[libvirt] [PATCH] snapshot: Fix use-after-free during snapshot delete

[Eric Blake]

On 4/8/19 1:35 PM, Roman Bogorodskiy wrote:
>   Eric Blake wrote:
> 
>> Commit b647d2195 introduced a use-after-free situation when the caller
>> is trying to delete a snapshot and its children: if the callback

>>
>> Fixes: b647d2195
>> Reported-by: Roman Bogorodskiy <bogorodskiy at gmail.com>
>> Signed-off-by: Eric Blake <eblake at redhat.com>
>> ---
>>  src/conf/virdomainmomentobjlist.c | 4 +++-
>>  1 file changed, 3 insertions(+), 1 deletion(-)
>>
>> diff --git a/src/conf/virdomainmomentobjlist.c b/src/conf/virdomainmomentobjlist.c
>> index 65e82f632c..66eb66017b 100644
>> --- a/src/conf/virdomainmomentobjlist.c
>> +++ b/src/conf/virdomainmomentobjlist.c
>> @@ -80,9 +80,11 @@ virDomainMomentActOnDescendant(void *payload,
>>  {
>>      virDomainMomentObjPtr obj = payload;
>>      struct moment_act_on_descendant *curr = data;
>> +    virDomainMomentObj tmp = *obj;
>>
>> +    /* Careful: curr->iter can delete obj, hence the need for tmp */
>>      (curr->iter)(payload, name, curr->data);
>> -    curr->number += 1 + virDomainMomentForEachDescendant(obj,
>> +    curr->number += 1 + virDomainMomentForEachDescendant(&tmp,
>>                                                           curr->iter,
>>                                                           curr->data);
>>      return 0;
> 
> This fixes the problem for me, thanks.
> The change itself looks reasonable to me, but I'm not familiar with the code
> enough to go with Reviewed-by I guess.

Well, Tested-by is better than nothing; so I've gone ahead and pushed
it. Thanks for checking that it works :)

-- 
Eric Blake, Principal Software Engineer
Red Hat, Inc.           +1-919-301-3226
Virtualization:  qemu.org | libvirt.org

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