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More API documentation in Doxygen format (block ciphers, PEM).

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This commit is contained in:
Thomas Pornin 2016-11-21 16:29:51 +01:00
parent 292f433578
commit ccd43452e6
3 changed files with 989 additions and 135 deletions
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@ -771,7 +771,7 @@ WARN_LOGFILE =
# spaces. See also FILE_PATTERNS and EXTENSION_MAPPING # spaces. See also FILE_PATTERNS and EXTENSION_MAPPING
# Note: If this tag is empty the current directory is searched. # Note: If this tag is empty the current directory is searched.
INPUT = inc/bearssl.h inc/bearssl_hash.h inc/bearssl_hmac.h inc/bearssl_prf.h inc/bearssl_rand.h inc/bearssl_rsa.h INPUT = inc/bearssl.h inc/bearssl_block.h inc/bearssl_hash.h inc/bearssl_hmac.h inc/bearssl_pem.h inc/bearssl_prf.h inc/bearssl_rand.h inc/bearssl_rsa.h
# This tag can be used to specify the character encoding of the source files # This tag can be used to specify the character encoding of the source files
# that doxygen parses. Internally doxygen uses the UTF-8 encoding. Doxygen uses # that doxygen parses. Internally doxygen uses the UTF-8 encoding. Doxygen uses

888
inc/bearssl_block.h
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File diff suppressed because it is too large Load diff

170
inc/bearssl_pem.h
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@ -28,10 +28,85 @@
#include <stddef.h> #include <stddef.h>
#include <stdint.h> #include <stdint.h>
/* /** \file bearssl_pem.h
* Context for a PEM decoder. *
* # 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 { typedef struct {
#ifndef BR_DOXYGEN_IGNORE
/* CPU for the T0 virtual machine. */ /* CPU for the T0 virtual machine. */
struct { struct {
uint32_t *dp; uint32_t *dp;
@ -52,27 +127,45 @@ typedef struct {
char name[128]; char name[128];
unsigned char buf[255]; unsigned char buf[255];
size_t ptr; size_t ptr;
#endif
} br_pem_decoder_context; } br_pem_decoder_context;
/* /**
* Initialise a PEM decoder structure. * \brief Initialise a PEM decoder structure.
*
* \param ctx decoder context to initialise.
*/ */
void br_pem_decoder_init(br_pem_decoder_context *ctx); void br_pem_decoder_init(br_pem_decoder_context *ctx);
/* /**
* Push some bytes into the decoder. Returned value is the number of * \brief Push some bytes into the decoder.
* bytes actually consumed; this may be less than the number of provided *
* bytes if an event is produced. When an event is produced, it must * Returned value is the number of bytes actually consumed; this may be
* be read (with br_pem_decoder_event()); until the event is read, this * less than the number of provided bytes if an event is raised. When an
* function will return 0. * 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, size_t br_pem_decoder_push(br_pem_decoder_context *ctx,
const void *data, size_t len); const void *data, size_t len);
/* /**
* Set the receiver for decoded data. The provided function (with opaque * \brief Set the receiver for decoded data.
* context pointer) will be called with successive data chunks. *
* 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 static inline void
br_pem_decoder_setdest(br_pem_decoder_context *ctx, br_pem_decoder_setdest(br_pem_decoder_context *ctx,
@ -83,38 +176,55 @@ br_pem_decoder_setdest(br_pem_decoder_context *ctx,
ctx->dest_ctx = dest_ctx; ctx->dest_ctx = dest_ctx;
} }
/* /**
* Get the last event. This is 0 if no event has been produced. Calling * \brief Get the last event.
* ths function clears the event and allows new source bytes to be *
* processed. * 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); int br_pem_decoder_event(br_pem_decoder_context *ctx);
/* /**
* This event is called when the start of a new object has been detected. * \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 * The object name (normalised to uppercase) can be accessed with
* br_pem_decoder_name(). The caller MUST provide an appropriate receiver * `br_pem_decoder_name()`.
* (with br_pem_decoder_setdest()) before sending new data bytes.
*/ */
#define BR_PEM_BEGIN_OBJ 1 #define BR_PEM_BEGIN_OBJ 1
/* /**
* This event is called when the end of the current object is reached * \brief Event: end of object.
* (normally). *
* 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 #define BR_PEM_END_OBJ 2
/* /**
* This event is called when decoding fails while decoding an object. * \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 * This formally closes the current object and brings the decoder back
* to the "out of any object" state. The offending line in the source * to the "out of any object" state. The offending line in the source
* is consumed. * is consumed.
*/ */
#define BR_PEM_ERROR 3 #define BR_PEM_ERROR 3
/* /**
* Get the name of the encountered object. That name is normalised to * \brief Get the name of the encountered object.
* uppercase (for ASCII characters). *
* 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 * static inline const char *
br_pem_decoder_name(br_pem_decoder_context *ctx) br_pem_decoder_name(br_pem_decoder_context *ctx)