Fix crash in client side DoH code

This commit fixes a situation when a cstream object could get unlinked
from the list as a result of a cstream->read_cb call. Thus, unlinking
it after the call could crash the program.

diff --git a/lib/isc/netmgr/http.c b/lib/isc/netmgr/http.c
index c2e403a5d023fc384560c54aa6cc62301b93189e..9dc5e4d5c3c8f8bf92aa1add06e7f019322899ee 100644 (file)
--- a/lib/isc/netmgr/http.c
+++ b/lib/isc/netmgr/http.c
@@ -528,10 +528,10 @@ call_unlink_cstream_readcb(http_cstream_t *cstream,
                           isc_result_t result) {
        REQUIRE(VALID_HTTP2_SESSION(session));
        REQUIRE(cstream != NULL);
+       ISC_LIST_UNLINK(session->cstreams, cstream, link);
        cstream->read_cb(session->handle, result,
                         &(isc_region_t){ cstream->rbuf, cstream->rbufsize },
                         cstream->read_cbarg);
-       ISC_LIST_UNLINK(session->cstreams, cstream, link);
        put_http_cstream(session->mctx, cstream);
 }