gpgv: show always webportal error on NODATA

gpg doesn't give use a UID on NODATA, which we were "expecting" (but not
using for anything), but just an error number. Instead of collecting
these as badsigners which will trigger a "invald signature" error with
remarks like "NODATA 1" we instead adapt a message similar to the NODATA
error of a clearsigned file (which is actually not reached anymore as we
split them up, which fails with a NOSPLIT error, which uses the same
general error message).

In other words: Not a security relevant change, just a user experience
improvement as we now point them to the most likely cause of the
problem instead of saying "invalid signature" which would point them in
the direction of the archive being broken (for everyone) instead.

Closes: 823746

4 files changed, 58 insertions, 41 deletions

diff --git a/methods/gpgv.cc b/methods/gpgv.cc
index b9fb09a8f..dd395d659 100644
--- a/methods/gpgv.cc
+++ b/methods/gpgv.cc
@@ -173,6 +173,7 @@ string GPGVMethod::VerifyGetSigners(const char *file, const char *outfile,
    std::vector<std::string> ErrSigners;
    size_t buffersize = 0;
    char *buffer = NULL;
+   bool gotNODATA = false;
    while (1)
    {
       if (getline(&buffer, &buffersize, pipein) == -1)
@@ -194,8 +195,8 @@ string GPGVMethod::VerifyGetSigners(const char *file, const char *outfile,
 	 ErrSigners.erase(std::remove_if(ErrSigners.begin(), ErrSigners.end(), [&](std::string const &errsig) {
 		  return errsig.compare(strlen("ERRSIG "), 16, buffer, sizeof(GNUPGNOPUBKEY), 16) == 0;  }), ErrSigners.end());
       }
-      else if (strncmp(buffer, GNUPGNODATA, sizeof(GNUPGBADSIG)-1) == 0)
-	 PushEntryWithUID(BadSigners, buffer, Debug);
+      else if (strncmp(buffer, GNUPGNODATA, sizeof(GNUPGNODATA)-1) == 0)
+	 gotNODATA = true;
       else if (strncmp(buffer, GNUPGEXPKEYSIG, sizeof(GNUPGEXPKEYSIG)-1) == 0)
 	 PushEntryWithUID(WorthlessSigners, buffer, Debug);
       else if (strncmp(buffer, GNUPGEXPSIG, sizeof(GNUPGEXPSIG)-1) == 0)
@@ -293,10 +294,26 @@ string GPGVMethod::VerifyGetSigners(const char *file, const char *outfile,
       std::for_each(SoonWorthlessSigners.begin(), SoonWorthlessSigners.end(), [](Signer const &sig) { std::cerr << sig.key << ", "; });
       std::cerr << std::endl << "  NoPubKey: ";
       std::copy(NoPubKeySigners.begin(), NoPubKeySigners.end(), std::ostream_iterator<std::string>(std::cerr, ", "));
-      std::cerr << std::endl;
+      std::cerr << std::endl << "  NODATA: " << (gotNODATA ? "yes" : "no") << std::endl;
    }
 
