Diff: sha1.c

Revision:

0:fa2de1b79154

Child:

15:956c6d205aa7

--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/sha1.c	Fri Apr 08 12:01:36 2016 -0700
@@ -0,0 +1,441 @@
+// Copyright (c) Microsoft. All rights reserved.
+// Licensed under the MIT license. See LICENSE file in the project root for full license information.
+
+/**************************** sha1.c ****************************/
+/******************** See RFC 4634 for details ******************/
+/*
+*  Description:
+*      This file implements the Secure Hash Signature Standard
+*      algorithms as defined in the National Institute of Standards
+*      and Technology Federal Information Processing Standards
+*      Publication (FIPS PUB) 180-1 published on April 17, 1995, 180-2
+*      published on August 1, 2002, and the FIPS PUB 180-2 Change
+*      Notice published on February 28, 2004.
+*
+*      A combined document showing all algorithms is available at
+*              http://csrc.nist.gov/publications/fips/
+*              fips180-2/fips180-2withchangenotice.pdf
+*
+*      The SHA-1 algorithm produces a 160-bit message digest for a
+*      given data stream.  It should take about 2**n steps to find a
+*      message with the same digest as a given message and
+*      2**(n/2) to find any two messages with the same digest,
+*      when n is the digest size in bits.  Therefore, this
+*      algorithm can serve as a means of providing a
+*      "fingerprint" for a message.
+*
+*  Portability Issues:
+*      SHA-1 is defined in terms of 32-bit "words".  This code
+*      uses <stdint.h> (included via "sha.h") to define 32 and 8
+*      bit unsigned integer types.  If your C compiler does not
+*      support 32 bit unsigned integers, this code is not
+*      appropriate.
+*
+*  Caveats:
+*      SHA-1 is designed to work with messages less than 2^64 bits
+*      long. This implementation uses SHA1Input() to hash the bits
+*      that are a multiple of the size of an 8-bit character, and then
+*      uses SHA1FinalBits() to hash the final few bits of the input.
+*/
+
+#include <stdlib.h>
+#ifdef _CRTDBG_MAP_ALLOC
+#include <crtdbg.h>
+#endif
+#include "azure_c_shared_utility/gballoc.h"
+
+#include "azure_c_shared_utility/sha.h"
+#include "azure_c_shared_utility/sha-private.h"
+
+/*
+*  Define the SHA1 circular left shift macro
+*/
+#define SHA1_ROTL(bits,word) \
+                (((word) << (bits)) | ((word) >> (32-(bits))))
+
+/*
+* add "length" to the length
+*/
+static uint32_t addTemp;
+#define SHA1AddLength(context, length)                     \
+    (addTemp = (context)->Length_Low,                      \
+     (context)->Corrupted =                                \
+        (((context)->Length_Low += (length)) < addTemp) && \
+        (++(context)->Length_High == 0) ? 1 : 0)
+
+/* Local Function Prototypes */
+static void SHA1Finalize(SHA1Context *context, uint8_t Pad_Byte);
+static void SHA1PadMessage(SHA1Context *, uint8_t Pad_Byte);
+static void SHA1ProcessMessageBlock(SHA1Context *);
+
+/*
+*  SHA1Reset
+*
+*  Description:
+*      This function will initialize the SHA1Context in preparation
+*      for computing a new SHA1 message digest.
+*
+*  Parameters:
+*      context: [in/out]
+*          The context to reset.
+*
+*  Returns:
+*      sha Error Code.
