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cpython/Modules/shamodule.c
Jeremy Hylton 55087f0c35 Cleanup logic a little. Check args first, then try to create the 
object.  This avoids creation + decref if bogus arguments are passed.
2001-01-29 22:46:35 +00:00

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/* SHA module */
/* This module provides an interface to NIST's Secure Hash Algorithm */
/* See below for information about the original code this module was
based upon. Additional work performed by:
Andrew Kuchling (amk1@bigfoot.com)
Greg Stein (gstein@lyra.org)
*/
/* SHA objects */
#include "Python.h"
/* Endianness testing and definitions */
#define TestEndianness(variable) {int i=1; variable=PCT_BIG_ENDIAN;\
if (*((char*)&i)==1) variable=PCT_LITTLE_ENDIAN;}
#define PCT_LITTLE_ENDIAN 1
#define PCT_BIG_ENDIAN 0
/* Some useful types */
typedef unsigned char SHA_BYTE;
#if SIZEOF_INT == 4
typedef unsigned int SHA_INT32; /* 32-bit integer */
#else
/* not defined. compilation will die. */
#endif
/* The SHA block size and message digest sizes, in bytes */
#define SHA_BLOCKSIZE 64
#define SHA_DIGESTSIZE 20
/* The structure for storing SHS info */
typedef struct {
PyObject_HEAD
SHA_INT32 digest[5]; /* Message digest */
SHA_INT32 count_lo, count_hi; /* 64-bit bit count */
SHA_BYTE data[SHA_BLOCKSIZE]; /* SHA data buffer */
int Endianness;
int local; /* unprocessed amount in data */
} SHAobject;
/* When run on a little-endian CPU we need to perform byte reversal on an
array of longwords. */
static void longReverse(SHA_INT32 *buffer, int byteCount, int Endianness)
{
SHA_INT32 value;
if ( Endianness == PCT_BIG_ENDIAN )
return;
byteCount /= sizeof(*buffer);
while (byteCount--) {
value = *buffer;
value = ( ( value & 0xFF00FF00L ) >> 8 ) | \
( ( value & 0x00FF00FFL ) << 8 );
*buffer++ = ( value << 16 ) | ( value >> 16 );
}
}
static void SHAcopy(SHAobject *src, SHAobject *dest)
{
dest->Endianness = src->Endianness;
dest->local = src->local;
dest->count_lo = src->count_lo;
dest->count_hi = src->count_hi;
memcpy(dest->digest, src->digest, sizeof(src->digest));
memcpy(dest->data, src->data, sizeof(src->data));
}
/* ------------------------------------------------------------------------
*
* This code for the SHA algorithm was noted as public domain. The original
* headers are pasted below.
*
* Several changes have been made to make it more compatible with the
* Python environment and desired interface.
