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[crypto] Expose pem_asn1() for use with non-image data
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Signed-off-by: Michael Brown <mcb30@ipxe.org>
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@mcb30
mcb30 committed Jun 20, 2017
1 parent b506528 commit 14e3b4b
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Showing 2 changed files with 81 additions and 42 deletions.
115 changes: 74 additions & 41 deletions src/image/pem.c
View file
Expand Up @@ -27,10 +27,10 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
#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>
#include <ipxe/pem.h>

/** @file
*
Expand All @@ -41,103 +41,106 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
/**
* Locate next line
*
* @v image PEM image
* @v data PEM data
* @v len Length of PEM data
* @v offset Starting offset
* @ret next Offset to next line
*/
static size_t pem_next ( struct image *image, size_t offset ) {
static size_t pem_next ( userptr_t data, size_t len, size_t offset ) {
off_t eol;

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

/**
* Locate boundary marker line
*
* @v image PEM image
* @v data PEM data
* @v len Length of PEM data
* @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,
static int pem_marker ( userptr_t data, size_t len, size_t offset,
const char *marker ) {
char buf[ strlen ( marker ) ];

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

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

/* Check for marker */
if ( ( image->len - offset ) < sizeof ( buf ) )
if ( ( len - offset ) < sizeof ( buf ) )
break;
copy_from_user ( buf, image->data, offset, sizeof ( buf ) );
copy_from_user ( buf, 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 );
offset = pem_next ( data, len, offset );
assert ( offset <= len );
}

return -ENOENT;
}

/**
* Extract ASN.1 object from image
* Extract ASN.1 object from PEM data
*
* @v image PEM image
* @v offset Offset within image
* @v data PEM data
* @v len Length of PEM data
* @v offset Offset within data
* @v cursor ASN.1 cursor to fill in
* @ret next Offset to next image, or negative error
* @ret next Offset to next object, 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 ) {
int pem_asn1 ( userptr_t data, size_t len, size_t offset,
struct asn1_cursor **cursor ) {
size_t encoded_len;
size_t decoded_max_len;
char *encoded;
void *decoded;
int decoded_len;
int begin;
int end;
int len;
int rc;

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

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

/* Allocate cursor and data buffer */
Expand All @@ -150,24 +153,23 @@ static int pem_asn1 ( struct image *image, size_t offset,
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 ) );
decoded_len = base64_decode ( encoded, decoded, decoded_max_len );
if ( decoded_len < 0 ) {
rc = decoded_len;
DBGC ( data, "PEM could not decode: %s\n", strerror ( rc ) );
goto err_decode;
}
(*cursor)->data = decoded;
(*cursor)->len = len;
(*cursor)->len = decoded_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;
if ( pem_marker ( data, len, offset, PEM_BEGIN ) < 0 )
offset = len;

return offset;

Expand All @@ -188,11 +190,14 @@ static int pem_asn1 ( struct image *image, size_t offset,
* @v image PEM image
* @ret rc Return status code
*/
static int pem_probe ( struct image *image ) {
static int pem_image_probe ( struct image *image ) {
int offset;
int rc;

/* Check that image contains a BEGIN marker */
if ( ( rc = pem_marker ( image, 0, PEM_BEGIN ) ) < 0 ) {
if ( ( offset = pem_marker ( image->data, image->len, 0,
PEM_BEGIN ) ) < 0 ) {
rc = offset;
DBGC ( image, "PEM %s has no BEGIN marker: %s\n",
image->name, strerror ( rc ) );
return rc;
Expand All @@ -201,9 +206,37 @@ static int pem_probe ( struct image *image ) {
return 0;
}

/**
* 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_image_asn1 ( struct image *image, size_t offset,
struct asn1_cursor **cursor ) {
int next;
int rc;

/* Extract ASN.1 object */
if ( ( next = pem_asn1 ( image->data, image->len, offset,
cursor ) ) < 0 ) {
rc = next;
DBGC ( image, "PEM %s could not extract ASN.1: %s\n",
image->name, strerror ( rc ) );
return rc;
}

return next;
}

/** PEM image type */
struct image_type pem_image_type __image_type ( PROBE_NORMAL ) = {
.name = "PEM",
.probe = pem_probe,
.asn1 = pem_asn1,
.probe = pem_image_probe,
.asn1 = pem_image_asn1,
};
8 changes: 7 additions & 1 deletion src/include/ipxe/pem.h
View file
Expand Up @@ -3,12 +3,15 @@

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

FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );

#include <stdint.h>
#include <ipxe/uaccess.h>
#include <ipxe/asn1.h>
#include <ipxe/image.h>

/** Pre-encapsulation boundary marker */
Expand All @@ -17,6 +20,9 @@ FILE_LICENCE ( GPL2_OR_LATER_OR_UBDL );
/** Post-encapsulation boundary marker */
#define PEM_END "-----END"

extern int pem_asn1 ( userptr_t data, size_t len, size_t offset,
struct asn1_cursor **cursor );

extern struct image_type pem_image_type __image_type ( PROBE_NORMAL );

#endif /* _IPXE_PEM_H */

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