The Tor Browser: netwerk/sctp/src/netinet/sctp_sha1.c@97036ab72558 (annotated)

netwerk/sctp/src/netinet/sctp_sha1.c@97036ab72558 (annotated)

netwerk/sctp/src/netinet/sctp_sha1.c

Tue, 06 Jan 2015 21:39:09 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Tue, 06 Jan 2015 21:39:09 +0100
branch: TOR_BUG_9701
changeset 8: 97036ab72558
permissions: -rwxr-xr-x

Conditionally force memory storage according to privacy.thirdparty.isolate;
This solves Tor bug #9701, complying with disk avoidance documented in
https://www.torproject.org/projects/torbrowser/design/#disk-avoidance.

 /*-
  * Copyright (c) 2001-2007, by Cisco Systems, Inc. All rights reserved.
  * Copyright (c) 2008-2012, by Randall Stewart. All rights reserved.
  * Copyright (c) 2008-2013, by Michael Tuexen. All rights reserved.
  * Copyright (c) 2013,      by Lally Singh. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are met:
  *
  * a) Redistributions of source code must retain the above copyright notice,
  *   this list of conditions and the following disclaimer.
  *
  * b) Redistributions in binary form must reproduce the above copyright
  *    notice, this list of conditions and the following disclaimer in
  *   the documentation and/or other materials provided with the distribution.
  *
  * c) Neither the name of Cisco Systems, Inc. nor the names of its
  *    contributors may be used to endorse or promote products derived
  *    from this software without specific prior written permission.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
  * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF
  * THE POSSIBILITY OF SUCH DAMAGE.
  */
 #include <netinet/sctp_sha1.h>
 #if defined(SCTP_USE_NSS_SHA1)
 /* A SHA-1 Digest is 160 bits, or 20 bytes */
 #define SHA_DIGEST_LENGTH (20)
 void
 sctp_sha1_init(struct sctp_sha1_context *ctx)
 {
 	ctx->pk11_ctx = PK11_CreateDigestContext(SEC_OID_SHA1);
 	PK11_DigestBegin(ctx->pk11_ctx);
 }
 void
 sctp_sha1_update(struct sctp_sha1_context *ctx, const unsigned char *ptr, unsigned int siz)
 {
 	PK11_DigestOp(ctx->pk11_ctx, ptr, siz);
 }
 void
 sctp_sha1_final(unsigned char *digest, struct sctp_sha1_context *ctx)
 {
 	unsigned int output_len = 0;
 	PK11_DigestFinal(ctx->pk11_ctx, digest, &output_len, SHA_DIGEST_LENGTH);
 	PK11_DestroyContext(ctx->pk11_ctx, PR_TRUE);
 }
 #elif defined(SCTP_USE_OPENSSL_SHA1)
 void
 sctp_sha1_init(struct sctp_sha1_context *ctx)
 {
 	SHA1_Init(&ctx->sha_ctx);
 }
 void
 sctp_sha1_update(struct sctp_sha1_context *ctx, const unsigned char *ptr, unsigned int siz)
 {
 	SHA1_Update(&ctx->sha_ctx, ptr, (unsigned long)siz);
 }
 void
 sctp_sha1_final(unsigned char *digest, struct sctp_sha1_context *ctx)
 {
 	SHA1_Final(digest, &ctx->sha_ctx);
 }
 #else
 #include <string.h>
 #if defined(__Userspace_os_Windows)
 #include <winsock2.h>
 #elif !defined(__Windows__)
 #include <arpa/inet.h>
 #endif
 #define F1(B,C,D) (((B & C) | ((~B) & D)))	/* 0  <= t <= 19 */
 #define F2(B,C,D) (B ^ C ^ D)	/* 20 <= t <= 39 */