+*
+*/
+int SHA1Reset(SHA1Context *context)
+{
+    if (!context)
+        return shaNull;
+
+    context->Length_Low = 0;
+    context->Length_High = 0;
+    context->Message_Block_Index = 0;
+
+
+    /* Initial Hash Values: FIPS-180-2 section 5.3.1 */
+    context->Intermediate_Hash[0] = 0x67452301;
+    context->Intermediate_Hash[1] = 0xEFCDAB89;
+    context->Intermediate_Hash[2] = 0x98BADCFE;
+    context->Intermediate_Hash[3] = 0x10325476;
+    context->Intermediate_Hash[4] = 0xC3D2E1F0;
+
+    context->Computed = 0;
+    context->Corrupted = 0;
+
+    return shaSuccess;
+}
+
+/*
+*  SHA1Input
+*
+*  Description:
+*      This function accepts an array of octets as the next portion
+*      of the message.
+*
+*  Parameters:
+*      context: [in/out]
+*          The SHA context to update
+*      message_array: [in]
+*          An array of characters representing the next portion of
+*          the message.
+*      length: [in]
+*          The length of the message in message_array
+*
+*  Returns:
+*      sha Error Code.
+*
+*/
+int SHA1Input(SHA1Context *context,
+    const uint8_t *message_array, unsigned length)
+{
+    if (!length)
+        return shaSuccess;
+
+    if (!context || !message_array)
+        return shaNull;
+
+    if (context->Computed) {
+        context->Corrupted = shaStateError;
+        return shaStateError;
+    }
+
+    if (context->Corrupted)
+        return context->Corrupted;
+
+    while (length-- && !context->Corrupted) {
+        context->Message_Block[context->Message_Block_Index++] =
+            (*message_array & 0xFF);
+
+        if (!SHA1AddLength(context, 8) &&
+            (context->Message_Block_Index == SHA1_Message_Block_Size))
+            SHA1ProcessMessageBlock(context);
+
+        message_array++;
+    }
+
+    return shaSuccess;
+}
+
+/*
+* SHA1FinalBits
+*
+* Description:
+*   This function will add in any final bits of the message.
+*
+* Parameters:
+*   context: [in/out]
+*     The SHA context to update
+*   message_bits: [in]
+*     The final bits of the message, in the upper portion of the
+*     byte. (Use 0b###00000 instead of 0b00000### to input the
+*     three bits ###.)
+*   length: [in]
+*     The number of bits in message_bits, between 1 and 7.
+*
+* Returns:
+*   sha Error Code.
+*/
+int SHA1FinalBits(SHA1Context *context, const uint8_t message_bits,
+    unsigned int length)
+{
+    uint8_t masks[8] = {
+        /* 0 0b00000000 */ 0x00, /* 1 0b10000000 */ 0x80,
+        /* 2 0b11000000 */ 0xC0, /* 3 0b11100000 */ 0xE0,
+        /* 4 0b11110000 */ 0xF0, /* 5 0b11111000 */ 0xF8,
+        /* 6 0b11111100 */ 0xFC, /* 7 0b11111110 */ 0xFE
+    };
+    uint8_t markbit[8] = {
+        /* 0 0b10000000 */ 0x80, /* 1 0b01000000 */ 0x40,
+        /* 2 0b00100000 */ 0x20, /* 3 0b00010000 */ 0x10,
+        /* 4 0b00001000 */ 0x08, /* 5 0b00000100 */ 0x04,
+        /* 6 0b00000010 */ 0x02, /* 7 0b00000001 */ 0x01
+    };
+
+    if (!length)
+        return shaSuccess;
+
+    if (!context)
+        return shaNull;
+
+    if (context->Computed || (length >= 8) || (length == 0)) {
+        context->Corrupted = shaStateError;
+        return shaStateError;
+    }
+
+    if (context->Corrupted)
+        return context->Corrupted;
+
+    SHA1AddLength(context, length);
+    SHA1Finalize(context,
+        (uint8_t)((message_bits & masks[length]) | markbit[length]));
+
+    return shaSuccess;
+}
+
+/*
+* SHA1Result
+*
+* Description:
+*   This function will return the 160-bit message digest into the
+*   Message_Digest array provided by the caller.
+*   NOTE: The first octet of hash is stored in the 0th element,
+*      the last octet of hash in the 19th element.
