This file is indexed.

/usr/share/doc/libxmlsec1-dev/examples/verify4.c is in libxmlsec1-dev 1.2.23-0.1.

This file is owned by root:root, with mode 0o644.

The actual contents of the file can be viewed below.

  1
  2
  3
  4
  5
  6
  7
  8
  9
 10
 11
 12
 13
 14
 15
 16
 17
 18
 19
 20
 21
 22
 23
 24
 25
 26
 27
 28
 29
 30
 31
 32
 33
 34
 35
 36
 37
 38
 39
 40
 41
 42
 43
 44
 45
 46
 47
 48
 49
 50
 51
 52
 53
 54
 55
 56
 57
 58
 59
 60
 61
 62
 63
 64
 65
 66
 67
 68
 69
 70
 71
 72
 73
 74
 75
 76
 77
 78
 79
 80
 81
 82
 83
 84
 85
 86
 87
 88
 89
 90
 91
 92
 93
 94
 95
 96
 97
 98
 99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
/** 
 * XML Security Library example: Verifying a simple SAML response with X509 certificate
 *
 * Verifies a simple SAML response. In addition to refular verification
 * we ensure that the signature has only one <dsig:Reference/> element
 * with an empty or NULL URI attribute and one enveloped signature transform
 * as it is required by SAML specification.
 * 
 * This example was developed and tested with OpenSSL crypto library. The 
 * certificates management policies for another crypto library may break it.
 *
 * Usage: 
 *      verify4 <signed-file> <trusted-cert-pem-file1> [<trusted-cert-pem-file2> [...]]
 *
 * Example (sucecess):
 *      ./verify4 verify4-res.xml ca2cert.pem cacert.pem
 *
 * Example (failure):
 *      ./verify4 verify4-bad-res.xml ca2cert.pem cacert.pem
 * In the same time, verify3 example successfuly verifies this signature:
 *      ./verify3 verify4-bad-res.xml ca2cert.pem cacert.pem
 *
 * This is free software; see Copyright file in the source
 * distribution for preciese wording.
 * 
 * Copyright (C) 2002-2016 Aleksey Sanin <aleksey@aleksey.com>. All Rights Reserved.
 */
#include <stdlib.h>
#include <string.h>
#include <assert.h>

#include <libxml/tree.h>
#include <libxml/xmlmemory.h>
#include <libxml/parser.h>

#ifndef XMLSEC_NO_XSLT
#include <libxslt/xslt.h>
#include <libxslt/security.h>
#endif /* XMLSEC_NO_XSLT */

#include <xmlsec/xmlsec.h>
#include <xmlsec/xmltree.h>
#include <xmlsec/xmldsig.h>
#include <xmlsec/crypto.h>

xmlSecKeysMngrPtr load_trusted_certs(char** files, int files_size);
int verify_file(xmlSecKeysMngrPtr mngr, const char* xml_file);

int 
main(int argc, char **argv) {
#ifndef XMLSEC_NO_XSLT
    xsltSecurityPrefsPtr xsltSecPrefs = NULL;
#endif /* XMLSEC_NO_XSLT */
    xmlSecKeysMngrPtr mngr;
    
    assert(argv);

    if(argc < 3) {
        fprintf(stderr, "Error: wrong number of arguments.\n");
        fprintf(stderr, "Usage: %s <xml-file> <cert-file1> [<cert-file2> [...]]\n", argv[0]);
        return(1);
    }

    /* Init libxml and libxslt libraries */
    xmlInitParser();
    LIBXML_TEST_VERSION
    xmlLoadExtDtdDefaultValue = XML_DETECT_IDS | XML_COMPLETE_ATTRS;
    xmlSubstituteEntitiesDefault(1);
#ifndef XMLSEC_NO_XSLT
    xmlIndentTreeOutput = 1; 
#endif /* XMLSEC_NO_XSLT */

    /* Init libxslt */
#ifndef XMLSEC_NO_XSLT
    /* disable everything */
    xsltSecPrefs = xsltNewSecurityPrefs(); 
    xsltSetSecurityPrefs(xsltSecPrefs,  XSLT_SECPREF_READ_FILE,        xsltSecurityForbid);
    xsltSetSecurityPrefs(xsltSecPrefs,  XSLT_SECPREF_WRITE_FILE,       xsltSecurityForbid);
    xsltSetSecurityPrefs(xsltSecPrefs,  XSLT_SECPREF_CREATE_DIRECTORY, xsltSecurityForbid);
    xsltSetSecurityPrefs(xsltSecPrefs,  XSLT_SECPREF_READ_NETWORK,     xsltSecurityForbid);
    xsltSetSecurityPrefs(xsltSecPrefs,  XSLT_SECPREF_WRITE_NETWORK,    xsltSecurityForbid);
    xsltSetDefaultSecurityPrefs(xsltSecPrefs); 
#endif /* XMLSEC_NO_XSLT */
                