*
*/
/* NIST Secure Hash Algorithm */
/* heavily modified by Uwe Hollerbach <uh@alumni.caltech edu> */
/* from Peter C. Gutmann's implementation as found in */
/* Applied Cryptography by Bruce Schneier */
/* Further modifications to include the "UNRAVEL" stuff, below */
/* This code is in the public domain */
/* UNRAVEL should be fastest & biggest */
/* UNROLL_LOOPS should be just as big, but slightly slower */
/* both undefined should be smallest and slowest */
#define UNRAVEL
/* #define UNROLL_LOOPS */
/* The SHA f()-functions. The f1 and f3 functions can be optimized to
save one boolean operation each - thanks to Rich Schroeppel,
rcs@cs.arizona.edu for discovering this */
/*#define f1(x,y,z) ((x & y) | (~x & z)) // Rounds 0-19 */
#define f1(x,y,z) (z ^ (x & (y ^ z))) /* Rounds 0-19 */
#define f2(x,y,z) (x ^ y ^ z) /* Rounds 20-39 */
/*#define f3(x,y,z) ((x & y) | (x & z) | (y & z)) // Rounds 40-59 */
#define f3(x,y,z) ((x & y) | (z & (x | y))) /* Rounds 40-59 */
#define f4(x,y,z) (x ^ y ^ z) /* Rounds 60-79 */
/* SHA constants */
#define CONST1 0x5a827999L /* Rounds 0-19 */
#define CONST2 0x6ed9eba1L /* Rounds 20-39 */
#define CONST3 0x8f1bbcdcL /* Rounds 40-59 */
#define CONST4 0xca62c1d6L /* Rounds 60-79 */
/* 32-bit rotate */
#define R32(x,n) ((x << n) | (x >> (32 - n)))
/* the generic case, for when the overall rotation is not unraveled */
#define FG(n) \
T = R32(A,5) + f##n(B,C,D) + E + *WP++ + CONST##n; \
E = D; D = C; C = R32(B,30); B = A; A = T
/* specific cases, for when the overall rotation is unraveled */
#define FA(n) \
T = R32(A,5) + f##n(B,C,D) + E + *WP++ + CONST##n; B = R32(B,30)
#define FB(n) \
E = R32(T,5) + f##n(A,B,C) + D + *WP++ + CONST##n; A = R32(A,30)
#define FC(n) \
D = R32(E,5) + f##n(T,A,B) + C + *WP++ + CONST##n; T = R32(T,30)
#define FD(n) \
C = R32(D,5) + f##n(E,T,A) + B + *WP++ + CONST##n; E = R32(E,30)
#define FE(n) \
B = R32(C,5) + f##n(D,E,T) + A + *WP++ + CONST##n; D = R32(D,30)
#define FT(n) \
A = R32(B,5) + f##n(C,D,E) + T + *WP++ + CONST##n; C = R32(C,30)
/* do SHA transformation */
static void
sha_transform(SHAobject *sha_info)
{
int i;
SHA_INT32 T, A, B, C, D, E, W[80], *WP;
memcpy(W, sha_info->data, sizeof(sha_info->data));
longReverse(W, (int)sizeof(sha_info->data), sha_info->Endianness);
for (i = 16; i < 80; ++i) {
W[i] = W[i-3] ^ W[i-8] ^ W[i-14] ^ W[i-16];
/* extra rotation fix */
W[i] = R32(W[i], 1);
}
A = sha_info->digest[0];
B = sha_info->digest[1];
C = sha_info->digest[2];
D = sha_info->digest[3];
E = sha_info->digest[4];
WP = W;
#ifdef UNRAVEL
FA(1); FB(1); FC(1); FD(1); FE(1); FT(1); FA(1); FB(1); FC(1); FD(1);
FE(1); FT(1); FA(1); FB(1); FC(1); FD(1); FE(1); FT(1); FA(1); FB(1);
FC(2); FD(2); FE(2); FT(2); FA(2); FB(2); FC(2); FD(2); FE(2); FT(2);
FA(2); FB(2); FC(2); FD(2); FE(2); FT(2); FA(2); FB(2); FC(2); FD(2);
FE(3); FT(3); FA(3); FB(3); FC(3); FD(3); FE(3); FT(3); FA(3); FB(3);
FC(3); FD(3); FE(3); FT(3); FA(3); FB(3); FC(3); FD(3); FE(3); FT(3);
FA(4); FB(4); FC(4); FD(4); FE(4); FT(4); FA(4); FB(4); FC(4); FD(4);
FE(4); FT(4); FA(4); FB(4); FC(4); FD(4); FE(4); FT(4); FA(4); FB(4);