+*
+* Parameters:
+*   context: [in/out]
+*     The context to use to calculate the SHA-1 hash.
+*   Message_Digest: [out]
+*     Where the digest is returned.
+*
+* Returns:
+*   sha Error Code.
+*
+*/
+int SHA1Result(SHA1Context *context,
+    uint8_t Message_Digest[SHA1HashSize])
+{
+    int i;
+
+    if (!context || !Message_Digest)
+        return shaNull;
+
+    if (context->Corrupted)
+        return context->Corrupted;
+
+    if (!context->Computed)
+        SHA1Finalize(context, 0x80);
+
+    for (i = 0; i < SHA1HashSize; ++i)
+        Message_Digest[i] = (uint8_t)(context->Intermediate_Hash[i >> 2]
+        >> 8 * (3 - (i & 0x03)));
+
+    return shaSuccess;
+}
+
+/*
+* SHA1Finalize
+*
+* Description:
+*   This helper function finishes off the digest calculations.
+*
+* Parameters:
+*   context: [in/out]
+*     The SHA context to update
+*   Pad_Byte: [in]
+*     The last byte to add to the digest before the 0-padding
+*     and length. This will contain the last bits of the message
+*     followed by another single bit. If the message was an
+*     exact multiple of 8-bits long, Pad_Byte will be 0x80.
+*
+* Returns:
+*   sha Error Code.
+*
+*/
+static void SHA1Finalize(SHA1Context *context, uint8_t Pad_Byte)
+{
+    int i;
+    SHA1PadMessage(context, Pad_Byte);
+    /* message may be sensitive, clear it out */
+    for (i = 0; i < SHA1_Message_Block_Size; ++i)
+        context->Message_Block[i] = 0;
+    context->Length_Low = 0;  /* and clear length */
+    context->Length_High = 0;
+    context->Computed = 1;
+}
+
+/*
+* SHA1PadMessage
+*
+* Description:
+*   According to the standard, the message must be padded to an
+*   even 512 bits. The first padding bit must be a '1'. The last
+*   64 bits represent the length of the original message. All bits
+*   in between should be 0. This helper function will pad the
+*   message according to those rules by filling the Message_Block
+*   array accordingly. When it returns, it can be assumed that the
+*   message digest has been computed.
+*
+* Parameters:
+*   context: [in/out]
+*     The context to pad
+*   Pad_Byte: [in]
+*     The last byte to add to the digest before the 0-padding
+*     and length. This will contain the last bits of the message
+*     followed by another single bit. If the message was an
+*     exact multiple of 8-bits long, Pad_Byte will be 0x80.
+*
+* Returns:
+*   Nothing.
+*/
+static void SHA1PadMessage(SHA1Context *context, uint8_t Pad_Byte)
+{
+    /*
+    * Check to see if the current message block is too small to hold
+    * the initial padding bits and length. If so, we will pad the
+    * block, process it, and then continue padding into a second
+    * block.
+    */
+    if (context->Message_Block_Index >= (SHA1_Message_Block_Size - 8)) {
+        context->Message_Block[context->Message_Block_Index++] = Pad_Byte;
+        while (context->Message_Block_Index < SHA1_Message_Block_Size)
+            context->Message_Block[context->Message_Block_Index++] = 0;
+
+        SHA1ProcessMessageBlock(context);
+    }
+    else
+        context->Message_Block[context->Message_Block_Index++] = Pad_Byte;
+
+    while (context->Message_Block_Index < (SHA1_Message_Block_Size - 8))
+        context->Message_Block[context->Message_Block_Index++] = 0;
+
+    /*
+    * Store the message length as the last 8 octets
+    */
+    context->Message_Block[56] = (uint8_t)(context->Length_High >> 24);
+    context->Message_Block[57] = (uint8_t)(context->Length_High >> 16);
+
+    context->Message_Block[58] = (uint8_t)(context->Length_High >> 8);
+    context->Message_Block[59] = (uint8_t)(context->Length_High);
+    context->Message_Block[60] = (uint8_t)(context->Length_Low >> 24);
+    context->Message_Block[61] = (uint8_t)(context->Length_Low >> 16);
+    context->Message_Block[62] = (uint8_t)(context->Length_Low >> 8);
+    context->Message_Block[63] = (uint8_t)(context->Length_Low);
+
+    SHA1ProcessMessageBlock(context);
+}
+
+/*
+* SHA1ProcessMessageBlock
+*
+* Description:
+*   This helper function will process the next 512 bits of the
+*   message stored in the Message_Block array.
