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[crypto] Add PEM image format
Add PEM-encoded ASN.1 as an image format.  We accept as PEM any image
containing a line starting with a "-----BEGIN" boundary marker.

We allow for PEM files containing multiple ASN.1 objects, such as a
certificate chain produced by concatenating individual certificate
files.

Signed-off-by: Michael Brown <mcb30@ipxe.org>
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mcb30 committed Jul 29, 2016
1 parent eb7188d commit 84add97
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3 changes: 3 additions & 0 deletions src/config/config.c
Expand Up @@ -191,6 +191,9 @@ REQUIRE_OBJECT ( png );
#ifdef IMAGE_DER
REQUIRE_OBJECT ( der );
#endif
#ifdef IMAGE_PEM
REQUIRE_OBJECT ( pem );
#endif

/*
* Drag in all requested commands
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1 change: 1 addition & 0 deletions src/config/general.h
Expand Up @@ -113,6 +113,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
//#define IMAGE_PNM /* PNM image support */
//#define IMAGE_PNG /* PNG image support */
//#define IMAGE_DER /* DER image support */
//#define IMAGE_PEM /* PEM image support */

/*
* Command-line commands to include
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208 changes: 208 additions & 0 deletions src/image/pem.c
@@ -0,0 +1,208 @@
/*
* Copyright (C) 2016 Michael Brown <mbrown@fensystems.co.uk>.
*
* 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 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.
*
* You can also choose to distribute this program under the terms of
* the Unmodified Binary Distribution Licence (as given in the file
* COPYING.UBDL), provided that you have satisfied its requirements.
*/

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );

#include <stdlib.h>
#include <errno.h>
#include <assert.h>
#include <ipxe/asn1.h>
#include <ipxe/pem.h>
#include <ipxe/base64.h>
#include <ipxe/uaccess.h>
#include <ipxe/image.h>

/** @file
*
* PEM-encoded ASN.1 data
*
*/

/**
* Locate next line
*
* @v image PEM image
* @v offset Starting offset
* @ret next Offset to next line
*/
static size_t pem_next ( struct image *image, size_t offset ) {
off_t eol;

/* Find and skip next newline character, if any */
eol = memchr_user ( image->data, offset, '\n', ( image->len - offset ));
if ( eol < 0 )
return image->len;
return ( eol + 1 );
}

/**
* Locate boundary marker line
*
* @v image PEM image
* @v offset Starting offset
* @v marker Boundary marker
* @ret offset Offset to boundary marker line, or negative error
*/
static int pem_marker ( struct image *image, size_t offset,
const char *marker ) {
char buf[ strlen ( marker ) ];

/* Sanity check */
assert ( offset <= image->len );

/* Scan for marker at start of line */
while ( offset < image->len ) {

/* Check for marker */
if ( ( image->len - offset ) < sizeof ( buf ) )
break;
copy_from_user ( buf, image->data, offset, sizeof ( buf ) );
if ( memcmp ( buf, marker, sizeof ( buf ) ) == 0 )
return offset;

/* Move to next line */
offset = pem_next ( image, offset );
assert ( offset <= image->len );
}

return -ENOENT;
}

/**
* Extract ASN.1 object from image
*
* @v image PEM image
* @v offset Offset within image
* @v cursor ASN.1 cursor to fill in
* @ret next Offset to next image, or negative error
*
* The caller is responsible for eventually calling free() on the
* allocated ASN.1 cursor.
*/
static int pem_asn1 ( struct image *image, size_t offset,
struct asn1_cursor **cursor ) {
size_t encoded_len;
size_t decoded_max_len;
char *encoded;
void *decoded;
int begin;
int end;
int len;
int rc;

/* Locate and skip BEGIN marker */
begin = pem_marker ( image, offset, PEM_BEGIN );
if ( begin < 0 ) {
rc = begin;
DBGC ( image, "PEM %s [%#zx,%#zx) missing BEGIN marker: %s\n",
image->name, offset, image->len, strerror ( rc ) );
goto err_begin;
}
begin = pem_next ( image, begin );

/* Locate and skip END marker */
end = pem_marker ( image, begin, PEM_END );
if ( end < 0 ) {
rc = end;
DBGC ( image, "PEM %s [%#zx,%#zx) missing END marker: %s\n",
image->name, offset, image->len, strerror ( rc ) );
goto err_end;
}
encoded_len = ( end - begin );
end = pem_next ( image, end );