    /* Init xmlsec library */
    if(xmlSecInit() < 0) {
        fprintf(stderr, "Error: xmlsec initialization failed.\n");
        return(-1);
    }

    /* Check loaded library version */
    if(xmlSecCheckVersion() != 1) {
        fprintf(stderr, "Error: loaded xmlsec library version is not compatible.\n");
        return(-1);
    }

    /* Load default crypto engine if we are supporting dynamic
     * loading for xmlsec-crypto libraries. Use the crypto library
     * name ("openssl", "nss", etc.) to load corresponding 
     * xmlsec-crypto library.
     */
#ifdef XMLSEC_CRYPTO_DYNAMIC_LOADING
    if(xmlSecCryptoDLLoadLibrary(NULL) < 0) {
        fprintf(stderr, "Error: unable to load default xmlsec-crypto library. Make sure\n"
                        "that you have it installed and check shared libraries path\n"
                        "(LD_LIBRARY_PATH) envornment variable.\n");
        return(-1);     
    }
#endif /* XMLSEC_CRYPTO_DYNAMIC_LOADING */

    /* Init crypto library */
    if(xmlSecCryptoAppInit(NULL) < 0) {
        fprintf(stderr, "Error: crypto initialization failed.\n");
        return(-1);
    }

    /* Init xmlsec-crypto library */
    if(xmlSecCryptoInit() < 0) {
        fprintf(stderr, "Error: xmlsec-crypto initialization failed.\n");
        return(-1);
    }

    /* create keys manager and load trusted certificates */
    mngr = load_trusted_certs(&(argv[2]), argc - 2);
    if(mngr == NULL) {
        return(-1);
    }
    
    /* verify file */
    if(verify_file(mngr, argv[1]) < 0) {
        xmlSecKeysMngrDestroy(mngr);    
        return(-1);
    }    
    
    /* destroy keys manager */
    xmlSecKeysMngrDestroy(mngr);
    
    /* Shutdown xmlsec-crypto library */
    xmlSecCryptoShutdown();
    
    /* Shutdown crypto library */
    xmlSecCryptoAppShutdown();
    
    /* Shutdown xmlsec library */
    xmlSecShutdown();

    /* Shutdown libxslt/libxml */
#ifndef XMLSEC_NO_XSLT
    xsltFreeSecurityPrefs(xsltSecPrefs);
    xsltCleanupGlobals();            
#endif /* XMLSEC_NO_XSLT */
    xmlCleanupParser();
    
    return(0);
}

/**
 * load_trusted_certs:
 * @files:              the list of filenames.
 * @files_size:         the number of filenames in #files.
 *
 * Creates simple keys manager and load trusted certificates from PEM #files.
 * The caller is responsible for destroing returned keys manager using
 * @xmlSecKeysMngrDestroy.
 *
 * Returns the pointer to newly created keys manager or NULL if an error
 * occurs.
 */
xmlSecKeysMngrPtr 
load_trusted_certs(char** files, int files_size) {
    xmlSecKeysMngrPtr mngr;
    int i;
        
    assert(files);
    assert(files_size > 0);
    
    /* create and initialize keys manager, we use a simple list based
     * keys manager, implement your own xmlSecKeysStore klass if you need
     * something more sophisticated 
     */
    mngr = xmlSecKeysMngrCreate();
    if(mngr == NULL) {
        fprintf(stderr, "Error: failed to create keys manager.\n");
        return(NULL);
    }
    if(xmlSecCryptoAppDefaultKeysMngrInit(mngr) < 0) {
        fprintf(stderr, "Error: failed to initialize keys manager.\n");
        xmlSecKeysMngrDestroy(mngr);
        return(NULL);
    }    
    
    for(i = 0; i < files_size; ++i) {
        assert(files[i]);

