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mbedtls/library/x509_csr.c
Andres AG 3df4e4e1d0 Prevent signed integer overflow in CSR parsing 
Modify the function x509_csr_parse_der() so that it checks the parsed
CSR version integer before it increments the value. This prevents a
potential signed integer overflow, as these have undefined behaviour in
the C standard.
2017-07-27 11:50:58 +01:00

466 lines
11 KiB
C
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/*
* X.509 Certificate Signing Request (CSR) parsing
*
* Copyright (C) 2006-2014, ARM Limited, All Rights Reserved
*
* This file is part of mbed TLS (https://tls.mbed.org)
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/
/*
* The ITU-T X.509 standard defines a certificate format for PKI.
*
* http://www.ietf.org/rfc/rfc5280.txt (Certificates and CRLs)
* http://www.ietf.org/rfc/rfc3279.txt (Alg IDs for CRLs)
* http://www.ietf.org/rfc/rfc2986.txt (CSRs, aka PKCS#10)
*
* http://www.itu.int/ITU-T/studygroups/com17/languages/X.680-0207.pdf
* http://www.itu.int/ITU-T/studygroups/com17/languages/X.690-0207.pdf
*/
#if !defined(POLARSSL_CONFIG_FILE)
#include "polarssl/config.h"
#else
#include POLARSSL_CONFIG_FILE
#endif
#if defined(POLARSSL_X509_CSR_PARSE_C)
#include "polarssl/x509_csr.h"
#include "polarssl/oid.h"
#include <string.h>
#if defined(POLARSSL_PEM_PARSE_C)
#include "polarssl/pem.h"
#endif
#if defined(POLARSSL_PLATFORM_C)
#include "polarssl/platform.h"
#else
#include <stdlib.h>
#include <stdio.h>
#define polarssl_free free
#define polarssl_malloc malloc
#define polarssl_snprintf snprintf
#endif
#if defined(POLARSSL_FS_IO) || defined(EFIX64) || defined(EFI32)
#include <stdio.h>
#endif
/* Implementation that should never be optimized out by the compiler */
static void polarssl_zeroize( void *v, size_t n ) {
volatile unsigned char *p = v; while( n-- ) *p++ = 0;
}
/*
* Version ::= INTEGER { v1(0) }
*/
static int x509_csr_get_version( unsigned char **p,
const unsigned char *end,
int *ver )
{
int ret;
if( ( ret = asn1_get_int( p, end, ver ) ) != 0 )
{
if( ret == POLARSSL_ERR_ASN1_UNEXPECTED_TAG )
{
*ver = 0;
return( 0 );
}
return( POLARSSL_ERR_X509_INVALID_VERSION + ret );
}
return( 0 );
}
/*
* Parse a CSR in DER format
*/
int x509_csr_parse_der( x509_csr *csr,
const unsigned char *buf, size_t buflen )
{
int ret;
size_t len;
unsigned char *p, *end;
x509_buf sig_params;
memset( &sig_params, 0, sizeof( x509_buf ) );
/*
* Check for valid input
*/
if( csr == NULL || buf == NULL )
return( POLARSSL_ERR_X509_BAD_INPUT_DATA );
x509_csr_init( csr );
/*
* first copy the raw DER data
*/
p = polarssl_malloc( len = buflen );
if( p == NULL )
return( POLARSSL_ERR_X509_MALLOC_FAILED );
memcpy( p, buf, buflen );
csr->raw.p = p;
csr->raw.len = len;
end = p + len;
/*
* CertificationRequest ::= SEQUENCE {
* certificationRequestInfo CertificationRequestInfo,
* signatureAlgorithm AlgorithmIdentifier,
* signature BIT STRING
* }
*/
if( ( ret = asn1_get_tag( &p, end, &len,
ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 )
{
x509_csr_free( csr );
return( POLARSSL_ERR_X509_INVALID_FORMAT );
}
if( len != (size_t) ( end - p ) )
{
x509_csr_free( csr );
return( POLARSSL_ERR_X509_INVALID_FORMAT +
POLARSSL_ERR_ASN1_LENGTH_MISMATCH );
}
/*
* CertificationRequestInfo ::= SEQUENCE {
*/
csr->cri.p = p;
if( ( ret = asn1_get_tag( &p, end, &len,
ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 )
{
x509_csr_free( csr );
return( POLARSSL_ERR_X509_INVALID_FORMAT + ret );
}
end = p + len;
csr->cri.len = end - csr->cri.p;
/*
* Version ::= INTEGER { v1(0) }
*/
if( ( ret = x509_csr_get_version( &p, end, &csr->version ) ) != 0 )
{
x509_csr_free( csr );
return( ret );
}
if( csr->version != 0 )
{
x509_csr_free( csr );
return( POLARSSL_ERR_X509_UNKNOWN_VERSION );
}
csr->version++;
/*
* subject Name
*/
csr->subject_raw.p = p;
if( ( ret = asn1_get_tag( &p, end, &len,
ASN1_CONSTRUCTED | ASN1_SEQUENCE ) ) != 0 )
{
x509_csr_free( csr );
return( POLARSSL_ERR_X509_INVALID_FORMAT + ret );
}
if( ( ret = x509_get_name( &p, p + len, &csr->subject ) ) != 0 )
{
x509_csr_free( csr );
return( ret );
}
csr->subject_raw.len = p - csr->subject_raw.p;
/*
* subjectPKInfo SubjectPublicKeyInfo
*/
if( ( ret = pk_parse_subpubkey( &p, end, &csr->pk ) ) != 0 )
{
x509_csr_free( csr );
return( ret );
}
/*
* attributes [0] Attributes
*/
if( ( ret = asn1_get_tag( &p, end, &len,
ASN1_CONSTRUCTED | ASN1_CONTEXT_SPECIFIC ) ) != 0 )
{
x509_csr_free( csr );
return( POLARSSL_ERR_X509_INVALID_FORMAT + ret );
}
// TODO Parse Attributes / extension requests
p += len;
end = csr->raw.p + csr->raw.len;
/*
* signatureAlgorithm AlgorithmIdentifier,
* signature BIT STRING
*/
if( ( ret = x509_get_alg( &p, end, &csr->sig_oid, &sig_params ) ) != 0 )
{
x509_csr_free( csr );
return( ret );
}
if( ( ret = x509_get_sig_alg( &csr->sig_oid, &sig_params,
&csr->sig_md, &csr->sig_pk,
&csr->sig_opts ) ) != 0 )
{
x509_csr_free( csr );
return( POLARSSL_ERR_X509_UNKNOWN_SIG_ALG );
}
if( ( ret = x509_get_sig( &p, end, &csr->sig ) ) != 0 )
{
x509_csr_free( csr );
return( ret );
}
if( p != end )
{
x509_csr_free( csr );
return( POLARSSL_ERR_X509_INVALID_FORMAT +
POLARSSL_ERR_ASN1_LENGTH_MISMATCH );
}
return( 0 );
}
/*
* Parse a CSR, allowing for PEM or raw DER encoding
*/
int x509_csr_parse( x509_csr *csr, const unsigned char *buf, size_t buflen )
{
#if defined(POLARSSL_PEM_PARSE_C)
int ret;
size_t use_len;
pem_context pem;
#endif
/*
* Check for valid input
*/
if( csr == NULL || buf == NULL )
return( POLARSSL_ERR_X509_BAD_INPUT_DATA );
#if defined(POLARSSL_PEM_PARSE_C)
pem_init( &pem );
ret = pem_read_buffer( &pem,
"-----BEGIN CERTIFICATE REQUEST-----",
"-----END CERTIFICATE REQUEST-----",
buf, NULL, 0, &use_len );
if( ret == 0 )
{
/*
* Was PEM encoded, parse the result
*/
if( ( ret = x509_csr_parse_der( csr, pem.buf, pem.buflen ) ) != 0 )
return( ret );
pem_free( &pem );
return( 0 );
}
else if( ret != POLARSSL_ERR_PEM_NO_HEADER_FOOTER_PRESENT )
{
pem_free( &pem );
return( ret );
}
else
#endif /* POLARSSL_PEM_PARSE_C */
return( x509_csr_parse_der( csr, buf, buflen ) );
}
#if defined(POLARSSL_FS_IO)
/*
* Load a CSR into the structure
*/
int x509_csr_parse_file( x509_csr *csr, const char *path )
{
int ret;
size_t n;
unsigned char *buf;
if( ( ret = pk_load_file( path, &buf, &n ) ) != 0 )
return( ret );
ret = x509_csr_parse( csr, buf, n );
polarssl_zeroize( buf, n + 1 );
polarssl_free( buf );
return( ret );
}
#endif /* POLARSSL_FS_IO */
#if defined(_MSC_VER) && !defined snprintf && !defined(EFIX64) && \
!defined(EFI32)
#include <stdarg.h>
#if !defined vsnprintf
#define vsnprintf _vsnprintf
#endif // vsnprintf
/*
* Windows _snprintf and _vsnprintf are not compatible to linux versions.
