Description of problem:
Signing an S/MIME message generates a truncated message without any signature. Tried on fc13 i686 and x86_64 and got the same result. However it works in Ubuntu 10.04 with package version python-m2crypto-0.20.1.

Version-Release number of selected component (if applicable):
m2crypto-0.20.2-7.fc13

How reproducible:
Follow this tutorial up to the "Sign" section:
http://sandbox.rulemaker.net/ngps/m2/howto.smime.html

Steps to Reproduce:
1.Generate some example keys and certificates:
openssl req -newkey rsa:1024 -nodes -x509 -days 365 -out signer.pem
mv privkey.pem signer_key.pem

2.Run the following python script:
    from M2Crypto import BIO, Rand, SMIME

    def makebuf(text):
        return BIO.MemoryBuffer(text)

    # Make a MemoryBuffer of the message.
    buf = makebuf('a sign of our times')

    # Seed the PRNG.
    Rand.load_file('randpool.dat', -1)

    # Instantiate an SMIME object; set it up; sign the buffer.
    s = SMIME.SMIME()
    s.load_key('signer_key.pem', 'signer.pem')
    p7 = s.sign(buf)

    # Recreate buf.
    buf = makebuf('a sign of our times')

    # Output p7 in mail-friendly format.
    out = BIO.MemoryBuffer()
    out.write('From: sender\n')
    out.write('To: recipient\n')
    out.write('Subject: M2Crypto S/MIME testing\n')
    s.write(out, p7, buf)

    print out.read()
  

Actual results:

From: sender
To: recipient
Subject: M2Crypto S/MIME testing
MIME-Version: 1.0
Content-Type: multipart/signed; protocol="application/x-pkcs7-signature"; micalg="sha1"; boundary="----03D6C4E70DC75EF73B1EC56752C7DB8D"

This is an S/MIME signed message

------03D6C4E70DC75EF73B1EC56752C7DB8D
a sign of our times


Expected results:

From: sender
To: recipient
Subject: M2Crypto S/MIME testing
MIME-Version: 1.0
Content-Type: multipart/signed; protocol="application/x-pkcs7-signature"; micalg=sha1; boundary="----3F7BF7C54B3B0FC83AA1763644002CC8"

This is an S/MIME signed message

------3F7BF7C54B3B0FC83AA1763644002CC8
a sign of our times
------3F7BF7C54B3B0FC83AA1763644002CC8
Content-Type: application/x-pkcs7-signature; name="smime.p7s"
Content-Transfer-Encoding: base64
Content-Disposition: attachment; filename="smime.p7s"

MIIETgYJKoZIhvcNAQcCoIIEPzCCBDsCAQExCzAJBgUrDgMCGgUAMCIGCSqGSIb3
DQEHAaAVBBNhIHNpZ24gb2Ygb3VyIHRpbWVzoIICVjCCAlIwggG7oAMCAQICCQC9
Y/e4Pl4ZJTANBgkqhkiG9w0BAQUFADBCMQswCQYDVQQGEwJBUjEVMBMGA1UEBwwM
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Ojqnq1NZvsGQru6ksKxO4kdjKUhEB5C69K49Tphnhsoc8wKilMYeX/T0ft4TBJAO
uhk=

------3F7BF7C54B3B0FC83AA1763644002CC8--