The Tor Browser: security/nss/lib/util/nssb64e.c@6474c204b198 (annotated)

security/nss/lib/util/nssb64e.c@6474c204b198 (annotated)

security/nss/lib/util/nssb64e.c

Wed, 31 Dec 2014 06:09:35 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Wed, 31 Dec 2014 06:09:35 +0100
changeset 0: 6474c204b198
permissions: -rw-r--r--

Cloned upstream origin tor-browser at tor-browser-31.3.0esr-4.5-1-build1
revision ID fc1c9ff7c1b2defdbc039f12214767608f46423f for hacking purpose.

 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 /*
  * Base64 encoding (binary to ascii).
  */
 #include "nssb64.h"
 #include "nspr.h"
 #include "secitem.h"
 #include "secerr.h"
 /*
  * XXX See the big comment at the top of nssb64d.c about moving the
  * bulk of this code over into NSPR (the PL part).  It all applies
  * here but I didn't want to duplicate it, to avoid divergence problems.
  */
 /*
  **************************************************************
  * XXX Beginning of base64 encoding code to be moved into NSPR.
  */
 struct PLBase64EncodeStateStr {
     unsigned chunks;
     unsigned saved;
     unsigned char buf[3];
 };
 /*
  * This typedef would belong in the NSPR header file (i.e. plbase64.h).
  */
 typedef struct PLBase64EncoderStr PLBase64Encoder;
 /*
  * The following implementation of base64 encoding was based on code
  * found in libmime (specifically, in mimeenc.c).  It has been adapted to
  * use PR types and naming as well as to provide other necessary semantics
  * (like buffer-in/buffer-out in addition to "streaming" without undue
  * performance hit of extra copying if you made the buffer versions
  * use the output_fn).  It also incorporates some aspects of the current
  * NSPR base64 encoding code.  As such, you may find similarities to
  * both of those implementations.  I tried to use names that reflected
  * the original code when possible.  For this reason you may find some
  * inconsistencies -- libmime used lots of "in" and "out" whereas the
  * NSPR version uses "src" and "dest"; sometimes I changed one to the other
  * and sometimes I left them when I thought the subroutines were at least
  * self-consistent.
  */
 PR_BEGIN_EXTERN_C
 /*
  * Opaque object used by the encoder to store state.
  */
 struct PLBase64EncoderStr {
     /*
      * The one or two bytes pending.  (We need 3 to create a "token",
      * and hold the leftovers here.  in_buffer_count is *only* ever
      * 0, 1, or 2.
      */
     unsigned char in_buffer[2];
     int in_buffer_count;
     /*
      * If the caller wants linebreaks added, line_length specifies
      * where they come out.  It must be a multiple of 4; if the caller
      * provides one that isn't, we round it down to the nearest
      * multiple of 4.
      *
      * The value of current_column counts how many characters have been
      * added since the last linebreaks (or since the beginning, on the
      * first line).  It is also always a multiple of 4; it is unused when
      * line_length is 0.
      */
     PRUint32 line_length;
     PRUint32 current_column;
     /*
      * Where to write the encoded data (used when streaming, not when
      * doing all in-memory (buffer) operations).
      *
      * Note that this definition is chosen to be compatible with PR_Write.
      */
     PRInt32 (*output_fn) (void *output_arg, const char *buf, PRInt32 size);
     void *output_arg;
     /*
      * Where the encoded output goes -- either temporarily (in the streaming
      * case, staged here before it goes to the output function) or what will
      * be the entire buffered result for users of the buffer version.
      */
     char *output_buffer;
     PRUint32 output_buflen;	/* the total length of allocated buffer */
     PRUint32 output_length;	/* the length that is currently populated */
 };
 PR_END_EXTERN_C
 /*
  * Table to convert a binary value to its corresponding ascii "code".
  */
 static unsigned char base64_valuetocode[64] =
     "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
 #define B64_PAD	'='
 #define B64_CR	'\r'
 #define B64_LF	'\n'
 static PRStatus
 pl_base64_encode_buffer (PLBase64Encoder *data, const unsigned char *in,
 			 PRUint32 size)
 {
     const unsigned char *end = in + size;
     char *out = data->output_buffer + data->output_length;
     unsigned int i = data->in_buffer_count;
     PRUint32 n = 0;
     int off;
     PRUint32 output_threshold;
     /* If this input buffer is too small, wait until next time. */
     if (size < (3 - i)) {
 	data->in_buffer[i++] = in[0];
 	if (size > 1)
 	    data->in_buffer[i++] = in[1];
 	PR_ASSERT(i < 3);
 	data->in_buffer_count = i;
 	return PR_SUCCESS;
     }
     /* If there are bytes that were put back last time, take them now. */
     if (i > 0) {
 	n = data->in_buffer[0];
 	if (i > 1)
 	    n = (n << 8) | data->in_buffer[1];
 	data->in_buffer_count = 0;
     }
     /* If our total is not a multiple of three, put one or two bytes back. */
     off = (size + i) % 3;
     if (off > 0) {
 	size -= off;
 	data->in_buffer[0] = in[size];
 	if (off > 1)
 	    data->in_buffer[1] = in[size + 1];
 	data->in_buffer_count = off;
 	end -= off;
     }
     output_threshold = data->output_buflen - 3;
     /*
      * Populate the output buffer with base64 data, one line (or buffer)
      * at a time.
