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gecko-dev/security/nss/lib/smime/cmsdecode.c

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21 KiB
C
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/*
* The contents of this file are subject to the Mozilla Public
* License Version 1.1 (the "License"); you may not use this file
* except in compliance with the License. You may obtain a copy of
* the License at http://www.mozilla.org/MPL/
*
* Software distributed under the License is distributed on an "AS
* IS" basis, WITHOUT WARRANTY OF ANY KIND, either express or
* implied. See the License for the specific language governing
* rights and limitations under the License.
*
* The Original Code is the Netscape security libraries.
*
* The Initial Developer of the Original Code is Netscape
* Communications Corporation. Portions created by Netscape are
* Copyright (C) 1994-2000 Netscape Communications Corporation. All
* Rights Reserved.
*
* Contributor(s):
*
* Alternatively, the contents of this file may be used under the
* terms of the GNU General Public License Version 2 or later (the
* "GPL"), in which case the provisions of the GPL are applicable
* instead of those above. If you wish to allow use of your
* version of this file only under the terms of the GPL and not to
* allow others to use your version of this file under the MPL,
* indicate your decision by deleting the provisions above and
* replace them with the notice and other provisions required by
* the GPL. If you do not delete the provisions above, a recipient
* may use your version of this file under either the MPL or the
* GPL.
*/
/*
* CMS decoding.
*
* $Id: cmsdecode.c,v 1.4 2002/02/01 17:57:05 relyea%netscape.com Exp $
*/
#include "cmslocal.h"
#include "cert.h"
#include "key.h"
#include "secasn1.h"
#include "secitem.h"
#include "secoid.h"
#include "prtime.h"
#include "secerr.h"
struct NSSCMSDecoderContextStr {
SEC_ASN1DecoderContext * dcx; /* ASN.1 decoder context */
NSSCMSMessage * cmsg; /* backpointer to the root message */
SECOidTag type; /* type of message */
NSSCMSContent content; /* pointer to message */
NSSCMSDecoderContext * childp7dcx; /* inner CMS decoder context */
PRBool saw_contents;
int error;
NSSCMSContentCallback cb;
void * cb_arg;
};
static void nss_cms_decoder_update_filter (void *arg, const char *data, unsigned long len,
int depth, SEC_ASN1EncodingPart data_kind);
static SECStatus nss_cms_before_data(NSSCMSDecoderContext *p7dcx);
static SECStatus nss_cms_after_data(NSSCMSDecoderContext *p7dcx);
static SECStatus nss_cms_after_end(NSSCMSDecoderContext *p7dcx);
static void nss_cms_decoder_work_data(NSSCMSDecoderContext *p7dcx,
const unsigned char *data, unsigned long len, PRBool final);
extern const SEC_ASN1Template NSSCMSMessageTemplate[];
/*
* nss_cms_decoder_notify -
* this is the driver of the decoding process. It gets called by the ASN.1
* decoder before and after an object is decoded.
* at various points in the decoding process, we intercept to set up and do
* further processing.
*/
static void
nss_cms_decoder_notify(void *arg, PRBool before, void *dest, int depth)
{
NSSCMSDecoderContext *p7dcx;
NSSCMSContentInfo *rootcinfo, *cinfo;
PRBool after = !before;
p7dcx = (NSSCMSDecoderContext *)arg;
rootcinfo = &(p7dcx->cmsg->contentInfo);
/* XXX error handling: need to set p7dcx->error */
#ifdef CMSDEBUG
fprintf(stderr, "%6.6s, dest = 0x%08x, depth = %d\n", before ? "before" : "after", dest, depth);
#endif
/* so what are we working on right now? */
switch (p7dcx->type) {
case SEC_OID_UNKNOWN:
/*
* right now, we are still decoding the OUTER (root) cinfo
* As soon as we know the inner content type, set up the info,
* but NO inner decoder or filter. The root decoder handles the first
* level children by itself - only for encapsulated contents (which
* are encoded as DER inside of an OCTET STRING) we need to set up a
* child decoder...
