Get SHA-1 from RFC 4634 instead of RFC 3174, since it has a clearer license.

git-svn-id: svn://bind10.isc.org/svn/bind10/trunk@1490 e5f2f494-b856-4b98-b285-d166d9295462

src/lib/dns/sha1.cc

@@ -1,13 +1,18 @@
 /*
- *  sha1.c
- *  Adapted from RFC 3174, "US Secure Hash Algorithm 1", D. Eastlake et al
- *
  *  Description:
- *      This file implements the Secure Hashing Algorithm 1 as
- *      defined in FIPS PUB 180-1 published April 17, 1995.
+ *      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, produces a 160-bit message digest for a given
- *      data stream.  It should take about 2**n steps to find a
+ *      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
@@ -16,26 +21,77 @@
  *
  *  Portability Issues:
  *      SHA-1 is defined in terms of 32-bit "words".  This code
- *      uses <stdint.h> (included via "sha1.h" to define 32 and 8
+ *      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.  Although SHA-1 allows a message digest to be generated
- *      for messages of any number of bits less than 2^64, this
- *      implementation only works with messages with a length that is
- *      a multiple of the size of an 8-bit character.
+ *      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.
+ *
+ *  Authorship:
+ *      This file is adapted from RFC 4634, by D. Eastlake et al.
+ *      Copyright (C) The Internet Society (2006).
+ *
+ *      Permission is granted for all uses, commercial and non-commercial,
+ *      of the sample code found in Section 8.  Royalty free license to
+ *      use, copy, modify and distribute the software found in Section 8 is
+ *      granted, provided that this document is identified in all material
+ *      mentioning or referencing this software, and provided that
+ *      redistributed derivative works do not contain misleading author or
+ *      version information.
+ *
+ *      The authors make no representations concerning either the
+ *      merchantability of this software or the suitability of this
+ *      software for any particular purpose.  It is provided "as is"
+ *      without express or implied warranty of any kind.
+ *      
  */
-
 #include "sha1.h"
 
 /* Local Function Prototyptes */
-static void SHA1PadMessage(SHA1Context *);
+static void SHA1Finalize(SHA1Context *, uint8_t Pad_Byte);
+static void SHA1PadMessage(SHA1Context *, uint8_t Pad_Byte);
 static void SHA1ProcessMessageBlock(SHA1Context *);
 
 /*
+ * Define functions used by SHA1 hash
+ */
+static inline uint32_t
+SHA_Ch(const uint32_t x, const uint32_t y, const uint32_t z) {
+    return (((x) & ((y) ^ (z))) ^ (z));
+}
+
+static inline uint32_t
+SHA_Maj(const uint32_t x, const uint32_t y, const uint32_t z) {
+    return (((x) & ((y) | (z))) | ((y) & (z)));
+}
+
+static inline uint32_t
+SHA_Parity(const uint32_t x, const uint32_t y, const uint32_t z) {
+    return ((x) ^ (y) ^ (z));
+}
+
+static inline int 
+SHA1CircularShift(uint8_t bits, uint32_t word) {
+    return ((word << bits) | (word >> (32 - bits)));
+}
+
+static inline bool
+SHA1AddLength(SHA1Context *context, uint32_t length) {
+    uint32_t addTemp = context->Length_Low;
+    context->Length_Low += length;
+    if (context->Length_Low < addTemp && ++context->Length_High == 0) {
+        return true;
+    } else {
+        return false;
+    }
+}
+
+/*
  *  SHA1Reset
  *
  *  Description:
@@ -71,6 +127,129 @@ SHA1Reset(SHA1Context *context) {
     return (SHA_SUCCESS);
 }
 
