Diff: features/mbedtls/mbed-crypto/src/asn1write.c

Revision:

0:5b88d5760320

Child:

1:9db0e321a9f4

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/features/mbedtls/mbed-crypto/src/asn1write.c	Tue Dec 17 23:23:45 2019 +0000
@@ -0,0 +1,464 @@
+/*
+ * ASN.1 buffer writing functionality
+ *
+ *  Copyright (C) 2006-2015, ARM Limited, All Rights Reserved
+ *  SPDX-License-Identifier: Apache-2.0
+ *
+ *  Licensed under the Apache License, Version 2.0 (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.apache.org/licenses/LICENSE-2.0
+ *
+ *  Unless required by applicable law or agreed to in writing, software
+ *  distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ *  WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ *  See the License for the specific language governing permissions and
+ *  limitations under the License.
+ *
+ *  This file is part of mbed TLS (https://tls.mbed.org)
+ */
+
+#if !defined(MBEDTLS_CONFIG_FILE)
+#include "mbedtls/config.h"
+#else
+#include MBEDTLS_CONFIG_FILE
+#endif
+
+#if defined(MBEDTLS_ASN1_WRITE_C)
+
+#include "mbedtls/asn1write.h"
+
+#include <string.h>
+
+#if defined(MBEDTLS_PLATFORM_C)
+#include "mbedtls/platform.h"
+#else
+#include <stdlib.h>
+#define mbedtls_calloc    calloc
+#define mbedtls_free       free
+#endif
+
+int mbedtls_asn1_write_len( unsigned char **p, unsigned char *start, size_t len )
+{
+    if( len < 0x80 )
+    {
+        if( *p - start < 1 )
+            return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
+
+        *--(*p) = (unsigned char) len;
+        return( 1 );
+    }
+
+    if( len <= 0xFF )
+    {
+        if( *p - start < 2 )
+            return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
+
+        *--(*p) = (unsigned char) len;
+        *--(*p) = 0x81;
+        return( 2 );
+    }
+
+    if( len <= 0xFFFF )
+    {
+        if( *p - start < 3 )
+            return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
+
+        *--(*p) = ( len       ) & 0xFF;
+        *--(*p) = ( len >>  8 ) & 0xFF;
+        *--(*p) = 0x82;
+        return( 3 );
+    }
+
+    if( len <= 0xFFFFFF )
+    {
+        if( *p - start < 4 )
+            return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
+
+        *--(*p) = ( len       ) & 0xFF;
+        *--(*p) = ( len >>  8 ) & 0xFF;
+        *--(*p) = ( len >> 16 ) & 0xFF;
+        *--(*p) = 0x83;
+        return( 4 );
+    }
+
+#if SIZE_MAX > 0xFFFFFFFF
+    if( len <= 0xFFFFFFFF )
+#endif
+    {
+        if( *p - start < 5 )
+            return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
+
+        *--(*p) = ( len       ) & 0xFF;
+        *--(*p) = ( len >>  8 ) & 0xFF;
+        *--(*p) = ( len >> 16 ) & 0xFF;
+        *--(*p) = ( len >> 24 ) & 0xFF;
+        *--(*p) = 0x84;
+        return( 5 );
+    }
+
+#if SIZE_MAX > 0xFFFFFFFF
+    return( MBEDTLS_ERR_ASN1_INVALID_LENGTH );
+#endif
+}
+
+int mbedtls_asn1_write_tag( unsigned char **p, unsigned char *start, unsigned char tag )
+{
+    if( *p - start < 1 )
+        return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
+
+    *--(*p) = tag;
+
+    return( 1 );
+}
+
+int mbedtls_asn1_write_raw_buffer( unsigned char **p, unsigned char *start,
+                           const unsigned char *buf, size_t size )
+{
+    size_t len = 0;
+
+    if( *p < start || (size_t)( *p - start ) < size )
+        return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
+
+    len = size;
+    (*p) -= len;
+    memcpy( *p, buf, len );
+
+    return( (int) len );
+}
+
+#if defined(MBEDTLS_BIGNUM_C)
+int mbedtls_asn1_write_mpi( unsigned char **p, unsigned char *start, const mbedtls_mpi *X )
+{
+    int ret;
+    size_t len = 0;
+
+    // Write the MPI
+    //
+    len = mbedtls_mpi_size( X );
+
+    if( *p < start || (size_t)( *p - start ) < len )
+        return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
+
+    (*p) -= len;
+    MBEDTLS_MPI_CHK( mbedtls_mpi_write_binary( X, *p, len ) );
+
+    // DER format assumes 2s complement for numbers, so the leftmost bit
+    // should be 0 for positive numbers and 1 for negative numbers.
+    //
+    if( X->s ==1 && **p & 0x80 )
+    {
+        if( *p - start < 1 )
+            return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
+
+        *--(*p) = 0x00;
+        len += 1;
+    }
+
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_INTEGER ) );