      */
     while (in < end) {
 	int j, k;
 	while (i < 3) {
 	    n = (n << 8) | *in++;
 	    i++;
 	}
 	i = 0;
 	if (data->line_length > 0) {
 	    if (data->current_column >= data->line_length) {
 		data->current_column = 0;
 		*out++ = B64_CR;
 		*out++ = B64_LF;
 		data->output_length += 2;
 	    }
 	    data->current_column += 4;	/* the bytes we are about to add */
 	}
 	for (j = 18; j >= 0; j -= 6) {
 	    k = (n >> j) & 0x3F;
 	    *out++ = base64_valuetocode[k];
 	}
 	n = 0;
 	data->output_length += 4;
 	if (data->output_length >= output_threshold) {
 	    PR_ASSERT(data->output_length <= data->output_buflen);
 	    if (data->output_fn != NULL) {
 		PRInt32 output_result;
 		output_result = data->output_fn (data->output_arg,
 						 data->output_buffer,
 						 (PRInt32) data->output_length);
 		if (output_result < 0)
 		    return PR_FAILURE;
 		out = data->output_buffer;
 		data->output_length = 0;
 	    } else {
 		/*
 		 * Check that we are about to exit the loop.  (Since we
 		 * are over the threshold, there isn't enough room in the
 		 * output buffer for another trip around.)
 		 */
 		PR_ASSERT(in == end);
 		if (in < end) {
 		    PR_SetError (PR_BUFFER_OVERFLOW_ERROR, 0);
 		    return PR_FAILURE;
 		}
 	    }
 	}
     }
     return PR_SUCCESS;
 }
 static PRStatus
 pl_base64_encode_flush (PLBase64Encoder *data)
 {
     int i = data->in_buffer_count;
     if (i == 0 && data->output_length == 0)
 	return PR_SUCCESS;
     if (i > 0) {
 	char *out = data->output_buffer + data->output_length;
 	PRUint32 n;
 	int j, k;
 	n = ((PRUint32) data->in_buffer[0]) << 16;
 	if (i > 1)
 	    n |= ((PRUint32) data->in_buffer[1] << 8);
 	data->in_buffer_count = 0;
 	if (data->line_length > 0) {
 	    if (data->current_column >= data->line_length) {
 		data->current_column = 0;
 		*out++ = B64_CR;
 		*out++ = B64_LF;
 		data->output_length += 2;
 	    }
 	}
 	/*
 	 * This will fill in more than we really have data for, but the
 	 * valid parts will end up in the correct position and the extras
 	 * will be over-written with pad characters below.
 	 */
 	for (j = 18; j >= 0; j -= 6) {
 	    k = (n >> j) & 0x3F;
 	    *out++ = base64_valuetocode[k];
 	}
 	/* Pad with equal-signs. */
 	if (i == 1)
 	    out[-2] = B64_PAD;
 	out[-1] = B64_PAD;
 	data->output_length += 4;
     }
     if (data->output_fn != NULL) {
 	PRInt32 output_result;
 	output_result = data->output_fn (data->output_arg, data->output_buffer,
 					 (PRInt32) data->output_length);
 	data->output_length = 0;
 	if (output_result < 0)
 	    return PR_FAILURE;
     }
     return PR_SUCCESS;
 }
 /*
  * The maximum space needed to hold the output of the encoder given input
  * data of length "size", and allowing for CRLF added at least every
  * line_length bytes (we will add it at nearest lower multiple of 4).
  * There is no trailing CRLF.