*/
if (after && dest == &(rootcinfo->contentType)) {
p7dcx->type = NSS_CMSContentInfo_GetContentTypeTag(rootcinfo);
p7dcx->content = rootcinfo->content; /* is this ready already ? need to alloc? */
/* XXX yes we need to alloc -- continue here */
}
break;
case SEC_OID_PKCS7_DATA:
/* this can only happen if the outermost cinfo has DATA in it */
/* otherwise, we handle this type implicitely in the inner decoders */
if (before && dest == &(rootcinfo->content)) {
/* fake it to cause the filter to put the data in the right place... */
/* we want the ASN.1 decoder to deliver the decoded bytes to us from now on */
SEC_ASN1DecoderSetFilterProc(p7dcx->dcx,
nss_cms_decoder_update_filter,
p7dcx,
(PRBool)(p7dcx->cb != NULL));
break;
}
if (after && dest == &(rootcinfo->content.data)) {
/* remove the filter */
SEC_ASN1DecoderClearFilterProc(p7dcx->dcx);
}
break;
case SEC_OID_PKCS7_SIGNED_DATA:
case SEC_OID_PKCS7_ENVELOPED_DATA:
case SEC_OID_PKCS7_DIGESTED_DATA:
case SEC_OID_PKCS7_ENCRYPTED_DATA:
if (before && dest == &(rootcinfo->content))
break; /* we're not there yet */
if (p7dcx->content.pointer == NULL)
p7dcx->content = rootcinfo->content;
/* get this data type's inner contentInfo */
cinfo = NSS_CMSContent_GetContentInfo(p7dcx->content.pointer, p7dcx->type);
if (before && dest == &(cinfo->contentType)) {
/* at this point, set up the &%$&$ back pointer */
/* we cannot do it later, because the content itself is optional! */
/* please give me C++ */
switch (p7dcx->type) {
case SEC_OID_PKCS7_SIGNED_DATA:
p7dcx->content.signedData->cmsg = p7dcx->cmsg;
break;
case SEC_OID_PKCS7_DIGESTED_DATA:
p7dcx->content.digestedData->cmsg = p7dcx->cmsg;
break;
case SEC_OID_PKCS7_ENVELOPED_DATA:
p7dcx->content.envelopedData->cmsg = p7dcx->cmsg;
break;
case SEC_OID_PKCS7_ENCRYPTED_DATA:
p7dcx->content.encryptedData->cmsg = p7dcx->cmsg;
break;
default:
PORT_Assert(0);
break;
}
}
if (before && dest == &(cinfo->rawContent)) {
/* we want the ASN.1 decoder to deliver the decoded bytes to us from now on */
SEC_ASN1DecoderSetFilterProc(p7dcx->dcx, nss_cms_decoder_update_filter,
p7dcx, (PRBool)(p7dcx->cb != NULL));
/* we're right in front of the data */
if (nss_cms_before_data(p7dcx) != SECSuccess) {
SEC_ASN1DecoderClearFilterProc(p7dcx->dcx); /* stop all processing */
p7dcx->error = PORT_GetError();
}
}
if (after && dest == &(cinfo->rawContent)) {
/* we're right after of the data */
if (nss_cms_after_data(p7dcx) != SECSuccess)
p7dcx->error = PORT_GetError();
/* we don't need to see the contents anymore */
SEC_ASN1DecoderClearFilterProc(p7dcx->dcx);
}
break;
#if 0 /* NIH */
case SEC_OID_PKCS7_AUTHENTICATED_DATA:
#endif
default:
/* unsupported or unknown message type - fail (more or less) gracefully */
p7dcx->error = SEC_ERROR_UNSUPPORTED_MESSAGE_TYPE;
break;
}
}
/*
* nss_cms_before_data - set up the current encoder to receive data
*/
static SECStatus
nss_cms_before_data(NSSCMSDecoderContext *p7dcx)
{
SECStatus rv;
SECOidTag childtype;
PLArenaPool *poolp;
NSSCMSDecoderContext *childp7dcx;
NSSCMSContentInfo *cinfo;
const SEC_ASN1Template *template;
