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| -rw-r--r-- | src/tpm2/TpmAsn1.c | 508 |
1 files changed, 508 insertions, 0 deletions
diff --git a/src/tpm2/TpmAsn1.c b/src/tpm2/TpmAsn1.c new file mode 100644 index 0000000..f23b2a9 --- /dev/null +++ b/src/tpm2/TpmAsn1.c @@ -0,0 +1,508 @@ +/********************************************************************************/ +/* */ +/* TPM ASN.1 */ +/* Written by Ken Goldman */ +/* IBM Thomas J. Watson Research Center */ +/* $Id: TpmAsn1.c 1519 2019-11-15 20:43:51Z kgoldman $ */ +/* */ +/* Licenses and Notices */ +/* */ +/* 1. Copyright Licenses: */ +/* */ +/* - Trusted Computing Group (TCG) grants to the user of the source code in */ +/* this specification (the "Source Code") a worldwide, irrevocable, */ +/* nonexclusive, royalty free, copyright license to reproduce, create */ +/* derivative works, distribute, display and perform the Source Code and */ +/* derivative works thereof, and to grant others the rights granted herein. */ +/* */ +/* - The TCG grants to the user of the other parts of the specification */ +/* (other than the Source Code) the rights to reproduce, distribute, */ +/* display, and perform the specification solely for the purpose of */ +/* developing products based on such documents. */ +/* */ +/* 2. Source Code Distribution Conditions: */ +/* */ +/* - Redistributions of Source Code must retain the above copyright licenses, */ +/* this list of conditions and the following disclaimers. */ +/* */ +/* - Redistributions in binary form must reproduce the above copyright */ +/* licenses, this list of conditions and the following disclaimers in the */ +/* documentation and/or other materials provided with the distribution. */ +/* */ +/* 3. Disclaimers: */ +/* */ +/* - THE COPYRIGHT LICENSES SET FORTH ABOVE DO NOT REPRESENT ANY FORM OF */ +/* LICENSE OR WAIVER, EXPRESS OR IMPLIED, BY ESTOPPEL OR OTHERWISE, WITH */ +/* RESPECT TO PATENT RIGHTS HELD BY TCG MEMBERS (OR OTHER THIRD PARTIES) */ +/* THAT MAY BE NECESSARY TO IMPLEMENT THIS SPECIFICATION OR OTHERWISE. */ +/* Contact TCG Administration (admin@trustedcomputinggroup.org) for */ +/* information on specification licensing rights available through TCG */ +/* membership agreements. */ +/* */ +/* - THIS SPECIFICATION IS PROVIDED "AS IS" WITH NO EXPRESS OR IMPLIED */ +/* WARRANTIES WHATSOEVER, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR */ +/* FITNESS FOR A PARTICULAR PURPOSE, ACCURACY, COMPLETENESS, OR */ +/* NONINFRINGEMENT OF INTELLECTUAL PROPERTY RIGHTS, OR ANY WARRANTY */ +/* OTHERWISE ARISING OUT OF ANY PROPOSAL, SPECIFICATION OR SAMPLE. */ +/* */ +/* - Without limitation, TCG and its members and licensors disclaim all */ +/* liability, including liability for infringement of any proprietary */ +/* rights, relating to use of information in this specification and to the */ +/* implementation of this specification, and TCG disclaims all liability for */ +/* cost of procurement of substitute goods or services, lost profits, loss */ +/* of use, loss of data or any incidental, consequential, direct, indirect, */ +/* or special damages, whether under contract, tort, warranty or otherwise, */ +/* arising in any way out of use or reliance upon this specification or any */ +/* information herein. */ +/* */ +/* (c) Copyright IBM Corp. and others, 2019 */ +/* */ +/********************************************************************************/ + +/* 10.2.23 TpmAsn1.c */ +/* 10.2.23.1 