/*************************************************************************** * * This file is provided under a dual BSD/GPLv2 license. When using or * redistributing this file, you may do so under either license. * * GPL LICENSE SUMMARY * * Copyright(c) 2007,2008 Intel Corporation. All rights reserved. * * This program is free software; you can redistribute it and/or modify * it under the terms of version 2 of the GNU General Public License as * published by the Free Software Foundation. * * This program is distributed in the hope that it will be useful, but * WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU * General Public License for more details. * * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA. * The full GNU General Public License is included in this distribution * in the file called LICENSE.GPL. * * Contact Information: * Intel Corporation * * BSD LICENSE * * Copyright(c) 2007,2008 Intel Corporation. All rights reserved. * All rights reserved. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * * * Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * * Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in * the documentation and/or other materials provided with the * distribution. * * Neither the name of Intel Corporation nor the names of its * contributors may be used to endorse or promote products derived * from this software without specific prior written permission. * * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. * * * version: Security.L.1.0.130 * ***************************************************************************/ /* * An OCF module that uses the API for Intel® QuickAssist Technology to do the * cryptography. * * This driver requires the ICP Access Library that is available from Intel in * order to operate. */ #include "icp_ocf.h" /*This is the call back function for all symmetric cryptographic processes. Its main functionality is to free driver crypto operation structure and to call back to OCF*/ static void icp_ocfDrvSymCallBack(void *callbackTag, CpaStatus status, const CpaCySymOp operationType, void *pOpData, CpaBufferList * pDstBuffer, CpaBoolean verifyResult); /*This function is used to extract crypto processing information from the OCF inputs, so as that it may be passed onto LAC*/ static int icp_ocfDrvProcessDataSetup(struct icp_drvOpData *drvOpData, struct cryptodesc *crp_desc); /*This function checks whether the crp_desc argument pertains to a digest or a cipher operation*/ static int icp_ocfDrvAlgCheck(struct cryptodesc *crp_desc); /*This function copies all the passed in session context information and stores it in a LAC context structure*/ static int icp_ocfDrvAlgorithmSetup(struct cryptoini *cri, CpaCySymSessionSetupData * lacSessCtx); /*This top level function is used to find a pointer to where a digest is stored/needs to be inserted. */ static uint8_t *icp_ocfDrvDigestPointerFind(struct icp_drvOpData *drvOpData, struct cryptodesc *crp_desc); /*This function is called when a digest pointer has to be found within a SKBUFF.*/ static inline uint8_t *icp_ocfDrvSkbuffDigestPointerFind(struct icp_drvOpData *drvOpData, int offsetInBytes, uint32_t digestSizeInBytes); /*The following two functions are called if the SKBUFF digest pointer is not positioned in the linear portion of the buffer (i.e. it is in a linked SKBUFF or page fragment).*/ /*This function takes care of the page fragment case.*/ static inline uint8_t *icp_ocfDrvDigestSkbNRFragsCheck(struct sk_buff *skb, struct skb_shared_info *skb_shared, int offsetInBytes, uint32_t digestSizeInBytes); /*This function takes care of the linked list case.*/ static inline uint8_t *icp_ocfDrvDigestSkbFragListCheck(struct sk_buff *skb, struct skb_shared_info *skb_shared, int offsetInBytes, uint32_t digestSizeInBytes); /*This function is used to free an OCF->OCF_DRV session object*/ static void icp_ocfDrvFreeOCFSession(struct icp_drvSessionData *sessionData); /*max IOV buffs supported in a UIO structure*/ #define NUM_IOV_SUPPORTED (1) /* Name : icp_ocfDrvSymCallBack * * Description : When this function returns it signifies that the LAC * component has completed the relevant symmetric operation. * * Notes : The callbackTag is a pointer to an icp_drvOpData. This memory * object was passed to LAC for the cryptographic processing and contains all * the relevant information for cleaning up buffer handles etc. so that the * OCF Tolapai Driver portion of this crypto operation can be fully completed. */ static void icp_ocfDrvSymCallBack(void *callbackTag, CpaStatus status, const CpaCySymOp operationType, void *pOpData, CpaBufferList * pDstBuffer, CpaBoolean verifyResult) { struct cryptop *crp = NULL; struct icp_drvOpData *temp_drvOpData = (struct icp_drvOpData *)callbackTag; uint64_t *tempBasePtr = NULL; uint32_t tempLen = 0; if (NULL == temp_drvOpData) { DPRINTK("%s(): The callback from the LAC component" " has failed due to Null userOpaque data" "(status == %d).