--
 src/security/security_selinux.c  | 28 +++++++++++++++++-----------
 5 files changed, 54 insertions(+), 21 deletions(-)

diff --git a/src/lxc/lxc_container.c b/src/lxc/lxc_container.c
index db1f6ed..ebeaca1 100644
--- a/src/lxc/lxc_container.c
+++ b/src/lxc/lxc_container.c
@@ -571,7 +571,7 @@ static int lxcContainerMountBasicFS(bool pivotRoot,
          */
 
         ignore_value(virAsprintf(&opts,
-                                 "mode=755,size=65536%s",(sec_mount_options ? sec_mount_options : "")));
+                                 "mode=755,size=65536%s", sec_mount_options));
         if (!opts) {
             virReportOOMError();
             goto cleanup;
@@ -1083,7 +1083,7 @@ static int lxcContainerMountFSTmpfs(virDomainFSDefPtr fs,
     char *data = NULL;
 
     if (virAsprintf(&data,
-                    "size=%lldk%s", fs->usage, (sec_mount_options ? sec_mount_options : "")) < 0) {
+                    "size=%lldk%s", fs->usage, sec_mount_options) < 0) {
         virReportOOMError();
         goto cleanup;
     }
@@ -1456,7 +1456,7 @@ static int lxcContainerMountCGroups(struct lxcContainerCGroup *mounts,
     }
 
     if (virAsprintf(&opts,
-                    "mode=755,size=65536%s",(sec_mount_options ? sec_mount_options : "")) < 0) {
+                    "mode=755,size=65536%s", sec_mount_options) < 0) {
         virReportOOMError();
         return -1;
     }
@@ -1689,7 +1689,9 @@ static int lxcContainerSetupMounts(virDomainDefPtr vmDef,
     if (lxcContainerResolveSymlinks(vmDef) < 0)
         return -1;
 
-    sec_mount_options = virSecurityManagerGetMountOptions(securityDriver, vmDef);
+    if (!(sec_mount_options = virSecurityManagerGetMountOptions(securityDriver, vmDef)))
+        return -1;
+
     if (root && root->src)
         rc =  lxcContainerSetupPivotRoot(vmDef, root, ttyPaths, nttyPaths, sec_mount_options);
     else
diff --git a/src/security/security_apparmor.c b/src/security/security_apparmor.c
index 1315fe1..b0cdb65 100644
--- a/src/security/security_apparmor.c
+++ b/src/security/security_apparmor.c
@@ -881,6 +881,21 @@ AppArmorSetTapFDLabel(virSecurityManagerPtr mgr ATTRIBUTE_UNUSED,
     return 0;
 }
 
+
+static char *
+AppArmorGetMountOptions(virSecurityManagerPtr mgr ATTRIBUTE_UNUSED,
+                        virDomainDefPtr vm ATTRIBUTE_UNUSED)
+{
+    char *opts;
+
+    if (!(opts = strdup(""))) {
+        virReportOOMError();
+        return NULL;
+    }
+    return opts;
+}
+
+
 virSecurityDriver virAppArmorSecurityDriver = {
     .privateDataLen                     = 0,
     .name                               = SECURITY_APPARMOR_NAME,
@@ -918,4 +933,6 @@ virSecurityDriver virAppArmorSecurityDriver = {
 
     .domainSetSecurityImageFDLabel      = AppArmorSetImageFDLabel,
     .domainSetSecurityTapFDLabel        = AppArmorSetTapFDLabel,
+
+    .domainGetSecurityMountOptions      = AppArmorGetMountOptions,
 };
diff --git a/src/security/security_manager.c b/src/security/security_manager.c
index d446607..0ebd53b 100644
--- a/src/security/security_manager.c
+++ b/src/security/security_manager.c
@@ -486,10 +486,7 @@ char *virSecurityManagerGetMountOptions(virSecurityManagerPtr mgr,
     if (mgr->drv->domainGetSecurityMountOptions)
         return mgr->drv->domainGetSecurityMountOptions(mgr, vm);
 
-    /*
-      I don't think this is an error, these should be optional
-      virReportError(VIR_ERR_NO_SUPPORT, __FUNCTION__);
-    */
+    virReportError(VIR_ERR_NO_SUPPORT, __FUNCTION__);
     return NULL;
 }
 
diff --git a/src/security/security_nop.c b/src/security/security_nop.c
index 86f644b..5f3270a 100644
--- a/src/security/security_nop.c
+++ b/src/security/security_nop.c
@@ -21,6 +21,10 @@
 
 #include "security_nop.h"
 
+#include "virterror_internal.h"
+
+#define VIR_FROM_THIS VIR_FROM_SECURITY
+
 static virSecurityDriverStatus virSecurityDriverProbeNop(const char *virtDriver ATTRIBUTE_UNUSED)
 {
     return SECURITY_DRIVER_ENABLE;
@@ -165,8 +169,15 @@ static int virSecurityDomainSetFDLabelNop(virSecurityManagerPtr mgr ATTRIBUTE_UN
 }
 
 static char *virSecurityDomainGetMountOptionsNop(virSecurityManagerPtr mgr ATTRIBUTE_UNUSED,
-                                                 virDomainDefPtr vm ATTRIBUTE_UNUSED) {
-    return NULL;
+                                                 virDomainDefPtr vm ATTRIBUTE_UNUSED)
+{
+    char *opts;
+
+    if (!(opts = strdup(""))) {
+        virReportOOMError();
+        return NULL;
+    }
+    return opts;
 }
 
 virSecurityDriver virSecurityDriverNop = {
diff --git a/src/security/security_selinux.c b/src/security/security_selinux.c
index 8fcaaa8..0e49ded 100644
--- a/src/security/security_selinux.c
+++ b/src/security/security_selinux.c
@@ -1974,20 +1974,26 @@ virSecuritySELinuxGetSecurityMountOptions(virSecurityManagerPtr mgr,
     char *opts = NULL;
     virSecurityLabelDefPtr secdef;
 
-    secdef = virDomainDefGetSecurityLabelDef(def, SECURITY_SELINUX_NAME);
-    if (secdef == NULL)
-        return NULL;
-
-    if (! secdef->imagelabel)
-        secdef->imagelabel = virSecuritySELinuxGenImageLabel(mgr,def);
+    if ((secdef = virDomainDefGetSecurityLabelDef(def, SECURITY_SELINUX_NAME))) {
+        if (!secdef->imagelabel)
+            secdef->imagelabel = virSecuritySELinuxGenImageLabel(mgr,def);
+
+        if (secdef->imagelabel &&
+            virAsprintf(&opts,
+                        ",context=\"%s\"",
+                        (const char*) secdef->imagelabel) < 0) {
+            virReportOOMError();
+            return NULL;
+        }
+    }
 
-    if (secdef->imagelabel) {
-        virAsprintf(&opts,
-                    ",context=\"%s\"",
-                    (const char*) secdef->imagelabel);
+    if (!opts &&
+        !(opts = strdup(""))) {
+        virReportOOMError();
+        return NULL;
     }
 
-    VIR_DEBUG("imageLabel=%s", secdef->imagelabel);
+    VIR_DEBUG("imageLabel=%s opts=%s", secdef->imagelabel, opts);
     return opts;
 }
 
-- 
1.7.11.2