[PATCH] conf: avoid memory leaks while parsing seclabel

[Eric Blake <eblake@xxxxxxxxxx>]

Our seclabel parsing was repeatedly assigning malloc'd data into a
temporary variable, without first freeing the previous use.  Among
other leaks flagged by valgrind:

==9312== 8 bytes in 1 blocks are definitely lost in loss record 88 of 821
==9312==    at 0x4A0645D: malloc (in /usr/lib64/valgrind/vgpreload_memcheck-amd64-linux.so)
==9312==    by 0x8C40369: strdup (strdup.c:42)
==9312==    by 0x50EA799: virStrdup (virstring.c:676)
==9312==    by 0x50FAEB9: virXPathString (virxml.c:90)
==9312==    by 0x50FAF1E: virXPathStringLimit (virxml.c:112)
==9312==    by 0x510F516: virSecurityLabelDefParseXML (domain_conf.c:4571)
==9312==    by 0x510FB20: virSecurityLabelDefsParseXML (domain_conf.c:4720)

While it was multiple problems, it looks like commit da78351 was
to blame for all of them.

* src/conf/domain_conf.c (virSecurityLabelDefParseXML): Plug leaks
detected by valgrind.

Signed-off-by: Eric Blake <eblake@xxxxxxxxxx>
---
 src/conf/domain_conf.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/src/conf/domain_conf.c b/src/conf/domain_conf.c
index 6ed6155..077e035 100644
--- a/src/conf/domain_conf.c
+++ b/src/conf/domain_conf.c
@@ -4573,6 +4573,7 @@ virSecurityLabelDefParseXML(xmlXPathContextPtr ctxt,

     if (!(seclabel = virSecurityLabelDefNew(p)))
         goto error;
+    VIR_FREE(p);

     /* set default value */
     seclabel->type = VIR_DOMAIN_SECLABEL_DYNAMIC;
@@ -4606,6 +4607,7 @@ virSecurityLabelDefParseXML(xmlXPathContextPtr ctxt,
             goto error;
         }
     }
+    VIR_FREE(p);

     if (seclabel->type == VIR_DOMAIN_SECLABEL_DYNAMIC &&
         !seclabel->relabel) {
@@ -4656,6 +4658,7 @@ virSecurityLabelDefParseXML(xmlXPathContextPtr ctxt,
         }

         seclabel->label = p;
+        p = NULL;
     }

     /* Only parse imagelabel, if requested live XML with relabeling */
@@ -4670,6 +4673,7 @@ virSecurityLabelDefParseXML(xmlXPathContextPtr ctxt,
             goto error;
         }
         seclabel->imagelabel = p;
+        p = NULL;
     }

     /* Only parse baselabel for dynamic label type */
@@ -4677,6 +4681,7 @@ virSecurityLabelDefParseXML(xmlXPathContextPtr ctxt,
         p = virXPathStringLimit("string(./baselabel[1])",
                                 VIR_SECURITY_LABEL_BUFLEN-1, ctxt);
         seclabel->baselabel = p;
+        p = NULL;
     }

     return seclabel;
-- 
1.9.3

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