void *mark = NULL;
size_t size;
poolp = p7dcx->cmsg->poolp;
/* call _Decode_BeforeData handlers */
switch (p7dcx->type) {
case SEC_OID_PKCS7_SIGNED_DATA:
/* we're decoding a signedData, so set up the digests */
rv = NSS_CMSSignedData_Decode_BeforeData(p7dcx->content.signedData);
if (rv != SECSuccess)
return SECFailure;
break;
case SEC_OID_PKCS7_DIGESTED_DATA:
/* we're encoding a digestedData, so set up the digest */
rv = NSS_CMSDigestedData_Decode_BeforeData(p7dcx->content.digestedData);
if (rv != SECSuccess)
return SECFailure;
break;
case SEC_OID_PKCS7_ENVELOPED_DATA:
rv = NSS_CMSEnvelopedData_Decode_BeforeData(p7dcx->content.envelopedData);
if (rv != SECSuccess)
return SECFailure;
break;
case SEC_OID_PKCS7_ENCRYPTED_DATA:
rv = NSS_CMSEncryptedData_Decode_BeforeData(p7dcx->content.encryptedData);
if (rv != SECSuccess)
return SECFailure;
break;
default:
return SECFailure;
}
/* ok, now we have a pointer to cinfo */
/* find out what kind of data is encapsulated */
cinfo = NSS_CMSContent_GetContentInfo(p7dcx->content.pointer, p7dcx->type);
childtype = NSS_CMSContentInfo_GetContentTypeTag(cinfo);
if (childtype == SEC_OID_PKCS7_DATA) {
cinfo->content.data = SECITEM_AllocItem(poolp, NULL, 0);
if (cinfo->content.data == NULL)
/* set memory error */
return SECFailure;
p7dcx->childp7dcx = NULL;
return SECSuccess;
}
/* set up inner decoder */
if ((template = NSS_CMSUtil_GetTemplateByTypeTag(childtype)) == NULL)
return SECFailure;
childp7dcx = (NSSCMSDecoderContext *)PORT_ZAlloc(sizeof(NSSCMSDecoderContext));
if (childp7dcx == NULL)
return SECFailure;
mark = PORT_ArenaMark(poolp);
/* allocate space for the stuff we're creating */
size = NSS_CMSUtil_GetSizeByTypeTag(childtype);
childp7dcx->content.pointer = (void *)PORT_ArenaZAlloc(poolp, size);
if (childp7dcx->content.pointer == NULL)
goto loser;
/* start the child decoder */
childp7dcx->dcx = SEC_ASN1DecoderStart(poolp, childp7dcx->content.pointer, template);
if (childp7dcx->dcx == NULL)
goto loser;
/* the new decoder needs to notify, too */
SEC_ASN1DecoderSetNotifyProc(childp7dcx->dcx, nss_cms_decoder_notify, childp7dcx);
/* tell the parent decoder that it needs to feed us the content data */
p7dcx->childp7dcx = childp7dcx;
childp7dcx->type = childtype; /* our type */
childp7dcx->cmsg = p7dcx->cmsg; /* backpointer to root message */
/* should the child decoder encounter real data, it needs to give it to the caller */
childp7dcx->cb = p7dcx->cb;
childp7dcx->cb_arg = p7dcx->cb_arg;
/* now set up the parent to hand decoded data to the next level decoder */
p7dcx->cb = (NSSCMSContentCallback)NSS_CMSDecoder_Update;
p7dcx->cb_arg = childp7dcx;
PORT_ArenaUnmark(poolp, mark);
return SECSuccess;
loser:
if (mark)
PORT_ArenaRelease(poolp, mark);
if (childp7dcx)
PORT_Free(childp7dcx);
p7dcx->childp7dcx = NULL;
return SECFailure;
}
static SECStatus
nss_cms_after_data(NSSCMSDecoderContext *p7dcx)
{
PLArenaPool *poolp;
NSSCMSDecoderContext *childp7dcx;
SECStatus rv = SECFailure;
poolp = p7dcx->cmsg->poolp;
/* Handle last block. This is necessary to flush out the last bytes
