[sup-devel] [PATCH] fix GPG "hang" on malformed PGP message (detached signature)

From: Sascha Silbe <sascha-pgp@silbe.org>
To: sup-devel <sup-devel@rubyforge.org>
Subject: [sup-devel] [PATCH] fix GPG "hang" on malformed PGP message (detached signature)
Date: Tue,  5 Oct 2010 13:25:33 +0200	[thread overview]
Message-ID: <1286277933-4686-1-git-send-email-sascha-pgp@silbe.org> (raw)

A PGP message chunk (bounded by "-----BEGIN PGP MESSAGE-----" and
"-----END PGP MESSAGE-----") can contain a detached signature. By default GPG
will wait for the payload to be supplied on stdin if it gets passed a lone
detached signature. To the user it will appear as GPG (or sup, since they
don't see any output from GPG) hanging.

The best way to solve this would be enabling batch mode, but then passphrase
querying without gpg-agent wouldn't work anymore. So we resort to passing
--multifile which has the side effect of not allowing detached signatures.

Encountered and tested with message
<AANLkTin1Ysn7Fp32Eoyjo3jjhHwVrc=hMuq+okgKNfmr@mail.gmail.com> [1] on the git
mailing list.

[1] http://marc.info/?l=git&m=128623349711269&q=raw

Signed-off-by: Sascha Silbe <sascha-pgp@silbe.org>
---
 lib/sup/crypto.rb |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/lib/sup/crypto.rb b/lib/sup/crypto.rb
index 289fb0e..68a57c8 100644
--- a/lib/sup/crypto.rb
+++ b/lib/sup/crypto.rb
@@ -144,7 +144,7 @@ def decrypt payload, armor=false # a RubyMail::Message object
     output_fn = Tempfile.new "redwood.output"
     output_fn.close
 
-    message = run_gpg "--output #{output_fn.path} --skip-verify --yes --decrypt #{payload_fn.path}", :interactive => true
+    message = run_gpg "--output #{output_fn.path} --multifile --skip-verify --yes --decrypt #{payload_fn.path}", :interactive => true
 
     unless $?.success?
       info "Error while running gpg: #{message}"
-- 
1.7.1

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