\n", __FUNCTION__, status); DPRINTK("%s(): Unable to call OCF back! \n", __FUNCTION__); return; } crp = temp_drvOpData->crp; crp->crp_etype = ICP_OCF_DRV_NO_CRYPTO_PROCESS_ERROR; if (NULL == pOpData) { DPRINTK("%s(): The callback from the LAC component" " has failed due to Null Symmetric Op data" "(status == %d).\n", __FUNCTION__, status); crp->crp_etype = ECANCELED; crypto_done(crp); return; } if (NULL == pDstBuffer) { DPRINTK("%s(): The callback from the LAC component" " has failed due to Null Dst Bufferlist data" "(status == %d).\n", __FUNCTION__, status); crp->crp_etype = ECANCELED; crypto_done(crp); return; } if (CPA_STATUS_SUCCESS == status) { if (temp_drvOpData->bufferType == CRYPTO_F_SKBUF) { if (ICP_OCF_DRV_STATUS_SUCCESS != icp_ocfDrvBufferListToSkBuff(pDstBuffer, (struct sk_buff **) &(crp->crp_buf))) { EPRINTK("%s(): BufferList to SkBuff " "conversion error.\n", __FUNCTION__); crp->crp_etype = EPERM; } } else { icp_ocfDrvBufferListToPtrAndLen(pDstBuffer, (void **)&tempBasePtr, &tempLen); crp->crp_olen = (int)tempLen; } } else { DPRINTK("%s(): The callback from the LAC component has failed" "(status == %d).\n", __FUNCTION__, status); crp->crp_etype = ECANCELED; } if (temp_drvOpData->numBufferListArray > ICP_OCF_DRV_DEFAULT_BUFFLIST_ARRAYS) { kfree(pDstBuffer->pBuffers); } icp_ocfDrvFreeMetaData(pDstBuffer); kmem_cache_free(drvOpData_zone, temp_drvOpData); /* Invoke the OCF callback function */ crypto_done(crp); return; } /* Name : icp_ocfDrvNewSession * * Description : This function will create a new Driver<->OCF session * * Notes : LAC session registration happens during the first perform call. * That is the first time we know all information about a given session. */ int icp_ocfDrvNewSession(device_t dev, uint32_t * sid, struct cryptoini *cri) { struct icp_drvSessionData *sessionData = NULL; uint32_t delete_session = 0; /* The SID passed in should be our driver ID. We can return the */ /* local ID (LID) which is a unique identifier which we can use */ /* to differentiate between the encrypt/decrypt LAC session handles */ if (NULL == sid) { EPRINTK("%s(): Invalid input parameters - NULL sid.\n", __FUNCTION__); return EINVAL; } if (NULL == cri) { EPRINTK("%s(): Invalid input parameters - NULL cryptoini.\n", __FUNCTION__); return EINVAL; } if (icp_ocfDrvDriverId != *sid) { EPRINTK("%s(): Invalid input parameters - bad driver ID\n", __FUNCTION__); EPRINTK("\t sid = 0x08%p \n \t cri = 0x08%p \n", sid, cri); return EINVAL; } sessionData = kmem_cache_zalloc(drvSessionData_zone, GFP_ATOMIC); if (NULL == sessionData) { DPRINTK("%s():No memory for Session Data\n", __FUNCTION__); return ENOMEM; } /*ENTER CRITICAL SECTION */ spin_lock_bh(&icp_ocfDrvSymSessInfoListSpinlock); /*put this check in the spinlock so no new sessions can be added to the linked list when we are exiting */ if (CPA_TRUE == atomic_read(&icp_ocfDrvIsExiting)) { delete_session++; } else if (NO_OCF_TO_DRV_MAX_SESSIONS != max_sessions) { if (atomic_read(&num_ocf_to_drv_registered_sessions) >= (max_sessions - atomic_read(&lac_session_failed_dereg_count))) { delete_session++; } else { atomic_inc(&num_ocf_to_drv_registered_sessions); /* Add to session data linked list */ list_add(&(sessionData->listNode), &icp_ocfDrvGlobalSymListHead); } } else if (NO_OCF_TO_DRV_MAX_SESSIONS == max_sessions) { list_add(&(sessionData->listNode), &icp_ocfDrvGlobalSymListHead); } sessionData->inUse = ICP_SESSION_INITIALISED; /*EXIT CRITICAL SECTION */ spin_unlock_bh(&icp_ocfDrvSymSessInfoListSpinlock); if (delete_session) { DPRINTK("%s():No Session handles available\n", __FUNCTION__); kmem_cache_free(drvSessionData_zone, sessionData); return EPERM; } if (ICP_OCF_DRV_STATUS_SUCCESS != icp_ocfDrvAlgorithmSetup(cri, &(sessionData->lacSessCtx))) { DPRINTK("%s():algorithm not supported\n", __FUNCTION__); icp_ocfDrvFreeOCFSession(sessionData); return EINVAL; } if (cri->cri_next) { if (cri->cri_next->cri_next != NULL) { DPRINTK("%s():only two chained algorithms supported\n", __FUNCTION__); icp_ocfDrvFreeOCFSession(sessionData); return EPERM; } if (ICP_OCF_DRV_STATUS_SUCCESS != icp_ocfDrvAlgorithmSetup(cri->cri_next, &(sessionData->lacSessCtx))) { DPRINTK("%s():second algorithm not supported\n", __FUNCTION__); icp_ocfDrvFreeOCFSession(sessionData); return EINVAL; } sessionData->lacSessCtx.symOperation = CPA_CY_SYM_OP_ALGORITHM_CHAINING; } *sid = (uint32_t) sessionData; return ICP_OCF_DRV_STATUS_SUCCESS; } /* Name : icp_ocfDrvAlgorithmSetup * * Description : This function builds the session context data from the * information supplied through OCF. Algorithm chain order and whether the * session is Encrypt/Decrypt can only be found out at perform time however, so * the session is registered with LAC at that time. */ static int icp_ocfDrvAlgorithmSetup(struct cryptoini *cri, CpaCySymSessionSetupData * lacSessCtx) { lacSessCtx->sessionPriority = CPA_CY_PRIORITY_NORMAL; switch (cri->cri_alg) { case CRYPTO_NULL_CBC: DPRINTK("%s(): NULL CBC\n", __FUNCTION__); lacSessCtx->symOperation = CPA_CY_SYM_OP_CIPHER; lacSessCtx->cipherSetupData.cipherAlgorithm = CPA_CY_SYM_CIPHER_NULL; lacSessCtx->cipherSetupData.cipherKeyLenInBytes = cri->cri_klen / NUM_BITS_IN_BYTE; lacSessCtx->cipherSetupData.pCipherKey = cri->cri_key; break; case CRYPTO_DES_CBC: DPRINTK("%s(): DES CBC\n", __FUNCTION__); lacSessCtx->symOperation = CPA_CY_SYM_OP_CIPHER; lacSessCtx->cipherSetupData.cipherAlgorithm = CPA_CY_SYM_CIPHER_DES_CBC; lacSessCtx->cipherSetupData.cipherKeyLenInBytes = cri->cri_klen / NUM_BITS_IN_BYTE; lacSessCtx->cipherSetupData.pCipherKey = cri->cri_key; break; case CRYPTO_3DES_CBC: DPRINTK("%s(): 3DES CBC\n", __FUNCTION__); lacSessCtx->symOperation = CPA_CY_SYM_OP_CIPHER; lacSessCtx->cipherSetupData.cipherAlgorithm = CPA_CY_SYM_CIPHER_3DES_CBC; lacSessCtx->cipherSetupData.cipherKeyLenInBytes = cri->cri_klen / NUM_BITS_IN_BYTE; lacSessCtx->cipherSetupData.pCipherKey = cri->cri_key; break; case CRYPTO_AES_CBC: DPRINTK("%s(): AES CBC\n", __FUNCTION__); lacSessCtx->symOperation = CPA_CY_SYM_OP_CIPHER; lacSessCtx->cipherSetupData.cipherAlgorithm = CPA_CY_SYM_CIPHER_AES_CBC; lacSessCtx->cipherSetupData.cipherKeyLenInBytes = cri->cri_klen / NUM_BITS_IN_BYTE; lacSessCtx->cipherSetupData.pCipherKey = cri->cri_key; break; case CRYPTO_ARC4: DPRINTK("%s(): ARC4\n", __FUNCTION__); lacSessCtx->symOperation = CPA_CY_SYM_OP_CIPHER; lacSessCtx->cipherSetupData.cipherAlgorithm = CPA_CY_SYM_CIPHER_ARC4; lacSessCtx->cipherSetupData.cipherKeyLenInBytes = cri->cri_klen / NUM_BITS_IN_BYTE; lacSessCtx->cipherSetupData.pCipherKey = cri->cri_key; break; case CRYPTO_SHA1: DPRINTK("%s(): SHA1\n", __FUNCTION__); lacSessCtx->symOperation = CPA_CY_SYM_OP_HASH; lacSessCtx->hashSetupData.hashAlgorithm = CPA_CY_SYM_HASH_SHA1; lacSessCtx->hashSetupData.hashMode = CPA_CY_SYM_HASH_MODE_PLAIN; lacSessCtx->hashSetupData.digestResultLenInBytes = (cri->cri_mlen ? cri->cri_mlen : ICP_SHA1_DIGEST_SIZE_IN_BYTES); break; case CRYPTO_SHA1_HMAC: DPRINTK("%s(): SHA1_HMAC\n", __FUNCTION__); lacSessCtx->symOperation = CPA_CY_SYM_OP_HASH; lacSessCtx->hashSetupData.hashAlgorithm = CPA_CY_SYM_HASH_SHA1; lacSessCtx->hashSetupData.hashMode = CPA_CY_SYM_HASH_MODE_AUTH; lacSessCtx->hashSetupData.digestResultLenInBytes = (cri->cri_mlen ? cri->cri_mlen : ICP_SHA1_DIGEST_SIZE_IN_BYTES); lacSessCtx->hashSetupData.authModeSetupData.authKey = cri->cri_key; lacSessCtx->hashSetupData.authModeSetupData.authKeyLenInBytes = cri->cri_klen / NUM_BITS_IN_BYTE; lacSessCtx->hashSetupData.authModeSetupData.aadLenInBytes = 0; break; case CRYPTO_SHA2_256: DPRINTK("%s(): SHA256\n", __FUNCTION__); lacSessCtx->symOperation = CPA_CY_SYM_OP_HASH; lacSessCtx->hashSetupData.hashAlgorithm = CPA_CY_SYM_HASH_SHA256; lacSessCtx->hashSetupData.hashMode = CPA_CY_SYM_HASH_MODE_PLAIN; lacSessCtx->hashSetupData.digestResultLenInBytes = (cri->cri_mlen ? cri->cri_mlen : ICP_SHA256_DIGEST_SIZE_IN_BYTES); break; case CRYPTO_SHA2_256_HMAC: DPRINTK("%s(): SHA256_HMAC\n", __FUNCTION__); lacSessCtx->symOperation = CPA_CY_SYM_OP_HASH; lacSessCtx->hashSetupData.hashAlgorithm = CPA_CY_SYM_HASH_SHA256; lacSessCtx->hashSetupData.hashMode = CPA_CY_SYM_HASH_MODE_AUTH; lacSessCtx->hashSetupData.digestResultLenInBytes = (cri->cri_mlen ? cri->cri_mlen : ICP_SHA256_DIGEST_SIZE_IN_BYTES); lacSessCtx->hashSetupData.authModeSetupData.authKey = cri->cri_key; lacSessCtx->hashSetupData.authModeSetupData.authKeyLenInBytes = cri->cri_klen / NUM_BITS_IN_BYTE; lacSessCtx->hashSetupData.authModeSetupData.aadLenInBytes = 0; break; case CRYPTO_SHA2_384: DPRINTK("%s(): SHA384\n", __FUNCTION__); lacSessCtx->symOperation = CPA_CY_SYM_OP_HASH; lacSessCtx->hashSetupData.hashAlgorithm = CPA_CY_SYM_HASH_SHA384; lacSessCtx->hashSetupData.hashMode = CPA_CY_SYM_HASH_MODE_PLAIN; lacSessCtx->hashSetupData.digestResultLenInBytes = (cri->cri_mlen ? cri->cri_mlen : ICP_SHA384_DIGEST_SIZE_IN_BYTES); break; case CRYPTO_SHA2_384_HMAC: DPRINTK("%s(): SHA384_HMAC\n", __FUNCTION__); lacSessCtx->symOperation = CPA_CY_SYM_OP_HASH; lacSessCtx->hashSetupData.hashAlgorithm = CPA_CY_SYM_HASH_SHA384; lacSessCtx->hashSetupData.hashMode = CPA_CY_SYM_HASH_MODE_AUTH; lacSessCtx->hashSetupData.digestResultLenInBytes = (cri->cri_mlen ? cri->cri_mlen : ICP_SHA384_DIGEST_SIZE_IN_BYTES); lacSessCtx->hashSetupData.authModeSetupData.authKey = cri->cri_key; lacSessCtx->hashSetupData.authModeSetupData.authKeyLenInBytes = cri->cri_klen / NUM_BITS_IN_BYTE; lacSessCtx->hashSetupData.authModeSetupData.aadLenInBytes = 0; break; case CRYPTO_SHA2_512: DPRINTK("%s(): SHA512\n", __FUNCTION__); lacSessCtx->symOperation = CPA_CY_SYM_OP_HASH; lacSessCtx->hashSetupData.hashAlgorithm = CPA_CY_SYM_HASH_SHA512; lacSessCtx->hashSetupData.hashMode = CPA_CY_SYM_HASH_MODE_PLAIN; lacSessCtx->hashSetupData.digestResultLenInBytes = (cri->cri_mlen ? cri->cri_mlen : ICP_SHA512_DIGEST_SIZE_IN_BYTES); break; case CRYPTO_SHA2_512_HMAC: DPRINTK("%s(): SHA512_HMAC\n", __FUNCTION__); lacSessCtx->symOperation = CPA_CY_SYM_OP_HASH; lacSessCtx->hashSetupData.hashAlgorithm = CPA_CY_SYM_HASH_SHA512; lacSessCtx->hashSetupData.hashMode = CPA_CY_SYM_HASH_MODE_AUTH; lacSessCtx->hashSetupData.digestResultLenInBytes = (cri->cri_mlen ? cri->cri_mlen : ICP_SHA512_DIGEST_SIZE_IN_BYTES); lacSessCtx->hashSetupData.authModeSetupData.authKey = cri->cri_key; lacSessCtx->hashSetupData.authModeSetupData.authKeyLenInBytes = cri->cri_klen / NUM_BITS_IN_BYTE; lacSessCtx->hashSetupData.authModeSetupData.aadLenInBytes = 0; break; case CRYPTO_MD5: DPRINTK("%s(): MD5\n", __FUNCTION__); lacSessCtx->symOperation = CPA_CY_SYM_OP_HASH; lacSessCtx->hashSetupData.hashAlgorithm = CPA_CY_SYM_HASH_MD5; lacSessCtx->hashSetupData.hashMode = CPA_CY_SYM_HASH_MODE_PLAIN; lacSessCtx->hashSetupData.digestResultLenInBytes = (cri->cri_mlen ? cri->cri_mlen : ICP_MD5_DIGEST_SIZE_IN_BYTES); break; case CRYPTO_MD5_HMAC: DPRINTK("%s(): MD5_HMAC\n", __FUNCTION__); lacSessCtx->symOperation = CPA_CY_SYM_OP_HASH; lacSessCtx->hashSetupData.hashAlgorithm = CPA_CY_SYM_HASH_MD5; lacSessCtx->hashSetupData.hashMode = CPA_CY_SYM_HASH_MODE_AUTH; lacSessCtx->hashSetupData.digestResultLenInBytes = (cri->cri_mlen ? cri->cri_mlen : ICP_MD5_DIGEST_SIZE_IN_BYTES); lacSessCtx->hashSetupData.authModeSetupData.authKey = cri->cri_key; lacSessCtx->hashSetupData.authModeSetupData.authKeyLenInBytes = cri->cri_klen / NUM_BITS_IN_BYTE; lacSessCtx->hashSetupData.authModeSetupData.aadLenInBytes = 0; break; default: DPRINTK("%s(): ALG Setup FAIL\n", __FUNCTION__); return ICP_OCF_DRV_STATUS_FAIL; } return ICP_OCF_DRV_STATUS_SUCCESS; } /* Name : icp_ocfDrvFreeOCFSession * * Description : This function deletes all existing Session data representing * the Cryptographic session established between OCF and this driver. This * also includes freeing the memory allocated for the session context. The * session object is also removed from the session linked list. */ static void icp_ocfDrvFreeOCFSession(struct icp_drvSessionData *sessionData) { sessionData->inUse = ICP_SESSION_DEREGISTERED; /*ENTER CRITICAL SECTION */ spin_lock_bh(&icp_ocfDrvSymSessInfoListSpinlock); if (CPA_TRUE == atomic_read(&icp_ocfDrvIsExiting)) { /*If the Driver is exiting, allow that process to handle any deletions */ /*EXIT CRITICAL SECTION */ spin_unlock_bh(&icp_ocfDrvSymSessInfoListSpinlock); return; } atomic_dec(&num_ocf_to_drv_registered_sessions); list_del(&(sessionData->listNode)); /*EXIT CRITICAL SECTION */ spin_unlock_bh(&icp_ocfDrvSymSessInfoListSpinlock); if (NULL != sessionData->sessHandle) { kfree(sessionData->sessHandle); } kmem_cache_free(drvSessionData_zone, sessionData); } /* Name : icp_ocfDrvFreeLACSession * * Description : This attempts to deregister a LAC session. If it fails, the * deregistation retry function is called. */ int icp_ocfDrvFreeLACSession(device_t dev, uint64_t sid) { CpaCySymSessionCtx sessionToDeregister = NULL; struct icp_drvSessionData *sessionData = NULL; CpaStatus lacStatus = CPA_STATUS_SUCCESS; int retval = 0; sessionData = (struct icp_drvSessionData *)CRYPTO_SESID2LID(sid); if (NULL == sessionData) { EPRINTK("%s(): OCF Free session called with Null Session ID.\n", __FUNCTION__); return EINVAL; } sessionToDeregister = sessionData->sessHandle; if (ICP_SESSION_INITIALISED == sessionData->inUse) { DPRINTK("%s() Session not registered with LAC\n", __FUNCTION__); } else if (NULL == sessionData->sessHandle) { EPRINTK ("%s(): OCF Free session called with Null Session Handle.\n", __FUNCTION__); return EINVAL; } else { lacStatus = cpaCySymRemoveSession(CPA_INSTANCE_HANDLE_SINGLE, sessionToDeregister); if (CPA_STATUS_RETRY == lacStatus) { if (ICP_OCF_DRV_STATUS_SUCCESS != icp_ocfDrvDeregRetry(&sessionToDeregister)) { /* the retry function increments the dereg failed count */ DPRINTK("%s(): LAC failed to deregister the " "session. (localSessionId= %p)\n", __FUNCTION__, sessionToDeregister); retval = EPERM; } } else if (CPA_STATUS_SUCCESS != lacStatus) { DPRINTK("%s(): LAC failed to deregister the session. " "localSessionId= %p, lacStatus = %d\n", __FUNCTION__, sessionToDeregister, lacStatus); atomic_inc(&lac_session_failed_dereg_count); retval = EPERM; } } icp_ocfDrvFreeOCFSession(sessionData); return retval; } /* Name : icp_ocfDrvAlgCheck * * Description : This function checks whether the cryptodesc argument pertains * to a sym or hash function */ static int icp_ocfDrvAlgCheck(struct cryptodesc *crp_desc) { if (crp_desc->crd_alg == CRYPTO_3DES_CBC || crp_desc->crd_alg == CRYPTO_AES_CBC || crp_desc->crd_alg == CRYPTO_DES_CBC || crp_desc->crd_alg == CRYPTO_NULL_CBC || crp_desc->crd_alg == CRYPTO_ARC4) { return ICP_OCF_DRV_ALG_CIPHER; } return