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lightning-sunbird  0.9+nobinonly
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cmscipher.c File Reference
#include "cmslocal.h"
#include "secoid.h"
#include "secitem.h"
#include "pk11func.h"
#include "secerr.h"
#include "secpkcs5.h"

Go to the source code of this file.

Classes

struct  NSSCMSCipherContextStr

Defines

#define BLOCK_SIZE   4096

Typedefs

typedef SECStatus(* nss_cms_cipher_function )(void *, unsigned char *, unsigned int *, unsigned int, const unsigned char *, unsigned int)
typedef SECStatus(* nss_cms_cipher_destroy )(void *, PRBool)

Functions

NSSCMSCipherContext * NSS_CMSCipherContext_StartDecrypt (PK11SymKey *key, SECAlgorithmID *algid)
NSSCMSCipherContext * NSS_CMSCipherContext_StartEncrypt (PRArenaPool *poolp, PK11SymKey *key, SECAlgorithmID *algid)
void NSS_CMSCipherContext_Destroy (NSSCMSCipherContext *cc)
unsigned int NSS_CMSCipherContext_DecryptLength (NSSCMSCipherContext *cc, unsigned int input_len, PRBool final)
unsigned int NSS_CMSCipherContext_EncryptLength (NSSCMSCipherContext *cc, unsigned int input_len, PRBool final)
SECStatus NSS_CMSCipherContext_Decrypt (NSSCMSCipherContext *cc, unsigned char *output, unsigned int *output_len_p, unsigned int max_output_len, const unsigned char *input, unsigned int input_len, PRBool final)
SECStatus NSS_CMSCipherContext_Encrypt (NSSCMSCipherContext *cc, unsigned char *output, unsigned int *output_len_p, unsigned int max_output_len, const unsigned char *input, unsigned int input_len, PRBool final)

Class Documentation

struct NSSCMSCipherContextStr

Definition at line 62 of file cmscipher.c.

Collaboration diagram for NSSCMSCipherContextStr:
Class Members
int block_size
void * cx
nss_cms_cipher_destroy destroy
nss_cms_cipher_function doit
PRBool encrypt
int pad_size
unsigned char pending_buf
int pending_count

Define Documentation

#define BLOCK_SIZE   4096

Definition at line 60 of file cmscipher.c.


Typedef Documentation

Definition at line 58 of file cmscipher.c.

typedef SECStatus(* nss_cms_cipher_function)(void *, unsigned char *, unsigned int *, unsigned int, const unsigned char *, unsigned int)

Definition at line 56 of file cmscipher.c.


Function Documentation

SECStatus NSS_CMSCipherContext_Decrypt ( NSSCMSCipherContext *  cc,
unsigned char *  output,
unsigned int output_len_p,
unsigned int  max_output_len,
const unsigned char *  input,
unsigned int  input_len,
PRBool  final 
)

Definition at line 438 of file cmscipher.c.

{
    int blocks, bsize, pcount, padsize;
    unsigned int max_needed, ifraglen, ofraglen, output_len;
    unsigned char *pbuf;
    SECStatus rv;

    PORT_Assert (! cc->encrypt);

    /*
     * Check that we have enough room for the output.  Our caller should
     * already handle this; failure is really an internal error (i.e. bug).
     */
    max_needed = NSS_CMSCipherContext_DecryptLength(cc, input_len, final);
    PORT_Assert (max_output_len >= max_needed);
    if (max_output_len < max_needed) {
       /* PORT_SetError (XXX); */
       return SECFailure;
    }

    /*
     * hardware encryption does not like small decryption sizes here, so we
     * allow both blocking and padding.
     */
    bsize = cc->block_size;
    padsize = cc->pad_size;

    /*
     * When no blocking or padding work to do, we can simply call the
     * cipher function and we are done.
     */
    if (bsize == 0) {
       return (* cc->doit) (cc->cx, output, output_len_p, max_output_len,
                           input, input_len);
    }

    pcount = cc->pending_count;
    pbuf = cc->pending_buf;

    output_len = 0;

    if (pcount) {
       /*
        * Try to fill in an entire block, starting with the bytes
        * we already have saved away.
        */
       while (input_len && pcount < bsize) {
           pbuf[pcount++] = *input++;
           input_len--;
       }
       /*
        * If we have at most a whole block and this is not our last call,
        * then we are done for now.  (We do not try to decrypt a lone
        * single block because we cannot interpret the padding bytes
        * until we know we are handling the very last block of all input.)
        */
       if (input_len == 0 && !final) {
           cc->pending_count = pcount;
           if (output_len_p)
              *output_len_p = 0;
           return SECSuccess;
       }
       /*
        * Given the logic above, we expect to have a full block by now.
        * If we do not, there is something wrong, either with our own
        * logic or with (length of) the data given to us.
        */
       if ((padsize != 0) && (pcount % padsize) != 0) {
           PORT_Assert (final);    
           PORT_SetError (SEC_ERROR_BAD_DATA);
           return SECFailure;
       }
       /*
        * Decrypt the block.
        */
       rv = (*cc->doit)(cc->cx, output, &ofraglen, max_output_len,
                         pbuf, pcount);
       if (rv != SECSuccess)
           return rv;