+
+/*
+ *  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 (SHA_SUCCESS);
+    }
+
+    if (!context || !message_array) {
+        return (SHA_NULL);
+    }
+
+    if (context->Computed) {
+        context->Corrupted = SHA_STATEERROR;
+        return (SHA_STATEERROR);
+    }
+
+    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_BLOCKSIZE))
+        {
+            SHA1ProcessMessageBlock(context);
+        }
+
+        message_array++;
+    }
+
+    return (SHA_SUCCESS);
+}
+
+/*
+ * 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 (SHA_SUCCESS);
+    }
+
+    if (!context) {
+        return (SHA_NULL);
+    }
+
+    if (context->Computed || (length >= 8) || (length == 0)) {
+        context->Corrupted = SHA_STATEERROR;
+        return (SHA_STATEERROR);
+    }
+
+    if (context->Corrupted) {
+        return (context->Corrupted);
+    }
+
+    SHA1AddLength(context, length);
+    SHA1Finalize(context,
+                 (uint8_t) ((message_bits & masks[length]) | markbit[length]));
+
+    return (SHA_SUCCESS);
+}
+
 /*
  *  SHA1Result
  *
@@ -103,14 +282,7 @@ SHA1Result(SHA1Context *context, uint8_t Message_Digest[SHA1_HASHSIZE]) {
     }
 
     if (!context->Computed) {
-        SHA1PadMessage(context);
-        for(i = 0; i < 64; ++i) {
-            /* message may be sensitive, clear it out */
-            context->Message_Block[i] = 0;
-        }
-        context->Length_Low = 0;    /* and clear length */
-        context->Length_High = 0;
-        context->Computed = 1;
+        SHA1Finalize(context, 0x80);
     }
 
     for(i = 0; i < SHA1_HASHSIZE; ++i) {
@@ -122,81 +294,104 @@ SHA1Result(SHA1Context *context, uint8_t Message_Digest[SHA1_HASHSIZE]) {
 }
 
 /*
- *  SHA1Input
+ * 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_BLOCKSIZE; ++i)
+        context->Message_Block[i] = 0;
+    context->Length_Low = 0;  /* and clear length */
+    context->Length_High = 0;
+    context->Computed = 1;
+}
+
+/*
+ *  SHA1PadMessage
  *
  *  Description:
- *      This function accepts an array of octets as the next portion
- *      of the message.
+ *      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 function will pad the message
+ *      according to those rules by filling the Message_Block array
+ *      accordingly.  It will also call the ProcessMessageBlock function
+ *      provided appropriately.  When it returns, it can be assumed that
+ *      the message digest has been computed.
  *
  *  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
+ *          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:
- *      sha Error Code.
+ *      Nothing.
  *
  */
-int
-SHA1Input(SHA1Context *context, const uint8_t *message_array, unsigned length) {
-    if (!length) {
-        return (SHA_SUCCESS);
-    }
-
-    if (!context || !message_array) {
-        return (SHA_NULL);
-    }
-
-    if (context->Computed) {
-        context->Corrupted = SHA_STATEERROR;
-        return (SHA_STATEERROR);
-    }
-
-    if (context->Corrupted) {
-         return (context->Corrupted);
-    }
-
-    while(length-- && !context->Corrupted) {
-        context->Message_Block[context->Message_Block_Index++] =
-                        (*message_array & 0xFF);
-
-        context->Length_Low += 8;
-        if (context->Length_Low == 0) {
-            context->Length_High++;
-            if (context->Length_High == 0) {
-                /* Message is too long */
-                context->Corrupted = 1;
-            }
+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_BLOCKSIZE - 8)) {
+        context->Message_Block[context->Message_Block_Index++] = Pad_Byte;
+        while (context->Message_Block_Index < SHA1_BLOCKSIZE) {
+            context->Message_Block[context->Message_Block_Index++] = 0;
         }
 
-        if (context->Message_Block_Index == 64) {
-            SHA1ProcessMessageBlock(context);
-        }
+        SHA1ProcessMessageBlock(context);
+    } else
+        context->Message_Block[context->Message_Block_Index++] = Pad_Byte;
 
-        message_array++;
-    }
+    while (context->Message_Block_Index < (SHA1_BLOCKSIZE - 8))
+        context->Message_Block[context->Message_Block_Index++] = 0;
 
-    return (SHA_SUCCESS);
-}
+    /*
+     * 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);
 
-/*
- *  Define the SHA1 circular left shift
- */
-static inline int 
-SHA1CircularShift(uint8_t bits, uint32_t word) {
-    return ((word << bits) | (word >> (32 - bits)));
+    SHA1ProcessMessageBlock(context);
 }
 
