I note that "the best" seems like it might be a pretty subjective thing. The standard GnuPG framing asks about the validity of keys for the User ID in question. Perhaps the caller could indicate whether they want to require full validity for each key to make this key selection more strict.

The function would do something like:

• from msg, extract all e-mail addresses from to, cc, bcc fields
• find "the best" keys that match these addresses, storing them in keylist
• copy msg to tmp, remove bcc header from tmp
• wrap armored output of gpg.Context.encrypt(bytes(tmp), recipients=keylist) in the necessary RFC 3156 cladding, copying most headers from msg (maybe stubbing out the subject), producing an email.message.EmailMessage object.

I tried to apply&push, since we changed the file a bit, I needed to apply it manually.
Anyway, it's done.
Closing.

Merged. Thanks again for your work on this.

Thanks for the explanation. That addresses my concerns.

I agree that this is a minor API shift, but i *don't* think it's a security problem, because i was particularly careful to maintain the invariant that decrypt(verify=True) will only ever return valid signatures.

I'm for merging this as I understand the rationale. In Kleo / GpgOL I also only need one valid signature.

I've just published a branch dkg/fix-T4276 (with commit 4100794e305ba22241ea5a4f7b42bb5189fbd948) which i think resolves this issue.

@dkg If you propose a patch here I'm pretty sure that we will accept it. As one of our Python binding users you know better then us how the API should behave.

Reading through this issue and the related documentation: Thanks for writing this all down and adding links!

I sent a message to gnupg-devel about this issue as it will probably hit more people now that the keys used are expired :-(

Oh,.. it is even worse. The conflict keys expired 2019-01-06 so they are actually expired right now.

I don't know why @BenM closed this bug given that he mentioned that the qt part is yet not solved.

We've run into the testTofuConflict failure on NixOS. gpgme v1.12, gnupg v2.2.12.

Though not directly related to our issues, this bug report on the MSYS2 site reported by their users encountering trouble with GPGME provides additional weight to irreconcilable differences between MSYS2 and GnuPG:

Though apparently resolved back in May, this is what ultimately led to T4191 and was thus only properly resolved quite recently.

Confirmed that this is indeed fixed and made the (rather minor) change to the HOWTO that was needed. No changes were needed for the example script (decrypt-file.py).

This has now been tested on a 32-bit Gentoo VM and it behaves as expected with 32-bit system detection and creating keys with pre-2038 expirations working.

Commit 8613727f1ee985c3cfa2c815523312914f033ffd adds considerable detail on both the issues affecting compiling and installing a Windows version of the bindings and what it would take to actually resolve it.

I'll deploy one on AWS somewhere briefly once I've replaced a certain external keyboard, there will almost certainly be an existing image of some Linux distro in the AWS marketplace and I'd be very surprised if it took more than an hour or two of compute time to confirm.

One more semantic question about how folks think Context.decrypt(verify=True) should work: if the decrypted thing has no signature at all, should the function succeed without throwing an exception? it currently does, but the returned verify_result has its signatures member set to the empty list.

Ooh, nice catch @dkg, I just stepped through each of your changes and it all looks good. I'll tweak the relevant sections of the HOWTO dealing with this in the next few days (I need to replace a keyboard here before properly diving back in) and then close this case once done.

since @aheinecke merged my changes, i think this bug is now resolved. I'll let @BenM close it though :)

@aheinecke thanks for the merge of my other branch! sadly, that branch does *not* address this issue yet. It doesn't even test for it. :( I can work on trying to fix it (and test it) if there's a consensus that we want this particular change in behavior.

Is this fixed now?

Ben is not even subscribed to this issue.
With the volatility of gpgme-python I think that this can easily be merged. I did a quick review and it looked good to me.

Needs to be merged. (Note that Phabricator does not show the branch in the tooltip for commit ids.)

note that the branch also updates the test suite to make sure the verify=False case is tested.

I've just pushed a branch dkg/fix-T4271 , currently at ac8d7238dbf165950c9844e5cb41da8eb4d37bc0 that resolves this problem.

Regression introduced with 1.12.0.

please add a unit to the test suite to make sure something like this doesn't happen in the future!

i'd be happy to help you set up your own x86 32-bit guest VM for testing
if you like, even if you're running on x86_64 hardware. they're cheap
and easy to run, and have a delightfully small memory footprint :P just
let me know!

I consider this bug to be solved.

MacPorts doesn't currently ship the bindings at all, but I'll see what they need to make that a reality too.