/* Extract Base64-encoded data */
encoded = malloc ( encoded_len + 1 /* NUL */ );
if ( ! encoded ) {
rc = -ENOMEM;
goto err_alloc_encoded;
}
copy_from_user ( encoded, image->data, begin, encoded_len );
encoded[encoded_len] = '\0';

/* Allocate cursor and data buffer */
decoded_max_len = base64_decoded_max_len ( encoded );
*cursor = malloc ( sizeof ( **cursor ) + decoded_max_len );
if ( ! *cursor ) {
rc = -ENOMEM;
goto err_alloc_decoded;
}
decoded = ( ( ( void * ) *cursor ) + sizeof ( **cursor ) );

/* Decode Base64-encoded data */
len = base64_decode ( encoded, decoded, decoded_max_len );
if ( len < 0 ) {
rc = len;
DBGC ( image, "PEM %s could not decode: %s\n",
image->name, strerror ( rc ) );
goto err_decode;
}
(*cursor)->data = decoded;
(*cursor)->len = len;
assert ( (*cursor)->len <= decoded_max_len );

/* Free Base64-encoded data */
free ( encoded );

/* Update offset and skip any unencapsulated trailer */
offset = end;
if ( pem_marker ( image, offset, PEM_BEGIN ) < 0 )
offset = image->len;

return offset;

err_decode:
free ( decoded );
err_alloc_decoded:
free ( encoded );
err_alloc_encoded:
err_end:
err_begin:
return rc;
}

/**
* Probe PEM image
*
* @v image PEM image
* @ret rc Return status code
*/
static int pem_probe ( struct image *image ) {
int rc;

/* Check that image contains a BEGIN marker */
if ( ( rc = pem_marker ( image, 0, PEM_BEGIN ) ) < 0 ) {
DBGC ( image, "PEM %s has no BEGIN marker: %s\n",
image->name, strerror ( rc ) );
return rc;
}

return 0;
}

/** PEM image type */
struct image_type pem_image_type __image_type ( PROBE_NORMAL ) = {
.name = "PEM",
.probe = pem_probe,
.asn1 = pem_asn1,
};
1 change: 1 addition & 0 deletions src/include/ipxe/errfile.h
Expand Up @@ -277,6 +277,7 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#define ERRFILE_pnm ( ERRFILE_IMAGE | 0x00060000 )
#define ERRFILE_png ( ERRFILE_IMAGE | 0x00070000 )
#define ERRFILE_der ( ERRFILE_IMAGE | 0x00080000 )
#define ERRFILE_pem ( ERRFILE_IMAGE | 0x00090000 )

#define ERRFILE_asn1 ( ERRFILE_OTHER | 0x00000000 )
#define ERRFILE_chap ( ERRFILE_OTHER | 0x00010000 )
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22 changes: 22 additions & 0 deletions src/include/ipxe/pem.h
@@ -0,0 +1,22 @@
#ifndef _IPXE_PEM_H
#define _IPXE_PEM_H

/** @file
*
* PEM image format
*
*/

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );

#include <ipxe/image.h>

/** Pre-encapsulation boundary marker */
#define PEM_BEGIN "-----BEGIN"

/** Post-encapsulation boundary marker */
#define PEM_END "-----END"

extern struct image_type pem_image_type __image_type ( PROBE_NORMAL );

#endif /* _IPXE_PEM_H */
107 changes: 107 additions & 0 deletions src/tests/pem_test.c
@@ -0,0 +1,107 @@
/*
* Copyright (C) 2016 Michael Brown <mbrown@fensystems.co.uk>.
*
* 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 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.
*
* You can also choose to distribute this program under the terms of
* the Unmodified Binary Distribution Licence (as given in the file
* COPYING.UBDL), provided that you have satisfied its requirements.
*/

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );

/** @file
*
* PEM self-tests
*
*/

/* Forcibly enable assertions */
#undef NDEBUG

#include <string.h>
#include <assert.h>
#include <ipxe/test.h>
#include <ipxe/pem.h>
#include "asn1_test.h"

/** Define inline expected digest */
#define DIGEST(...) { { __VA_ARGS__ } }

/** Single RSA private key */
ASN1 ( single, &pem_image_type,
"-----BEGIN RSA PRIVATE KEY-----\n"
"MCwCAQACBQC6loItAgMBAAECBCqhYIkCAwDyVwIDAMUbAgMAr9kCAmr9AgIaWQ==\n"
"-----END RSA PRIVATE KEY-----\n",
DIGEST ( 0xb9, 0x38, 0x83, 0xcd, 0xf4, 0x58, 0xa9, 0xa2, 0x84, 0x11,
0xfa, 0x0b, 0x6f, 0xdc, 0x3e, 0xa3, 0x7c, 0x90, 0x7c, 0x2d ) );

