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<a class="el" href="dir_000000.html">src</a> / <a class="el" href="dir_000006.html">libcodec</a></div>
<h1>cipher.c</h1><a href="cipher_8c.html">Go to the documentation of this file.</a><div class="fragment"><pre class="fragment">00001 <span class="comment">/*</span>
00002 <span class="comment"> * Copyright (c) 2005, 2006 by KoanLogic s.r.l. <http://www.koanlogic.com></span>
00003 <span class="comment"> * All rights reserved.</span>
00004 <span class="comment"> *</span>
00005 <span class="comment"> * This file is part of KLone, and as such it is subject to the license stated</span>
00006 <span class="comment"> * in the LICENSE file which you have received as part of this distribution.</span>
00007 <span class="comment"> *</span>
00008 <span class="comment"> * $Id: cipher.c,v 1.10 2006/01/09 12:38:38 tat Exp $</span>
00009 <span class="comment"> */</span>
00010
00011 <span class="preprocessor">#include "klone_conf.h"</span>
00012 <span class="preprocessor">#include <u/libu.h></span>
00013 <span class="preprocessor">#include <<a class="code" href="codec_8h.html">klone/codec.h</a>></span>
00014 <span class="preprocessor">#include <<a class="code" href="ccipher_8h.html">klone/ccipher.h</a>></span>
00015 <span class="preprocessor">#include <<a class="code" href="utils_8h.html">klone/utils.h</a>></span>
00016
00017 <span class="keyword">enum</span> { <a class="code" href="cipher_8c.html#a9a3">CODEC_CIPHER_MAX_INPUT</a> = 4096 <span class="comment">/* max src block size for transform() */</span> };
00018
<a name="l00019"></a><a class="code" href="cipher_8c.html#a0">00019</a> <span class="keyword">typedef</span> int (*EVP_Update_t)(EVP_CIPHER_CTX *ctx, <span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> *out,
00020 <span class="keywordtype">int</span> *outl, <span class="keyword">const</span> <span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> *in, <span class="keywordtype">int</span> inl);
<a name="l00021"></a><a class="code" href="cipher_8c.html#a1">00021</a> <span class="keyword">typedef</span> int (*EVP_Final_ex_t)(EVP_CIPHER_CTX *ctx, <span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> *out,
00022 <span class="keywordtype">int</span> *outl);
00023
00024 <span class="keyword">struct </span>codec_cipher_s
00025 {
00026 <a class="code" href="structcodec__s.html">codec_t</a> codec;
00027 <span class="keyword">const</span> EVP_CIPHER *cipher; <span class="comment">/* encryption cipher algorithm */</span>
00028 EVP_CIPHER_CTX cipher_ctx; <span class="comment">/* encrypt context */</span>
00029 <span class="keywordtype">char</span> *cbuf;
00030 size_t coff, ccount, cbuf_size;
00031 <a class="code" href="cipher_8c.html#a0">EVP_Update_t</a> update; <span class="comment">/* EVP_{Encrypt,Decrypt}Update func ptr */</span>
00032 <a class="code" href="cipher_8c.html#a1">EVP_Final_ex_t</a> <span class="keyword">final</span>; <span class="comment">/* EVP_{Encrypt,Decrypt}Final_ex func ptr */</span>
00033 };
00034
<a name="l00035"></a><a class="code" href="cipher_8c.html#a2">00035</a> <span class="keyword">typedef</span> <span class="keyword">struct </span>codec_cipher_s <a class="code" href="cipher_8c.html#a2">codec_cipher_t</a>;
00036
00037 <span class="keyword">static</span> <span class="keywordtype">void</span> codec_cbufcpy(codec_cipher_t *cc, <span class="keywordtype">char</span> *dst, size_t *dcount)
00038 {
00039 size_t count;
00040