  */
 static PRUint32
 PL_Base64MaxEncodedLength (PRUint32 size, PRUint32 line_length)
 {
     PRUint32 tokens, tokens_per_line, full_lines, line_break_chars, remainder;
     tokens = (size + 2) / 3;
     if (line_length == 0)
 	return tokens * 4;
     if (line_length < 4)	/* too small! */
 	line_length = 4;
     tokens_per_line = line_length / 4;
     full_lines = tokens / tokens_per_line;
     remainder = (tokens - (full_lines * tokens_per_line)) * 4;
     line_break_chars = full_lines * 2;
     if (remainder == 0)
 	line_break_chars -= 2;
     return (full_lines * tokens_per_line * 4) + line_break_chars + remainder;
 }
 /*
  * A distinct internal creation function for the buffer version to use.
  * (It does not want to specify an output_fn, and we want the normal
  * Create function to require that.)  All common initialization of the
  * encoding context should be done *here*.
  *
  * Save "line_length", rounded down to nearest multiple of 4 (if not
  * already even multiple).  Allocate output_buffer, if not provided --
  * based on given size if specified, otherwise based on line_length.
  */
 static PLBase64Encoder *
 pl_base64_create_encoder (PRUint32 line_length, char *output_buffer,
 			  PRUint32 output_buflen)
 {
     PLBase64Encoder *data;
     PRUint32 line_tokens;
     data = PR_NEWZAP(PLBase64Encoder);
     if (data == NULL)
 	return NULL;
     if (line_length > 0 && line_length < 4)	/* too small! */
 	line_length = 4;
     line_tokens = line_length / 4;
     data->line_length = line_tokens * 4;
     if (output_buffer == NULL) {
 	if (output_buflen == 0) {
 	    if (data->line_length > 0)	/* need to include room for CRLF */
 		output_buflen = data->line_length + 2;
 	    else
 		output_buflen = 64;		/* XXX what is a good size? */
 	}
 	output_buffer = (char *) PR_Malloc(output_buflen);
 	if (output_buffer == NULL) {
 	    PR_Free(data);
 	    return NULL;
 	}
     }
     data->output_buffer = output_buffer;
     data->output_buflen = output_buflen;
     return data;
 }
 /*
  * Function to start a base64 encoding context.
  * An "output_fn" is required; the "output_arg" parameter to that is optional.
  * If linebreaks in the encoded output are desired, "line_length" specifies
  * where to place them -- it will be rounded down to the nearest multiple of 4
  * (if it is not already an even multiple of 4).  If it is zero, no linebreaks
  * will be added.  (FYI, a linebreak is CRLF -- two characters.)
  */
 static PLBase64Encoder *
 PL_CreateBase64Encoder (PRInt32 (*output_fn) (void *, const char *, PRInt32),
 			void *output_arg, PRUint32 line_length)
 {
     PLBase64Encoder *data;
     if (output_fn == NULL) {
 	PR_SetError (PR_INVALID_ARGUMENT_ERROR, 0);
 	return NULL;
     }
     data = pl_base64_create_encoder (line_length, NULL, 0);
     if (data == NULL)
 	return NULL;
     data->output_fn = output_fn;
     data->output_arg = output_arg;
     return data;
 }
 /*
  * Push data through the encoder, causing the output_fn (provided to Create)
  * to be called with the encoded data.
  */
 static PRStatus
 PL_UpdateBase64Encoder (PLBase64Encoder *data, const unsigned char *buffer,
 			PRUint32 size)
 {
     /* XXX Should we do argument checking only in debug build? */
     if (data == NULL || buffer == NULL || size == 0) {
 	PR_SetError (PR_INVALID_ARGUMENT_ERROR, 0);
 	return PR_FAILURE;
     }
     return pl_base64_encode_buffer (data, buffer, size);
 }
 /*
  * When you're done encoding, call this to free the data.  If "abort_p"
  * is false, then calling this may cause the output_fn to be called
  * one last time (as the last buffered data is flushed out).
  */
 static PRStatus
 PL_DestroyBase64Encoder (PLBase64Encoder *data, PRBool abort_p)
 {
     PRStatus status = PR_SUCCESS;
     /* XXX Should we do argument checking only in debug build? */
     if (data == NULL) {
 	PR_SetError (PR_INVALID_ARGUMENT_ERROR, 0);
 	return PR_FAILURE;
     }
     /* Flush out the last few buffered characters. */
     if (!abort_p)
 	status = pl_base64_encode_flush (data);
     if (data->output_buffer != NULL)
 	PR_Free(data->output_buffer);
     PR_Free(data);
     return status;
 }
 /*
  * Perform base64 encoding from an input buffer to an output buffer.
  * The output buffer can be provided (as "dest"); you can also pass in
  * a NULL and this function will allocate a buffer large enough for you,
  * and return it.  If you do provide the output buffer, you must also
  * provide the maximum length of that buffer (as "maxdestlen").
  * The actual encoded length of output will be returned to you in
  * "output_destlen".
