Blame SOURCES/libvirt-snapshot-conf-Fix-NULL-dereference-when-driver-element-is-empty.patch

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From 31d35776ac5aa93f97d1f3516630137664f48881 Mon Sep 17 00:00:00 2001
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Message-Id: <31d35776ac5aa93f97d1f3516630137664f48881@dist-git>
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From: Peter Krempa <pkrempa@redhat.com>
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Date: Wed, 26 Feb 2014 14:54:48 +0100
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Subject: [PATCH] snapshot: conf: Fix NULL dereference when <driver> element is
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 empty
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https://bugzilla.redhat.com/show_bug.cgi?id=1032370
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Consider the following valid snapshot XML as the <driver> element is
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allowed to be empty in the domainsnapshot.rng schema:
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$ cat snap.xml
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<domainsnapshot>
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  <disks>
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    <disk name='vda' snapshot='external'>
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      <source file='/tmp/foo'/>
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      <driver/>
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    </disk>
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  </disks>
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</domainsnapshot>
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produces the following error:
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$ virsh snapshot-create domain snap.xml
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error: internal error: unknown disk snapshot driver '(null)'
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The driver type is parsed as NULL from the XML as the attribute is not
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present and then directly used to produce the error message.
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With this patch the attempt to parse the driver type is skipped if not
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present to avoid changing the schema to forbid the empty driver element.
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(cherry picked from commit 5a66c667ff5cae61c2ad2e646c8eb3eedc67f925)
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Signed-off-by: Jiri Denemark <jdenemar@redhat.com>
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---
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 src/conf/snapshot_conf.c | 16 +++++++++-------
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 1 file changed, 9 insertions(+), 7 deletions(-)
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diff --git a/src/conf/snapshot_conf.c b/src/conf/snapshot_conf.c
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index 29e12b7..a1fd723 100644
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--- a/src/conf/snapshot_conf.c
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+++ b/src/conf/snapshot_conf.c
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@@ -154,15 +154,17 @@ virDomainSnapshotDiskDefParseXML(xmlNodePtr node,
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         } else if (!def->format &&
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                    xmlStrEqual(cur->name, BAD_CAST "driver")) {
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             char *driver = virXMLPropString(cur, "type");
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-            def->format = virStorageFileFormatTypeFromString(driver);
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-            if (def->format <= 0) {
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-                virReportError(VIR_ERR_INTERNAL_ERROR,
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-                               _("unknown disk snapshot driver '%s'"),
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-                               driver);
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+            if (driver) {
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+                def->format = virStorageFileFormatTypeFromString(driver);
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+                if (def->format <= 0) {
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+                    virReportError(VIR_ERR_INTERNAL_ERROR,
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+                                   _("unknown disk snapshot driver '%s'"),
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+                                   driver);
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+                    VIR_FREE(driver);
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+                    goto cleanup;
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+                }
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                 VIR_FREE(driver);
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-                goto cleanup;
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             }
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-            VIR_FREE(driver);
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         }
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     }
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-- 
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1.9.0
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