* of a possibly incomplete block */
nss_cms_decoder_work_data(p7dcx, NULL, 0, PR_TRUE);
/* finish any "inner" decoders - there's no more data coming... */
if (p7dcx->childp7dcx != NULL) {
childp7dcx = p7dcx->childp7dcx;
if (childp7dcx->dcx != NULL) {
if (SEC_ASN1DecoderFinish(childp7dcx->dcx) != SECSuccess) {
/* do what? free content? */
rv = SECFailure;
} else {
rv = nss_cms_after_end(childp7dcx);
}
if (rv != SECSuccess)
goto done;
}
PORT_Free(p7dcx->childp7dcx);
p7dcx->childp7dcx = NULL;
}
switch (p7dcx->type) {
case SEC_OID_PKCS7_SIGNED_DATA:
/* this will finish the digests and verify */
rv = NSS_CMSSignedData_Decode_AfterData(p7dcx->content.signedData);
break;
case SEC_OID_PKCS7_ENVELOPED_DATA:
rv = NSS_CMSEnvelopedData_Decode_AfterData(p7dcx->content.envelopedData);
break;
case SEC_OID_PKCS7_DIGESTED_DATA:
rv = NSS_CMSDigestedData_Decode_AfterData(p7dcx->content.digestedData);
break;
case SEC_OID_PKCS7_ENCRYPTED_DATA:
rv = NSS_CMSEncryptedData_Decode_AfterData(p7dcx->content.encryptedData);
break;
case SEC_OID_PKCS7_DATA:
/* do nothing */
break;
default:
rv = SECFailure;
break;
}
done:
return rv;
}
static SECStatus
nss_cms_after_end(NSSCMSDecoderContext *p7dcx)
{
SECStatus rv;
PLArenaPool *poolp;
poolp = p7dcx->cmsg->poolp;
switch (p7dcx->type) {
case SEC_OID_PKCS7_SIGNED_DATA:
rv = NSS_CMSSignedData_Decode_AfterEnd(p7dcx->content.signedData);
break;
case SEC_OID_PKCS7_ENVELOPED_DATA:
rv = NSS_CMSEnvelopedData_Decode_AfterEnd(p7dcx->content.envelopedData);
break;
case SEC_OID_PKCS7_DIGESTED_DATA:
rv = NSS_CMSDigestedData_Decode_AfterEnd(p7dcx->content.digestedData);
break;
case SEC_OID_PKCS7_ENCRYPTED_DATA:
rv = NSS_CMSEncryptedData_Decode_AfterEnd(p7dcx->content.encryptedData);
break;
case SEC_OID_PKCS7_DATA:
rv = SECSuccess;
break;
default:
rv = SECFailure; /* we should not have got that far... */
break;
}
return rv;
}
/*
* nss_cms_decoder_work_data - handle decoded data bytes.
*
* This function either decrypts the data if needed, and/or calculates digests
* on it, then either stores it or passes it on to the next level decoder.
*/
static void
nss_cms_decoder_work_data(NSSCMSDecoderContext *p7dcx,
const unsigned char *data, unsigned long len,
PRBool final)
{
NSSCMSContentInfo *cinfo;
unsigned char *buf = NULL;
unsigned char *dest;
unsigned int offset;
SECStatus rv;
SECItem *storage;
/*
* We should really have data to process, or we should be trying
* to finish/flush the last block. (This is an overly paranoid
* check since all callers are in this file and simple inspection
* proves they do it right. But it could find a bug in future
* modifications/development, that is why it is here.)
*/
PORT_Assert ((data != NULL && len) || final);
cinfo = NSS_CMSContent_GetContentInfo(p7dcx->content.pointer, p7dcx->type);
if (cinfo->ciphcx != NULL) {
/*
* we are decrypting.
*
* XXX If we get an error, we do not want to do the digest or callback,
* but we want to keep decoding. Or maybe we want to stop decoding
* altogether if there is a callback, because obviously we are not
* sending the data back and they want to know that.
