[BUG] Decryption fails if message was signed with an unknown key

[Daniel Kahn Gillmor]

On 09/23/2013 07:23 PM, Simon Hirscher wrote:
> Now, in order for you to test that behavior I'm going to send you a
> signed and encrypted message because that should exactly reproduce the
> bug, as long as you don't import my key (id EBACABE5 /
> http://simonhirscher.de/public_key.asc) for signature verification.

message received and tested on debian jessie using notmuch 0.16-1, and i
did not see this misbehavior.

Simon, for future reference, you can also test this sort of thing
yourself by making multiple (phony) gpg homedirectories and notmuch
config files, and setting GNUPGHOME and NOTMUCH_CONFIG environment
variables appropriately.  I find this a pretty handy diagnostic approach.

--dkg

-- next part --
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URL: 

Re: [BUG] Decryption fails if message was signed with an unknown key

[Daniel Kahn Gillmor]

On 09/23/2013 07:23 PM, Simon Hirscher wrote:
> Now, in order for you to test that behavior I'm going to send you a
> signed and encrypted message because that should exactly reproduce the
> bug, as long as you don't import my key (id EBACABE5 /
> http://simonhirscher.de/public_key.asc) for signature verification.

message received and tested on debian jessie using notmuch 0.16-1, and i
did not see this misbehavior.

Simon, for future reference, you can also test this sort of thing
yourself by making multiple (phony) gpg homedirectories and notmuch
config files, and setting GNUPGHOME and NOTMUCH_CONFIG environment
variables appropriately.  I find this a pretty handy diagnostic approach.

--dkg



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Re: [BUG] Decryption fails if message was signed with an unknown key

[Simon Hirscher]

Hi Daniel,

First of all, sorry for the delay – I had locked myself out from
everything digital to study for my exams.

On Thu, Sep 5, 2013 at 5:03 PM, Daniel Kahn Gillmor
 wrote:
> I just tried to replicate this, and i do not see this misbehavior.  I'm
> using notmuch 0.16-1 on a debian testing/unstable system.

I'm using notmuch 0.15.2 on Ubuntu 12.04. Maybe the bug got fixed
somehow in the meantime? If you really can't reproduce the bug (see
below) I will build the newest version from source (as well as send
you the output of notmuch show --format=raw id:x...@example.com |
devel/printmimestructure).

>  A) how does it know that there was a signature if the message was
> encrypted?  normal PGP/MIME messages contain a single OpenPGP chunk that
> contains signatures wrapped inside the encryption, so that an observer
> can't tell whether there is a signature or not (or who made the signature)

That's a good question. I suppose that although GnuPG successfully
decrypts the message, notmuch somehow discards the decrypted content
because the signature verification failed. As I said: GnuPG is
perfectly able to decrypt the message if I do it manually.

>  B) the date of the message is the unix epoch date (1970-01-01), and the
> date of the signature appears to be the unix epoch date as well.  this
> seems suspicious and likely to be false.  how are these messages being
> generated?

I'm sorry, that was just me being ultra paranoid. :)

>  C) you appear to be using gnupg 2.0.17.  the latest version of the
> 2.0.x line of gpg is 2.0.21.  maybe you can upgrade your gpg
> installation and try again?

>  D) you have the mingw32 version of gpg.  Does this mean you're running
> notmuch on windows?

No, as far as I can see this was the sender's GPG version. I'm using
GnuPG 1.4.11 on Ubuntu.

>  E) i'd be curious to see what printmimestructure looks like on the
> message in question.  if you've got a decent shell and the notmuch
> source code, you should be able to do:
>
> […]
>
> if you can clarify any of the above, i'd appreciate it.
>
> Also, if you can, you're welcome to send a signed/encrypted message
> using the same framework that generated the problematic message directly
> to me (my OpenPGP fingerprint is
> 0EE5BE979282D80B9F7540F1CCD2ED94D21739E9), and i'd be happy to take a
> look at it.