sha_info->digest[0] += E;
sha_info->digest[1] += T;
sha_info->digest[2] += A;
sha_info->digest[3] += B;
sha_info->digest[4] += C;
#else /* !UNRAVEL */
#ifdef UNROLL_LOOPS
FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1);
FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1); FG(1);
FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2);
FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2); FG(2);
FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3);
FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3); FG(3);
FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4);
FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4); FG(4);
#else /* !UNROLL_LOOPS */
for (i = 0; i < 20; ++i) { FG(1); }
for (i = 20; i < 40; ++i) { FG(2); }
for (i = 40; i < 60; ++i) { FG(3); }
for (i = 60; i < 80; ++i) { FG(4); }
#endif /* !UNROLL_LOOPS */
sha_info->digest[0] += A;
sha_info->digest[1] += B;
sha_info->digest[2] += C;
sha_info->digest[3] += D;
sha_info->digest[4] += E;
#endif /* !UNRAVEL */
}
/* initialize the SHA digest */
static void
sha_init(SHAobject *sha_info)
{
TestEndianness(sha_info->Endianness)
sha_info->digest[0] = 0x67452301L;
sha_info->digest[1] = 0xefcdab89L;
sha_info->digest[2] = 0x98badcfeL;
sha_info->digest[3] = 0x10325476L;
sha_info->digest[4] = 0xc3d2e1f0L;
sha_info->count_lo = 0L;
sha_info->count_hi = 0L;
sha_info->local = 0;
}
/* update the SHA digest */
static void
sha_update(SHAobject *sha_info, SHA_BYTE *buffer, int count)
{
int i;
SHA_INT32 clo;
clo = sha_info->count_lo + ((SHA_INT32) count << 3);
if (clo < sha_info->count_lo) {
++sha_info->count_hi;
}
sha_info->count_lo = clo;
sha_info->count_hi += (SHA_INT32) count >> 29;
if (sha_info->local) {
i = SHA_BLOCKSIZE - sha_info->local;
if (i > count) {
i = count;
}
memcpy(((SHA_BYTE *) sha_info->data) + sha_info->local, buffer, i);
count -= i;
buffer += i;
sha_info->local += i;
if (sha_info->local == SHA_BLOCKSIZE) {
sha_transform(sha_info);
}
else {
return;
}
}
while (count >= SHA_BLOCKSIZE) {
memcpy(sha_info->data, buffer, SHA_BLOCKSIZE);
buffer += SHA_BLOCKSIZE;
count -= SHA_BLOCKSIZE;
sha_transform(sha_info);
}
memcpy(sha_info->data, buffer, count);
sha_info->local = count;
}
/* finish computing the SHA digest */
static void
sha_final(unsigned char digest[20], SHAobject *sha_info)
{
int count;
SHA_INT32 lo_bit_count, hi_bit_count;
lo_bit_count = sha_info->count_lo;
hi_bit_count = sha_info->count_hi;
count = (int) ((lo_bit_count >> 3) & 0x3f);
((SHA_BYTE *) sha_info->data)[count++] = 0x80;
if (count > SHA_BLOCKSIZE - 8) {
memset(((SHA_BYTE *) sha_info->data) + count, 0,
SHA_BLOCKSIZE - count);
sha_transform(sha_info);
memset((SHA_BYTE *) sha_info->data, 0, SHA_BLOCKSIZE - 8);
}
else {
memset(((SHA_BYTE *) sha_info->data) + count, 0,
SHA_BLOCKSIZE - 8 - count);
}
/* GJS: note that we add the hi/lo in big-endian. sha_transform will
swap these values into host-order. */
sha_info->data[56] = (hi_bit_count >> 24) & 0xff;
sha_info->data[57] = (hi_bit_count >> 16) & 0xff;
sha_info->data[58] = (hi_bit_count >> 8) & 0xff;
