The Tor Browser: security/nss/lib/util/derenc.c@b8a032363ba2 (annotated)

security/nss/lib/util/derenc.c@b8a032363ba2 (annotated)

security/nss/lib/util/derenc.c

Thu, 22 Jan 2015 13:21:57 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Thu, 22 Jan 2015 13:21:57 +0100
branch: TOR_BUG_9701
changeset 15: b8a032363ba2
permissions: -rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 #include "secder.h"
 #include "secerr.h"
 #if 0
 /*
  * Generic templates for individual/simple items.
  */
 DERTemplate SECAnyTemplate[] = {
     { DER_ANY,
 , NULL, sizeof(SECItem) }
 };
 DERTemplate SECBitStringTemplate[] = {
     { DER_BIT_STRING,
 , NULL, sizeof(SECItem) }
 };
 DERTemplate SECBooleanTemplate[] = {
     { DER_BOOLEAN,
 , NULL, sizeof(SECItem) }
 };
 DERTemplate SECIA5StringTemplate[] = {
     { DER_IA5_STRING,
 , NULL, sizeof(SECItem) }
 };
 DERTemplate SECIntegerTemplate[] = {
     { DER_INTEGER,
 , NULL, sizeof(SECItem) }
 };
 DERTemplate SECNullTemplate[] = {
     { DER_NULL,
 , NULL, sizeof(SECItem) }
 };
 DERTemplate SECObjectIDTemplate[] = {
     { DER_OBJECT_ID,
 , NULL, sizeof(SECItem) }
 };
 DERTemplate SECOctetStringTemplate[] = {
     { DER_OCTET_STRING,
 , NULL, sizeof(SECItem) }
 };
 DERTemplate SECPrintableStringTemplate[] = {
     { DER_PRINTABLE_STRING,
 , NULL, sizeof(SECItem) }
 };
 DERTemplate SECT61StringTemplate[] = {
     { DER_T61_STRING,
 , NULL, sizeof(SECItem) }
 };
 DERTemplate SECUTCTimeTemplate[] = {
     { DER_UTC_TIME,
 , NULL, sizeof(SECItem) }
 };
 #endif
 static int
 header_length(DERTemplate *dtemplate, PRUint32 contents_len)
 {
     PRUint32 len;
     unsigned long encode_kind, under_kind;
     PRBool explicit, optional, universal;
     encode_kind = dtemplate->kind;
     explicit = (encode_kind & DER_EXPLICIT) ? PR_TRUE : PR_FALSE;
     optional = (encode_kind & DER_OPTIONAL) ? PR_TRUE : PR_FALSE;
     universal = ((encode_kind & DER_CLASS_MASK) == DER_UNIVERSAL)
 		? PR_TRUE : PR_FALSE;
     PORT_Assert (!(explicit && universal));	/* bad templates */
     if (encode_kind & DER_POINTER) {
 	if (dtemplate->sub != NULL) {
 	    under_kind = dtemplate->sub->kind;
 	    if (universal) {
 		encode_kind = under_kind;
 	    }
 	} else if (universal) {
 	    under_kind = encode_kind & ~DER_POINTER;
 	} else {
 	    under_kind = dtemplate->arg;
 	}
     } else if (encode_kind & DER_INLINE) {
 	PORT_Assert (dtemplate->sub != NULL);
 	under_kind = dtemplate->sub->kind;
 	if (universal) {
 	    encode_kind = under_kind;
 	}
     } else if (universal) {
 	under_kind = encode_kind;
     } else {
 	under_kind = dtemplate->arg;
     }
     /* This is only used in decoding; it plays no part in encoding.  */
     if (under_kind & DER_DERPTR)
 	return 0;
     /* No header at all for an "empty" optional.  */
     if ((contents_len == 0) && optional)
 	return 0;
     /* And no header for a full DER_ANY.  */
     if (encode_kind & DER_ANY)
 	return 0;
     /*
      * The common case: one octet for identifier and as many octets
      * as necessary to hold the content length.
      */
     len = 1 + DER_LengthLength(contents_len);
     /* Account for the explicit wrapper, if necessary.  */
     if (explicit) {
 #if 0		/*
 		 * Well, I was trying to do something useful, but these
 		 * assertions are too restrictive on valid templates.
 		 * I wanted to make sure that the top-level "kind" of
 		 * a template does not also specify DER_EXPLICIT, which
 		 * should only modify a component field.  Maybe later
 		 * I can figure out a better way to detect such a problem,
 		 * but for now I must remove these checks altogether.
 		 */
 	/*
 	 * This modifier applies only to components of a set or sequence;
 	 * it should never be used on a set/sequence itself -- confirm.
 	 */
 	PORT_Assert (under_kind != DER_SEQUENCE);
 	PORT_Assert (under_kind != DER_SET);
 #endif
 	len += 1 + DER_LengthLength(len + contents_len);
     }
     return len;
 }
 static PRUint32
 contents_length(DERTemplate *dtemplate, void *src)
 {
     PRUint32 len;
     unsigned long encode_kind, under_kind;
     PRBool universal;
     PORT_Assert (src != NULL);