+
+    ret = (int) len;
+
+cleanup:
+    return( ret );
+}
+#endif /* MBEDTLS_BIGNUM_C */
+
+int mbedtls_asn1_write_null( unsigned char **p, unsigned char *start )
+{
+    int ret;
+    size_t len = 0;
+
+    // Write NULL
+    //
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, 0) );
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_NULL ) );
+
+    return( (int) len );
+}
+
+int mbedtls_asn1_write_oid( unsigned char **p, unsigned char *start,
+                    const char *oid, size_t oid_len )
+{
+    int ret;
+    size_t len = 0;
+
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start,
+                                  (const unsigned char *) oid, oid_len ) );
+    MBEDTLS_ASN1_CHK_ADD( len , mbedtls_asn1_write_len( p, start, len ) );
+    MBEDTLS_ASN1_CHK_ADD( len , mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_OID ) );
+
+    return( (int) len );
+}
+
+int mbedtls_asn1_write_algorithm_identifier( unsigned char **p, unsigned char *start,
+                                     const char *oid, size_t oid_len,
+                                     size_t par_len )
+{
+    int ret;
+    size_t len = 0;
+
+    if( par_len == 0 )
+        MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_null( p, start ) );
+    else
+        len += par_len;
+
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_oid( p, start, oid, oid_len ) );
+
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start,
+                                       MBEDTLS_ASN1_CONSTRUCTED | MBEDTLS_ASN1_SEQUENCE ) );
+
+    return( (int) len );
+}
+
+int mbedtls_asn1_write_bool( unsigned char **p, unsigned char *start, int boolean )
+{
+    int ret;
+    size_t len = 0;
+
+    if( *p - start < 1 )
+        return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
+
+    *--(*p) = (boolean) ? 255 : 0;
+    len++;
+
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_BOOLEAN ) );
+
+    return( (int) len );
+}
+
+int mbedtls_asn1_write_int( unsigned char **p, unsigned char *start, int val )
+{
+    int ret;
+    size_t len = 0;
+
+    if( *p - start < 1 )
+        return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
+
+    len += 1;
+    *--(*p) = val;
+
+    if( val > 0 && **p & 0x80 )
+    {
+        if( *p - start < 1 )
+            return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
+
+        *--(*p) = 0x00;
+        len += 1;
+    }
+
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_INTEGER ) );
+
+    return( (int) len );
+}
+
+int mbedtls_asn1_write_tagged_string( unsigned char **p, unsigned char *start, int tag,
+    const char *text, size_t text_len )
+{
+    int ret;
+    size_t len = 0;
+
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start,
+        (const unsigned char *) text, text_len ) );
+
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, tag ) );
+
+    return( (int) len );
+}
+
+int mbedtls_asn1_write_utf8_string( unsigned char **p, unsigned char *start,
+    const char *text, size_t text_len )
+{
+    return( mbedtls_asn1_write_tagged_string(p, start, MBEDTLS_ASN1_UTF8_STRING, text, text_len) );
+}
+
+int mbedtls_asn1_write_printable_string( unsigned char **p, unsigned char *start,
+                                 const char *text, size_t text_len )
+{
+    return( mbedtls_asn1_write_tagged_string(p, start, MBEDTLS_ASN1_PRINTABLE_STRING, text, text_len) );
+}
+
+int mbedtls_asn1_write_ia5_string( unsigned char **p, unsigned char *start,
+                           const char *text, size_t text_len )
+{
+    return( mbedtls_asn1_write_tagged_string(p, start, MBEDTLS_ASN1_IA5_STRING, text, text_len) );
+}
+
+int mbedtls_asn1_write_named_bitstring( unsigned char **p,
+                                        unsigned char *start,
+                                        const unsigned char *buf,
+                                        size_t bits )
+{
+    size_t unused_bits, byte_len;
+    const unsigned char *cur_byte;
+    unsigned char cur_byte_shifted;
+    unsigned char bit;
+
+    byte_len = ( bits + 7 ) / 8;
+    unused_bits = ( byte_len * 8 ) - bits;
+
+    /*
+     * Named bitstrings require that trailing 0s are excluded in the encoding
+     * of the bitstring. Trailing 0s are considered part of the 'unused' bits
+     * when encoding this value in the first content octet
+     */
+    if( bits != 0 )
+    {
