The Tor Browser: security/nss/lib/util/secasn1u.c@b8a032363ba2

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

     1 /* This Source Code Form is subject to the terms of the Mozilla Public

     2  * License, v. 2.0. If a copy of the MPL was not distributed with this

     3  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */

     5 /*

     6  * Utility routines to complement the ASN.1 encoding and decoding functions.

     7  */

     9 #include "secasn1.h"

    12 /*

    13  * We have a length that needs to be encoded; how many bytes will the

    14  * encoding take?

    15  *

    16  * The rules are that 0 - 0x7f takes one byte (the length itself is the

    17  * entire encoding); everything else takes one plus the number of bytes

    18  * in the length.

    19  */

    20 int

    21 SEC_ASN1LengthLength (unsigned long len)

    22 {

    23     int lenlen = 1;

    25     if (len > 0x7f) {

    26 	do {

    27 	    lenlen++;

    28 	    len >>= 8;

    29 	} while (len);

    30     }

    32     return lenlen;

    33 }

    36 /*

    37  * XXX Move over (and rewrite as appropriate) the rest of the

    38  * stuff in dersubr.c!

    39  */

    42 /*

    43  * Find the appropriate subtemplate for the given template.

    44  * This may involve calling a "chooser" function, or it may just

    45  * be right there.  In either case, it is expected to *have* a

    46  * subtemplate; this is asserted in debug builds (in non-debug

    47  * builds, NULL will be returned).

    48  *

    49  * "thing" is a pointer to the structure being encoded/decoded

    50  * "encoding", when true, means that we are in the process of encoding

    51  *	(as opposed to in the process of decoding)

    52  */

    53 const SEC_ASN1Template *

    54 SEC_ASN1GetSubtemplate (const SEC_ASN1Template *theTemplate, void *thing,

    55 			PRBool encoding)

    56 {

    57     const SEC_ASN1Template *subt = NULL;

    59     PORT_Assert (theTemplate->sub != NULL);

    60     if (theTemplate->sub != NULL) {

    61 	if (theTemplate->kind & SEC_ASN1_DYNAMIC) {

    62 	    SEC_ASN1TemplateChooserPtr chooserp;

    64 	    chooserp = *(SEC_ASN1TemplateChooserPtr *) theTemplate->sub;

    65 	    if (chooserp) {

    66 		if (thing != NULL)

    67 		    thing = (char *)thing - theTemplate->offset;

    68 		subt = (* chooserp)(thing, encoding);

    69 	    }

    70 	} else {

    71 	    subt = (SEC_ASN1Template*)theTemplate->sub;

    72 	}

    73     }

    74     return subt;

    75 }

    77 PRBool SEC_ASN1IsTemplateSimple(const SEC_ASN1Template *theTemplate)

    78 {

    79     if (!theTemplate) {

    80 	return PR_TRUE; /* it doesn't get any simpler than NULL */

    81     }

    82     /* only templates made of one primitive type or a choice of primitive

    83        types are considered simple */

    84     if (! (theTemplate->kind & (~SEC_ASN1_TAGNUM_MASK))) {

    85 	return PR_TRUE; /* primitive type */

    86     }

    87     if (!(theTemplate->kind & SEC_ASN1_CHOICE)) {

    88 	return PR_FALSE; /* no choice means not simple */

    89     }

    90     while (++theTemplate && theTemplate->kind) {

    91 	if (theTemplate->kind & (~SEC_ASN1_TAGNUM_MASK)) {

    92 	    return PR_FALSE; /* complex type */

    93 	}

    94     }

    95     return PR_TRUE; /* choice of primitive types */

    96 }

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