     encode_kind = dtemplate->kind;
     universal = ((encode_kind & DER_CLASS_MASK) == DER_UNIVERSAL)
 		? PR_TRUE : PR_FALSE;
     encode_kind &= ~DER_OPTIONAL;
     if (encode_kind & DER_POINTER) {
 	src = *(void **)src;
 	if (src == NULL) {
 	    return 0;
 	}
 	if (dtemplate->sub != NULL) {
 	    dtemplate = dtemplate->sub;
 	    under_kind = dtemplate->kind;
 	    src = (void *)((char *)src + dtemplate->offset);
 	} else if (universal) {
 	    under_kind = encode_kind & ~DER_POINTER;
 	} else {
 	    under_kind = dtemplate->arg;
 	}
     } else if (encode_kind & DER_INLINE) {
 	PORT_Assert (dtemplate->sub != NULL);
 	dtemplate = dtemplate->sub;
 	under_kind = dtemplate->kind;
 	src = (void *)((char *)src + dtemplate->offset);
     } else if (universal) {
 	under_kind = encode_kind;
     } else {
 	under_kind = dtemplate->arg;
     }
     /* Having any of these bits is not expected here...  */
     PORT_Assert ((under_kind & (DER_EXPLICIT | DER_INLINE | DER_OPTIONAL
 				| DER_POINTER | DER_SKIP)) == 0);
     /* This is only used in decoding; it plays no part in encoding.  */
     if (under_kind & DER_DERPTR)
 	return 0;
     if (under_kind & DER_INDEFINITE) {
 	PRUint32 sub_len;
 	void   **indp = *(void ***)src;
 	if (indp == NULL)
 	    return 0;
 	len = 0;
 	under_kind &= ~DER_INDEFINITE;
 	if (under_kind == DER_SET || under_kind == DER_SEQUENCE) {
 	    DERTemplate *tmpt = dtemplate->sub;
 	    PORT_Assert (tmpt != NULL);
 	    for (; *indp != NULL; indp++) {
 		void *sub_src = (void *)((char *)(*indp) + tmpt->offset);
 		sub_len = contents_length (tmpt, sub_src);
 		len += sub_len + header_length (tmpt, sub_len);
 	    }
 	} else {
 	    /*
 	     * XXX Lisa is not sure this code (for handling, for example,
 	     * DER_INDEFINITE | DER_OCTET_STRING) is right.
 	     */
 	    for (; *indp != NULL; indp++) {
 		SECItem *item = (SECItem *)(*indp);
 		sub_len = item->len;
 		if (under_kind == DER_BIT_STRING) {
 		    sub_len = (sub_len + 7) >> 3;
 		    /* bit string contents involve an extra octet */
 		    if (sub_len)
 			sub_len++;
 		}
 		if (under_kind != DER_ANY)
 		    len += 1 + DER_LengthLength (sub_len);
 	    }
 	}
 	return len;
     }
     switch (under_kind) {
       case DER_SEQUENCE:
       case DER_SET:
 	{
 	    DERTemplate *tmpt;
 	    void *sub_src;
 	    PRUint32 sub_len;
 	    len = 0;
 	    for (tmpt = dtemplate + 1; tmpt->kind; tmpt++) {
 		sub_src = (void *)((char *)src + tmpt->offset);
 		sub_len = contents_length (tmpt, sub_src);
 		len += sub_len + header_length (tmpt, sub_len);
 	    }
 	}
 	break;
       case DER_BIT_STRING:
 	len = (((SECItem *)src)->len + 7) >> 3;
 	/* bit string contents involve an extra octet */
 	if (len)
 	    len++;
 	break;
       default:
 	len = ((SECItem *)src)->len;
 	break;
     }
     return len;
 }
 static unsigned char *
 der_encode(unsigned char *buf, DERTemplate *dtemplate, void *src)
 {
     int header_len;
     PRUint32 contents_len;
     unsigned long encode_kind, under_kind;
     PRBool explicit, optional, universal;
     /*
      * First figure out how long the encoding will be.  Do this by
      * traversing the template from top to bottom and accumulating
      * the length of each leaf item.
      */
     contents_len = contents_length (dtemplate, src);
     header_len = header_length (dtemplate, contents_len);
     /*
      * Enough smarts was involved already, so that if both the
      * header and the contents have a length of zero, then we
      * are not doing any encoding for this element.
      */
     if (header_len == 0 && contents_len == 0)
 	return buf;
     encode_kind = dtemplate->kind;
     explicit = (encode_kind & DER_EXPLICIT) ? PR_TRUE : PR_FALSE;
     optional = (encode_kind & DER_OPTIONAL) ? PR_TRUE : PR_FALSE;
     encode_kind &= ~DER_OPTIONAL;
     universal = ((encode_kind & DER_CLASS_MASK) == DER_UNIVERSAL)
 		? PR_TRUE : PR_FALSE;
     if (encode_kind & DER_POINTER) {
 	if (contents_len) {
 	    src = *(void **)src;
 	    PORT_Assert (src != NULL);
 	}
 	if (dtemplate->sub != NULL) {
 	    dtemplate = dtemplate->sub;
 	    under_kind = dtemplate->kind;