Well, so far the problematic messages have always come from my
contacts, i.e. I didn't generate them myself. But I just tried out the
following in order to reproduce the bug: I created a fresh dummy key
pair, sent a signed and encrypted email (via Emacs'
mml-secure-message-sign-encrypt) in the dummy's name to my regular
email address and checked whether I could open that email. Of course I
could – because I had both, the recipient's private key (for
decryption) and the sender's public key (for signature verification).
Then I removed the dummy key pair from my key ring – and voilà:
notmuch failed at decrypting the message (or at least told me there
was a decryption error, as described in my previous mail).

Now, in order for you to test that behavior I'm going to send you a
signed and encrypted message because that should exactly reproduce the
bug, as long as you don't import my key (id EBACABE5 /
http://simonhirscher.de/public_key.asc) for signature verification.

Best,

Simon
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[BUG] Decryption fails if message was signed with an unknown key

[Simon Hirscher]

Hi Daniel,

First of all, sorry for the delay ? I had locked myself out from
everything digital to study for my exams.

On Thu, Sep 5, 2013 at 5:03 PM, Daniel Kahn Gillmor
 wrote:
> I just tried to replicate this, and i do not see this misbehavior.  I'm
> using notmuch 0.16-1 on a debian testing/unstable system.

I'm using notmuch 0.15.2 on Ubuntu 12.04. Maybe the bug got fixed
somehow in the meantime? If you really can't reproduce the bug (see
below) I will build the newest version from source (as well as send
you the output of notmuch show --format=raw id:xyz at example.com |
devel/printmimestructure).

>  A) how does it know that there was a signature if the message was
> encrypted?  normal PGP/MIME messages contain a single OpenPGP chunk that
> contains signatures wrapped inside the encryption, so that an observer
> can't tell whether there is a signature or not (or who made the signature)

That's a good question. I suppose that although GnuPG successfully
decrypts the message, notmuch somehow discards the decrypted content
because the signature verification failed. As I said: GnuPG is
perfectly able to decrypt the message if I do it manually.

>  B) the date of the message is the unix epoch date (1970-01-01), and the
> date of the signature appears to be the unix epoch date as well.  this
> seems suspicious and likely to be false.  how are these messages being
> generated?

I'm sorry, that was just me being ultra paranoid. :)

>  C) you appear to be using gnupg 2.0.17.  the latest version of the
> 2.0.x line of gpg is 2.0.21.  maybe you can upgrade your gpg
> installation and try again?

>  D) you have the mingw32 version of gpg.  Does this mean you're running
> notmuch on windows?

No, as far as I can see this was the sender's GPG version. I'm using
GnuPG 1.4.11 on Ubuntu.

>  E) i'd be curious to see what printmimestructure looks like on the
> message in question.  if you've got a decent shell and the notmuch
> source code, you should be able to do:
>
> [?]
>
> if you can clarify any of the above, i'd appreciate it.
>
> Also, if you can, you're welcome to send a signed/encrypted message
> using the same framework that generated the problematic message directly
> to me (my OpenPGP fingerprint is
> 0EE5BE979282D80B9F7540F1CCD2ED94D21739E9), and i'd be happy to take a
> look at it.

Well, so far the problematic messages have always come from my
contacts, i.e. I didn't generate them myself. But I just tried out the
following in order to reproduce the bug: I created a fresh dummy key
pair, sent a signed and encrypted email (via Emacs'
mml-secure-message-sign-encrypt) in the dummy's name to my regular
email address and checked whether I could open that email. Of course I
could ? because I had both, the recipient's private key (for
decryption) and the sender's public key (for signature verification).
Then I removed the dummy key pair from my key ring ? and voil?:
notmuch failed at decrypting the message (or at least told me there
was a decryption error, as described in my previous mail).

Now, in order for you to test that behavior I'm going to send you a
signed and encrypted message because that should exactly reproduce the
bug, as long as you don't import my key (id EBACABE5 /
http://simonhirscher.de/public_key.asc) for signature verification.