+*
+* Parameters:
+*   None.
+*
+* Returns:
+*   Nothing.
+*
+* Comments:
+*   Many of the variable names in this code, especially the
+*   single character names, were used because those were the
+*   names used in the publication.
+*/
+static void SHA1ProcessMessageBlock(SHA1Context *context)
+{
+    /* Constants defined in FIPS-180-2, section 4.2.1 */
+    const uint32_t K[4] = {
+        0x5A827999, 0x6ED9EBA1, 0x8F1BBCDC, 0xCA62C1D6
+    };
+    int        t;               /* Loop counter */
+    uint32_t   temp;            /* Temporary word value */
+    uint32_t   W[80];           /* Word sequence */
+    uint32_t   A, B, C, D, E;   /* Word buffers */
+
+    /*
+    * Initialize the first 16 words in the array W
+    */
+    for (t = 0; t < 16; t++) {
+        W[t] = ((uint32_t)context->Message_Block[t * 4]) << 24;
+        W[t] |= ((uint32_t)context->Message_Block[t * 4 + 1]) << 16;
+        W[t] |= ((uint32_t)context->Message_Block[t * 4 + 2]) << 8;
+        W[t] |= ((uint32_t)context->Message_Block[t * 4 + 3]);
+    }
+
+    for (t = 16; t < 80; t++)
+        W[t] = SHA1_ROTL(1, W[t - 3] ^ W[t - 8] ^ W[t - 14] ^ W[t - 16]);
+
+    A = context->Intermediate_Hash[0];
+    B = context->Intermediate_Hash[1];
+    C = context->Intermediate_Hash[2];
+    D = context->Intermediate_Hash[3];
+    E = context->Intermediate_Hash[4];
+
+    for (t = 0; t < 20; t++) {
+        temp = SHA1_ROTL(5, A) + SHA_Ch(B, C, D) + E + W[t] + K[0];
+        E = D;
+        D = C;
+        C = SHA1_ROTL(30, B);
+        B = A;
+        A = temp;
+    }
+
+    for (t = 20; t < 40; t++) {
+        temp = SHA1_ROTL(5, A) + SHA_Parity(B, C, D) + E + W[t] + K[1];
+        E = D;
+        D = C;
+        C = SHA1_ROTL(30, B);
+        B = A;
+        A = temp;
+    }
+
+    for (t = 40; t < 60; t++) {
+        temp = SHA1_ROTL(5, A) + SHA_Maj(B, C, D) + E + W[t] + K[2];
+        E = D;
+        D = C;
+        C = SHA1_ROTL(30, B);
+        B = A;
+        A = temp;
+    }
+
+    for (t = 60; t < 80; t++) {
+        temp = SHA1_ROTL(5, A) + SHA_Parity(B, C, D) + E + W[t] + K[3];
+        E = D;
+        D = C;
+        C = SHA1_ROTL(30, B);
+        B = A;
+        A = temp;
+    }
+
+    context->Intermediate_Hash[0] += A;
+    context->Intermediate_Hash[1] += B;
+    context->Intermediate_Hash[2] += C;
+
+    context->Intermediate_Hash[3] += D;
+    context->Intermediate_Hash[4] += E;
+
+    context->Message_Block_Index = 0;
+}
+