       /*
        * For now anyway, all of our ciphers have the same number of
        * bytes of output as they do input.  If this ever becomes untrue,
        * then NSS_CMSCipherContext_DecryptLength needs to be made smarter!
        */
       PORT_Assert(ofraglen == pcount);

       /*
        * Account for the bytes now in output.
        */
       max_output_len -= ofraglen;
       output_len += ofraglen;
       output += ofraglen;
    }

    /*
     * If this is our last call, we expect to have an exact number of
     * blocks left to be decrypted; we will decrypt them all.
     * 
     * If not our last call, we always save between 1 and bsize bytes
     * until next time.  (We must do this because we cannot be sure
     * that none of the decrypted bytes are padding bytes until we
     * have at least another whole block of data.  You cannot tell by
     * looking -- the data could be anything -- you can only tell by
     * context, knowing you are looking at the last block.)  We could
     * decrypt a whole block now but it is easier if we just treat it
     * the same way we treat partial block bytes.
     */
    if (final) {
       if (padsize) {
           blocks = input_len / padsize;
           ifraglen = blocks * padsize;
       } else ifraglen = input_len;
       PORT_Assert (ifraglen == input_len);

       if (ifraglen != input_len) {
           PORT_SetError(SEC_ERROR_BAD_DATA);
           return SECFailure;
       }
    } else {
       blocks = (input_len - 1) / bsize;
       ifraglen = blocks * bsize;
       PORT_Assert (ifraglen < input_len);

       pcount = input_len - ifraglen;
       PORT_Memcpy (pbuf, input + ifraglen, pcount);
       cc->pending_count = pcount;
    }

    if (ifraglen) {
       rv = (* cc->doit)(cc->cx, output, &ofraglen, max_output_len,
                         input, ifraglen);
       if (rv != SECSuccess)
           return rv;

       /*
        * For now anyway, all of our ciphers have the same number of
        * bytes of output as they do input.  If this ever becomes untrue,
        * then sec_PKCS7DecryptLength needs to be made smarter!
        */
       PORT_Assert (ifraglen == ofraglen);
       if (ifraglen != ofraglen) {
           PORT_SetError(SEC_ERROR_BAD_DATA);
           return SECFailure;
       }

       output_len += ofraglen;
    } else {
       ofraglen = 0;
    }

    /*
     * If we just did our very last block, "remove" the padding by
     * adjusting the output length.
     */
    if (final && (padsize != 0)) {
       unsigned int padlen = *(output + ofraglen - 1);

       if (padlen == 0 || padlen > padsize) {
           PORT_SetError(SEC_ERROR_BAD_DATA);
           return SECFailure;
       }
       output_len -= padlen;
    }

    PORT_Assert (output_len_p != NULL || output_len == 0);
    if (output_len_p != NULL)
       *output_len_p = output_len;

    return SECSuccess;
}

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unsigned int NSS_CMSCipherContext_DecryptLength ( NSSCMSCipherContext *  cc,
unsigned int  input_len,
PRBool  final 
)

Definition at line 306 of file cmscipher.c.

{
    int blocks, block_size;

    PORT_Assert (! cc->encrypt);

    block_size = cc->block_size;

    /*
     * If this is not a block cipher, then we always have the same
     * number of output bytes as we had input bytes.
     */
    if (block_size == 0)
       return input_len;

    /*
     * On the final call, we will always use up all of the pending
     * bytes plus all of the input bytes, *but*, there will be padding
     * at the end and we cannot predict how many bytes of padding we
     * will end up removing.  The amount given here is actually known
     * to be at least 1 byte too long (because we know we will have
     * at least 1 byte of padding), but seemed clearer/better to me.
     */
    if (final)
       return cc->pending_count + input_len;

    /*
     * Okay, this amount is exactly what we will output on the
     * next cipher operation.  We will always hang onto the last
     * 1 - block_size bytes for non-final operations.  That is,
     * we will do as many complete blocks as we can *except* the
     * last block (complete or partial).  (This is because until
     * we know we are at the end, we cannot know when to interpret
     * and removing the padding byte(s), which are guaranteed to
     * be there.)
     */
    blocks = (cc->pending_count + input_len - 1) / block_size;
    return blocks * block_size;
}

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void NSS_CMSCipherContext_Destroy ( NSSCMSCipherContext *  cc)

Definition at line 275 of file cmscipher.c.