Includes */ +#include "Tpm.h" +#define _OIDS_ +#include "OIDs.h" +#include "TpmAsn1.h" +#include "TpmAsn1_fp.h" +/* 10.2.23.2 Unmarshaling Functions */ +/* 10.2.23.2.1 ASN1UnmarshalContextInitialize() */ +/* Function does standard initialization of a context. */ +/* Return Value Meaning */ +/* TRUE(1) success */ +/* FALSE(0) failure */ +BOOL +ASN1UnmarshalContextInitialize( + ASN1UnmarshalContext *ctx, + INT16 size, + BYTE *buffer + ) +{ + VERIFY(buffer != NULL); + VERIFY(size > 0); + ctx->buffer = buffer; + ctx->size = size; + ctx->offset = 0; + ctx->tag = 0xFF; + return TRUE; + Error: + return FALSE; +} +/* 10.2.23.2.2 ASN1DecodeLength() */ +/* This function extracts the length of an element from buffer starting at offset. */ +/* Return Value Meaning */ +/* >=0 the extracted length */ +/* <0 an error */ +INT16 +ASN1DecodeLength( + ASN1UnmarshalContext *ctx + ) +{ + BYTE first; // Next octet in buffer + INT16 value; + // + VERIFY(ctx->offset < ctx->size); + first = NEXT_OCTET(ctx); + // If the number of octets of the entity is larger than 127, then the first octet + // is the number of octets in the length specifier. + if(first >= 0x80) + { + // Make sure that this length field is contained with the structure being + // parsed + CHECK_SIZE(ctx, (first & 0x7F)); + if(first == 0x82) + { + // Two octets of size + // get the next value + value = (INT16)NEXT_OCTET(ctx); + // Make sure that the result will fit in an INT16 + VERIFY(value < 0x0080); + // Shift up and add next octet + value = (value << 8) + NEXT_OCTET(ctx); + } + else if(first == 0x81) + value = NEXT_OCTET(ctx); + // Sizes larger than will fit in a INT16 are an error + else + goto Error; + } + else + value = first; + // Make sure that the size defined something within the current context + CHECK_SIZE(ctx, value); + return value; + Error: + ctx->size = -1; // Makes everything fail from now on. + return -1; +} +/* 10.2.23.2.3 ASN1NextTag() */ +/* This function extracts the next type from buffer starting at offset. It advances offset as it + parses the type and the length of the type. It returns the length of the type. On return, the + length octets starting at offset are the octets of the type. */ +/* Return Value Meaning */ +/* >=0 the number of octets in type */ +/* <0 an error */ +INT16 +ASN1NextTag( + ASN1UnmarshalContext *ctx + ) +{ + // A tag to get? + VERIFY(ctx->offset < ctx->size); + // Get it + ctx->tag = NEXT_OCTET(ctx); + // Make sure that it is not an extended tag + VERIFY((ctx->tag & 0x1F) != 0x1F); + // Get the length field and return that + return ASN1DecodeLength(ctx); + + Error: + // Attempt to read beyond the end of the context or an illegal tag + ctx->size = -1; // Persistent failure + ctx->tag = 0xFF; + return -1; +} +/* 10.2.23.2.4 ASN1GetBitStringValue() */ +/* Try to parse a bit string of up to 32 bits from a value that is expected to be a bit string. The + bit string is left justified so that the MSb of the input is the MSb of the returned value. If + there is a general parsing error, the context->size is set to -1. */ +/* Return Value Meaning */ +/* TRUE(1) success */ +/* FALSE(0) failure */ + +BOOL +ASN1GetBitStringValue( + ASN1UnmarshalContext *ctx, + UINT32 *val + ) +{ + int shift; + INT16 length; + UINT32 value = 0; + int inputBits; + // + length = ASN1NextTag(ctx); + VERIFY(length >= 1); + VERIFY(ctx->tag == ASN1_BITSTRING); + // Get the shift value for the bit field (how many bits to lop off of the end) + shift = NEXT_OCTET(ctx); + length--; + // Get the number of bits in the input + inputBits = (8 * length) - shift; + // the shift count has to make sense + VERIFY((shift < 8) && ((length > 0) || (shift == 0))); + // if there are any bytes left + for(; length > 1; length--) + { + + // for all but the last octet, just shift and add the new octet + VERIFY((value & 0xFF000000) == 0); // can't loose significant bits + value = (value << 8) + NEXT_OCTET(ctx); + + } + if(length == 1) + { + // for the last octet, just shift the accumulated value enough to + // accept the significant bits in the last octet and shift the last + // octet down + VERIFY(((value & (0xFF000000 << (8 - shift)))) == 0); + value = (value << (8 - shift)) + (NEXT_OCTET(ctx) >> shift); + + } + // 'Left justify' the result + if(inputBits > 0) + value <<= (32 - inputBits); + *val = value; + return TRUE; + Error: + ctx->size = -1; + return FALSE; +} + +/* 10.2.23.3 Marshaling Functions */ +/* 10.2.23.3.1 Introduction */ +/* Marshaling of an ASN.1 structure is accomplished from the bottom up. That is, the things that + will be at the end of the structure are added last. To manage the collecting of the relative + sizes, start a context for the outermost container, if there is one, and then placing items in + from the bottom up. If the bottom-most item is also within a structure, create a nested context + by calling ASN1StartMarshalingContext(). */ +/* The context control structure contains a buffer pointer, an offset, an end and a stack. offset is + the offset from the start of the buffer of the last added byte. When offset reaches 0, the buffer + is full. offset is a signed value so that, when it becomes negative, there is an overflow. Only + two functions are allowed to move bytes into the buffer: ASN1PushByte() and + ASN1PushBytes(). These functions make sure that no data is written beyond the end of the + buffer. */ +/* When a new context is started, the current value of end is pushed on the stack and end is set to + 'offset. As bytes are added, offset gets smaller. At any time, the count of bytes in the current + context is simply end - offset. */ +/* Since starting a new context involves setting end = offset, the number of bytes in the context + starts at 0. The nominal way of ending a context is to use end - offset to set the length value, + and then a tag is added to the buffer. Then the previous end value is popped meaning that the + context just ended becomes a member of the now current context. */ +/* The nominal strategy for building a completed ASN.1 structure is to push everything into the + buffer and then move everything to the start of the buffer. The move is simple as the size of the + move is the initial end value minus the final offset value. The destination is buffer and the + source is buffer + offset. As Skippy would say "Easy peasy, Joe." */ +/* It is not necessary to provide a buffer into which the data is placed. If no buffer is provided, + then the marshaling process will return values needed for marshaling. On strategy for filling the + buffer would be to execute the process for building the structure without using a buffer. This + would return the overall size of the structure. Then that amount of data could be allocated for + the buffer and the fill process executed again with the data going into the buffer. At the end, + the data would be in its final resting place. */ +/* 10.2.23.3.2 ASN1InitialializeMarshalContext() */ +/* This