 /*
  *  SHA1ProcessMessageBlock
  *
  *  Description:
- *      This function will process the next 512 bits of the message
- *      stored in the Message_Block array.
+ *      This helper function will process the next 512 bits of the
+ *      message stored in the Message_Block array.
  *
  *  Parameters:
  *      None.
@@ -213,7 +408,8 @@ SHA1CircularShift(uint8_t bits, uint32_t word) {
  */
 static void
 SHA1ProcessMessageBlock(SHA1Context *context) {
-    const uint32_t K[] = {          /* Constants defined in SHA-1   */
+    /* Constants defined in FIPS-180-2, section 4.2.1 */
+    const uint32_t K[] = {
         0x5A827999,
         0x6ED9EBA1,
         0x8F1BBCDC,
@@ -225,17 +421,17 @@ SHA1ProcessMessageBlock(SHA1Context *context) {
     uint32_t      A, B, C, D, E;     /* Word buffers                */
 
     /*
-     *  Initialize the first 16 words in the array W
+     * Initialize the first 16 words in the array W
      */
-    for(t = 0; t < 16; t++) {
-        W[t] = context->Message_Block[t * 4] << 24;
-        W[t] |= context->Message_Block[t * 4 + 1] << 16;
-        W[t] |= context->Message_Block[t * 4 + 2] << 8;
-        W[t] |= context->Message_Block[t * 4 + 3];
+    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] = SHA1CircularShift(1,W[t-3] ^ W[t-8] ^ W[t-14] ^ W[t-16]);
+    for (t = 16; t < 80; t++) {
+        W[t] = SHA1CircularShift(1, W[t-3] ^ W[t-8] ^ W[t-14] ^ W[t-16]);
     }
 
     A = context->Intermediate_Hash[0];
@@ -244,9 +440,8 @@ SHA1ProcessMessageBlock(SHA1Context *context) {
     D = context->Intermediate_Hash[3];
     E = context->Intermediate_Hash[4];
 
-    for(t = 0; t < 20; t++) {
-        temp =  SHA1CircularShift(5,A) +
-                ((B & C) | ((~B) & D)) + E + W[t] + K[0];
+    for (t = 0; t < 20; t++) {
+        temp = SHA1CircularShift(5,A) + SHA_Ch(B, C, D) + E + W[t] + K[0];
         E = D;
         D = C;
         C = SHA1CircularShift(30,B);
@@ -254,8 +449,8 @@ SHA1ProcessMessageBlock(SHA1Context *context) {
         A = temp;
     }
 
-    for(t = 20; t < 40; t++) {
-        temp = SHA1CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[1];
+    for (t = 20; t < 40; t++) {
+        temp = SHA1CircularShift(5,A) + SHA_Parity(B, C, D) + E + W[t] + K[1];
         E = D;
         D = C;
         C = SHA1CircularShift(30,B);
@@ -263,9 +458,8 @@ SHA1ProcessMessageBlock(SHA1Context *context) {
         A = temp;
     }
 
-    for(t = 40; t < 60; t++) {
-        temp = SHA1CircularShift(5,A) +
-               ((B & C) | (B & D) | (C & D)) + E + W[t] + K[2];
+    for (t = 40; t < 60; t++) {
+        temp = SHA1CircularShift(5,A) + SHA_Maj(B, C, D) + E + W[t] + K[2];
         E = D;
         D = C;
         C = SHA1CircularShift(30,B);
@@ -273,8 +467,8 @@ SHA1ProcessMessageBlock(SHA1Context *context) {
         A = temp;
     }
 