-   if (WEXITSTATUS(status) == 0)
+   if (WEXITSTATUS(status) == 112)
+   {
+      // acquire system checks for "NODATA" to generate GPG errors (the others are only warnings)
+      std::string errmsg;
+      //TRANSLATORS: %s is a single techy word like 'NODATA'
+      strprintf(errmsg, _("Clearsigned file isn't valid, got '%s' (does the network require authentication?)"), "NODATA");
+      return errmsg;
+   }
+   else if (gotNODATA)
+   {
+      // acquire system checks for "NODATA" to generate GPG errors (the others are only warnings)
+      std::string errmsg;
+      //TRANSLATORS: %s is a single techy word like 'NODATA'
+      strprintf(errmsg, _("Signed file isn't valid, got '%s' (does the network require authentication?)"), "NODATA");
+      return errmsg;
+   }
+   else if (WEXITSTATUS(status) == 0)
    {
       if (keyIsID)
       {
@@ -316,14 +333,6 @@ string GPGVMethod::VerifyGetSigners(const char *file, const char *outfile,
       return _("At least one invalid signature was encountered.");
    else if (WEXITSTATUS(status) == 111)
       return _("Could not execute 'apt-key' to verify signature (is gnupg installed?)");
-   else if (WEXITSTATUS(status) == 112)
-   {
-      // acquire system checks for "NODATA" to generate GPG errors (the others are only warnings)
-      std::string errmsg;
-      //TRANSLATORS: %s is a single techy word like 'NODATA'
-      strprintf(errmsg, _("Clearsigned file isn't valid, got '%s' (does the network require authentication?)"), "NODATA");
-      return errmsg;
-   }
    else
       return _("Unknown error executing apt-key");
 }
diff --git a/test/integration/framework b/test/integration/framework
index 1f4da97f0..ea577c04e 100644
--- a/test/integration/framework
+++ b/test/integration/framework
@@ -1697,8 +1697,9 @@ testfailure() {
 		local EXITCODE=$?
 		if expr match "$1" '^apt.*' >/dev/null; then
 			if [ "$1" = 'aptkey' ]; then
-				if grep -q -E " Can't check signature: " "$OUTPUT" || \
-					grep -q -E " BAD signature from " "$OUTPUT"; then
+				if grep -q " Can't check signature: 
+ BAD signature from 
+ signature could not be verified" "$OUTPUT"; then
 					msgpass
 				else
 					msgfailoutput "run failed with exitcode ${EXITCODE}, but no signature error" "$OUTPUT" "$@"
diff --git a/test/integration/test-apt-key b/test/integration/test-apt-key
index ddb9bf9d2..666136098 100755
--- a/test/integration/test-apt-key
+++ b/test/integration/test-apt-key
@@ -179,10 +179,14 @@ gpg:              unchanged: 1' aptkey --fakeroot update
 	cp -a keys/testcase-multikey.pub rootdir/etc/apt/trusted.gpg.d/multikey.gpg
 	msgtest 'Test signing a file' 'with a key'
 	echo 'Verify me. This is my signature.' > signature
+	echo 'lalalalala' > signature2
 	testsuccess --nomsg aptkey --quiet --keyring keys/marvinparanoid.pub --secret-keyring keys/marvinparanoid.sec --readonly \
 		adv --batch --yes --default-key 'Marvin' --armor --detach-sign --sign --output signature.gpg signature
 	testsuccess test -s signature.gpg -a -s signature
 
+	msgtest 'Test verify a file' 'with no sig'
+	testfailure --nomsg aptkey --quiet --readonly --keyring keys/testcase-multikey.pub verify signature signature2
+
 	for GPGV in '' 'gpgv' 'gpgv2'; do
 		echo "APT::Key::GPGVCommand \"$GPGV\";" > rootdir/etc/apt/apt.conf.d/00gpgvcmd
 
@@ -210,7 +214,6 @@ gpg:              unchanged: 1' aptkey --fakeroot update
 		testfailure --nomsg aptkey --quiet --readonly --keyid 'Kalnischkies' verify signature.gpg signature
 
 		msgtest 'Test verify fails on' 'bad file'
-		echo 'lalalalala' > signature2
 		testfailure --nomsg aptkey --quiet --readonly verify signature.gpg signature2
 	done
 	rm -f rootdir/etc/apt/apt.conf.d/00gpgvcmd
@@ -257,7 +260,6 @@ gpg:              unchanged: 1' aptkey --fakeroot update
 		testfailure --nomsg aptkey --quiet --readonly --keyid 'Kalnischkies' verify signature.gpg signature
 
 		msgtest 'Test verify fails on' 'bad doublesigned file'
-		echo 'lalalalala' > signature2
 		testfailure --nomsg aptkey --quiet --readonly verify signature.gpg signature2
 	done
 	rm -f rootdir/etc/apt/apt.conf.d/00gpgvcmd
diff --git a/test/integration/test-ubuntu-bug-346386-apt-get-update-paywall b/test/integration/test-ubuntu-bug-346386-apt-get-update-paywall
index 07c13434c..a756b5df2 100755
--- a/test/integration/test-ubuntu-bug-346386-apt-get-update-paywall
+++ b/test/integration/test-ubuntu-bug-346386-apt-get-update-paywall
@@ -13,7 +13,7 @@ insertsource 'unstable' 'unrelated' 'all' '1.0' 'stable'
 echo 'ni ni ni' > aptarchive/knights
 
 setupaptarchive
-changetowebserver -o 'aptwebserver::overwrite::.*::filename=/knights'
+changetowebserver -o 'aptwebserver::overwrite::.*InRelease::filename=/knights' -o 'aptwebserver::overwrite::.*::filename=/knights'
 
 msgtest 'Acquire test file from the webserver to check' 'overwrite'
 if downloadfile http://localhost:${APTHTTPPORT}/holygrail ./knights-talking >/dev/null; then
@@ -34,34 +34,39 @@ ensure_n_canary_strings_in_dir() {
 	test "$N" = "$EXPECTED_N" && msgpass || msgfail "Expected $EXPECTED_N canaries, got $N"
 }
 
