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From ad3f8f1d128f726d1504079ec34b68f6db297d3a Mon Sep 17 00:00:00 2001
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Message-Id: <ad3f8f1d128f726d1504079ec34b68f6db297d3a@dist-git>
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From: Marc Hartmayer <mhartmay@linux.ibm.com>
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Date: Wed, 10 Jul 2019 11:49:45 +0200
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Subject: [PATCH] virDomainObjListAddLocked: fix double free
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MIME-Version: 1.0
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Content-Type: text/plain; charset=UTF-8
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Content-Transfer-Encoding: 8bit
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If @vm has flagged as "to be removed" virDomainObjListFindByNameLocked
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returns NULL (although the definition actually exists). Therefore, the
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possibility exits that "virHashAddEntry" will raise the error
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"Duplicate key" => virDomainObjListAddObjLocked fails =>
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virDomainObjEndAPI(&vm) is called and this leads to a freeing of @def
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since @def is already assigned to vm->def. But actually this leads to
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a double free since the common usage pattern is that the caller of
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virDomainObjListAdd(Locked) is responsible for freeing @def in case of
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an error.
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Let's fix this by setting vm->def to NULL in case of an error.
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Backtrace:
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   ➤  bt
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   #0  virFree (ptrptr=0x7575757575757575)
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   #1  0x000003ffb5b25b3e in virDomainResourceDefFree
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   #2  0x000003ffb5b37c34 in virDomainDefFree
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   #3  0x000003ff9123f734 in qemuDomainDefineXMLFlags
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   #4  0x000003ff9123f7f4 in qemuDomainDefineXML
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   #5  0x000003ffb5cd2c84 in virDomainDefineXML
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   #6  0x000000011745aa82 in remoteDispatchDomainDefineXML
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   ...
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Reviewed-by: Bjoern Walk <bwalk@linux.ibm.com>
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Signed-off-by: Marc Hartmayer <mhartmay@linux.ibm.com>
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(cherry picked from commit 7e760f61577e6c4adbb0b015f8f7ac1796570cdd)
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Signed-off-by: Ján Tomko <jtomko@redhat.com>
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Resolves: https://bugzilla.redhat.com/show_bug.cgi?id=1728530
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Message-Id: <b651c347f5775c8298347ef8602d0205fab9c3e7.1562752178.git.jtomko@redhat.com>
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Reviewed-by: Andrea Bolognani <abologna@redhat.com>
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---
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 src/conf/virdomainobjlist.c | 4 +++-
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 1 file changed, 3 insertions(+), 1 deletion(-)
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diff --git a/src/conf/virdomainobjlist.c b/src/conf/virdomainobjlist.c
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index 72064d7c66..e7c3e326ca 100644
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--- a/src/conf/virdomainobjlist.c
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+++ b/src/conf/virdomainobjlist.c
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@@ -329,8 +329,10 @@ virDomainObjListAddLocked(virDomainObjListPtr doms,
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             goto cleanup;
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         vm->def = def;
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-        if (virDomainObjListAddObjLocked(doms, vm) < 0)
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+        if (virDomainObjListAddObjLocked(doms, vm) < 0) {
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+            vm->def = NULL;
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             goto error;
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+        }
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     }
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  cleanup:
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     return vm;
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-- 
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2.22.0
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