Page MenuHomeFreeBSD
Differential D16334 Diff 55390 head/contrib/bearssl/inc/bearssl_pem.h

Changeset View

Standalone View

View Options

head/contrib/bearssl/inc/bearssl_pem.h

PropertyOld ValueNew Value
svn:eol-stylenullnative
\ No newline at end of property
svn:keywordsnullFreeBSD=%H
\ No newline at end of property
svn:mime-typenulltext/plain
\ No newline at end of property
/*
* Copyright (c) 2016 Thomas Pornin <pornin@bolet.org>
*
* Permission is hereby granted, free of charge, to any person obtaining
* a copy of this software and associated documentation files (the
* "Software"), to deal in the Software without restriction, including
* without limitation the rights to use, copy, modify, merge, publish,
* distribute, sublicense, and/or sell copies of the Software, and to
* permit persons to whom the Software is furnished to do so, subject to
* the following conditions:
*
* The above copyright notice and this permission notice shall be
* included in all copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
* BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
* ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
* CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
#ifndef BR_BEARSSL_PEM_H__
#define BR_BEARSSL_PEM_H__
#include <stddef.h>
#include <stdint.h>
#ifdef __cplusplus
extern "C" {
#endif
/** \file bearssl_pem.h
*
* # PEM Support
*
* PEM is a traditional encoding layer use to store binary objects (in
* particular X.509 certificates, and private keys) in text files. While
* the acronym comes from an old, defunct standard ("Privacy Enhanced
* Mail"), the format has been reused, with some variations, by many
* systems, and is a _de facto_ standard, even though it is not, actually,
* specified in all clarity anywhere.
*
* ## Format Details
*
* BearSSL contains a generic, streamed PEM decoder, which handles the
* following format:
*
* - The input source (a sequence of bytes) is assumed to be the
* encoding of a text file in an ASCII-compatible charset. This
* includes ISO-8859-1, Windows-1252, and UTF-8 encodings. Each
* line ends on a newline character (U+000A LINE FEED). The
* U+000D CARRIAGE RETURN characters are ignored, so the code
* accepts both Windows-style and Unix-style line endings.
*
* - Each object begins with a banner that occurs at the start of
* a line; the first banner characters are "`-----BEGIN `" (five
* dashes, the word "BEGIN", and a space). The banner matching is
* not case-sensitive.
*
* - The _object name_ consists in the characters that follow the
* banner start sequence, up to the end of the line, but without
* trailing dashes (in "normal" PEM, there are five trailing
* dashes, but this implementation is not picky about these dashes).
* The BearSSL decoder normalises the name characters to uppercase
* (for ASCII letters only) and accepts names up to 127 characters.
*
* - The object ends with a banner that again occurs at the start of
* a line, and starts with "`-----END `" (again case-insensitive).
*
* - Between that start and end banner, only Base64 data shall occur.
* Base64 converts each sequence of three bytes into four
* characters; the four characters are ASCII letters, digits, "`+`"
* or "`-`" signs, and one or two "`=`" signs may occur in the last
* quartet. Whitespace is ignored (whitespace is any ASCII character
* of code 32 or less, so control characters are whitespace) and
* lines may have arbitrary length; the only restriction is that the
* four characters of a quartet must appear on the same line (no
* line break inside a quartet).
*
* - A single file may contain more than one PEM object. Bytes that
* occur between objects are ignored.
*
*
* ## PEM Decoder API
*
* The PEM decoder offers a state-machine API. The caller allocates a
* decoder context, then injects source bytes. Source bytes are pushed
* with `br_pem_decoder_push()`. The decoder stops accepting bytes when
* it reaches an "event", which is either the start of an object, the
* end of an object, or a decoding error within an object.
*
* The `br_pem_decoder_event()` function is used to obtain the current
* event; it also clears it, thus allowing the decoder to accept more
* bytes. When a object start event is raised, the decoder context
* offers the found object name (normalised to ASCII uppercase).
*
* When an object is reached, the caller must set an appropriate callback
* function, which will receive (by chunks) the decoded object data.
*
* Since the decoder context makes no dynamic allocation, it requires
* no explicit deallocation.
*/
/**
* \brief PEM decoder context.
*
* Contents are opaque (they should not be accessed directly).
*/
typedef struct {
#ifndef BR_DOXYGEN_IGNORE
/* CPU for the T0 virtual machine. */
struct {
uint32_t *dp;
uint32_t *rp;
const unsigned char *ip;
} cpu;
uint32_t dp_stack[32];
uint32_t rp_stack[32];
int err;
const unsigned char *hbuf;
size_t hlen;
void (*dest)(void *dest_ctx, const void *src, size_t len);
void *dest_ctx;
unsigned char event;
char name[128];
unsigned char buf[255];
size_t ptr;
#endif