 #define F3(B,C,D) ((B & C) | (B & D) | (C & D))	/* 40 <= t <= 59 */
 #define F4(B,C,D) (B ^ C ^ D)	/* 600 <= t <= 79 */
 /* circular shift */
 #define CSHIFT(A,B) ((B << A) | (B >> (32-A)))
 #define K1 0x5a827999		/* 0  <= t <= 19 */
 #define K2 0x6ed9eba1		/* 20 <= t <= 39 */
 #define K3 0x8f1bbcdc		/* 40 <= t <= 59 */
 #define K4 0xca62c1d6		/* 60 <= t <= 79 */
 #define H0INIT 0x67452301
 #define H1INIT 0xefcdab89
 #define H2INIT 0x98badcfe
 #define H3INIT 0x10325476
 #define H4INIT 0xc3d2e1f0
 void
 sctp_sha1_init(struct sctp_sha1_context *ctx)
 {
 	/* Init the SHA-1 context structure */
 	ctx->A = 0;
 	ctx->B = 0;
 	ctx->C = 0;
 	ctx->D = 0;
 	ctx->E = 0;
 	ctx->H0 = H0INIT;
 	ctx->H1 = H1INIT;
 	ctx->H2 = H2INIT;
 	ctx->H3 = H3INIT;
 	ctx->H4 = H4INIT;
 	ctx->TEMP = 0;
 	memset(ctx->words, 0, sizeof(ctx->words));
 	ctx->how_many_in_block = 0;
 	ctx->running_total = 0;
 }
 static void
 sctp_sha1_process_a_block(struct sctp_sha1_context *ctx, unsigned int *block)
 {
 	int i;
 	/* init the W0-W15 to the block of words being hashed. */
 	/* step a) */
 	for (i = 0; i < 16; i++) {
 		ctx->words[i] = ntohl(block[i]);
 	}
 	/* now init the rest based on the SHA-1 formula, step b) */
 	for (i = 16; i < 80; i++) {
 		ctx->words[i] = CSHIFT(1, ((ctx->words[(i - 3)]) ^
 		    (ctx->words[(i - 8)]) ^
 		    (ctx->words[(i - 14)]) ^
 		    (ctx->words[(i - 16)])));
 	}
 	/* step c) */
 	ctx->A = ctx->H0;
 	ctx->B = ctx->H1;
 	ctx->C = ctx->H2;
 	ctx->D = ctx->H3;
 	ctx->E = ctx->H4;
 	/* step d) */
 	for (i = 0; i < 80; i++) {
 		if (i < 20) {
 			ctx->TEMP = ((CSHIFT(5, ctx->A)) +
 			    (F1(ctx->B, ctx->C, ctx->D)) +
 			    (ctx->E) +
 			    ctx->words[i] +
 			    K1);
 		} else if (i < 40) {
 			ctx->TEMP = ((CSHIFT(5, ctx->A)) +
 			    (F2(ctx->B, ctx->C, ctx->D)) +
 			    (ctx->E) +
 			    (ctx->words[i]) +
 			    K2);
 		} else if (i < 60) {
 			ctx->TEMP = ((CSHIFT(5, ctx->A)) +
 			    (F3(ctx->B, ctx->C, ctx->D)) +
 			    (ctx->E) +
 			    (ctx->words[i]) +
 			    K3);
 		} else {
 			ctx->TEMP = ((CSHIFT(5, ctx->A)) +
 			    (F4(ctx->B, ctx->C, ctx->D)) +
 			    (ctx->E) +
 			    (ctx->words[i]) +
 			    K4);
 		}
 		ctx->E = ctx->D;
 		ctx->D = ctx->C;
 		ctx->C = CSHIFT(30, ctx->B);
 		ctx->B = ctx->A;
 		ctx->A = ctx->TEMP;
 	}
 	/* step e) */
 	ctx->H0 = (ctx->H0) + (ctx->A);
 	ctx->H1 = (ctx->H1) + (ctx->B);
 	ctx->H2 = (ctx->H2) + (ctx->C);
 	ctx->H3 = (ctx->H3) + (ctx->D);
 	ctx->H4 = (ctx->H4) + (ctx->E);
 }
 void
 sctp_sha1_update(struct sctp_sha1_context *ctx, const unsigned char *ptr, unsigned int siz)
 {
 	unsigned int number_left, left_to_fill;
 	number_left = siz;
 	while (number_left > 0) {
 		left_to_fill = sizeof(ctx->sha_block) - ctx->how_many_in_block;
 		if (left_to_fill > number_left) {
 			/* can only partially fill up this one */
 			memcpy(&ctx->sha_block[ctx->how_many_in_block],
 			    ptr, number_left);
 			ctx->how_many_in_block += number_left;
 			ctx->running_total += number_left;
 			number_left = 0;
 			break;
 		} else {