  *
  * If linebreaks in the encoded output are desired, "line_length" specifies
  * where to place them -- it will be rounded down to the nearest multiple of 4
  * (if it is not already an even multiple of 4).  If it is zero, no linebreaks
  * will be added.  (FYI, a linebreak is CRLF -- two characters.)
  *
  * Return value is NULL on error, the output buffer (allocated or provided)
  * otherwise.
  */
 static char *
 PL_Base64EncodeBuffer (const unsigned char *src, PRUint32 srclen,
 		       PRUint32 line_length, char *dest, PRUint32 maxdestlen,
 		       PRUint32 *output_destlen)
 {
     PRUint32 need_length;
     PLBase64Encoder *data = NULL;
     PRStatus status;
     PR_ASSERT(srclen > 0);
     if (srclen == 0)
 	return dest;
     /*
      * How much space could we possibly need for encoding this input?
      */
     need_length = PL_Base64MaxEncodedLength (srclen, line_length);
     /*
      * Make sure we have at least that much, if output buffer provided.
      */
     if (dest != NULL) {
 	PR_ASSERT(maxdestlen >= need_length);
 	if (maxdestlen < need_length) {
 	    PR_SetError(PR_BUFFER_OVERFLOW_ERROR, 0);
 	    return NULL;
 	}
     } else {
 	maxdestlen = need_length;
     }
     data = pl_base64_create_encoder(line_length, dest, maxdestlen);
     if (data == NULL)
 	return NULL;
     status = pl_base64_encode_buffer (data, src, srclen);
     /*
      * We do not wait for Destroy to flush, because Destroy will also
      * get rid of our encoder context, which we need to look at first!
      */
     if (status == PR_SUCCESS)
 	status = pl_base64_encode_flush (data);
     if (status != PR_SUCCESS) {
 	(void) PL_DestroyBase64Encoder (data, PR_TRUE);
 	return NULL;
     }
     dest = data->output_buffer;
     /* Must clear this or Destroy will free it. */
     data->output_buffer = NULL;
     *output_destlen = data->output_length;
     status = PL_DestroyBase64Encoder (data, PR_FALSE);
     if (status == PR_FAILURE) {
 	PR_Free(dest);
 	return NULL;
     }
     return dest;
 }
 /*
  * XXX End of base64 encoding code to be moved into NSPR.
  ********************************************************
  */
 /*
  * This is the beginning of the NSS cover functions.  These will
  * provide the interface we want to expose as NSS-ish.  For example,
  * they will operate on our Items, do any special handling or checking
  * we want to do, etc.
  */
 PR_BEGIN_EXTERN_C
 /*
  * A boring cover structure for now.  Perhaps someday it will include
  * some more interesting fields.
  */
 struct NSSBase64EncoderStr {
     PLBase64Encoder *pl_data;
 };
 PR_END_EXTERN_C
 /*
  * Function to start a base64 encoding context.
  */
 NSSBase64Encoder *
 NSSBase64Encoder_Create (PRInt32 (*output_fn) (void *, const char *, PRInt32),
 			 void *output_arg)
 {
     PLBase64Encoder *pl_data;
     NSSBase64Encoder *nss_data;
     nss_data = PORT_ZNew(NSSBase64Encoder);
     if (nss_data == NULL)
 	return NULL;
     pl_data = PL_CreateBase64Encoder (output_fn, output_arg, 64);
     if (pl_data == NULL) {
 	PORT_Free(nss_data);
 	return NULL;
     }
     nss_data->pl_data = pl_data;
     return nss_data;
 }
 /*
  * Push data through the encoder, causing the output_fn (provided to Create)
  * to be called with the encoded data.
  */
 SECStatus
 NSSBase64Encoder_Update (NSSBase64Encoder *data, const unsigned char *buffer,
 			 PRUint32 size)
 {
     PRStatus pr_status;
     /* XXX Should we do argument checking only in debug build? */
     if (data == NULL) {
 	PORT_SetError (SEC_ERROR_INVALID_ARGS);
 	return SECFailure;
     }
     pr_status = PL_UpdateBase64Encoder (data->pl_data, buffer, size);
     if (pr_status == PR_FAILURE)
 	return SECFailure;
     return SECSuccess;
 }
 /*
  * When you're done encoding, call this to free the data.  If "abort_p"
  * is false, then calling this may cause the output_fn to be called
  * one last time (as the last buffered data is flushed out).
