Fix improper closed connection handling in tcpdns.

If dnslisten_readcb gets a read callback it needs to verify that the
outer socket wasn't closed in the meantime, and issue a CANCELED callback
if it was.

(cherry picked from commit 3ab3d90de039a3f086bba9c25792e42dd1b4a614)

diff --git a/lib/isc/netmgr/tcpdns.c b/lib/isc/netmgr/tcpdns.c
index 255c44fe2c3b6e0544a671d5e8a60a838ece13da..f5df92c10564b9d60f0fe63532a045f98c1f2632 100644 (file)
--- a/lib/isc/netmgr/tcpdns.c
+++ b/lib/isc/netmgr/tcpdns.c
@@ -259,6 +259,11 @@ dnslisten_readcb(isc_nmhandle_t *handle, isc_result_t eresult,
        REQUIRE(VALID_NMSOCK(dnssock));
        REQUIRE(dnssock->tid == isc_nm_tid());
        REQUIRE(VALID_NMHANDLE(handle));
+       if (eresult == ISC_R_SUCCESS &&
+           (!isc__nmsocket_active(dnssock) || dnssock->outerhandle == NULL))
+       {
+               eresult = ISC_R_CANCELED;
+       }
 
        if (region == NULL || eresult != ISC_R_SUCCESS) {
                /* Connection closed */