00041 count = <a class="code" href="utils_8h.html#a0">MIN</a>(*dcount, cc->ccount);
00042
00043 memcpy(dst, cc->cbuf + cc->coff, count);
00044 cc->ccount -= count;
00045 <span class="keywordflow">if</span>(cc->ccount)
00046 cc->coff += count;
00047 <span class="keywordflow">else</span>
00048 cc->coff = 0;
00049 *dcount = count;
00050 }
00051
00052 <span class="keyword">static</span> ssize_t cipher_flush(<a class="code" href="structcodec__s.html">codec_t</a> *codec, <span class="keywordtype">char</span> *dst, size_t *dcount)
00053 {
00054 <a class="code" href="cipher_8c.html#a2">codec_cipher_t</a> *cc;
00055 <span class="keywordtype">int</span> wr;
00056
00057 dbg_err_if (codec == NULL);
00058 dbg_err_if (dst == NULL);
00059 dbg_err_if (dcount == NULL);
00060
00061 cc = (<a class="code" href="cipher_8c.html#a2">codec_cipher_t</a>*)codec;
00062
00063 <span class="keywordflow">for</span>(;;)
00064 {
00065 <span class="keywordflow">if</span>(cc->ccount)
00066 {
00067 codec_cbufcpy(cc, dst, dcount);
00068 <span class="keywordflow">return</span> CODEC_FLUSH_CHUNK; <span class="comment">/* call flush again */</span>
00069 }
00070
00071 <span class="keywordflow">if</span>(cc->final)
00072 {
00073 wr = -1; <span class="comment">/* just used to return an int value */</span>
00074 dbg_err_if(!cc->final(&cc->cipher_ctx, cc->cbuf, &wr));
00075
00076 cc-><a class="code" href="structcodec__s.html#o4">ccount</a> += wr;
00077 cc->final = NULL; <span class="comment">/* can be called just once */</span>
00078
00079 <span class="keywordflow">if</span>(wr)
00080 <span class="keywordflow">continue</span>;
00081 }
00082 <span class="keywordflow">break</span>;
00083 }
00084
00085 *dcount = 0;
00086 <span class="keywordflow">return</span> CODEC_FLUSH_COMPLETE;
00087 err:
00088 <span class="keywordflow">return</span> -1;
00089 }
00090
00091 <span class="keyword">static</span> ssize_t cipher_transform(<a class="code" href="structcodec__s.html">codec_t</a> *codec, <span class="keywordtype">char</span> *dst, size_t *dcount,
00092 <span class="keyword">const</span> <span class="keywordtype">char</span> *src, size_t src_sz)
00093 {
00094 <a class="code" href="cipher_8c.html#a2">codec_cipher_t</a> *cc;
00095 ssize_t c;
00096 <span class="keywordtype">int</span> wr;
00097
00098 dbg_err_if (codec == NULL);
00099 dbg_err_if (src == NULL);
00100 dbg_err_if (dst == NULL);
00101 dbg_err_if (dcount == NULL || *dcount == 0);
00102 dbg_err_if (src_sz == 0);
00103
00104 cc = (<a class="code" href="cipher_8c.html#a2">codec_cipher_t</a>*)codec;
00105
00106 c = 0;
00107 <span class="keywordflow">for</span>(;;)
00108 {
00109 <span class="keywordflow">if</span>(cc->ccount)
00110 {
00111 codec_cbufcpy(cc, dst, dcount);
00112 <span class="keywordflow">return</span> c; <span class="comment">/* consumed */</span>
00113 }
00114
00115 <span class="comment">/* the cbuf must be empty because we need the whole buffer to be sure to</span>
00116 <span class="comment"> have enough output space for EVP_{Encrypt,Decrypt}Update */</span>
00117
00118 c = <a class="code" href="utils_8h.html#a0">MIN</a>(src_sz, CODEC_CIPHER_MAX_INPUT);
00119
00120 wr = -1; <span class="comment">/* just used to return an int value */</span>
00121 dbg_err_if(!cc->update(&cc->cipher_ctx, cc->cbuf, &wr, src, c));
00122 cc-><a class="code" href="structcodec__s.html#o4">ccount</a> += wr;
00123
00124 <span class="keywordflow">if</span>(wr == 0)
00125 {
00126 *dcount = 0;