+        cur_byte = buf + byte_len - 1;
+        cur_byte_shifted = *cur_byte >> unused_bits;
+
+        for( ; ; )
+        {
+            bit = cur_byte_shifted & 0x1;
+            cur_byte_shifted >>= 1;
+
+            if( bit != 0 )
+                break;
+
+            bits--;
+            if( bits == 0 )
+                break;
+
+            if( bits % 8 == 0 )
+                cur_byte_shifted = *--cur_byte;
+        }
+    }
+
+    return( mbedtls_asn1_write_bitstring( p, start, buf, bits ) );
+}
+
+int mbedtls_asn1_write_bitstring( unsigned char **p, unsigned char *start,
+                          const unsigned char *buf, size_t bits )
+{
+    int ret;
+    size_t len = 0;
+    size_t unused_bits, byte_len;
+
+    byte_len = ( bits + 7 ) / 8;
+    unused_bits = ( byte_len * 8 ) - bits;
+
+    if( *p < start || (size_t)( *p - start ) < byte_len + 1 )
+        return( MBEDTLS_ERR_ASN1_BUF_TOO_SMALL );
+
+    len = byte_len + 1;
+
+    /* Write the bitstring. Ensure the unused bits are zeroed */
+    if( byte_len > 0 )
+    {
+        byte_len--;
+        *--( *p ) = buf[byte_len] & ~( ( 0x1 << unused_bits ) - 1 );
+        ( *p ) -= byte_len;
+        memcpy( *p, buf, byte_len );
+    }
+
+    /* Write unused bits */
+    *--( *p ) = (unsigned char)unused_bits;
+
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_BIT_STRING ) );
+
+    return( (int) len );
+}
+
+int mbedtls_asn1_write_octet_string( unsigned char **p, unsigned char *start,
+                             const unsigned char *buf, size_t size )
+{
+    int ret;
+    size_t len = 0;
+
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_raw_buffer( p, start, buf, size ) );
+
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_len( p, start, len ) );
+    MBEDTLS_ASN1_CHK_ADD( len, mbedtls_asn1_write_tag( p, start, MBEDTLS_ASN1_OCTET_STRING ) );
+
+    return( (int) len );
+}
+
+
+/* This is a copy of the ASN.1 parsing function mbedtls_asn1_find_named_data(),
+ * which is replicated to avoid a dependency ASN1_WRITE_C on ASN1_PARSE_C. */
+static mbedtls_asn1_named_data *asn1_find_named_data(
+                                               mbedtls_asn1_named_data *list,
+                                               const char *oid, size_t len )
+{
+    while( list != NULL )
+    {
+        if( list->oid.len == len &&
+            memcmp( list->oid.p, oid, len ) == 0 )
+        {
+            break;
+        }
+
+        list = list->next;
+    }
+
+    return( list );
+}
+
+mbedtls_asn1_named_data *mbedtls_asn1_store_named_data(
+                                        mbedtls_asn1_named_data **head,
+                                        const char *oid, size_t oid_len,
+                                        const unsigned char *val,
+                                        size_t val_len )
+{
+    mbedtls_asn1_named_data *cur;
+
+    if( ( cur = asn1_find_named_data( *head, oid, oid_len ) ) == NULL )
+    {
+        // Add new entry if not present yet based on OID
+        //
+        cur = (mbedtls_asn1_named_data*)mbedtls_calloc( 1,
+                                            sizeof(mbedtls_asn1_named_data) );
+        if( cur == NULL )
+            return( NULL );
+
+        cur->oid.len = oid_len;
+        cur->oid.p = mbedtls_calloc( 1, oid_len );
+        if( cur->oid.p == NULL )
+        {
+            mbedtls_free( cur );
+            return( NULL );
+        }
+
+        memcpy( cur->oid.p, oid, oid_len );
+
+        cur->val.len = val_len;
+        cur->val.p = mbedtls_calloc( 1, val_len );
+        if( cur->val.p == NULL )
+        {
+            mbedtls_free( cur->oid.p );
+            mbedtls_free( cur );
+            return( NULL );
+        }
+
+        cur->next = *head;
+        *head = cur;
+    }
+    else if( cur->val.len < val_len )
+    {
+        /*
+         * Enlarge existing value buffer if needed
+         * Preserve old data until the allocation succeeded, to leave list in
+         * a consistent state in case allocation fails.
+         */
+        void *p = mbedtls_calloc( 1, val_len );
+        if( p == NULL )
+            return( NULL );
+
+        mbedtls_free( cur->val.p );
+        cur->val.p = p;
+        cur->val.len = val_len;
+    }
+
+    if( val != NULL )
+        memcpy( cur->val.p, val, val_len );
+
+    return( cur );
+}
+#endif /* MBEDTLS_ASN1_WRITE_C */