[libvirt] [PATCH] nwfilter: Resolve SEGV for NWFilter Snoop processing

https://bugzilla.redhat.com/show_bug.cgi?id=1599973 Commit id fca9afa08 changed the @req->ifname to use @req->binding->portdevname fillingin the @req->binding in a similar way that @req->ifname would have been filled in during virNWFilterDHCPSnoopReq processing. However, in doing so it did not take into account some code paths where the @req->binding should be checked instead of @req->binding->portdevname. These checks led to SEGVs in some cases during libvirtd reload processing in virNWFilterSnoopRemAllReqIter (for stop during nwfilterStateCleanup processing) and virNWFilterSnoopReqLeaseDel (for start during nwfilterStateInitialize processing). In particular, when reading the nwfilter.leases file a new @req is created, but the @req->binding is not filled in. That's left to virNWFilterDHCPSnoopReq processing which checks if the @req already exists in the @virNWFilterSnoopState.snoopReqs hash table after adding a virNWFilterSnoopState.ifnameToKey entry for the @req->binding->portdevname by a @ref->ikey value. NB: virNWFilterSnoopIPLeaseInstallRule and virNWFilterDHCPSnoopThread do not need the req->binding check since they can only be called after the filter->binding is created/assigned. Signed-off-by: John Ferlan <jferlan(a)redhat.com&gt; --- src/nwfilter/nwfilter_dhcpsnoop.c | 7 ++++--- 1 file changed, 4 insertions(+), 3 deletions(-) diff --git a/src/nwfilter/nwfilter_dhcpsnoop.c b/src/nwfilter/nwfilter_dhcpsnoop.c index c7fd370598..2330ba0479 100644 --- a/src/nwfilter/nwfilter_dhcpsnoop.c +++ b/src/nwfilter/nwfilter_dhcpsnoop.c @@ -846,7 +846,7 @@ virNWFilterSnoopReqLeaseDel(virNWFilterSnoopReqPtr req, int ret = 0; virNWFilterSnoopIPLeasePtr ipl; char *ipstr = NULL; - int ipAddrLeft; + int ipAddrLeft = 0; /* protect req->start, req->ifname and the lease */ virNWFilterSnoopReqLock(req); @@ -867,7 +867,8 @@ virNWFilterSnoopReqLeaseDel(virNWFilterSnoopReqPtr req, if (update_leasefile) virNWFilterSnoopLeaseFileSave(ipl); - ipAddrLeft = virNWFilterIPAddrMapDelIPAddr(req->binding->portdevname, ipstr); + if (req->binding) + ipAddrLeft = virNWFilterIPAddrMapDelIPAddr(req->binding->portdevname, ipstr); if (!req->threadkey || !instantiate) goto skip_instantiate; @@ -2037,7 +2038,7 @@ virNWFilterSnoopRemAllReqIter(const void *payload, /* protect req->binding->portdevname */ virNWFilterSnoopReqLock(req); - if (req->binding->portdevname) { + if (req->binding && req->binding->portdevname) { ignore_value(virHashRemoveEntry(virNWFilterSnoopState.ifnameToKey, req->binding->portdevname)); -- 2.17.1