dnstap-read: clear buffer before expanding it

When printing a packet, dnstap-read checks whether its text form takes
up more than the 2048 bytes allocated for the output buffer by default.
If that is the case, the output buffer is automatically expanded, but
the truncated output is left in the buffer, resulting in malformed data
being printed.  Clear the output buffer before expanding it to prevent
this issue from occurring.

diff --git a/bin/tests/system/dnstap/README b/bin/tests/system/dnstap/README
new file mode 100644 (file)
index 0000000..f4cb385
--- /dev/null
+++ b/bin/tests/system/dnstap/README
@@ -0,0 +1,20 @@
+Copyright (C) Internet Systems Consortium, Inc. ("ISC")
+
+See COPYRIGHT in the source root or http://isc.org/copyright.html for terms.
+
+The "large-answer.fstrm" file was generated by configuring a named instance
+compiled with --enable-dnstap and --enable-fixed-rrset with the following
+directives:
+
+    minimal-responses yes;
+    rrset-order { order fixed; };
+    dnstap { auth response; };
+    dnstap-identity none;
+    dnstap-output file "large-answer.fstrm";
+
+The captured RRset from the "example." zone was created using:
+
+    $GENERATE 1-48 @ IN A 127.0.0.$
+
+A server instance set up this way was then queried non-recursively (RD=0) for
+"example/A".

diff --git a/bin/tests/system/dnstap/large-answer.fstrm b/bin/tests/system/dnstap/large-answer.fstrm
new file mode 100644 (file)
index 0000000..873b315
Binary files /dev/null and b/bin/tests/system/dnstap/large-answer.fstrm differ

diff --git a/bin/tests/system/dnstap/tests.sh b/bin/tests/system/dnstap/tests.sh
index 13969950262f7901e7cbff41178b7698e5670838..83877b102f229e1a3c914c1705cd92d4f99c57c1 100644 (file)
--- a/bin/tests/system/dnstap/tests.sh
+++ b/bin/tests/system/dnstap/tests.sh
@@ -736,5 +736,14 @@ EOF
        status=`expr $status + $ret`
 fi
 
+echo_i "checking large packet printing"
+ret=0
+# Expect one occurrence of "opcode: QUERY" below "reponse_message_data" and
+# another one below "response_message".
+lines=`$DNSTAPREAD -y large-answer.fstrm | grep -c "opcode: QUERY"`
+[ $lines -eq 2 ] || ret=1
+if [ $ret != 0 ]; then echo_i "failed"; fi
+status=`expr $status + $ret`
+
 echo_i "exit status: $status"
 [ $status -eq 0 ] || exit 1

diff --git a/bin/tools/dnstap-read.c b/bin/tools/dnstap-read.c
index 2548bf0fac9d16f72a0478f9484df9c54176dfdd..94fc49a01cef027833bc0d34950eec168e8e3220 100644 (file)
--- a/bin/tools/dnstap-read.c
+++ b/bin/tools/dnstap-read.c
@@ -155,6 +155,7 @@ print_packet(dns_dtdata_t *dt, const dns_master_style_t *style) {
 
                        result = dns_message_totext(dt->msg, style, 0, b);
                        if (result == ISC_R_NOSPACE) {
+                               isc_buffer_clear(b);
                                textlen *= 2;
                                continue;
                        } else if (result == ISC_R_SUCCESS) {

diff --git a/util/copyrights b/util/copyrights
index aa2f95cee545e1006358dd9dfa282e2d084facd6..835d7db1aad7c1ac3035c6e203c711fe64d11a33 100644 (file)
--- a/util/copyrights
+++ b/util/copyrights
@@ -558,7 +558,9 @@
 ./bin/tests/system/dnssec/signer/general/bogus-ksk.key X       2018,2019
 ./bin/tests/system/dnssec/signer/general/bogus-zsk.key X       2018,2019
 ./bin/tests/system/dnssec/tests.sh             SH      2000,2001,2002,2004,2005,2006,2007,2008,2009,2010,2011,2012,2013,2014,2015,2016,2017,2018,2019
+./bin/tests/system/dnstap/README               TXT.BRIEF       2019
 ./bin/tests/system/dnstap/clean.sh             SH      2015,2016,2017,2018,2019
+./bin/tests/system/dnstap/large-answer.fstrm   X       2019
 ./bin/tests/system/dnstap/setup.sh             SH      2018,2019
 ./bin/tests/system/dnstap/tests.sh             SH      2015,2016,2017,2018,2019
 ./bin/tests/system/dnstap/ydump.py             PYTHON  2016,2017,2018,2019