/** Three concatenated RSA private keys */
ASN1 ( multiple, &pem_image_type,
"-----BEGIN RSA PRIVATE KEY-----\n"
"MCwCAQACBQDtbjyVAgMBAAECBQCEOtJxAgMA+xsCAwDyDwICLGsCAgqTAgIxVQ==\n"
"-----END RSA PRIVATE KEY-----\n"
"-----BEGIN RSA PRIVATE KEY-----\n"
"MCwCAQACBQC3VlyxAgMBAAECBGakxDUCAwDanwIDANavAgIBWQICTuECAwCmWg==\n"
"-----END RSA PRIVATE KEY-----\n"
"-----BEGIN RSA PRIVATE KEY-----\n"
"MCwCAQACBQC89dS1AgMBAAECBQCxjnLBAgMA3qcCAwDZQwICP3cCAgpRAgI57A==\n"
"-----END RSA PRIVATE KEY-----\n",
DIGEST ( 0x9c, 0xb2, 0xc1, 0xa0, 0x9c, 0xcb, 0x11, 0xbf, 0x80, 0xd0,
0x8c, 0xe5, 0xda, 0xf2, 0x3b, 0x2c, 0xca, 0x64, 0x25, 0x8a ),
DIGEST ( 0x82, 0x66, 0x24, 0xd9, 0xc3, 0x98, 0x1e, 0x5e, 0x56, 0xed,
0xd0, 0xd0, 0x2a, 0x5e, 0x9c, 0x3a, 0x58, 0xdf, 0x76, 0x0d ),
DIGEST ( 0x01, 0xd2, 0x8a, 0x74, 0x42, 0x08, 0x0f, 0xb0, 0x03, 0x82,
0xcd, 0xa3, 0xdc, 0x78, 0xfe, 0xd7, 0xa3, 0x28, 0xfc, 0x29 ) );

/** Two RSA private keys with various bits of noise added */
ASN1 ( noisy, &pem_image_type,
"Hello world! This is uninteresting stuff before the actual data.\n"
"-----BEGIN RSA PRIVATE KEY-----\n"
"MCwCAQACBQC3VlyxAgMBAAECBGakxDUCAwDanwIDANavAgIBWQICTuECAwCmWg==\n"
"-----END RSA PRIVATE KEY-----\n"
"Here is some more uninteresting stuff.\n"
"Followed by what is actually another RSA private key, but with "
"extra whitespace added, and the description change to pretend "
"it's a certificate\n"
"-----BEGIN CERTIFICATE-----\n"
" MCwCAQACBQC6loItAgMBAAECBCqhYIkCAwD\r\n"
" yVwIDAMUbAgMAr9kCAmr9AgIaWQ== \r\n"
"-----END CERTIFICATE-----\n"
"and some trailing garbage as well\n"
"and more garbage with no final newline",
DIGEST ( 0x82, 0x66, 0x24, 0xd9, 0xc3, 0x98, 0x1e, 0x5e, 0x56, 0xed,
0xd0, 0xd0, 0x2a, 0x5e, 0x9c, 0x3a, 0x58, 0xdf, 0x76, 0x0d ),
DIGEST ( 0xb9, 0x38, 0x83, 0xcd, 0xf4, 0x58, 0xa9, 0xa2, 0x84, 0x11,
0xfa, 0x0b, 0x6f, 0xdc, 0x3e, 0xa3, 0x7c, 0x90, 0x7c, 0x2d ) );

/**
* Perform PEM self-test
*
*/
static void pem_test_exec ( void ) {

/* Perform tests */
asn1_ok ( &single );
asn1_ok ( &multiple );
asn1_ok ( &noisy );
}

/** PEM self-test */
struct self_test pem_test __self_test = {
.name = "pem",
.exec = pem_test_exec,
};
1 change: 1 addition & 0 deletions src/tests/tests.c
Expand Up @@ -70,3 +70,4 @@ REQUIRE_OBJECT ( linebuf_test );
REQUIRE_OBJECT ( iobuf_test );
REQUIRE_OBJECT ( bitops_test );
REQUIRE_OBJECT ( der_test );
REQUIRE_OBJECT ( pem_test );

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