* Result value is not size of buffer needed, but -1 if no fit is possible.
*
* This fuction tries to 'fix' this by at least suggesting enlarging the
* size by 20.
*/
static int compat_snprintf( char *str, size_t size, const char *format, ... )
{
va_list ap;
int res = -1;
va_start( ap, format );
res = vsnprintf( str, size, format, ap );
va_end( ap );
// No quick fix possible
if( res < 0 )
return( (int) size + 20 );
return( res );
}
#define snprintf compat_snprintf
#endif /* _MSC_VER && !snprintf && !EFIX64 && !EFI32 */
#define POLARSSL_ERR_DEBUG_BUF_TOO_SMALL -2
#define SAFE_SNPRINTF() \
{ \
if( ret == -1 ) \
return( -1 ); \
\
if( (unsigned int) ret > n ) { \
p[n - 1] = '\0'; \
return( POLARSSL_ERR_DEBUG_BUF_TOO_SMALL ); \
} \
\
n -= (unsigned int) ret; \
p += (unsigned int) ret; \
}
#define BEFORE_COLON 14
#define BC "14"
/*
* Return an informational string about the CSR.
*/
int x509_csr_info( char *buf, size_t size, const char *prefix,
const x509_csr *csr )
{
int ret;
size_t n;
char *p;
char key_size_str[BEFORE_COLON];
p = buf;
n = size;
ret = polarssl_snprintf( p, n, "%sCSR version : %d",
prefix, csr->version );
SAFE_SNPRINTF();
ret = polarssl_snprintf( p, n, "\n%ssubject name : ", prefix );
SAFE_SNPRINTF();
ret = x509_dn_gets( p, n, &csr->subject );
SAFE_SNPRINTF();
ret = polarssl_snprintf( p, n, "\n%ssigned using : ", prefix );
SAFE_SNPRINTF();
ret = x509_sig_alg_gets( p, n, &csr->sig_oid, csr->sig_pk, csr->sig_md,
csr->sig_opts );
SAFE_SNPRINTF();
if( ( ret = x509_key_size_helper( key_size_str, BEFORE_COLON,
pk_get_name( &csr->pk ) ) ) != 0 )
{
return( ret );
}
ret = polarssl_snprintf( p, n, "\n%s%-" BC "s: %d bits\n", prefix, key_size_str,
(int) pk_get_size( &csr->pk ) );
SAFE_SNPRINTF();
return( (int) ( size - n ) );
}
/*
* Initialize a CSR
*/
void x509_csr_init( x509_csr *csr )
{
memset( csr, 0, sizeof(x509_csr) );
}
/*
* Unallocate all CSR data
*/
void x509_csr_free( x509_csr *csr )
{
x509_name *name_cur;
x509_name *name_prv;
if( csr == NULL )
return;
pk_free( &csr->pk );
#if defined(POLARSSL_X509_RSASSA_PSS_SUPPORT)
polarssl_free( csr->sig_opts );
#endif
name_cur = csr->subject.next;
while( name_cur != NULL )
{
name_prv = name_cur;
name_cur = name_cur->next;
polarssl_zeroize( name_prv, sizeof( x509_name ) );
polarssl_free( name_prv );
}
if( csr->raw.p != NULL )
{
polarssl_zeroize( csr->raw.p, csr->raw.len );
polarssl_free( csr->raw.p );
}
polarssl_zeroize( csr, sizeof( x509_csr ) );
}
#endif /* POLARSSL_X509_CSR_PARSE_C */
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