sha_info->data[59] = (hi_bit_count >> 0) & 0xff;
sha_info->data[60] = (lo_bit_count >> 24) & 0xff;
sha_info->data[61] = (lo_bit_count >> 16) & 0xff;
sha_info->data[62] = (lo_bit_count >> 8) & 0xff;
sha_info->data[63] = (lo_bit_count >> 0) & 0xff;
sha_transform(sha_info);
digest[ 0] = (unsigned char) ((sha_info->digest[0] >> 24) & 0xff);
digest[ 1] = (unsigned char) ((sha_info->digest[0] >> 16) & 0xff);
digest[ 2] = (unsigned char) ((sha_info->digest[0] >> 8) & 0xff);
digest[ 3] = (unsigned char) ((sha_info->digest[0] ) & 0xff);
digest[ 4] = (unsigned char) ((sha_info->digest[1] >> 24) & 0xff);
digest[ 5] = (unsigned char) ((sha_info->digest[1] >> 16) & 0xff);
digest[ 6] = (unsigned char) ((sha_info->digest[1] >> 8) & 0xff);
digest[ 7] = (unsigned char) ((sha_info->digest[1] ) & 0xff);
digest[ 8] = (unsigned char) ((sha_info->digest[2] >> 24) & 0xff);
digest[ 9] = (unsigned char) ((sha_info->digest[2] >> 16) & 0xff);
digest[10] = (unsigned char) ((sha_info->digest[2] >> 8) & 0xff);
digest[11] = (unsigned char) ((sha_info->digest[2] ) & 0xff);
digest[12] = (unsigned char) ((sha_info->digest[3] >> 24) & 0xff);
digest[13] = (unsigned char) ((sha_info->digest[3] >> 16) & 0xff);
digest[14] = (unsigned char) ((sha_info->digest[3] >> 8) & 0xff);
digest[15] = (unsigned char) ((sha_info->digest[3] ) & 0xff);
digest[16] = (unsigned char) ((sha_info->digest[4] >> 24) & 0xff);
digest[17] = (unsigned char) ((sha_info->digest[4] >> 16) & 0xff);
digest[18] = (unsigned char) ((sha_info->digest[4] >> 8) & 0xff);
digest[19] = (unsigned char) ((sha_info->digest[4] ) & 0xff);
}
/*
* End of copied SHA code.
*
* ------------------------------------------------------------------------
*/
staticforward PyTypeObject SHAtype;
static SHAobject *
newSHAobject(void)
{
return (SHAobject *)PyObject_New(SHAobject, &SHAtype);
}
/* Internal methods for a hashing object */
static void
SHA_dealloc(PyObject *ptr)
{
PyObject_Del(ptr);
}
/* External methods for a hashing object */
static char SHA_copy__doc__[] =
"Return a copy of the hashing object.";
static PyObject *
SHA_copy(SHAobject *self, PyObject *args)
{
SHAobject *newobj;
if (!PyArg_ParseTuple(args, ":copy")) {
return NULL;
}
if ( (newobj = newSHAobject())==NULL)
return NULL;
SHAcopy(self, newobj);
return (PyObject *)newobj;
}
static char SHA_digest__doc__[] =
"Return the digest value as a string of binary data.";
static PyObject *
SHA_digest(SHAobject *self, PyObject *args)
{
unsigned char digest[SHA_DIGESTSIZE];
SHAobject temp;
if (!PyArg_ParseTuple(args, ":digest"))
return NULL;
SHAcopy(self, &temp);
sha_final(digest, &temp);
return PyString_FromStringAndSize((const char *)digest, sizeof(digest));
}
static char SHA_hexdigest__doc__[] =
"Return the digest value as a string of hexadecimal digits.";
static PyObject *
SHA_hexdigest(SHAobject *self, PyObject *args)
{
unsigned char digest[SHA_DIGESTSIZE];
SHAobject temp;
PyObject *retval;
char *hex_digest;
int i, j;
if (!PyArg_ParseTuple(args, ":hexdigest"))
return NULL;
/* Get the raw (binary) digest value */
SHAcopy(self, &temp);
sha_final(digest, &temp);