-LISTS='rootdir/var/lib/apt/lists'
-rm -rf rootdir/var/lib/apt/lists
-testfailure aptget update
-testsuccess grep '^E:.*Clearsigned file .*NOSPLIT.*' rootdir/tmp/testfailure.output
+runtests() {
+	LISTS='rootdir/var/lib/apt/lists'
+	rm -rf "$LISTS"
+	testfailure aptget update
+	testsuccess grep "$1" rootdir/tmp/testfailure.output
 
-ensure_n_canary_strings_in_dir "$LISTS" 'ni ni ni' 0
-testequal 'lock
+	ensure_n_canary_strings_in_dir "$LISTS" 'ni ni ni' 0
+	testequal 'lock
 partial' ls "$LISTS"
 
-# and again with pre-existing files with "valid data" which should remain
-for f in Release Release.gpg main_binary-amd64_Packages main_source_Sources; do
-	echo 'peng neee-wom' > "$LISTS/localhost:${APTHTTPPORT}_dists_stable_${f}"
-	chmod 644 "$LISTS/localhost:${APTHTTPPORT}_dists_stable_${f}"
-done
+	# and again with pre-existing files with "valid data" which should remain
+	for f in Release Release.gpg main_binary-amd64_Packages main_source_Sources; do
+		echo 'peng neee-wom' > "$LISTS/localhost:${APTHTTPPORT}_dists_stable_${f}"
+		chmod 644 "$LISTS/localhost:${APTHTTPPORT}_dists_stable_${f}"
+	done
 
-testfailure aptget update
-testsuccess grep '^E:.*Clearsigned file .*NOSPLIT.*' rootdir/tmp/testfailure.output
+	testfailure aptget update
+	testsuccess grep "$1" rootdir/tmp/testfailure.output
 
-ensure_n_canary_strings_in_dir "$LISTS" 'peng neee-wom' 4
-ensure_n_canary_strings_in_dir "$LISTS" 'ni ni ni' 0
+	ensure_n_canary_strings_in_dir "$LISTS" 'peng neee-wom' 4
+	ensure_n_canary_strings_in_dir "$LISTS" 'ni ni ni' 0
 
-# and now with a pre-existing InRelease file
-echo 'peng neee-wom' > "$LISTS/localhost:${APTHTTPPORT}_dists_stable_InRelease"
-chmod 644 "$LISTS/localhost:${APTHTTPPORT}_dists_stable_InRelease"
-rm -f "$LISTS/localhost:${APTHTTPPORT}_dists_stable_Release" "$LISTS/localhost:${APTHTTPPORT}_dists_stable_Release.gpg"
-msgtest 'excpected failure of' 'apt-get update'
-testfailure aptget update
-testsuccess grep '^E:.*Clearsigned file .*NOSPLIT.*' rootdir/tmp/testfailure.output
+	# and now with a pre-existing InRelease file
+	echo 'peng neee-wom' > "$LISTS/localhost:${APTHTTPPORT}_dists_stable_InRelease"
+	chmod 644 "$LISTS/localhost:${APTHTTPPORT}_dists_stable_InRelease"
+	rm -f "$LISTS/localhost:${APTHTTPPORT}_dists_stable_Release" "$LISTS/localhost:${APTHTTPPORT}_dists_stable_Release.gpg"
+	msgtest 'excpected failure of' 'apt-get update'
+	testfailure aptget update
+	testsuccess grep "$1" rootdir/tmp/testfailure.output
 
-ensure_n_canary_strings_in_dir "$LISTS" 'peng neee-wom' 3
-ensure_n_canary_strings_in_dir "$LISTS" 'ni ni ni' 0
+	ensure_n_canary_strings_in_dir "$LISTS" 'peng neee-wom' 3
+	ensure_n_canary_strings_in_dir "$LISTS" 'ni ni ni' 0
+}
+runtests '^E:.*Clearsigned file .*NOSPLIT.*'
+webserverconfig 'aptwebserver::overwrite::.*InRelease::filename' '/404'
+runtests '^E:.*Signed file .*NODATA.*'