*/
unsigned int outlen = 0; /* length of decrypted data */
unsigned int buflen; /* length available for decrypted data */
/* find out about the length of decrypted data */
buflen = NSS_CMSCipherContext_DecryptLength(cinfo->ciphcx, len, final);
/*
* it might happen that we did not provide enough data for a full
* block (decryption unit), and that there is no output available
*/
/* no output available, AND no input? */
if (buflen == 0 && len == 0)
goto loser; /* bail out */
/*
* have inner decoder: pass the data on (means inner content type is NOT data)
* no inner decoder: we have DATA in here: either call callback or store
*/
if (buflen != 0) {
/* there will be some output - need to make room for it */
/* allocate buffer from the heap */
buf = (unsigned char *)PORT_Alloc(buflen);
if (buf == NULL) {
p7dcx->error = SEC_ERROR_NO_MEMORY;
goto loser;
}
}
/*
* decrypt incoming data
* buf can still be NULL here (and buflen == 0) here if we don't expect
* any output (see above), but we still need to call NSS_CMSCipherContext_Decrypt to
* keep track of incoming data
*/
rv = NSS_CMSCipherContext_Decrypt(cinfo->ciphcx, buf, &outlen, buflen,
data, len, final);
if (rv != SECSuccess) {
p7dcx->error = PORT_GetError();
goto loser;
}
PORT_Assert (final || outlen == buflen);
/* swap decrypted data in */
data = buf;
len = outlen;
}
if (len == 0)
goto done; /* nothing more to do */
/*
* Update the running digests with plaintext bytes (if we need to).
*/
if (cinfo->digcx)
NSS_CMSDigestContext_Update(cinfo->digcx, data, len);
/* at this point, we have the plain decoded & decrypted data */
/* which is either more encoded DER which we need to hand to the child decoder */
/* or data we need to hand back to our caller */
/* pass the content back to our caller or */
/* feed our freshly decrypted and decoded data into child decoder */
if (p7dcx->cb != NULL) {
(*p7dcx->cb)(p7dcx->cb_arg, (const char *)data, len);
}
#if 1
else
#endif
if (NSS_CMSContentInfo_GetContentTypeTag(cinfo) == SEC_OID_PKCS7_DATA) {
/* store it in "inner" data item as well */
/* find the DATA item in the encapsulated cinfo and store it there */
storage = cinfo->content.data;
offset = storage->len;
if (storage->len == 0) {
dest = (unsigned char *)PORT_ArenaAlloc(p7dcx->cmsg->poolp, len);
} else {
dest = (unsigned char *)PORT_ArenaGrow(p7dcx->cmsg->poolp,
storage->data,
storage->len,
storage->len + len);
}
if (dest == NULL) {
p7dcx->error = SEC_ERROR_NO_MEMORY;
goto loser;
}
storage->data = dest;
storage->len += len;
/* copy it in */
PORT_Memcpy(storage->data + offset, data, len);
}
done:
loser:
if (buf)
PORT_Free (buf);
}
/*
* nss_cms_decoder_update_filter - process ASN.1 data
*
* once we have set up a filter in nss_cms_decoder_notify(),
* all data processed by the ASN.1 decoder is also passed through here.
* we pass the content bytes (as opposed to length and tag bytes) on to
* nss_cms_decoder_work_data().
*/
static void
nss_cms_decoder_update_filter (void *arg, const char *data, unsigned long len,
int depth, SEC_ASN1EncodingPart data_kind)
{
NSSCMSDecoderContext *p7dcx;
PORT_Assert (len); /* paranoia */
if (len == 0)
return;
p7dcx = (NSSCMSDecoderContext*)arg;
p7dcx->saw_contents = PR_TRUE;
/* pass on the content bytes only */
if (data_kind == SEC_ASN1_Contents)
nss_cms_decoder_work_data(p7dcx, (const unsigned char *) data, len, PR_FALSE);
