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Date: Sat, 26 Jan 2013 19:51:19 +0530
From: Dhiru Kholia <dhiru.kholia@...il.com>
To: john-dev@...ts.openwall.com
Subject: Re: Office format bug

On Sat, Jan 26, 2013 at 7:05 PM, magnum <john.magnum@...hmail.com> wrote:
> On 01/26/2013 01:54 PM, magnum wrote:
>>
>> According to Valgrind, the office format seem to read data from all over
>> the place.
>>
>> Benchmarking: Office 2007/2010 (SHA-1) / 2013 (SHA-512), with AES [32/64
>> OpenSSL]... ==22939== Use of uninitialised value of size 8
>> ==22939==    at 0x510B254: _x86_64_AES_decrypt_compact (aes-x86_64.s:577)
>> ==22939==    by 0x510B571: AES_decrypt (aes-x86_64.s:828)
>> ==22939==    by 0x7FEFFD60F: ???
>> ==22939==    by 0x7FEFFD6AF: ???
>> ==22939==    by 0x7FEFFD74F: ???
>> ==22939==    by 0x7FEFFD487: ???
>> ==22939==    by 0x1B806F31BFF453C9: ???
>> ==22939==    by 0xD342D7A2989D9B7F: ???
>> ==22939==    by 0x9A9C13A0008FA466: ???
>> ==22939==    by 0x73F06698C26CEE8: ???
>> ==22939==    by 0x491480AF3479AF71: ???
>> ==22939==    by 0x5CD4A62CAB0D44C6: ???
>> According to this, it reads an "uninitialized value" from mysql-netauth
>> format's buffer space... not that I get how a calloc'ed buffer can be
>> uninitialized. The above is from --test=0 under linux 64-bit, built with
>> OMP but using only one thread.

This is a genuine problem and here is a patch to fix this.

diff --git a/src/office_fmt_plug.c b/src/office_fmt_plug.c
index f4f9b19..7131893 100644
--- a/src/office_fmt_plug.c
+++ b/src/office_fmt_plug.c
@@ -190,7 +190,6 @@ static int PasswordVerifier(unsigned char * key)
                return 0;
        }
        AES_ecb_encrypt(cur_salt->encryptedVerifierHash,
decryptedVerifierHash, &akey, AES_DECRYPT);
-       AES_ecb_encrypt(cur_salt->encryptedVerifierHash+16,
decryptedVerifierHash+16, &akey, AES_DECRYPT);

        /* find SHA1 hash of decryptedVerifier */
        SHA1_Init(&ctx);

-- 
Dhiru

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