Best,

Simon

[BUG] Decryption fails if message was signed with an unknown key

[David Bremner]

Simon Hirscher  writes:
>
> $ gpg --recv-keys 
>
> $ notmuch show --decrypt id:xyz at example.com
>
> [?]
> Hey there,
> Now the decryption worked!
> [?]
>

Is this related to Jamie's report?

   id:87obwrix8s.fsf at servo.finestructure.net

Jamie, did you ever narrow down the gmime problem? is it fixed in
current gmime?

d

Re: [BUG] Decryption fails if message was signed with an unknown key

[David Bremner]

Simon Hirscher  writes:
>
> $ gpg --recv-keys 
>
> $ notmuch show --decrypt id:x...@example.com
>
> […]
> Hey there,
> Now the decryption worked!
> […]
>

Is this related to Jamie's report?

   id:87obwrix8s@servo.finestructure.net

Jamie, did you ever narrow down the gmime problem? is it fixed in
current gmime?

d
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[BUG] Decryption fails if message was signed with an unknown key

[Daniel Kahn Gillmor]

Hi Simon--

On 09/04/2013 06:01 PM, Simon Hirscher wrote:
> This is now the second time the following has happened to me:

 [ decryption failure until adding sender's key]

> Also, I should add that manually decrypting the message with gpg (i.e.
> without using notmuch) already worked *before* I added the sender's
> key (not shown above). Still, notmuch obviously doesn't like it when
> the sender is unknown.

I just tried to replicate this, and i do not see this misbehavior.  I'm
using notmuch 0.16-1 on a debian testing/unstable system.

using --format=json and piping the output through json_pp, i do see the
following part of the response indicating that i don't have the signer's
key:

 "sigstatus" : [
 {
"errors" : 2,
"keyid" : "CB07362E3294B49E",
"status" : "error"
 }
  ],


but the message body is correctly decrypted and passed through.

I'm confused by a few things in your example above:

 A) how does it know that there was a signature if the message was
encrypted?  normal PGP/MIME messages contain a single OpenPGP chunk that
contains signatures wrapped inside the encryption, so that an observer
can't tell whether there is a signature or not (or who made the signature)

 B) the date of the message is the unix epoch date (1970-01-01), and the
date of the signature appears to be the unix epoch date as well.  this
seems suspicious and likely to be false.  how are these messages being
generated?

 C) you appear to be using gnupg 2.0.17.  the latest version of the
2.0.x line of gpg is 2.0.21.  maybe you can upgrade your gpg
installation and try again?

 D) you have the mingw32 version of gpg.  Does this mean you're running
notmuch on windows?

 E) i'd be curious to see what printmimestructure looks like on the
message in question.  if you've got a decent shell and the notmuch
source code, you should be able to do:

 notmuch show --format=raw id:xyz at example.com | devel/printmimestructure

I'd expect to see output like this:

???multipart/encrypted 3309 bytes
 ???application/pgp-encrypted 11 bytes
 ???application/octet-stream 1351 bytes


if you can clarify any of the above, i'd appreciate it.

Also, if you can, you're welcome to send a signed/encrypted message
using the same framework that generated the problematic message directly
to me (my OpenPGP fingerprint is
0EE5BE979282D80B9F7540F1CCD2ED94D21739E9), and i'd be happy to take a
look at it.

--dkg

-- next part --
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 1027 bytes
Desc: OpenPGP digital signature
URL: 

Re: [BUG] Decryption fails if message was signed with an unknown key

[Daniel Kahn Gillmor]

Hi Simon--

On 09/04/2013 06:01 PM, Simon Hirscher wrote:
> This is now the second time the following has happened to me:

 [ decryption failure until adding sender's key]

> Also, I should add that manually decrypting the message with gpg (i.e.
> without using notmuch) already worked *before* I added the sender's
> key (not shown above). Still, notmuch obviously doesn't like it when
> the sender is unknown.

I just tried to replicate this, and i do not see this misbehavior.  I'm
using notmuch 0.16-1 on a debian testing/unstable system.

using --format=json and piping the output through json_pp, i do see the
following part of the response indicating that i don't have the signer's
key:

 "sigstatus" : [
 {
"errors" : 2,
"keyid" : "CB07362E3294B49E",
"status" : "error"
 }
  ],


but the message body is correctly decrypted and passed through.

I'm confused by a few things in your example above:

 A) how does it know that there was a signature if the message was
encrypted?  normal PGP/MIME messages contain a single OpenPGP chunk that
contains signatures wrapped inside the encryption, so that an observer
can't tell whether there is a signature or not (or who made the signature)

 B) the date of the message is the unix epoch date (1970-01-01), and the
date of the signature appears to be the unix epoch date as well.  this
seems suspicious and likely to be false.  how are these messages being
generated?