{
    PORT_Assert(cc != NULL);
    if (cc == NULL)
       return;
    (*cc->destroy)(cc->cx, PR_TRUE);
    PORT_Free(cc);
}

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SECStatus NSS_CMSCipherContext_Encrypt ( NSSCMSCipherContext *  cc,
unsigned char *  output,
unsigned int output_len_p,
unsigned int  max_output_len,
const unsigned char *  input,
unsigned int  input_len,
PRBool  final 
)

Definition at line 649 of file cmscipher.c.

{
    int blocks, bsize, padlen, pcount, padsize;
    unsigned int max_needed, ifraglen, ofraglen, output_len;
    unsigned char *pbuf;
    SECStatus rv;

    PORT_Assert (cc->encrypt);

    /*
     * Check that we have enough room for the output.  Our caller should
     * already handle this; failure is really an internal error (i.e. bug).
     */
    max_needed = NSS_CMSCipherContext_EncryptLength (cc, input_len, final);
    PORT_Assert (max_output_len >= max_needed);
    if (max_output_len < max_needed) {
       /* PORT_SetError (XXX); */
       return SECFailure;
    }

    bsize = cc->block_size;
    padsize = cc->pad_size;

    /*
     * When no blocking and padding work to do, we can simply call the
     * cipher function and we are done.
     */
    if (bsize == 0) {
       return (*cc->doit)(cc->cx, output, output_len_p, max_output_len,
                           input, input_len);
    }

    pcount = cc->pending_count;
    pbuf = cc->pending_buf;

    output_len = 0;

    if (pcount) {
       /*
        * Try to fill in an entire block, starting with the bytes
        * we already have saved away.
        */
       while (input_len && pcount < bsize) {
           pbuf[pcount++] = *input++;
           input_len--;
       }
       /*
        * If we do not have a full block and we know we will be
        * called again, then we are done for now.
        */
       if (pcount < bsize && !final) {
           cc->pending_count = pcount;
           if (output_len_p != NULL)
              *output_len_p = 0;
           return SECSuccess;
       }
       /*
        * If we have a whole block available, encrypt it.
        */
       if ((padsize == 0) || (pcount % padsize) == 0) {
           rv = (* cc->doit) (cc->cx, output, &ofraglen, max_output_len,
                            pbuf, pcount);
           if (rv != SECSuccess)
              return rv;

           /*
            * For now anyway, all of our ciphers have the same number of
            * bytes of output as they do input.  If this ever becomes untrue,
            * then sec_PKCS7EncryptLength needs to be made smarter!
            */
           PORT_Assert (ofraglen == pcount);

           /*
            * Account for the bytes now in output.
            */
           max_output_len -= ofraglen;
           output_len += ofraglen;
           output += ofraglen;

           pcount = 0;
       }
    }

    if (input_len) {
       PORT_Assert (pcount == 0);

       blocks = input_len / bsize;
       ifraglen = blocks * bsize;

       if (ifraglen) {
           rv = (* cc->doit) (cc->cx, output, &ofraglen, max_output_len,
                            input, ifraglen);
           if (rv != SECSuccess)
              return rv;

           /*
            * For now anyway, all of our ciphers have the same number of
            * bytes of output as they do input.  If this ever becomes untrue,
            * then sec_PKCS7EncryptLength needs to be made smarter!
            */
           PORT_Assert (ifraglen == ofraglen);

           max_output_len -= ofraglen;
           output_len += ofraglen;
           output += ofraglen;
       }

       pcount = input_len - ifraglen;
       PORT_Assert (pcount < bsize);
       if (pcount)
           PORT_Memcpy (pbuf, input + ifraglen, pcount);
    }

    if (final) {
       padlen = padsize - (pcount % padsize);
       PORT_Memset (pbuf + pcount, padlen, padlen);
       rv = (* cc->doit) (cc->cx, output, &ofraglen, max_output_len,
                         pbuf, pcount+padlen);
       if (rv != SECSuccess)
           return rv;

       /*
        * For now anyway, all of our ciphers have the same number of
        * bytes of output as they do input.  If this ever becomes untrue,
        * then sec_PKCS7EncryptLength needs to be made smarter!
        */
       PORT_Assert (ofraglen == (pcount+padlen));
       output_len += ofraglen;
    } else {
       cc->pending_count = pcount;
    }

    PORT_Assert (output_len_p != NULL || output_len == 0);
    if (output_len_p != NULL)
       *output_len_p = output_len;

    return SECSuccess;
}

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unsigned int NSS_CMSCipherContext_EncryptLength ( NSSCMSCipherContext *  cc,
unsigned int  input_len,
PRBool  final 
)

Definition at line 364 of file cmscipher.c.