00127 <span class="keywordflow">break</span>; <span class="comment">/* cipher need more input to produce any output */</span>
00128 }
00129 }
00130
00131 dbg_err_if(c == 0 && *dcount == 0);
00132 <span class="keywordflow">return</span> c;
00133 err:
00134 <span class="keywordflow">return</span> -1;
00135 }
00136
00137 <span class="keyword">static</span> <span class="keywordtype">int</span> cipher_free(<a class="code" href="structcodec__s.html">codec_t</a> *codec)
00138 {
00139 <a class="code" href="cipher_8c.html#a2">codec_cipher_t</a> *cc;
00140
00141 nop_return_if (codec == NULL, 0);
00142
00143 cc = (<a class="code" href="cipher_8c.html#a2">codec_cipher_t</a>*)codec;
00144
00145 U_FREE(cc->cbuf);
00146 U_FREE(cc);
00147
00148 <span class="keywordflow">return</span> 0;
00149 }
00150
<a name="l00172"></a><a class="code" href="group__codec__t.html#ga2">00172</a> <span class="keywordtype">int</span> <a class="code" href="group__codec__t.html#ga2">codec_cipher_create</a>(<span class="keywordtype">int</span> op, <span class="keyword">const</span> EVP_CIPHER *cipher,
00173 <span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> *key, <span class="keywordtype">unsigned</span> <span class="keywordtype">char</span> *iv, <a class="code" href="structcodec__s.html">codec_t</a> **pcc)
00174 {
00175 <a class="code" href="cipher_8c.html#a2">codec_cipher_t</a> *cc = NULL;
00176
00177 dbg_return_if (cipher == NULL, ~0);
00178 dbg_return_if (key == NULL, ~0);
00179 <span class="comment">/* iv can be NULL */</span>
00180 dbg_return_if (pcc == NULL, ~0);
00181
00182 cc = u_zalloc(<span class="keyword">sizeof</span>(<a class="code" href="cipher_8c.html#a2">codec_cipher_t</a>));
00183 dbg_err_if(cc == NULL);
00184
00185 cc->codec.<a class="code" href="structcodec__s.html#o0">transform</a> = cipher_transform;
00186 cc->codec.<a class="code" href="structcodec__s.html#o1">flush</a> = cipher_flush;
00187 cc->codec.<a class="code" href="structcodec__s.html#o2">free</a> = cipher_free;
00188
00189 cc->cipher = cipher;
00190
00191 <span class="comment">/* be sure that the cipher stuff is loaded */</span>
00192 EVP_add_cipher(cc->cipher);
00193
00194 EVP_CIPHER_CTX_init(&cc->cipher_ctx);
00195
00196 cc->cbuf_size = <a class="code" href="cipher_8c.html#a9a3">CODEC_CIPHER_MAX_INPUT</a> +
00197 EVP_CIPHER_block_size(cc->cipher) -1;
00198
00199 cc-><a class="code" href="structcodec__s.html#o3">cbuf</a> = u_malloc(cc->cbuf_size);
00200 dbg_err_if(cc->cbuf == NULL);
00201
00202 <span class="keywordflow">switch</span>(op)
00203 {
00204 <span class="keywordflow">case</span> CIPHER_ENCRYPT:
00205 dbg_err_if(!EVP_EncryptInit_ex(&cc->cipher_ctx, cc->cipher, NULL,
00206 key, iv));
00207 cc->update = EVP_EncryptUpdate;
00208 cc->final = EVP_EncryptFinal_ex;
00209 <span class="keywordflow">break</span>;
00210 <span class="keywordflow">case</span> CIPHER_DECRYPT:
00211 dbg_err_if(!EVP_DecryptInit_ex(&cc->cipher_ctx, cc->cipher, NULL,
00212 key, iv));
00213 cc->update = EVP_DecryptUpdate;
00214 cc->final = EVP_DecryptFinal_ex;
00215 <span class="keywordflow">break</span>;
00216 <span class="keywordflow">default</span>:
00217 dbg_err_if(<span class="stringliteral">"bad cipher op"</span>);
00218 }
00219
00220
00221 *pcc = (<a class="code" href="structcodec__s.html">codec_t</a>*)cc;
00222
00223 <span class="keywordflow">return</span> 0;
00224 err:
00225 U_FREE(cc);
00226 <span class="keywordflow">return</span> ~0;
00227 }
00228
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