creates a structure for handling marshaling of an ASN.1 formatted data structure. */ +void +ASN1InitialializeMarshalContext( + ASN1MarshalContext *ctx, + INT16 length, + BYTE *buffer + ) +{ + ctx->buffer = buffer; + if(buffer) + ctx->offset = length; + else + ctx->offset = INT16_MAX; + ctx->end = ctx->offset; + ctx->depth = -1; +} +/* 10.2.23.3.3 ASN1StartMarshalContext() */ +/* This starts a new constructed element. It is constructed on top of the value that was previously placed in the structure. */ +void +ASN1StartMarshalContext( + ASN1MarshalContext *ctx + ) +{ + pAssert((ctx->depth + 1) < MAX_DEPTH); + ctx->depth++; + ctx->ends[ctx->depth] = ctx->end; + ctx->end = ctx->offset; +} +/* 10.2.23.3.4 ASN1EndMarshalContext() */ +/* This function restores the end pointer for an encapsulating structure. */ +/* Return Value Meaning */ +/* > 0 the size of the encapsulated structure that was just ended */ +/* <= 0 an error */ +INT16 +ASN1EndMarshalContext( + ASN1MarshalContext *ctx + ) +{ + INT16 length; + pAssert(ctx->depth >= 0); + length = ctx->end - ctx->offset; + ctx->end = ctx->ends[ctx->depth--]; + if((ctx->depth == -1) && (ctx->buffer)) + { + MemoryCopy(ctx->buffer, ctx->buffer + ctx->offset, ctx->end - ctx->offset); + } + return length; +} +/* 10.2.23.3.5 ASN1EndEncapsulation() */ +/* This function puts a tag and length in the buffer. In this function, an embedded BIT_STRING is + assumed to be a collection of octets. To indicate that all bits are used, a byte of zero is + prepended. If a raw bit-string is needed, a new function like ASN1PushInteger() would be + needed. */ +/* Return Value Meaning */ +/* > 0 number of octets in the encapsulation */ +/* == 0 failure */ +UINT16 +ASN1EndEncapsulation( + ASN1MarshalContext *ctx, + BYTE tag + ) +{ + // only add a leading zero for an encapsulated BIT STRING + if (tag == ASN1_BITSTRING) + ASN1PushByte(ctx, 0); + ASN1PushTagAndLength(ctx, tag, ctx->end - ctx->offset); + return ASN1EndMarshalContext(ctx); +} +/* 10.2.23.3.6 ASN1PushByte() */ +BOOL +ASN1PushByte( + ASN1MarshalContext *ctx, + BYTE b + ) +{ + if(ctx->offset > 0) + { + ctx->offset -= 1; + if(ctx->buffer) + ctx->buffer[ctx->offset] = b; + return TRUE; + } + ctx->offset = -1; + return FALSE; +} +/* 10.2.23.3.7 ASN1PushBytes() */ +/* Push some raw bytes onto the buffer. count cannot be zero. */ +/* Return Value Meaning */ +/* > 0 count bytes */ +/* == 0 failure unless count was zero */ +INT16 +ASN1PushBytes( + ASN1MarshalContext *ctx, + INT16 count, + const BYTE *buffer + ) +{ + // make sure that count is not negative which would mess up the math; and that + // if there is a count, there is a buffer + VERIFY((count >= 0) && ((buffer != NULL) || (count == 0))); + // back up the offset to determine where the new octets will get pushed + ctx->offset -= count; + // can't go negative + VERIFY(ctx->offset >= 0); + // if there are buffers, move the data, otherwise, assume that this is just a + // test. + if(count && buffer && ctx->buffer) + MemoryCopy(&ctx->buffer[ctx->offset], buffer, count); + return count; + Error: + ctx->offset = -1; + return 0; +} +/* 10.2.23.3.8 ASN1PushNull() */ +/* Return Value Meaning */ +/* > 0 count bytes */ +/* == 0 failure unless count was zero */ +INT16 +ASN1PushNull( + ASN1MarshalContext *ctx + ) +{ + ASN1PushByte(ctx, 0); + ASN1PushByte(ctx, ASN1_NULL); + return (ctx->offset >= 0) ? 