common: Fix iobuf_peek corner case.

Previously, iobuf_peek on a file smaller than 'buflen' would hang.

* common/iobuf.c (underflow): Generalize by adding a target parameter.
(iobuf_peek): Use this to prevent looping here.
* tests/openpgp/Makefile.am (TESTS): Add new test.
* tests/openpgp/setup.scm (dearmor): Move function...
* tests/openpgp/defs.scm (dearmor): ... here.
* tests/openpgp/issue2419.scm: New file.
* tests/openpgp/samplemsgs/issue2419.asc: Likewise.

GnuPG-bug-id: 2419
Signed-off-by: Justus Winter <[email protected]>

5 files changed, 43 insertions, 8 deletions

diff --git a/tests/openpgp/Makefile.am b/tests/openpgp/Makefile.am
index f8932d646..718b4bc07 100644
--- a/tests/openpgp/Makefile.am
+++ b/tests/openpgp/Makefile.am
@@ -84,6 +84,7 @@ TESTS = setup.scm \
 	ssh.scm \
 	issue2015.scm \
 	issue2346.scm \
+	issue2419.scm \
 	finish.scm
 
 
diff --git a/tests/openpgp/defs.scm b/tests/openpgp/defs.scm
index 06bc0b828..9408cd5f4 100644
--- a/tests/openpgp/defs.scm
+++ b/tests/openpgp/defs.scm
@@ -133,6 +133,13 @@
    (string-split
     (call-popen `(,@GPG --with-colons ,@args) input) #\newline)))
 
+;; Dearmor a file.
+(define (dearmor source-name sink-name)
+  (pipe:do
+   (pipe:open source-name (logior O_RDONLY O_BINARY))
+   (pipe:spawn `(,@GPG --dearmor))
+   (pipe:write-to sink-name (logior O_WRONLY O_CREAT O_BINARY) #o600)))
+
 (let ((verbose (string->number (getenv "verbose"))))
   (if (number? verbose)
       (*set-verbose!* verbose)))
diff --git a/tests/openpgp/issue2419.scm b/tests/openpgp/issue2419.scm
new file mode 100755
index 000000000..efc42a6ae
--- /dev/null
+++ b/tests/openpgp/issue2419.scm
@@ -0,0 +1,28 @@
+#!/usr/bin/env gpgscm
+
+;; Copyright (C) 2016 g10 Code GmbH
+;;
+;; This file is part of GnuPG.
+;;
+;; GnuPG is free software; you can redistribute it and/or modify
+;; it under the terms of the GNU General Public License as published by
+;; the Free Software Foundation; either version 3 of the License, or
+;; (at your option) any later version.
+;;
+;; GnuPG is distributed in the hope that it will be useful,
+;; but WITHOUT ANY WARRANTY; without even the implied warranty of
+;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+;; GNU General Public License for more details.
+;;
+;; You should have received a copy of the GNU General Public License
+;; along with this program; if not, see <http://www.gnu.org/licenses/>.
+
+(load (with-path "defs.scm"))
+
+(info "Checking iobuf_peek corner case (issue2419)...")
+(lettmp
+ (onebyte)
+ (dearmor (in-srcdir "samplemsgs/issue2419.asc") onebyte)
+ (catch (assert (string-contains? *error* "invalid packet"))
+	(call-popen `(,@GPG --list-packets ,onebyte) "")
+	(error "Expected an error but got none")))
diff --git a/tests/openpgp/samplemsgs/issue2419.asc b/tests/openpgp/samplemsgs/issue2419.asc
new file mode 100644
index 000000000..b73efedde
--- /dev/null
+++ b/tests/openpgp/samplemsgs/issue2419.asc
@@ -0,0 +1,7 @@
+-----BEGIN PGP ARMORED FILE-----
+Version: GnuPG v2
+Comment: Use "gpg --dearmor" for unpacking
+
+AA==
+=YWnT
+-----END PGP ARMORED FILE-----
diff --git a/tests/openpgp/setup.scm b/tests/openpgp/setup.scm
index 9ad19c284..8fc154346 100755
--- a/tests/openpgp/setup.scm
+++ b/tests/openpgp/setup.scm
@@ -55,14 +55,6 @@
 		     CLOSED_FD fd STDERR_FILENO)))
   '(500 9000 32000 80000))
 
-(define (dearmor source-name sink-name)
-  (pipe:do
-   (pipe:open source-name (logior O_RDONLY O_BINARY))
-   (pipe:spawn `(,@GPG --dearmor))
-   (pipe:write-to sink-name
-		  (logior O_WRONLY O_CREAT O_BINARY)
-		  #o600)))
-
 (for-each-p "Unpacking samples"
   (lambda (name)
     (dearmor (in-srcdir (string-append name "o.asc")) name))