-    for(t = 60; t < 80; t++) {
-        temp = SHA1CircularShift(5,A) + (B ^ C ^ D) + E + W[t] + K[3];
+    for (t = 60; t < 80; t++) {
+        temp = SHA1CircularShift(5,A) + SHA_Parity(B, C, D) + E + W[t] + K[3];
         E = D;
         D = C;
         C = SHA1CircularShift(30,B);
@@ -290,67 +484,3 @@ SHA1ProcessMessageBlock(SHA1Context *context) {
 
     context->Message_Block_Index = 0;
 }
-
-/*
- *  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 function will pad the message
- *      according to those rules by filling the Message_Block array
- *      accordingly.  It will also call the ProcessMessageBlock function
- *      provided appropriately.  When it returns, it can be assumed that
- *      the message digest has been computed.
- *
- *  Parameters:
- *      context: [in/out]
- *          The context to pad
- *      ProcessMessageBlock: [in]
- *          The appropriate SHA*ProcessMessageBlock function
- *  Returns:
- *      Nothing.
- *
- */
-
-static void
-SHA1PadMessage(SHA1Context *context) {
-    /*
-     *  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 > 55) {
-        context->Message_Block[context->Message_Block_Index++] = 0x80;
-        while(context->Message_Block_Index < 64) {
-            context->Message_Block[context->Message_Block_Index++] = 0;
-        }
-
-        SHA1ProcessMessageBlock(context);
-
-        while(context->Message_Block_Index < 56) {
-            context->Message_Block[context->Message_Block_Index++] = 0;
-        }
-    } else {
-        context->Message_Block[context->Message_Block_Index++] = 0x80;
-        while(context->Message_Block_Index < 56) {
-            context->Message_Block[context->Message_Block_Index++] = 0;
-        }
-    }
-
-    /*
-     *  Store the message length as the last 8 octets
-     */
-    context->Message_Block[56] = context->Length_High >> 24;
-    context->Message_Block[57] = context->Length_High >> 16;
-    context->Message_Block[58] = context->Length_High >> 8;
-    context->Message_Block[59] = context->Length_High;
-    context->Message_Block[60] = context->Length_Low >> 24;
-    context->Message_Block[61] = context->Length_Low >> 16;
-    context->Message_Block[62] = context->Length_Low >> 8;
-    context->Message_Block[63] = context->Length_Low;
-
-    SHA1ProcessMessageBlock(context);
-}

src/lib/dns/sha1.h

@@ -10,8 +10,24 @@
  *      single character names, were used because those were the names
  *      used in the publication.
  *
- *      Please read the file sha1.c for more information.
+ *      Please read the file sha1.cc for more information.
  *
+ *  Authorship:
+ *      This file is adapted from RFC 4634, by D. Eastlake et al.
+ *      Copyright (C) The Internet Society (2006).
+ *
+ *      Permission is granted for all uses, commercial and non-commercial,
+ *      of the sample code found in Section 8.  Royalty free license to
+ *      use, copy, modify and distribute the software found in Section 8 is
+ *      granted, provided that this document is identified in all material
+ *      mentioning or referencing this software, and provided that
+ *      redistributed derivative works do not contain misleading author or
+ *      version information.
+ *
+ *      The authors make no representations concerning either the
+ *      merchantability of this software or the suitability of this
+ *      software for any particular purpose.  It is provided "as is"
+ *      without express or implied warranty of any kind.
  */
 
 #ifndef _SHA1_H_
@@ -35,7 +51,9 @@ enum {
 };
 
 enum {
-    SHA1_HASHSIZE = 20
+    SHA1_HASHSIZE = 20,
+    SHA1_HASHBITS = 20,
+    SHA1_BLOCKSIZE = 64
 };
 
 /*
@@ -56,8 +74,11 @@ typedef struct SHA1Context
 /*
  *  Function Prototypes
  */
-int SHA1Reset(SHA1Context *);
-int SHA1Input(SHA1Context *, const uint8_t *, unsigned int);
-int SHA1Result(SHA1Context *, uint8_t Message_Digest[SHA1_HASHSIZE]);
+extern int SHA1Reset(SHA1Context *);
+extern int SHA1Input(SHA1Context *, const uint8_t *bytes,
+                     unsigned int bytecount);
+extern int SHA1FinalBits(SHA1Context *, const uint8_t bits,
+                         unsigned int bitcount);
+extern int SHA1Result(SHA1Context *, uint8_t Message_Digest[SHA1_HASHSIZE]);
 
 #endif