Re: [libvirt] [PATCH] nwfilter: Don't crash when trying to add an nwfilter that's already being removed

https://bugzilla.redhat.com/show_bug.cgi?id=1686927 When trying to create a nwfilter binding via nwfilterBindingCreateXML() we may encounter a crash. The sequence of functions called is as follows: 1) nwfilterBindingCreateXML() parses the XML and calls virNWFilterBindingObjListAdd() which calls virNWFilterBindingObjListAddLocked() 2) Here, @binding is not found because binding->remove is set. 3) Therefore, controls continue with creating new @binding, setting its def to the one from 1) and adding it to the hash table. 4) This fails, because the binding is still in the hash table (duplicate key is detected). 5) The control jumps to 'error' label where virNWFilterBindingObjEndAPI() is called which frees the binding definition passed. 6) Error is propagated to the caller, which calls virNWFilterBindingDefFree() over the definition again. Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; --- src/conf/virnwfilterbindingobjlist.c | 11 ++++++----- src/conf/virnwfilterbindingobjlist.h | 2 +- src/nwfilter/nwfilter_driver.c | 5 ++--- 3 files changed, 9 insertions(+), 9 deletions(-) diff --git a/src/conf/virnwfilterbindingobjlist.c b/src/conf/virnwfilterbindingobjlist.c index 06ccbf53af..87189da642 100644 --- a/src/conf/virnwfilterbindingobjlist.c +++ b/src/conf/virnwfilterbindingobjlist.c @@ -164,23 +164,24 @@ virNWFilterBindingObjListAddObjLocked(virNWFilterBindingObjListPtr bindings, */ static virNWFilterBindingObjPtr virNWFilterBindingObjListAddLocked(virNWFilterBindingObjListPtr bindings, - virNWFilterBindingDefPtr def) + virNWFilterBindingDefPtr *def)

{ virNWFilterBindingObjPtr binding; /* See if a binding with matching portdev already exists */ if ((binding = virNWFilterBindingObjListFindByPortDevLocked( - bindings, def->portdevname))) { + bindings, (*def)->portdevname))) { virReportError(VIR_ERR_OPERATION_FAILED, _("binding '%s' already exists"), - def->portdevname); + (*def)->portdevname); goto error; } if (!(binding = virNWFilterBindingObjNew())) goto error; - virNWFilterBindingObjSetDef(binding, def); + virNWFilterBindingObjSetDef(binding, *def); + *def = NULL; if (virNWFilterBindingObjListAddObjLocked(bindings, binding) < 0)