Hello everybody, I have a problem in making our OpenSSL Engine that drives our HW accelerator work fine for hash (SHA1 in particular). The problem seems to be related to my "Digest_Copy" or (less likely) "Digest_Cleanup" implementation (I'll explain this further on). The Engine works fine for the Cipher algorithms (both just operating on a file and using s_client/s_server), and works fine for SHA1 when operating on a file. Trying to run an s_client / s_server session, I noticed that multiple context are used and the calls to "Digest_Update" function are mixed, so I have to maintain coherency in some way.
- 1 - The easiest (and quickest) way to do this is to buffer the data that I receive at each call to "Digest_Update", for each context, and ask for a real hash operation only when I receive the "Digest_Final" for that context. Doing in this way, everything is ok, both operating on a single file (here only one context is used) and using s_client / s_server (multiple contexts). In this scenario, in the "Digest_Copy" function I make a "memcopy" of the EVP_MD_CTX->md_data field where our data structure sits, and moreover I manually allocate and copy the buffer in which I am keeping the stored data. In the "Digest_Cleanup" I make a "free" of the buffer in which I keep the data (it is dynamically allocated) and I set to zero the counters used to keep track of its size and actual occupation. In this way, as I said, everything works. - 2 - The previous solution is mainly a workaround and has a big disadvantage if you want to hash large files or amount of data. So I decided to use the capability of our HW accelerator to save and restore the current context of the hash block. Here I have some problem, when using s_client/ s_server. Even if I implement it in the most trivial and inefficient way (RESTORE/UPDATE/SAVE at *each* call to update) it does not work. In this scenario, we have a buffer for the context in our data structure. I allocate this buffer at the first call to "Digest_Update", obviously not setting the RESTORE flag for this first call. I call "free" for this buffer and put it to NULL in the "Digest_Cleanup" function and, if this buffer is valid (not null) I copy it in the "Digest_Copy" function, by allocating a proper memory area in the "to" context. If I use this solution on a single file, it works, so the SAVE/RESTORE mechanism works fine (and it has been proved elsewhere). But it fails in the s_client/s_server test. As the main difference is that here the "Digest_Copy" and "Digest_Cleanup" function are called, I suppose the problem is here, even if I do not see many differences with the scenario number -1- What am I missing? Could you help me? Can someone point me to some useful resource or describe me exactly what has to be implemented in the Digest_Copy (and Digest_Cleanup) function? Or do you know another way to avoid the problem of "mixed context"? I mean: sha1_init(ctx_A) sha1_update(ctx_A) sha1_init(ctx_B) sha1_update(ctx_B) sha1_update(ctx_A) .... Thank you very much and best regards, Marco Grella ______________________________________________________________________ OpenSSL Project http://www.openssl.org User Support Mailing List openssl-users@openssl.org Automated List Manager [EMAIL PROTECTED]
