/*
* Digest Commands
*
* Copyright (C) 2023 Brian O'Hagan
*
*/
#include "tlsInt.h"
#include "tclOpts.h"
#include <tcl.h>
#include <stdio.h>
#include <string.h>
#include <openssl/evp.h>
/* Constants */
const char *hex = "0123456789ABCDEF";
#define REASON() ERR_reason_error_string(ERR_get_error())
/*******************************************************************/
/*
*-------------------------------------------------------------------
*
* DigestFile --
*
* Return message digest for file using user specified hash function.
*
* Returns:
* TCL_OK or TCL_ERROR
*
* Side effects:
* Result is message digest or error message
*
*-------------------------------------------------------------------
*/
int
DigestFile(Tcl_Interp *interp, Tcl_Obj *filename, const EVP_MD *md, int format) {
EVP_MD_CTX *ctx;
Tcl_Channel chan;
char buf[32768];
unsigned char md_buf[EVP_MAX_MD_SIZE];
unsigned int md_len;
/* Open file channel */
chan = Tcl_FSOpenFileChannel(interp, filename, "rb", 0444);
if (chan == NULL) {
return TCL_ERROR;
}
/* Configure channel */
if (Tcl_SetChannelOption(interp, chan, "-translation", "binary") == TCL_ERROR ||
Tcl_SetChannelOption(interp, chan, "-buffersize", "32768") == TCL_ERROR) {
Tcl_Close(interp, chan);
return TCL_ERROR;
}
/* Create message digest context */
ctx = EVP_MD_CTX_new();
if (ctx == NULL) {
Tcl_AppendResult(interp, "Create digest context failed: ", REASON(), NULL);
Tcl_Close(interp, chan);
return TCL_ERROR;
}
/* Initialize hash function */
#if OPENSSL_VERSION_NUMBER < 0x30000000L
if (!EVP_DigestInit_ex(ctx, md, NULL))
#else
if (!EVP_DigestInit_ex2(ctx, md, NULL))
#endif
{
Tcl_AppendResult(interp, "Initialize digest failed: ", REASON(), NULL);
Tcl_Close(interp, chan);
EVP_MD_CTX_free(ctx);
return TCL_ERROR;
}
/* Read file data and update hash function */
while (!Tcl_Eof(chan)) {
int len = Tcl_ReadRaw(chan, buf, 32768);
if (!EVP_DigestUpdate(ctx, &buf, (size_t) len)) {
Tcl_AppendResult(interp, "Update digest failed: ", REASON(), NULL);
Tcl_Close(interp, chan);
EVP_MD_CTX_free(ctx);
return TCL_ERROR;
}
}
/* Close channel */
if (Tcl_Close(interp, chan) == TCL_ERROR) {
EVP_MD_CTX_free(ctx);
return TCL_ERROR;
}
/* Finalize hash function and calculate message digest */
if (!EVP_DigestFinal_ex(ctx, md_buf, &md_len)) {
Tcl_AppendResult(interp, "Finalize digest failed: ", REASON(), NULL);
EVP_MD_CTX_free(ctx);
return TCL_ERROR;
}
EVP_MD_CTX_free(ctx);
/* Return message digest as either a binary or hex string */
if (format == 0) {
Tcl_SetObjResult(interp, Tcl_NewByteArrayObj(md_buf, md_len));
} else {
Tcl_Obj *resultObj = Tcl_NewObj();
unsigned char *ptr = Tcl_SetByteArrayLength(resultObj, md_len*2);
for (unsigned int i = 0; i < md_len; i++) {
*ptr++ = hex[(md_buf[i] >> 4) & 0x0F];
*ptr++ = hex[md_buf[i] & 0x0F];
}
Tcl_SetObjResult(interp, resultObj);
}
return TCL_OK;
}
/*******************************************************************/
/*
*-------------------------------------------------------------------
*
* DigestHashFunction --
*
* Calculate message digest using hash function.
*
* Returns:
* TCL_OK or TCL_ERROR
*
* Side effects:
* Sets result to message digest or error message
*
*-------------------------------------------------------------------
*/
int
DigestHashFunction(Tcl_Interp *interp, int objc, Tcl_Obj *const objv[], const EVP_MD *md, int format) {
char *data;
int len;
unsigned int md_len;
unsigned char md_buf[EVP_MAX_MD_SIZE];
if (objc != 2) {
Tcl_WrongNumArgs(interp, 1, objv, "data");
return TCL_ERROR;
}
/* Get data */
data = Tcl_GetByteArrayFromObj(objv[1], &len);
if (data == NULL || len == 0) {
Tcl_SetResult(interp, "No data", NULL);
return TCL_ERROR;
}
/* Calculate hash value, create bin/hex representation, and write to result */
if (EVP_Digest(data, (size_t) len, md_buf, &md_len, md, NULL)) {
if (format == 0) {
Tcl_SetObjResult(interp, Tcl_NewByteArrayObj(md_buf, md_len));
} else {
Tcl_Obj *resultObj = Tcl_NewObj();
unsigned char *ptr = Tcl_SetByteArrayLength(resultObj, md_len*2);
for (unsigned int i = 0; i < md_len; i++) {
*ptr++ = hex[(md_buf[i] >> 4) & 0x0F];
*ptr++ = hex[md_buf[i] & 0x0F];
}
Tcl_SetObjResult(interp, resultObj);
}
} else {
Tcl_AppendResult(interp, "Hash calculation error:", REASON(), (char *) NULL);
return TCL_ERROR;
}
return TCL_OK;
}
/*
*-------------------------------------------------------------------
*
* DigestObjCmd --
*
* Return message digest using user specified hash function.