{
    int blocks, block_size;
    int pad_size;

    PORT_Assert (cc->encrypt);

    block_size = cc->block_size;
    pad_size = cc->pad_size;

    /*
     * If this is not a block cipher, then we always have the same
     * number of output bytes as we had input bytes.
     */
    if (block_size == 0)
       return input_len;

    /*
     * On the final call, we only send out what we need for
     * remaining bytes plus the padding.  (There is always padding,
     * so even if we have an exact number of blocks as input, we
     * will add another full block that is just padding.)
     */
    if (final) {
       if (pad_size == 0) {
           return cc->pending_count + input_len;
       } else {
           blocks = (cc->pending_count + input_len) / pad_size;
           blocks++;
           return blocks*pad_size;
       }
    }

    /*
     * Now, count the number of complete blocks of data we have.
     */
    blocks = (cc->pending_count + input_len) / block_size;


    return blocks * block_size;
}

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NSSCMSCipherContext* NSS_CMSCipherContext_StartDecrypt ( PK11SymKey *  key,
SECAlgorithmID *  algid 
)

Definition at line 82 of file cmscipher.c.

{
    NSSCMSCipherContext *cc;
    void *ciphercx;
    CK_MECHANISM_TYPE mechanism;
    SECItem *param;
    PK11SlotInfo *slot;
    SECOidTag algtag;

    algtag = SECOID_GetAlgorithmTag(algid);

    /* set param and mechanism */
    if (SEC_PKCS5IsAlgorithmPBEAlg(algid)) {
       CK_MECHANISM pbeMech, cryptoMech;
       SECItem *pbeParams, *pwitem;

       PORT_Memset(&pbeMech, 0, sizeof(CK_MECHANISM));
       PORT_Memset(&cryptoMech, 0, sizeof(CK_MECHANISM));

       pwitem = PK11_GetSymKeyUserData(key);
       if (!pwitem) 
           return NULL;

       /* find correct PK11 mechanism and parameters to initialize pbeMech */
       pbeMech.mechanism = PK11_AlgtagToMechanism(algtag);
       pbeParams = PK11_ParamFromAlgid(algid);
       if (!pbeParams)
           return NULL;
       pbeMech.pParameter = pbeParams->data;
       pbeMech.ulParameterLen = pbeParams->len;

       /* now map pbeMech to cryptoMech */
       if (PK11_MapPBEMechanismToCryptoMechanism(&pbeMech, &cryptoMech, pwitem,
                                            PR_FALSE) != CKR_OK) { 
           SECITEM_ZfreeItem(pbeParams, PR_TRUE);
           return NULL;
       }
       SECITEM_ZfreeItem(pbeParams, PR_TRUE);

       /* and use it to initialize param & mechanism */
       if ((param = (SECItem *)PORT_ZAlloc(sizeof(SECItem))) == NULL)
            return NULL;

       param->data = (unsigned char *)cryptoMech.pParameter;
       param->len = cryptoMech.ulParameterLen;
       mechanism = cryptoMech.mechanism;
    } else {
       mechanism = PK11_AlgtagToMechanism(algtag);
       if ((param = PK11_ParamFromAlgid(algid)) == NULL)
           return NULL;
    }

    cc = (NSSCMSCipherContext *)PORT_ZAlloc(sizeof(NSSCMSCipherContext));
    if (cc == NULL) {
       SECITEM_FreeItem(param,PR_TRUE);
       return NULL;
    }

    /* figure out pad and block sizes */
    cc->pad_size = PK11_GetBlockSize(mechanism, param);
    slot = PK11_GetSlotFromKey(key);
    cc->block_size = PK11_IsHW(slot) ? BLOCK_SIZE : cc->pad_size;
    PK11_FreeSlot(slot);

    /* create PK11 cipher context */
    ciphercx = PK11_CreateContextBySymKey(mechanism, CKA_DECRYPT, key, param);
    SECITEM_FreeItem(param, PR_TRUE);
    if (ciphercx == NULL) {
       PORT_Free (cc);
       return NULL;
    }

    cc->cx = ciphercx;
    cc->doit =  (nss_cms_cipher_function) PK11_CipherOp;
    cc->destroy = (nss_cms_cipher_destroy) PK11_DestroyContext;
    cc->encrypt = PR_FALSE;
    cc->pending_count = 0;

    return cc;
}

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NSSCMSCipherContext* NSS_CMSCipherContext_StartEncrypt ( PRArenaPool poolp,
PK11SymKey *  key,
SECAlgorithmID *  algid 
)

Definition at line 173 of file cmscipher.c.