 C) you appear to be using gnupg 2.0.17.  the latest version of the
2.0.x line of gpg is 2.0.21.  maybe you can upgrade your gpg
installation and try again?

 D) you have the mingw32 version of gpg.  Does this mean you're running
notmuch on windows?

 E) i'd be curious to see what printmimestructure looks like on the
message in question.  if you've got a decent shell and the notmuch
source code, you should be able to do:

 notmuch show --format=raw id:x...@example.com | devel/printmimestructure

I'd expect to see output like this:

└┬╴multipart/encrypted 3309 bytes
 ├─╴application/pgp-encrypted 11 bytes
 └─╴application/octet-stream 1351 bytes


if you can clarify any of the above, i'd appreciate it.

Also, if you can, you're welcome to send a signed/encrypted message
using the same framework that generated the problematic message directly
to me (my OpenPGP fingerprint is
0EE5BE979282D80B9F7540F1CCD2ED94D21739E9), and i'd be happy to take a
look at it.

--dkg



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[BUG] Decryption fails if message was signed with an unknown key

[Simon Hirscher]

Dear notmuch developers,

This is now the second time the following has happened to me:

#
$ notmuch show --decrypt id:xyz at example.com

message{ id:xyz at example.com depth:0 match:1 excluded:0 
filename:/home/simon/***

header{
John Doe  (Today 21:52) (encrypted inbox new)
Subject: foobar
From: John Doe 
To: ***
Date: Thu, 01 Jan 1970 00:00:00 +

header}

body{
Failed to decrypt part: gpg: ASCII-H?lle: Version: GnuPG v2.0.17 (MingW32)
gpg: 
gpg: AES256 encrypted data
gpg: Original file name=''
gpg: Signature from Thu 01 Jan 1970 00:00:00 UTC by DSA key ID 
gpg: Signature cannot be verified. Public key not found

part{ ID: 1, Content-type: multipart/encrypted

part{ ID: 2, Content-type: application/pgp-encrypted
Non-text part: application/pgp-encrypted

part}

part{ ID: 3, Filename: encrypted.asc, Content-type: application/octet-stream
Non-text part: application/octet-stream

part}

part}

body}

message}

$ gpg --recv-keys 

$ notmuch show --decrypt id:xyz at example.com

[?]
Hey there,
Now the decryption worked!
[?]



Also, I should add that manually decrypting the message with gpg (i.e.
without using notmuch) already worked *before* I added the sender's
key (not shown above). Still, notmuch obviously doesn't like it when
the sender is unknown.

I hope you're going to look into this. Thank you!

[BUG] Decryption fails if message was signed with an unknown key

[Simon Hirscher]

Dear notmuch developers,

This is now the second time the following has happened to me:

#
$ notmuch show --decrypt id:x...@example.com

message{ id:x...@example.com depth:0 match:1 excluded:0 filename:/home/simon/***

header{
John Doe  (Today 21:52) (encrypted inbox new)
Subject: foobar
From: John Doe 
To: ***
Date: Thu, 01 Jan 1970 00:00:00 +

header}

body{
Failed to decrypt part: gpg: ASCII-Hülle: Version: GnuPG v2.0.17 (MingW32)
gpg: 
gpg: AES256 encrypted data
gpg: Original file name=''
gpg: Signature from Thu 01 Jan 1970 00:00:00 UTC by DSA key ID 
gpg: Signature cannot be verified. Public key not found

part{ ID: 1, Content-type: multipart/encrypted

part{ ID: 2, Content-type: application/pgp-encrypted
Non-text part: application/pgp-encrypted

part}

part{ ID: 3, Filename: encrypted.asc, Content-type: application/octet-stream
Non-text part: application/octet-stream

part}

part}

body}

message}

$ gpg --recv-keys 

$ notmuch show --decrypt id:x...@example.com

[…]
Hey there,
Now the decryption worked!
[…]



Also, I should add that manually decrypting the message with gpg (i.e.
without using notmuch) already worked *before* I added the sender's
key (not shown above). Still, notmuch obviously doesn't like it when
the sender is unknown.

I hope you're going to look into this. Thank you!
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