ICP_OCF_DRV_ALG_HASH; } /* Name : icp_ocfDrvSymProcess * * Description : This function will map symmetric functionality calls from OCF * to the LAC API. It will also allocate memory to store the session context. * * Notes: If it is the first perform call for a given session, then a LAC * session is registered. After the session is registered, no checks as * to whether session paramaters have changed (e.g. alg chain order) are * done. */ int icp_ocfDrvSymProcess(device_t dev, struct cryptop *crp, int hint) { struct icp_drvSessionData *sessionData = NULL; struct icp_drvOpData *drvOpData = NULL; CpaStatus lacStatus = CPA_STATUS_SUCCESS; Cpa32U sessionCtxSizeInBytes = 0; uint16_t numBufferListArray = 0; if (NULL == crp) { DPRINTK("%s(): Invalid input parameters, cryptop is NULL\n", __FUNCTION__); return EINVAL; } if (NULL == crp->crp_desc) { DPRINTK("%s(): Invalid input parameters, no crp_desc attached " "to crp\n", __FUNCTION__); crp->crp_etype = EINVAL; return EINVAL; } if (NULL == crp->crp_buf) { DPRINTK("%s(): Invalid input parameters, no buffer attached " "to crp\n", __FUNCTION__); crp->crp_etype = EINVAL; return EINVAL; } if (CPA_TRUE == atomic_read(&icp_ocfDrvIsExiting)) { crp->crp_etype = EFAULT; return EFAULT; } sessionData = (struct icp_drvSessionData *) (CRYPTO_SESID2LID(crp->crp_sid)); if (NULL == sessionData) { DPRINTK("%s(): Invalid input parameters, Null Session ID \n", __FUNCTION__); crp->crp_etype = EINVAL; return EINVAL; } /*If we get a request against a deregisted session, cancel operation*/ if (ICP_SESSION_DEREGISTERED == sessionData->inUse) { DPRINTK("%s(): Session ID %d was deregistered \n", __FUNCTION__, (int)(CRYPTO_SESID2LID(crp->crp_sid))); crp->crp_etype = EFAULT; return EFAULT; } /*If none of the session states are set, then the session structure was either not initialised properly or we are reading from a freed memory area (possible due to OCF batch mode not removing queued requests against deregistered sessions*/ if (ICP_SESSION_INITIALISED != sessionData->inUse && ICP_SESSION_RUNNING != sessionData->inUse) { DPRINTK("%s(): Session - ID %d - not properly initialised or " "memory freed back to the kernel \n", __FUNCTION__, (int)(CRYPTO_SESID2LID(crp->crp_sid))); crp->crp_etype = EINVAL; return EINVAL; } /*For the below checks, remember error checking is already done in LAC. We're not validating inputs subsequent to registration */ if (sessionData->inUse == ICP_SESSION_INITIALISED) { DPRINTK("%s(): Initialising session\n", __FUNCTION__); if (NULL != crp->crp_desc->crd_next) { if (ICP_OCF_DRV_ALG_CIPHER == icp_ocfDrvAlgCheck(crp->crp_desc)) { sessionData->lacSessCtx.algChainOrder = CPA_CY_SYM_ALG_CHAIN_ORDER_CIPHER_THEN_HASH; if (crp->crp_desc->crd_flags & CRD_F_ENCRYPT) { sessionData->lacSessCtx.cipherSetupData. cipherDirection = CPA_CY_SYM_CIPHER_DIRECTION_ENCRYPT; } else { sessionData->lacSessCtx.cipherSetupData. cipherDirection = CPA_CY_SYM_CIPHER_DIRECTION_DECRYPT; } } else { sessionData->lacSessCtx.algChainOrder = CPA_CY_SYM_ALG_CHAIN_ORDER_HASH_THEN_CIPHER; if (crp->crp_desc->crd_next->crd_flags & CRD_F_ENCRYPT) { sessionData->lacSessCtx.cipherSetupData. cipherDirection = CPA_CY_SYM_CIPHER_DIRECTION_ENCRYPT; } else { sessionData->lacSessCtx.cipherSetupData. cipherDirection = CPA_CY_SYM_CIPHER_DIRECTION_DECRYPT; } } } else if (ICP_OCF_DRV_ALG_CIPHER == icp_ocfDrvAlgCheck(crp->crp_desc)) { if (crp->crp_desc->crd_flags & CRD_F_ENCRYPT) { sessionData->lacSessCtx.cipherSetupData. cipherDirection = CPA_CY_SYM_CIPHER_DIRECTION_ENCRYPT; } else { sessionData->lacSessCtx.cipherSetupData. cipherDirection = CPA_CY_SYM_CIPHER_DIRECTION_DECRYPT; } } /*No action required for standalone Auth here */ /* Allocate memory for SymSessionCtx before the Session Registration */ lacStatus = cpaCySymSessionCtxGetSize(CPA_INSTANCE_HANDLE_SINGLE, &(sessionData->lacSessCtx), &sessionCtxSizeInBytes); if (CPA_STATUS_SUCCESS != lacStatus) { EPRINTK("%s(): cpaCySymSessionCtxGetSize failed - %d\n", __FUNCTION__, lacStatus); return EINVAL; } sessionData->sessHandle = kmalloc(sessionCtxSizeInBytes, GFP_ATOMIC); if (NULL == sessionData->sessHandle) { EPRINTK ("%s(): Failed to get memory for SymSessionCtx\n", __FUNCTION__); return ENOMEM; } lacStatus = cpaCySymInitSession(CPA_INSTANCE_HANDLE_SINGLE, icp_ocfDrvSymCallBack, &(sessionData->lacSessCtx), sessionData->sessHandle); if (CPA_STATUS_SUCCESS != lacStatus) { EPRINTK("%s(): cpaCySymInitSession failed -%d \n", __FUNCTION__, lacStatus); return EFAULT; } sessionData->inUse = ICP_SESSION_RUNNING; } drvOpData = kmem_cache_zalloc(drvOpData_zone, GFP_ATOMIC); if (NULL == drvOpData) { EPRINTK("%s():Failed to get memory for drvOpData\n", __FUNCTION__); crp->crp_etype = ENOMEM; return ENOMEM; } drvOpData->lacOpData.pSessionCtx = sessionData->sessHandle; drvOpData->digestSizeInBytes = sessionData->lacSessCtx.hashSetupData. digestResultLenInBytes; drvOpData->crp = crp; /* Set the default buffer list array memory allocation */ drvOpData->srcBuffer.pBuffers = drvOpData->bufferListArray; drvOpData->numBufferListArray = ICP_OCF_DRV_DEFAULT_BUFFLIST_ARRAYS; /* * Allocate buffer list array memory allocation if the * data fragment is more than the default allocation */ if (crp->crp_flags & CRYPTO_F_SKBUF) { numBufferListArray = icp_ocfDrvGetSkBuffFrags((struct sk_buff *) crp->crp_buf); if (ICP_OCF_DRV_DEFAULT_BUFFLIST_ARRAYS < numBufferListArray) { DPRINTK("%s() numBufferListArray more than default\n", __FUNCTION__); drvOpData->srcBuffer.pBuffers = NULL; drvOpData->srcBuffer.pBuffers = kmalloc(numBufferListArray * sizeof(CpaFlatBuffer), GFP_ATOMIC); if (NULL == drvOpData->srcBuffer.pBuffers) { EPRINTK("%s() Failed to get memory for " "pBuffers\n", __FUNCTION__); kmem_cache_free(drvOpData_zone, drvOpData); crp->crp_etype = ENOMEM; return ENOMEM; } drvOpData->numBufferListArray = numBufferListArray; } } /* * Check the type of buffer structure we got and convert it into * CpaBufferList format. */ if (crp->crp_flags & CRYPTO_F_SKBUF) { if (ICP_OCF_DRV_STATUS_SUCCESS != icp_ocfDrvSkBuffToBufferList((struct sk_buff *)crp->crp_buf, &(drvOpData->srcBuffer))) { EPRINTK("%s():Failed to translate from SK_BUF " "to bufferlist\n", __FUNCTION__); crp->crp_etype = EINVAL; goto err; } drvOpData->bufferType = CRYPTO_F_SKBUF; } else if (crp->crp_flags & CRYPTO_F_IOV) { /* OCF only supports IOV of one entry. */ if (NUM_IOV_SUPPORTED == ((struct uio *)(crp->crp_buf))->uio_iovcnt) { icp_ocfDrvPtrAndLenToBufferList(((struct uio *)(crp-> crp_buf))-> uio_iov[0].iov_base, ((struct uio *)(crp-> crp_buf))-> uio_iov[0].iov_len, &(drvOpData-> srcBuffer)); drvOpData->bufferType = CRYPTO_F_IOV; } else { DPRINTK("%s():Unable to handle IOVs with lengths of " "greater than one!\n", __FUNCTION__); crp->crp_etype = EINVAL; goto err; } } else { icp_ocfDrvPtrAndLenToBufferList(crp->crp_buf, crp->crp_ilen, &(drvOpData->srcBuffer)); drvOpData->bufferType = CRYPTO_BUF_CONTIG; } if (ICP_OCF_DRV_STATUS_SUCCESS != icp_ocfDrvProcessDataSetup(drvOpData, drvOpData->crp->crp_desc)) { crp->crp_etype = EINVAL; goto err; } if (drvOpData->crp->crp_desc->crd_next != NULL) { if (icp_ocfDrvProcessDataSetup(drvOpData, drvOpData->crp-> crp_desc->crd_next)) { crp->crp_etype = EINVAL; goto err; } } /* Allocate srcBuffer's private meta data */ if (ICP_OCF_DRV_STATUS_SUCCESS != icp_ocfDrvAllocMetaData(&(drvOpData->srcBuffer), drvOpData)) { EPRINTK("%s() icp_ocfDrvAllocMetaData failed\n", __FUNCTION__); memset(&(drvOpData->lacOpData), 0, sizeof(CpaCySymOpData)); crp->crp_etype = EINVAL; goto err; } /* Perform "in-place" crypto operation */ lacStatus = cpaCySymPerformOp(CPA_INSTANCE_HANDLE_SINGLE, (void *)drvOpData, &(drvOpData->lacOpData), &(drvOpData->srcBuffer), &(drvOpData->srcBuffer), &(drvOpData->verifyResult)); if (CPA_STATUS_RETRY == lacStatus) { DPRINTK("%s(): cpaCySymPerformOp retry, lacStatus = %d\n", __FUNCTION__, lacStatus); memset(&(drvOpData->lacOpData), 0, sizeof(CpaCySymOpData)); crp->crp_etype = EINVAL; goto err; } if (CPA_STATUS_SUCCESS != lacStatus) { EPRINTK("%s(): cpaCySymPerformOp failed, lacStatus = %d\n", __FUNCTION__, lacStatus); memset(&(drvOpData->lacOpData), 0, sizeof(CpaCySymOpData)); crp->crp_etype = EINVAL; goto err; } return 0; //OCF success status value err: if (drvOpData->numBufferListArray > ICP_OCF_DRV_DEFAULT_BUFFLIST_ARRAYS) { kfree(drvOpData->srcBuffer.pBuffers); } icp_ocfDrvFreeMetaData(&(drvOpData->srcBuffer)); kmem_cache_free(drvOpData_zone, drvOpData); return crp->crp_etype; } /* Name : icp_ocfDrvProcessDataSetup * * Description : This function will setup all the cryptographic operation data * that is required by LAC to execute the operation. */ static int icp_ocfDrvProcessDataSetup(struct icp_drvOpData *drvOpData, struct cryptodesc *crp_desc) { CpaCyRandGenOpData randGenOpData; CpaFlatBuffer randData; drvOpData->lacOpData.packetType = CPA_CY_SYM_PACKET_TYPE_FULL; /* Convert from the cryptop to the ICP LAC crypto parameters */ switch (crp_desc->crd_alg) { case CRYPTO_NULL_CBC: drvOpData->lacOpData. cryptoStartSrcOffsetInBytes = crp_desc->crd_skip; drvOpData->lacOpData. messageLenToCipherInBytes = crp_desc->crd_len; drvOpData->verifyResult = CPA_FALSE; drvOpData->lacOpData.ivLenInBytes = NULL_BLOCK_LEN; break; case CRYPTO_DES_CBC: drvOpData->lacOpData. cryptoStartSrcOffsetInBytes = crp_desc->crd_skip; drvOpData->lacOpData. messageLenToCipherInBytes = crp_desc->crd_len; drvOpData->verifyResult = CPA_FALSE; drvOpData->lacOpData.ivLenInBytes = DES_BLOCK_LEN; break; case CRYPTO_3DES_CBC: drvOpData->lacOpData. cryptoStartSrcOffsetInBytes = crp_desc->crd_skip; drvOpData->lacOpData. messageLenToCipherInBytes = crp_desc->crd_len; drvOpData->verifyResult = CPA_FALSE; drvOpData->lacOpData.ivLenInBytes = DES3_BLOCK_LEN; break; case CRYPTO_ARC4: drvOpData->lacOpData. cryptoStartSrcOffsetInBytes = crp_desc->crd_skip; drvOpData->lacOpData. messageLenToCipherInBytes = crp_desc->crd_len; drvOpData->verifyResult = CPA_FALSE; drvOpData->lacOpData.ivLenInBytes = ARC4_COUNTER_LEN; break; case CRYPTO_AES_CBC: drvOpData->lacOpData. cryptoStartSrcOffsetInBytes = crp_desc->crd_skip; drvOpData->lacOpData. messageLenToCipherInBytes = crp_desc->crd_len; drvOpData->verifyResult = CPA_FALSE; drvOpData->lacOpData.ivLenInBytes = RIJNDAEL128_BLOCK_LEN; break; case CRYPTO_SHA1: case CRYPTO_SHA1_HMAC: case CRYPTO_SHA2_256: case CRYPTO_SHA2_256_HMAC: case CRYPTO_SHA2_384: case CRYPTO_SHA2_384_HMAC: case CRYPTO_SHA2_512: case CRYPTO_SHA2_512_HMAC: case CRYPTO_MD5: case CRYPTO_MD5_HMAC: drvOpData->lacOpData. hashStartSrcOffsetInBytes = crp_desc->crd_skip; drvOpData->lacOpData. messageLenToHashInBytes = crp_desc->crd_len; drvOpData->lacOpData. pDigestResult = icp_ocfDrvDigestPointerFind(drvOpData, crp_desc); if (NULL == drvOpData->lacOpData.pDigestResult) { DPRINTK("%s(): ERROR - could not calculate " "Digest Result memory address\n", __FUNCTION__); return ICP_OCF_DRV_STATUS_FAIL; } drvOpData->lacOpData.digestVerify = CPA_FALSE; break; default: DPRINTK("%s(): Crypto process error - algorithm not " "found \n", __FUNCTION__); return ICP_OCF_DRV_STATUS_FAIL; } /* Figure out what the IV is supposed to be */ if ((crp_desc->crd_alg == CRYPTO_DES_CBC) || (crp_desc->crd_alg == CRYPTO_3DES_CBC) || (crp_desc->crd_alg == CRYPTO_AES_CBC)) { /*ARC4 doesn't use an IV */ if (crp_desc->crd_flags & CRD_F_IV_EXPLICIT) { /* Explicit IV provided to OCF */ drvOpData->lacOpData.pIv = crp_desc->crd_iv; } else { /* IV is not explicitly provided to OCF */ /* Point the LAC OP Data IV pointer to our allocated storage location for this session. */ drvOpData->lacOpData.pIv = drvOpData->ivData; if ((crp_desc->crd_flags & CRD_F_ENCRYPT) && ((crp_desc->crd_flags & CRD_F_IV_PRESENT) == 0)) { /* Encrypting - need to create IV */ randGenOpData.generateBits = CPA_TRUE; randGenOpData.lenInBytes = MAX_IV_LEN_IN_BYTES; icp_ocfDrvPtrAndLenToFlatBuffer((Cpa8U *) drvOpData-> ivData, MAX_IV_LEN_IN_BYTES, &randData); if (CPA_STATUS_SUCCESS != cpaCyRandGen(CPA_INSTANCE_HANDLE_SINGLE, NULL, NULL, &randGenOpData, &randData)) { DPRINTK("%s(): ERROR - Failed to" " generate" " Initialisation Vector\n", __FUNCTION__); return ICP_OCF_DRV_STATUS_FAIL; } crypto_copyback(drvOpData->crp-> crp_flags, drvOpData->crp->crp_buf, crp_desc->crd_inject, drvOpData->lacOpData. ivLenInBytes, (caddr_t) (drvOpData->lacOpData. pIv)); } else { /* Reading IV from buffer */ crypto_copydata(drvOpData->crp-> crp_flags, drvOpData->crp->crp_buf, crp_desc->crd_inject, drvOpData->lacOpData. ivLenInBytes, (caddr_t) (drvOpData->lacOpData. pIv)); } } } return ICP_OCF_DRV_STATUS_SUCCESS; } /* Name : icp_ocfDrvDigestPointerFind * * Description : This function is used to find the memory address of where the * digest information shall be stored in. Input buffer types are an skbuff, iov * or flat buffer. The address is found using the buffer data start address and * an offset. * * Note: In the case of a linux skbuff, the digest address may exist within * a memory space linked to from the start buffer. These linked memory spaces * must be traversed by the data length offset in order to find the digest start * address. Whether there is enough space for the digest must also be checked. */ static uint8_t *icp_ocfDrvDigestPointerFind(struct icp_drvOpData *drvOpData, struct cryptodesc *crp_desc) { int offsetInBytes = crp_desc->crd_inject; uint32_t digestSizeInBytes = drvOpData->digestSizeInBytes; uint8_t *flat_buffer_base = NULL; int flat_buffer_length = 0; struct sk_buff *skb; if (drvOpData->crp->crp_flags & CRYPTO_F_SKBUF) { /*check if enough overall space to store hash */ skb = (struct sk_buff *)(drvOpData->crp->crp_buf); if (skb->len < (offsetInBytes + digestSizeInBytes)) { DPRINTK("%s() Not enough space for Digest" " payload after the offset (%d), " "digest size (%d) \n", __FUNCTION__, offsetInBytes, digestSizeInBytes); return NULL; } return icp_ocfDrvSkbuffDigestPointerFind(drvOpData, offsetInBytes, digestSizeInBytes); } else { /* IOV or flat buffer */ if (drvOpData->crp->crp_flags & CRYPTO_F_IOV) { /*single IOV check has already been done */ flat_buffer_base = ((struct uio *) (drvOpData->crp->crp_buf))-> uio_iov[0].iov_base; flat_buffer_length = ((struct uio *) (drvOpData->crp->crp_buf))-> uio_iov[0].iov_len; } else { flat_buffer_base = (uint8_t *) drvOpData->crp->crp_buf; flat_buffer_length = drvOpData->crp->crp_ilen; } if (flat_buffer_length < (offsetInBytes + digestSizeInBytes)) { DPRINTK("%s() Not enough space for Digest " "(IOV/Flat Buffer) \n", __FUNCTION__); return NULL; } else { return (uint8_t *) (flat_buffer_base + offsetInBytes); } } DPRINTK("%s() Should not reach this point\n", __FUNCTION__); return NULL; } /* Name : icp_ocfDrvSkbuffDigestPointerFind * * Description : This function is used by icp_ocfDrvDigestPointerFind to process * the non-linear portion of the skbuff if the fragmentation type is a linked * list (frag_list is not NULL in the skb_shared_info structure) */ static inline uint8_t *icp_ocfDrvSkbuffDigestPointerFind(struct icp_drvOpData *drvOpData, int offsetInBytes, uint32_t digestSizeInBytes) { struct sk_buff *skb = NULL; struct skb_shared_info *skb_shared = NULL; uint32_t skbuffisnonlinear = 0; uint32_t skbheadlen = 0; skb = (struct sk_buff *)(drvOpData->crp->crp_buf); skbuffisnonlinear = skb_is_nonlinear(skb); skbheadlen = skb_headlen(skb); /*Linear skb checks */ if (skbheadlen > offsetInBytes) { if (skbheadlen >= (offsetInBytes + digestSizeInBytes)) { return (uint8_t *) (skb->data + offsetInBytes); } else { DPRINTK("%s() Auth payload stretches " "accross contiguous memory\n", __FUNCTION__); return NULL; } } else { if (skbuffisnonlinear) { offsetInBytes -= skbheadlen; } else { DPRINTK("%s() Offset outside of buffer boundaries\n", __FUNCTION__); return NULL; } } /*Non Linear checks */ skb_shared = (struct skb_shared_info *)(skb->end); if (unlikely(NULL == skb_shared)) { DPRINTK("%s() skbuff shared info stucture is NULL! \n", __FUNCTION__); return NULL; } else if ((0 != skb_shared->nr_frags) && (skb_shared->frag_list != NULL)) { DPRINTK("%s() skbuff nr_frags AND " "frag_list not supported \n", __FUNCTION__); return NULL; } /*TCP segmentation more likely than IP fragmentation */ if (likely(0 != skb_shared->nr_frags)) { return icp_ocfDrvDigestSkbNRFragsCheck(skb, skb_shared, offsetInBytes, digestSizeInBytes); } else if (skb_shared->frag_list != NULL) { return icp_ocfDrvDigestSkbFragListCheck(skb, skb_shared, offsetInBytes, digestSizeInBytes); } else { DPRINTK("%s() skbuff is non-linear but does not show any " "linked data\n", __FUNCTION__); return NULL; } } /* Name : icp_ocfDrvDigestSkbNRFragsCheck * * Description : This function is used by icp_ocfDrvSkbuffDigestPointerFind to * process the non-linear portion of the skbuff, if the fragmentation type is * page fragments */ static inline uint8_t *icp_ocfDrvDigestSkbNRFragsCheck(struct sk_buff *skb, struct skb_shared_info *skb_shared, int offsetInBytes, uint32_t digestSizeInBytes) { int i = 0; /*nr_frags starts from 1 */ if (MAX_SKB_FRAGS < skb_shared->nr_frags) { DPRINTK("%s error processing skbuff " "page frame -- MAX FRAGS exceeded \n", __FUNCTION__); return NULL; } for (i = 0; i < skb_shared->nr_frags; i++) { if (offsetInBytes >= skb_shared->frags[i].size) { /*offset still greater than data position */ offsetInBytes -= skb_shared->frags[i].size; } else { /* found the page containing start of hash */ if (NULL == skb_shared->frags[i].page) { DPRINTK("%s() Linked page is NULL!\n", __FUNCTION__); return NULL; } if (offsetInBytes + digestSizeInBytes > skb_shared->frags[i].size) { DPRINTK("%s() Auth payload stretches accross " "contiguous memory\n", __FUNCTION__); return NULL; } else { return (uint8_t *) (skb_shared->frags[i].page + skb_shared->frags[i]. page_offset + offsetInBytes); } } /*only possible if internal page sizes are set wrong */ if (offsetInBytes < 0) { DPRINTK("%s error processing skbuff page frame " "-- offset calculation \n", __FUNCTION__); return NULL; } } /*only possible if internal page sizes are set wrong */ DPRINTK("%s error processing skbuff page frame " "-- ran out of page fragments, remaining offset = %d \n", __FUNCTION__, offsetInBytes); return NULL; } /* Name : icp_ocfDrvDigestSkbFragListCheck * * Description : This function is used by icp_ocfDrvSkbuffDigestPointerFind to * process the non-linear portion of the skbuff, if the fragmentation type is * a linked list * */ static inline uint8_t *icp_ocfDrvDigestSkbFragListCheck(struct sk_buff *skb, struct skb_shared_info *skb_shared, int offsetInBytes, uint32_t digestSizeInBytes) { struct sk_buff *skb_list = skb_shared->frag_list; /*check added for readability */ if (NULL == skb_list) { DPRINTK("%s error processing skbuff " "-- no more list! \n", __FUNCTION__); return NULL; } for (; skb_list; skb_list = skb_list->next) { if (NULL == skb_list) { DPRINTK("%s error processing skbuff " "-- no more list! \n", __FUNCTION__); return NULL; } if (offsetInBytes >= skb_list->len) { offsetInBytes -= skb_list->len; } else { if (offsetInBytes + digestSizeInBytes > skb_list->len) { DPRINTK("%s() Auth payload stretches accross " "contiguous memory\n", __FUNCTION__); return NULL; } else { return (uint8_t *) (skb_list->data + offsetInBytes); } } /*This check is only needed if internal skb_list length values are set wrong. */ if (0 > offsetInBytes) { DPRINTK("%s() error processing skbuff object -- offset " "calculation \n", __FUNCTION__); return NULL; } } /*catch all for unusual for-loop exit. This code should never be reached */ DPRINTK("%s() Catch-All hit! Process error.\n", __FUNCTION__); return NULL; }