*
* Returns:
* TCL_OK or TCL_ERROR
*
* Side effects:
* Sets result to message digest or error message
*
*-------------------------------------------------------------------
*/
static int
DigestObjCmd(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
int idx, len, format = 1, key_len = 0, data_len = 0;
const char *digestname;
Tcl_Obj *dataObj = NULL, *fileObj = NULL;
unsigned char *key = NULL;
const EVP_MD *md;
Tcl_ResetResult(interp);
if (objc < 3 || objc > 5) {
Tcl_WrongNumArgs(interp, 1, objv, "type ?-bin|-hex? [-channel chan | -file filename | ?-data? data]");
return TCL_ERROR;
}
/* Get digest */
digestname = Tcl_GetStringFromObj(objv[1], &len);
if (digestname == NULL || (md = EVP_get_digestbyname(digestname)) == NULL) {
Tcl_AppendResult(interp, "Invalid digest type \"", digestname, "\"", NULL);
return TCL_ERROR;
}
/* Optimal case for blob of data */
if (objc == 3) {
return DigestHashFunction(interp, --objc, ++objv, md, format);
}
/* Get options */
for (idx = 2; idx < objc-1; idx++) {
char *opt = Tcl_GetStringFromObj(objv[idx], NULL);
if (opt[0] != '-')
break;
OPTFLAG("-bin", format, 0);
OPTFLAG("-binary", format, 0);
OPTFLAG("-hex", format, 1);
OPTFLAG("-hexadecimal", format, 1);
OPTOBJ("-data", dataObj);
OPTOBJ("-file", fileObj);
OPTOBJ("-filename", fileObj);
OPTBAD("option", "-bin, -data, -file, -filename, -key, or -hex");
return TCL_ERROR;
}
/* If no option for last arg, then its the data */
if (idx < objc) {
dataObj = objv[idx];
}
/* Calc digest on file or data blob */
if (fileObj != NULL) {
return DigestFile(interp, fileObj, md, format);
} else if (dataObj != NULL) {
Tcl_Obj *objs[2];
objs[0] = NULL;
objs[1] = dataObj;
return DigestHashFunction(interp, 2, objs, md, format);
}
Tcl_AppendResult(interp, "No data specified.", NULL);
return TCL_ERROR;
}
/*
*-------------------------------------------------------------------
*
* Message Digest Convenience Commands --
*
* Convenience commands for message digests.
*
* Returns:
* TCL_OK or TCL_ERROR
*
* Side effects:
* Sets result to message digest or error message
*
*-------------------------------------------------------------------
*/
int DigestMD4Cmd(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
return DigestHashFunction(interp, objc, objv, EVP_md4(), 1);
}
int DigestMD5Cmd(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
return DigestHashFunction(interp, objc, objv, EVP_md5(), 1);
}
int DigestSHA1Cmd(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
return DigestHashFunction(interp, objc, objv, EVP_sha1(), 1);
}
int DigestSHA256Cmd(ClientData clientData, Tcl_Interp *interp, int objc, Tcl_Obj *const objv[]) {
return DigestHashFunction(interp, objc, objv, EVP_sha256(), 1);
}
/*
*-------------------------------------------------------------------
*
* Tls_DigestCommands --
*
* Create digest commands
*
* Returns:
* TCL_OK or TCL_ERROR
*
* Side effects:
* Creates commands
*
*-------------------------------------------------------------------
*/
int Tls_DigestCommands(Tcl_Interp *interp) {
Tcl_CreateObjCommand(interp, "tls::digest", DigestObjCmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
Tcl_CreateObjCommand(interp, "tls::md4", DigestMD4Cmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
Tcl_CreateObjCommand(interp, "tls::md5", DigestMD5Cmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
Tcl_CreateObjCommand(interp, "tls::sha1", DigestSHA1Cmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
Tcl_CreateObjCommand(interp, "tls::sha256", DigestSHA256Cmd, (ClientData) 0, (Tcl_CmdDeleteProc *) NULL);
return TCL_OK;
}
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