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kernel BUG() when using OCF library

DISCUSSION David McCullough 1 participant 1 message Aug 7, 2007 Crypto API

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David McCullough

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Quoted 1 line · Ico

Hello,

Hi, only just got this, luckily it was forwarded to me. For some reason I had been silently dropped off the linux-crypto list ;-)

Quoted 6 lines

I've been trying to use OCF in one of my projects, but I run into a nasty problem I can't seem to solve. I setup a session and call the crypto_dispatch() function, after which a kernel BUG() occurs in one of the linux crypto.h functions. There's problably something I forgot or did not properly initialize, I hope anybody can give me a hint on how to debug and solve this.

Quoted 6 lines

The following is an extract of my code involving the crypto library:

/* Create session */

  memset(&ci, 0, sizeof(ci));
  ci.cri_alg  = CRYPTO_ARC4;

This would be the problem. ARC4 is the only non-cbc cipher listed in cryptosoft and cryptosoft is not using the kernels crypto API appropriately for it.

Basically cryptosoft needs to be made aware that "ecb(arc4)" is different and not to call the "crypto_blkcipher_encrypt_iv" function but rather the "crypto_blkcipher_encrypt" one.

If you want to have a go at it and send some patches let me know, otherwise I'll try and get something done soon.

Which version of ocf-linux are you using ?

Cheers,
Davidm

Quoted 49 lines
  ci.cri_klen = (sizeof(info->key)-1) * 8;
  ci.cri_key  = info->key;
  r = crypto_newsession(&info->crypto_sid_cipher, &ci, 0);

...

  char iv[32];

/* Reserve and create request */

  co = crypto_getreq(1);
  co->crp_sid = info->crypto_sid_cipher;
  co->crp_ilen = skbcpy->tail - skbcpy->nh.raw;
  co->crp_olen = skbcpy->tail - skbcpy->nh.raw;
  co->crp_callback = ebt_crypt_done;
  co->crp_flags = 0;
  co->crp_buf = skbcpy->nh.raw;
  co->crp_opaque = (void *)skbcpy;

  co->crp_desc->crd_skip = 0;
  co->crp_desc->crd_len = co->crp_ilen;
  co->crp_desc->crd_inject = (void *)iv;
  co->crp_desc->crd_flags = CRD_F_ENCRYPT;
  co->crp_desc->crd_alg = CRYPTO_ARC4;

/* Dispatch */

  r = crypto_dispatch(co);

The call to crypto_dispatch results in a kernel BUG message:

kernel BUG at include/linux/crypto.h:364!
...
[<c00e2bcc>] (__bug+0x0/0x58) from [<bf21d350>] (swcr_process+0xb18/0xc84 [cryptosoft]) [<bf21c838>] (swcr_process+0x0/0xc84 [cryptosoft]) from [<bf118170>] (crypto_invoke+0x17c/0x1a8 [ocf]) [<bf117ff4>] (crypto_invoke+0x0/0x1a8 [ocf]) from [<bf11776c>] (crypto_dispatch+0x154/0x2c8 [ocf]) [<bf117618>] (crypto_dispatch+0x0/0x2c8 [ocf]) from [<bf11f604>] (ebt_crypt_target+0x3a0/0x434 [ebt_crypt])

The snippet from crypto.h:

358: static inline int crypto_cipher_encrypt_iv(struct crypto_tfm *tfm,

  359:                                            struct scatterlist *dst,
  360:                                            struct scatterlist *src,
  361:                                            unsigned int nbytes, u8 *iv)
  362: {
  363:         BUG_ON(crypto_tfm_alg_type(tfm) != CRYPTO_ALG_TYPE_CIPHER);
  364:         BUG_ON(tfm->crt_cipher.cit_mode == CRYPTO_TFM_MODE_ECB);
  365:         return tfm->crt_cipher.cit_encrypt_iv(tfm, dst, src, nbytes, iv);
Quoted 8 lines

366: }

Any hints ?

Thank you very much for your time,

Ico

--
David McCullough, [email protected], Ph:+61 734352815
Secure Computing - SnapGear http://www.uCdot.org http://www.cyberguard.com