/* Create a new string */
retval = PyString_FromStringAndSize(NULL, sizeof(digest) * 2);
if (!retval)
return NULL;
hex_digest = PyString_AsString(retval);
if (!hex_digest) {
Py_DECREF(retval);
return NULL;
}
/* Make hex version of the digest */
for(i=j=0; i<sizeof(digest); i++) {
char c;
c = (digest[i] >> 4) & 0xf;
c = (c>9) ? c+'a'-10 : c + '0';
hex_digest[j++] = c;
c = (digest[i] & 0xf);
c = (c>9) ? c+'a'-10 : c + '0';
hex_digest[j++] = c;
}
return retval;
}
static char SHA_update__doc__[] =
"Update this hashing object's state with the provided string.";
static PyObject *
SHA_update(SHAobject *self, PyObject *args)
{
unsigned char *cp;
int len;
if (!PyArg_ParseTuple(args, "s#:update", &cp, &len))
return NULL;
sha_update(self, cp, len);
Py_INCREF(Py_None);
return Py_None;
}
static PyMethodDef SHA_methods[] = {
{"copy", (PyCFunction)SHA_copy, METH_VARARGS, SHA_copy__doc__},
{"digest", (PyCFunction)SHA_digest, METH_VARARGS, SHA_digest__doc__},
{"hexdigest", (PyCFunction)SHA_hexdigest, METH_VARARGS, SHA_hexdigest__doc__},
{"update", (PyCFunction)SHA_update, METH_VARARGS, SHA_update__doc__},
{NULL, NULL} /* sentinel */
};
static PyObject *
SHA_getattr(PyObject *self, char *name)
{
if (strcmp(name, "blocksize")==0)
return PyInt_FromLong(1);
if (strcmp(name, "digestsize")==0)
return PyInt_FromLong(20);
return Py_FindMethod(SHA_methods, self, name);
}
static PyTypeObject SHAtype = {
PyObject_HEAD_INIT(NULL)
0, /*ob_size*/
"SHA", /*tp_name*/
sizeof(SHAobject), /*tp_size*/
0, /*tp_itemsize*/
/* methods */
SHA_dealloc, /*tp_dealloc*/
0, /*tp_print*/
SHA_getattr, /*tp_getattr*/
};
/* The single module-level function: new() */
static char SHA_new__doc__[] =
"Return a new SHA hashing object. An optional string "
"argument may be provided; if present, this string will be "
" automatically hashed.";
static PyObject *
SHA_new(PyObject *self, PyObject *args, PyObject *kwdict)
{
static char *kwlist[] = {"string", NULL};
SHAobject *new;
unsigned char *cp = NULL;
int len;
if (!PyArg_ParseTupleAndKeywords(args, kwdict, "|s#:new", kwlist,
&cp, &len)) {
return NULL;
}
if ((new = newSHAobject()) == NULL)
return NULL;
sha_init(new);
if (PyErr_Occurred()) {
Py_DECREF(new);
return NULL;
}
if (cp)
sha_update(new, cp, len);
return (PyObject *)new;
}
/* List of functions exported by this module */
static struct PyMethodDef SHA_functions[] = {
{"new", (PyCFunction)SHA_new, METH_VARARGS|METH_KEYWORDS, SHA_new__doc__},
{"sha", (PyCFunction)SHA_new, METH_VARARGS|METH_KEYWORDS, SHA_new__doc__},
{NULL, NULL} /* Sentinel */
};
/* Initialize this module. */
#define insint(n,v) { PyObject *o=PyInt_FromLong(v); \
if (o!=NULL) PyDict_SetItemString(d,n,o); \
Py_XDECREF(o); }
DL_EXPORT(void)
initsha(void)
{
PyObject *d, *m;
SHAtype.ob_type = &PyType_Type;
m = Py_InitModule("sha", SHA_functions);
/* Add some symbolic constants to the module */
d = PyModule_GetDict(m);
insint("blocksize", 1); /* For future use, in case some hash
functions require an integral number of
blocks */
insint("digestsize", 20);
}
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