} br_pem_decoder_context;
/**
* \brief Initialise a PEM decoder structure.
*
* \param ctx decoder context to initialise.
*/
void br_pem_decoder_init(br_pem_decoder_context *ctx);
/**
* \brief Push some bytes into the decoder.
*
* Returned value is the number of bytes actually consumed; this may be
* less than the number of provided bytes if an event is raised. When an
* event is raised, it must be read (with `br_pem_decoder_event()`);
* until the event is read, this function will return 0.
*
* \param ctx decoder context.
* \param data new data bytes.
* \param len number of new data bytes.
* \return the number of bytes actually received (may be less than `len`).
*/
size_t br_pem_decoder_push(br_pem_decoder_context *ctx,
const void *data, size_t len);
/**
* \brief Set the receiver for decoded data.
*
* When an object is entered, the provided function (with opaque context
* pointer) will be called repeatedly with successive chunks of decoded
* data for that object. If `dest` is set to 0, then decoded data is
* simply ignored. The receiver can be set at any time, but, in practice,
* it should be called immediately after receiving a "start of object"
* event.
*
* \param ctx decoder context.
* \param dest callback for receiving decoded data.
* \param dest_ctx opaque context pointer for the `dest` callback.
*/
static inline void
br_pem_decoder_setdest(br_pem_decoder_context *ctx,
void (*dest)(void *dest_ctx, const void *src, size_t len),
void *dest_ctx)
{
ctx->dest = dest;
ctx->dest_ctx = dest_ctx;
}
/**
* \brief Get the last event.
*
* If an event was raised, then this function returns the event value, and
* also clears it, thereby allowing the decoder to proceed. If no event
* was raised since the last call to `br_pem_decoder_event()`, then this
* function returns 0.
*
* \param ctx decoder context.
* \return the raised event, or 0.
*/
int br_pem_decoder_event(br_pem_decoder_context *ctx);
/**
* \brief Event: start of object.
*
* This event is raised when the start of a new object has been detected.
* The object name (normalised to uppercase) can be accessed with
* `br_pem_decoder_name()`.
*/
#define BR_PEM_BEGIN_OBJ 1
/**
* \brief Event: end of object.
*
* This event is raised when the end of the current object is reached
* (normally, i.e. with no decoding error).
*/
#define BR_PEM_END_OBJ 2
/**
* \brief Event: decoding error.
*
* This event is raised when decoding fails within an object.
* This formally closes the current object and brings the decoder back
* to the "out of any object" state. The offending line in the source
* is consumed.
*/
#define BR_PEM_ERROR 3
/**
* \brief Get the name of the encountered object.
*
* The encountered object name is defined only when the "start of object"
* event is raised. That name is normalised to uppercase (for ASCII letters
* only) and does not include trailing dashes.
*
* \param ctx decoder context.
* \return the current object name.
*/
static inline const char *
br_pem_decoder_name(br_pem_decoder_context *ctx)
{
return ctx->name;
}
/**
* \brief Encode an object in PEM.
*
* This function encodes the provided binary object (`data`, of length `len`
* bytes) into PEM. The `banner` text will be included in the header and
* footer (e.g. use `"CERTIFICATE"` to get a `"BEGIN CERTIFICATE"` header).
*
* The length (in characters) of the PEM output is returned; that length
* does NOT include the terminating zero, that this function nevertheless
* adds. If using the returned value for allocation purposes, the allocated
* buffer size MUST be at least one byte larger than the returned size.
*
* If `dest` is `NULL`, then the encoding does not happen; however, the
* length of the encoded object is still computed and returned.
*
* The `data` pointer may be `NULL` only if `len` is zero (when encoding
* an object of length zero, which is not very useful), or when `dest`
* is `NULL` (in that case, source data bytes are ignored).
*
* Some `flags` can be specified to alter the encoding behaviour:
*
* - If `BR_PEM_LINE64` is set, then line-breaking will occur after
* every 64 characters of output, instead of the default of 76.
*
* - If `BR_PEM_CRLF` is set, then end-of-line sequence will use
* CR+LF instead of a single LF.
*
* The `data` and `dest` buffers may overlap, in which case the source
* binary data is destroyed in the process. Note that the PEM-encoded output
* is always larger than the source binary.
*
* \param dest the destination buffer (or `NULL`).
* \param data the source buffer (can be `NULL` in some cases).
* \param len the source length (in bytes).
* \param banner the PEM banner expression.
* \param flags the behavioural flags.
* \return the PEM object length (in characters), EXCLUDING the final zero.
*/
size_t br_pem_encode(void *dest, const void *data, size_t len,
const char *banner, unsigned flags);
/**
* \brief PEM encoding flag: split lines at 64 characters.
*/
#define BR_PEM_LINE64 0x0001
/**
* \brief PEM encoding flag: use CR+LF line endings.
*/
#define BR_PEM_CRLF 0x0002
#ifdef __cplusplus
}
#endif
#endif