{
    NSSCMSCipherContext *cc;
    void *ciphercx;
    SECItem *param;
    SECStatus rv;
    CK_MECHANISM_TYPE mechanism;
    PK11SlotInfo *slot;
    PRBool needToEncodeAlgid = PR_FALSE;
    SECOidTag algtag = SECOID_GetAlgorithmTag(algid);

    /* set param and mechanism */
    if (SEC_PKCS5IsAlgorithmPBEAlg(algid)) {
       CK_MECHANISM pbeMech, cryptoMech;
       SECItem *pbeParams, *pwitem;

       PORT_Memset(&pbeMech, 0, sizeof(CK_MECHANISM));
       PORT_Memset(&cryptoMech, 0, sizeof(CK_MECHANISM));

       pwitem = PK11_GetSymKeyUserData(key);
       if (!pwitem) 
           return NULL;

       /* find correct PK11 mechanism and parameters to initialize pbeMech */
       pbeMech.mechanism = PK11_AlgtagToMechanism(algtag);
       pbeParams = PK11_ParamFromAlgid(algid);
       if (!pbeParams)
           return NULL;
       pbeMech.pParameter = pbeParams->data;
       pbeMech.ulParameterLen = pbeParams->len;

       /* now map pbeMech to cryptoMech */
       if (PK11_MapPBEMechanismToCryptoMechanism(&pbeMech, &cryptoMech, pwitem,
                                            PR_FALSE) != CKR_OK) { 
           SECITEM_ZfreeItem(pbeParams, PR_TRUE);
           return NULL;
       }
       SECITEM_ZfreeItem(pbeParams, PR_TRUE);

       /* and use it to initialize param & mechanism */
       if ((param = (SECItem *)PORT_ZAlloc(sizeof(SECItem))) == NULL)
           return NULL;

       param->data = (unsigned char *)cryptoMech.pParameter;
       param->len = cryptoMech.ulParameterLen;
       mechanism = cryptoMech.mechanism;
    } else {
       mechanism = PK11_AlgtagToMechanism(algtag);
       if ((param = PK11_GenerateNewParam(mechanism, key)) == NULL)
           return NULL;
       needToEncodeAlgid = PR_TRUE;
    }

    cc = (NSSCMSCipherContext *)PORT_ZAlloc(sizeof(NSSCMSCipherContext));
    if (cc == NULL) {
       goto loser;
    }

    /* now find pad and block sizes for our mechanism */
    cc->pad_size = PK11_GetBlockSize(mechanism,param);
    slot = PK11_GetSlotFromKey(key);
    cc->block_size = PK11_IsHW(slot) ? BLOCK_SIZE : cc->pad_size;
    PK11_FreeSlot(slot);

    /* and here we go, creating a PK11 cipher context */
    ciphercx = PK11_CreateContextBySymKey(mechanism, CKA_ENCRYPT, key, param);
    if (ciphercx == NULL) {
       PORT_Free(cc);
       cc = NULL;
       goto loser;
    }

    /*
     * These are placed after the CreateContextBySymKey() because some
     * mechanisms have to generate their IVs from their card (i.e. FORTEZZA).
     * Don't move it from here.
     * XXX is that right? the purpose of this is to get the correct algid
     *     containing the IVs etc. for encoding. this means we need to set this up
     *     BEFORE encoding the algid in the contentInfo, right?
     */
    if (needToEncodeAlgid) {
       rv = PK11_ParamToAlgid(algtag, param, poolp, algid);
       if(rv != SECSuccess) {
           PORT_Free(cc);
           cc = NULL;
           goto loser;
       }
    }

    cc->cx = ciphercx;
    cc->doit = (nss_cms_cipher_function)PK11_CipherOp;
    cc->destroy = (nss_cms_cipher_destroy)PK11_DestroyContext;
    cc->encrypt = PR_TRUE;
    cc->pending_count = 0;

loser:
    SECITEM_FreeItem(param, PR_TRUE);

    return cc;
}

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