}
/*
* NSS_CMSDecoder_Start - set up decoding of a DER-encoded CMS message
*
* "poolp" - pointer to arena for message, or NULL if new pool should be created
* "cb", "cb_arg" - callback function and argument for delivery of inner content
* "pwfn", pwfn_arg" - callback function for getting token password
* "decrypt_key_cb", "decrypt_key_cb_arg" - callback function for getting bulk key for encryptedData
*/
NSSCMSDecoderContext *
NSS_CMSDecoder_Start(PRArenaPool *poolp,
NSSCMSContentCallback cb, void *cb_arg,
PK11PasswordFunc pwfn, void *pwfn_arg,
NSSCMSGetDecryptKeyCallback decrypt_key_cb, void *decrypt_key_cb_arg)
{
NSSCMSDecoderContext *p7dcx;
NSSCMSMessage *cmsg;
cmsg = NSS_CMSMessage_Create(poolp);
if (cmsg == NULL)
return NULL;
NSS_CMSMessage_SetEncodingParams(cmsg, pwfn, pwfn_arg, decrypt_key_cb, decrypt_key_cb_arg,
NULL, NULL);
p7dcx = (NSSCMSDecoderContext*)PORT_ZAlloc(sizeof(NSSCMSDecoderContext));
if (p7dcx == NULL) {
NSS_CMSMessage_Destroy(cmsg);
return NULL;
}
p7dcx->dcx = SEC_ASN1DecoderStart(cmsg->poolp, cmsg, NSSCMSMessageTemplate);
if (p7dcx->dcx == NULL) {
PORT_Free (p7dcx);
NSS_CMSMessage_Destroy(cmsg);
return NULL;
}
SEC_ASN1DecoderSetNotifyProc (p7dcx->dcx, nss_cms_decoder_notify, p7dcx);
p7dcx->cmsg = cmsg;
p7dcx->type = SEC_OID_UNKNOWN;
p7dcx->cb = cb;
p7dcx->cb_arg = cb_arg;
return p7dcx;
}
/*
* NSS_CMSDecoder_Update - feed DER-encoded data to decoder
*/
SECStatus
NSS_CMSDecoder_Update(NSSCMSDecoderContext *p7dcx, const char *buf, unsigned long len)
{
if (p7dcx->dcx != NULL && p7dcx->error == 0) { /* if error is set already, don't bother */
if (SEC_ASN1DecoderUpdate (p7dcx->dcx, buf, len) != SECSuccess) {
p7dcx->error = PORT_GetError();
PORT_Assert (p7dcx->error);
if (p7dcx->error == 0)
p7dcx->error = -1;
}
}
if (p7dcx->error == 0)
return SECSuccess;
/* there has been a problem, let's finish the decoder */
if (p7dcx->dcx != NULL) {
(void) SEC_ASN1DecoderFinish (p7dcx->dcx);
p7dcx->dcx = NULL;
}
PORT_SetError (p7dcx->error);
return SECFailure;
}
/*
* NSS_CMSDecoder_Cancel - stop decoding in case of error
*/
void
NSS_CMSDecoder_Cancel(NSSCMSDecoderContext *p7dcx)
{
/* XXXX what about inner decoders? running digests? decryption? */
/* XXXX there's a leak here! */
NSS_CMSMessage_Destroy(p7dcx->cmsg);
(void)SEC_ASN1DecoderFinish(p7dcx->dcx);
PORT_Free(p7dcx);
}
/*
* NSS_CMSDecoder_Finish - mark the end of inner content and finish decoding
*/
NSSCMSMessage *
NSS_CMSDecoder_Finish(NSSCMSDecoderContext *p7dcx)
{
NSSCMSMessage *cmsg;
cmsg = p7dcx->cmsg;
if (p7dcx->dcx == NULL || SEC_ASN1DecoderFinish(p7dcx->dcx) != SECSuccess ||
nss_cms_after_end(p7dcx) != SECSuccess)
{
NSS_CMSMessage_Destroy(cmsg); /* needs to get rid of pool if it's ours */
cmsg = NULL;
}
PORT_Free(p7dcx);
return cmsg;
}
NSSCMSMessage *
NSS_CMSMessage_CreateFromDER(SECItem *DERmessage,
NSSCMSContentCallback cb, void *cb_arg,
PK11PasswordFunc pwfn, void *pwfn_arg,
NSSCMSGetDecryptKeyCallback decrypt_key_cb, void *decrypt_key_cb_arg)
{
NSSCMSDecoderContext *p7dcx;
/* first arg(poolp) == NULL => create our own pool */
p7dcx = NSS_CMSDecoder_Start(NULL, cb, cb_arg, pwfn, pwfn_arg, decrypt_key_cb, decrypt_key_cb_arg);
(void) NSS_CMSDecoder_Update(p7dcx, (char *)DERmessage->data, DERmessage->len);
return NSS_CMSDecoder_Finish(p7dcx);
}
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