2 : 0; +} +/* 10.2.23.3.9 ASN1PushLength() */ +/* Push a length value. This will only handle length values that fit in an INT16. */ +/* Return Value Meaning */ +/* > 0 number of bytes added */ +/* == 0 failure */ +INT16 +ASN1PushLength( + ASN1MarshalContext *ctx, + INT16 len + ) +{ + UINT16 start = ctx->offset; + VERIFY(len >= 0); + if(len <= 127) + ASN1PushByte(ctx, (BYTE)len); + else + { + ASN1PushByte(ctx, (BYTE)(len & 0xFF)); + len >>= 8; + if(len == 0) + ASN1PushByte(ctx, 0x81); + else + { + ASN1PushByte(ctx, (BYTE)(len)); + ASN1PushByte(ctx, 0x82); + } + } + goto Exit; + Error: + ctx->offset = -1; + Exit: + return (ctx->offset > 0) ? start - ctx->offset : 0; +} +/* 10.2.23.3.10 ASN1PushTagAndLength() */ +/* Return Value Meaning */ +/* > 0 number of bytes added */ +/* == 0 failure */ +INT16 +ASN1PushTagAndLength( + ASN1MarshalContext *ctx, + BYTE tag, + INT16 length + ) +{ + INT16 bytes; + bytes = ASN1PushLength(ctx, length); + bytes += (INT16)ASN1PushByte(ctx, tag); + return (ctx->offset < 0) ? 0 : bytes; +} +/* 10.2.23.3.11 ASN1PushTaggedOctetString() */ +/* This function will push a random octet string. */ +/* Return Value Meaning */ +/* > 0 number of bytes added */ +/* == 0 failure */ +INT16 +ASN1PushTaggedOctetString( + ASN1MarshalContext *ctx, + INT16 size, + const BYTE *string, + BYTE tag + ) +{ + ASN1PushBytes(ctx, size, string); + // PushTagAndLenght just tells how many octets it added so the total size of this + // element is the sum of those octets and input size. + size += ASN1PushTagAndLength(ctx, tag, size); + return size; +} +/* 10.2.23.3.12 ASN1PushUINT() */ +/* This function pushes an native-endian integer value. This just changes a native-endian integer + into a big-endian byte string and calls ASN1PushInteger(). That function will remove leading + zeros and make sure that the number is positive. */ +/* Return Value Meaning */ +/* > 0 count bytes */ +/* == 0 failure unless count was zero */ +INT16 +ASN1PushUINT( + ASN1MarshalContext *ctx, + UINT32 integer + ) +{ + BYTE marshaled[4]; + UINT32_TO_BYTE_ARRAY(integer, marshaled); + return ASN1PushInteger(ctx, 4, marshaled); +} +/* 10.2.23.3.13 ASN1PushInteger */ +/* Push a big-endian integer on the end of the buffer */ +/* Return Value Meaning */ +/* > 0 the number of bytes marshaled for the integer */ +/* == 0 failure */ +INT16 +ASN1PushInteger( + ASN1MarshalContext *ctx, // IN/OUT: buffer context + INT16 iLen, // IN: octets of the integer + BYTE *integer // IN: big-endian integer + ) +{ + // no leading 0's + while((*integer == 0) && (--iLen > 0)) + integer++; + // Move the bytes to the buffer + ASN1PushBytes(ctx, iLen, integer); + // if needed, add a leading byte of 0 to make the number positive + if(*integer & 0x80) + iLen += (INT16)ASN1PushByte(ctx, 0); + // PushTagAndLenght just tells how many octets it added so the total size of this + // element is the sum of those octets and the adjusted input size. + iLen += ASN1PushTagAndLength(ctx, ASN1_INTEGER, iLen); + return iLen; +} +/* 10.2.23.3.14 ASN1PushOID() */ +/* This function is used to add an OID. An OID is 0x06 followed by a byte of size followed by size + bytes. This is used to avoid having to do anything special in the definition of an OID. */ +/* Return Value Meaning */ +/* > 0 the number of bytes marshaled for the integer */ +/* == 0 failure */ +INT16 +ASN1PushOID( + ASN1MarshalContext *ctx, + const BYTE *OID + ) +{ + if((*OID == ASN1_OBJECT_IDENTIFIER) && ((OID[1] & 0x80) == 0)) + { + return ASN1PushBytes(ctx, OID[1] + 2, OID); + } + ctx->offset = -1; + return 0; +} |