  */
 SECStatus
 NSSBase64Encoder_Destroy (NSSBase64Encoder *data, PRBool abort_p)
 {
     PRStatus pr_status;
     /* XXX Should we do argument checking only in debug build? */
     if (data == NULL) {
 	PORT_SetError (SEC_ERROR_INVALID_ARGS);
 	return SECFailure;
     }
     pr_status = PL_DestroyBase64Encoder (data->pl_data, abort_p);
     PORT_Free(data);
     if (pr_status == PR_FAILURE)
 	return SECFailure;
     return SECSuccess;
 }
 /*
  * Perform base64 encoding of binary data "inItem" to an ascii string.
  * The output buffer may be provided (as "outStrOpt"); you can also pass
  * in a NULL and the buffer will be allocated for you.  The result will
  * be null-terminated, and if the buffer is provided, "maxOutLen" must
  * specify the maximum length of the buffer and will be checked to
  * supply sufficient space space for the encoded result.  (If "outStrOpt"
  * is NULL, "maxOutLen" is ignored.)
  *
  * If "outStrOpt" is NULL, allocation will happen out of the passed-in
  * "arenaOpt", if *it* is non-NULL, otherwise standard allocation (heap)
  * will be used.
  *
  * Return value is NULL on error, the output buffer (allocated or provided)
  * otherwise.
  */
 char *
 NSSBase64_EncodeItem (PLArenaPool *arenaOpt, char *outStrOpt,
 		      unsigned int maxOutLen, SECItem *inItem)
 {
     char *out_string = outStrOpt;
     PRUint32 max_out_len;
     PRUint32 out_len;
     void *mark = NULL;
     char *dummy;
     PORT_Assert(inItem != NULL && inItem->data != NULL && inItem->len != 0);
     if (inItem == NULL || inItem->data == NULL || inItem->len == 0) {
 	PORT_SetError (SEC_ERROR_INVALID_ARGS);
 	return NULL;
     }
     max_out_len = PL_Base64MaxEncodedLength (inItem->len, 64);
     if (arenaOpt != NULL)
 	mark = PORT_ArenaMark (arenaOpt);
     if (out_string == NULL) {
 	if (arenaOpt != NULL)
 	    out_string = PORT_ArenaAlloc (arenaOpt, max_out_len + 1);
 	else
 	    out_string = PORT_Alloc (max_out_len + 1);
 	if (out_string == NULL) {
 	    if (arenaOpt != NULL)
 		PORT_ArenaRelease (arenaOpt, mark);
 	    return NULL;
 	}
     } else {
 	if ((max_out_len + 1) > maxOutLen) {
 	    PORT_SetError (SEC_ERROR_OUTPUT_LEN);
 	    return NULL;
 	}
 	max_out_len = maxOutLen;
     }
     dummy = PL_Base64EncodeBuffer (inItem->data, inItem->len, 64,
 				   out_string, max_out_len, &out_len);
     if (dummy == NULL) {
 	if (arenaOpt != NULL) {
 	    PORT_ArenaRelease (arenaOpt, mark);
 	} else {
 	    PORT_Free (out_string);
 	}
 	return NULL;
     }
     if (arenaOpt != NULL)
 	PORT_ArenaUnmark (arenaOpt, mark);
     out_string[out_len] = '\0';
     return out_string;
 }
 /*
  * XXX Everything below is deprecated.  If you add new stuff, put it
  * *above*, not below.
  */
 /*
  * XXX The following "BTOA" functions are provided for backward compatibility
  * with current code.  They should be considered strongly deprecated.
  * When we can convert all our code over to using the new NSSBase64Encoder_
  * functions defined above, we should get rid of these altogether.  (Remove
  * protoypes from base64.h as well -- actually, remove that file completely).
  * If someone thinks either of these functions provides such a very useful
  * interface (though, as shown, the same functionality can already be
  * obtained by calling NSSBase64_EncodeItem directly), fine -- but then
  * that API should be provided with a nice new NSSFoo name and using
  * appropriate types, etc.
  */
 #include "base64.h"
 /*
 ** Return an PORT_Alloc'd ascii string which is the base64 encoded
 ** version of the input string.
 */
 char *
 BTOA_DataToAscii(const unsigned char *data, unsigned int len)
 {
     SECItem binary_item;
     binary_item.data = (unsigned char *)data;
     binary_item.len = len;
     return NSSBase64_EncodeItem (NULL, NULL, 0, &binary_item);
 }
 /*
 ** Convert from binary encoding of an item to ascii.
 */
 char *
 BTOA_ConvertItemToAscii (SECItem *binary_item)
 {
     return NSSBase64_EncodeItem (NULL, NULL, 0, binary_item);
 }

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security/nss/lib/util/nssb64e.c@6474c204b198 (annotated)

security/nss/lib/util/nssb64e.c