        /* load trusted cert */
        if(xmlSecCryptoAppKeysMngrCertLoad(mngr, files[i], xmlSecKeyDataFormatPem, xmlSecKeyDataTypeTrusted) < 0) {
            fprintf(stderr,"Error: failed to load pem certificate from \"%s\"\n", files[i]);
            xmlSecKeysMngrDestroy(mngr);
            return(NULL);
        }
    }

    return(mngr);
}

/** 
 * verify_file:
 * @mngr:               the pointer to keys manager.
 * @xml_file:           the signed XML file name.
 *
 * Verifies XML signature in #xml_file.
 *
 * Returns 0 on success or a negative value if an error occurs.
 */
int 
verify_file(xmlSecKeysMngrPtr mngr, const char* xml_file) {
    xmlDocPtr doc = NULL;
    xmlNodePtr node = NULL;
    xmlSecDSigCtxPtr dsigCtx = NULL;
    int res = -1;
    
    assert(mngr);
    assert(xml_file);

    /* load file */
    doc = xmlParseFile(xml_file);
    if ((doc == NULL) || (xmlDocGetRootElement(doc) == NULL)){
        fprintf(stderr, "Error: unable to parse file \"%s\"\n", xml_file);
        goto done;      
    }
    
    /* find start node */
    node = xmlSecFindNode(xmlDocGetRootElement(doc), xmlSecNodeSignature, xmlSecDSigNs);
    if(node == NULL) {
        fprintf(stderr, "Error: start node not found in \"%s\"\n", xml_file);
        goto done;      
    }

    /* create signature context */
    dsigCtx = xmlSecDSigCtxCreate(mngr);
    if(dsigCtx == NULL) {
        fprintf(stderr,"Error: failed to create signature context\n");
        goto done;
    }

    /* limit the Reference URI attributes to empty or NULL */
    dsigCtx->enabledReferenceUris = xmlSecTransformUriTypeEmpty;
    
    /* limit allowed transforms for signature and reference processing */
    if((xmlSecDSigCtxEnableSignatureTransform(dsigCtx, xmlSecTransformInclC14NId) < 0) ||
       (xmlSecDSigCtxEnableSignatureTransform(dsigCtx, xmlSecTransformExclC14NId) < 0) ||
       (xmlSecDSigCtxEnableSignatureTransform(dsigCtx, xmlSecTransformSha1Id) < 0) ||
       (xmlSecDSigCtxEnableSignatureTransform(dsigCtx, xmlSecTransformRsaSha1Id) < 0)) {

        fprintf(stderr,"Error: failed to limit allowed signature transforms\n");
        goto done;
    }
    if((xmlSecDSigCtxEnableReferenceTransform(dsigCtx, xmlSecTransformInclC14NId) < 0) ||
       (xmlSecDSigCtxEnableReferenceTransform(dsigCtx, xmlSecTransformExclC14NId) < 0) ||
       (xmlSecDSigCtxEnableReferenceTransform(dsigCtx, xmlSecTransformSha1Id) < 0) ||
       (xmlSecDSigCtxEnableReferenceTransform(dsigCtx, xmlSecTransformEnvelopedId) < 0)) {

        fprintf(stderr,"Error: failed to limit allowed reference transforms\n");
        goto done;
    }

    /* in addition, limit possible key data to valid X509 certificates only */
    if(xmlSecPtrListAdd(&(dsigCtx->keyInfoReadCtx.enabledKeyData), BAD_CAST xmlSecKeyDataX509Id) < 0) {
        fprintf(stderr,"Error: failed to limit allowed key data\n");
        goto done;
    }
    
    /* Verify signature */
    if(xmlSecDSigCtxVerify(dsigCtx, node) < 0) {
        fprintf(stderr,"Error: signature verify\n");
        goto done;
    }

    /* check that we have only one Reference */
    if((dsigCtx->status == xmlSecDSigStatusSucceeded) && 
        (xmlSecPtrListGetSize(&(dsigCtx->signedInfoReferences)) != 1)) {
        
        fprintf(stderr,"Error: only one reference is allowed\n");
        goto done;
    }
        
    /* print verification result to stdout */
    if(dsigCtx->status == xmlSecDSigStatusSucceeded) {
        fprintf(stdout, "Signature is OK\n");
    } else {
        fprintf(stdout, "Signature is INVALID\n");
    }    

    /* success */
    res = 0;

done:    
    /* cleanup */
    if(dsigCtx != NULL) {
        xmlSecDSigCtxDestroy(dsigCtx);
    }
    
    if(doc != NULL) {
        xmlFreeDoc(doc); 
    }
    return(res);
}