 	    if (universal) {
 		encode_kind = under_kind;
 	    }
 	    src = (void *)((char *)src + dtemplate->offset);
 	} else if (universal) {
 	    under_kind = encode_kind & ~DER_POINTER;
 	} else {
 	    under_kind = dtemplate->arg;
 	}
     } else if (encode_kind & DER_INLINE) {
 	dtemplate = dtemplate->sub;
 	under_kind = dtemplate->kind;
 	if (universal) {
 	    encode_kind = under_kind;
 	}
 	src = (void *)((char *)src + dtemplate->offset);
     } else if (universal) {
 	under_kind = encode_kind;
     } else {
 	under_kind = dtemplate->arg;
     }
     if (explicit) {
 	buf = DER_StoreHeader (buf, encode_kind,
 			       (1 + DER_LengthLength(contents_len)
 				+ contents_len));
 	encode_kind = under_kind;
     }
     if ((encode_kind & DER_ANY) == 0) {	/* DER_ANY already contains header */
 	buf = DER_StoreHeader (buf, encode_kind, contents_len);
     }
     /* If no real contents to encode, then we are done.  */
     if (contents_len == 0)
 	return buf;
     if (under_kind & DER_INDEFINITE) {
 	void **indp;
 	indp = *(void ***)src;
 	PORT_Assert (indp != NULL);
 	under_kind &= ~DER_INDEFINITE;
 	if (under_kind == DER_SET || under_kind == DER_SEQUENCE) {
 	    DERTemplate *tmpt = dtemplate->sub;
 	    PORT_Assert (tmpt != NULL);
 	    for (; *indp != NULL; indp++) {
 		void *sub_src = (void *)((char *)(*indp) + tmpt->offset);
 		buf = der_encode (buf, tmpt, sub_src);
 	    }
 	} else {
 	    for (; *indp != NULL; indp++) {
 		SECItem *item;
 		int sub_len;
 		item = (SECItem *)(*indp);
 		sub_len = item->len;
 		if (under_kind == DER_BIT_STRING) {
 		    if (sub_len) {
 			int rem;
 			sub_len = (sub_len + 7) >> 3;
 			buf = DER_StoreHeader (buf, under_kind, sub_len + 1);
 			rem = (sub_len << 3) - item->len;
 			*buf++ = rem;		/* remaining bits */
 		    } else {
 			buf = DER_StoreHeader (buf, under_kind, 0);
 		    }
 		} else if (under_kind != DER_ANY) {
 		    buf = DER_StoreHeader (buf, under_kind, sub_len);
 		}
 		PORT_Memcpy (buf, item->data, sub_len);
 		buf += sub_len;
 	    }
 	}
 	return buf;
     }
     switch (under_kind) {
       case DER_SEQUENCE:
       case DER_SET:
 	{
 	    DERTemplate *tmpt;
 	    void *sub_src;
 	    for (tmpt = dtemplate + 1; tmpt->kind; tmpt++) {
 		sub_src = (void *)((char *)src + tmpt->offset);
 		buf = der_encode (buf, tmpt, sub_src);
 	    }
 	}
 	break;
       case DER_BIT_STRING:
 	{
 	    SECItem *item;
 	    int rem;
 	    /*
 	     * The contents length includes our extra octet; subtract
 	     * it off so we just have the real string length there.
 	     */
 	    contents_len--;
 	    item = (SECItem *)src;
 	    PORT_Assert (contents_len == ((item->len + 7) >> 3));
 	    rem = (contents_len << 3) - item->len;
 	    *buf++ = rem;		/* remaining bits */
 	    PORT_Memcpy (buf, item->data, contents_len);
 	    buf += contents_len;
 	}
 	break;
       default:
 	{
 	    SECItem *item;
 	    item = (SECItem *)src;
 	    PORT_Assert (contents_len == item->len);
 	    PORT_Memcpy (buf, item->data, contents_len);
 	    buf += contents_len;
 	}
 	break;
     }
     return buf;
 }
 SECStatus
 DER_Encode(PLArenaPool *arena, SECItem *dest, DERTemplate *dtemplate, void *src)
 {
     unsigned int contents_len, header_len;
     src = (void **)((char *)src + dtemplate->offset);
     /*
      * First figure out how long the encoding will be. Do this by
      * traversing the template from top to bottom and accumulating
      * the length of each leaf item.
      */
     contents_len = contents_length (dtemplate, src);
     header_len = header_length (dtemplate, contents_len);
     dest->len = contents_len + header_len;
     /* Allocate storage to hold the encoding */
     dest->data = (unsigned char*) PORT_ArenaAlloc(arena, dest->len);
     if (dest->data == NULL) {
 	PORT_SetError(SEC_ERROR_NO_MEMORY);
 	return SECFailure;
     }
     /* Now encode into the buffer */
     (void) der_encode (dest->data, dtemplate, src);
     return SECSuccess;
 }

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security/nss/lib/util/derenc.c@b8a032363ba2 (annotated)

security/nss/lib/util/derenc.c