| Subject: | Fails to verify signatures made by GnuPG v2; SHA-2 and RIPEMD-160 also broken |
It seems that Crypt::OpenPGP handles clearsigned signatures very poorly. We first discovered this bug when working on Module::Signature (https://github.com/audreyt/module-signature/issues/23)
In short, Crypt::OpenPGP fails to verify all signatures generated by gpg2, as well as gpg1 signature using RIPEMD-160 and SHA-2.
The key used to sign is just a throwaway 1024-bit RSA key.
Test snippets:
$ for alg in MD5 SHA{1,224,256,384,512} RIPEMD160; do echo "Hello World" | gpg1 --default-key 4E8A44BB --clearsign --openpgp --digest-algo $alg --passphrase foobar --quiet --batch > SIGNATURE && echo -n "$alg: " && perl test.pl ; done
gpg: WARNING: digest algorithm MD5 is deprecated
MD5: Success
SHA1: Success
SHA224: Failure
SHA256: Failure
SHA384: Failure
SHA512: Failure
RIPEMD160: Failure
$ for alg in MD5 SHA{1,224,256,384,512} RIPEMD160; do echo "Hello World" | gpg --default-key 4E8A44BB --clearsign --openpgp --digest-algo $alg --passphrase foobar --quiet --batch > SIGNATURE && echo -n "$alg: " && perl test.pl ; done
gpg: WARNING: digest algorithm MD5 is deprecated
MD5: Message hash does not match signature checkbytes
SHA1: Message hash does not match signature checkbytes
SHA224: Message hash does not match signature checkbytes
SHA256: Message hash does not match signature checkbytes
SHA384: Message hash does not match signature checkbytes
SHA512: Message hash does not match signature checkbytes
RIPEMD160: Message hash does not match signature checkbytes
test.pl:
/* ----------------------------------------------------------- */
#!/usr/bin/perl
use Crypt::OpenPGP;
my $pgp = Crypt::OpenPGP->new(
Compat => "GnuPG",
);
my $res = $pgp->verify(SigFile => "./SIGNATURE");
if (defined $res) {
if ($res) { print "Success\n"; } else { print "Failure\n"; }
} else {
print $pgp->errstr;
}
/* ----------------------------------------------------------- */
$ uname -a
Linux bionic-vm 4.15.0-33-generic #36-Ubuntu SMP Wed Aug 15 16:00:05 UTC 2018 x86_64 x86_64 x86_64 GNU/Linux
$ perl -v | awk 'NR==2 {print $0}'
This is perl 5, version 26, subversion 1 (v5.26.1) built for x86_64-linux-gnu-thread-multi
$ gpg --version | head -n2
gpg (GnuPG) 2.2.4
libgcrypt 1.8.1
$ gpg1 --version | head -n1
gpg (GnuPG) 1.4.22
$ perl -MCrypt::OpenPGP -le 'print $Crypt::OpenPGP::VERSION'
1.12
========
Best regards
Niklas Holm