 			/* block is now full, process it */
 			memcpy(&ctx->sha_block[ctx->how_many_in_block],
 			    ptr, left_to_fill);
 			sctp_sha1_process_a_block(ctx,
 			    (unsigned int *)ctx->sha_block);
 			number_left -= left_to_fill;
 			ctx->running_total += left_to_fill;
 			ctx->how_many_in_block = 0;
 			ptr = (const unsigned char *)(ptr + left_to_fill);
 		}
 	}
 }
 void
 sctp_sha1_final(unsigned char *digest, struct sctp_sha1_context *ctx)
 {
 	/*
 	 * if any left in block fill with padding and process. Then transfer
 	 * the digest to the pointer. At the last block some special rules
 	 * need to apply. We must add a 1 bit following the message, then we
 	 * pad with 0's. The total size is encoded as a 64 bit number at the
 	 * end. Now if the last buffer has more than 55 octets in it we
 	 * cannot fit the 64 bit number + 10000000 pad on the end and must
 	 * add the 10000000 pad, pad the rest of the message with 0's and
 	 * then create an all 0 message with just the 64 bit size at the end
 	 * and run this block through by itself.  Also the 64 bit int must
 	 * be in network byte order.
 	 */
 	int left_to_fill;
 	unsigned int i, *ptr;
 	if (ctx->how_many_in_block > 55) {
 		/*
 		 * special case, we need to process two blocks here. One for
 		 * the current stuff plus possibly the pad. The other for
 		 * the size.
 		 */
 		left_to_fill = sizeof(ctx->sha_block) - ctx->how_many_in_block;
 		if (left_to_fill == 0) {
 			/* Should not really happen but I am paranoid */
 			sctp_sha1_process_a_block(ctx,
 			    (unsigned int *)ctx->sha_block);
 			/* init last block, a bit different than the rest */
 			ctx->sha_block[0] = '\x80';
 			for (i = 1; i < sizeof(ctx->sha_block); i++) {
 				ctx->sha_block[i] = 0x0;
 			}
 		} else if (left_to_fill == 1) {
 			ctx->sha_block[ctx->how_many_in_block] = '\x80';
 			sctp_sha1_process_a_block(ctx,
 			    (unsigned int *)ctx->sha_block);
 			/* init last block */
 			memset(ctx->sha_block, 0, sizeof(ctx->sha_block));
 		} else {
 			ctx->sha_block[ctx->how_many_in_block] = '\x80';
 			for (i = (ctx->how_many_in_block + 1);
 			    i < sizeof(ctx->sha_block);
 			    i++) {
 				ctx->sha_block[i] = 0x0;
 			}
 			sctp_sha1_process_a_block(ctx,
 			    (unsigned int *)ctx->sha_block);
 			/* init last block */
 			memset(ctx->sha_block, 0, sizeof(ctx->sha_block));
 		}
 		/* This is in bits so multiply by 8 */
 		ctx->running_total *= 8;
 		ptr = (unsigned int *)&ctx->sha_block[60];
 		*ptr = htonl(ctx->running_total);
 		sctp_sha1_process_a_block(ctx, (unsigned int *)ctx->sha_block);
 	} else {
 		/*
 		 * easy case, we just pad this message to size - end with 0
 		 * add the magic 0x80 to the next word and then put the
 		 * network byte order size in the last spot and process the
 		 * block.
 		 */
 		ctx->sha_block[ctx->how_many_in_block] = '\x80';
 		for (i = (ctx->how_many_in_block + 1);
 		    i < sizeof(ctx->sha_block);
 		    i++) {
 			ctx->sha_block[i] = 0x0;
 		}
 		/* get last int spot */
 		ctx->running_total *= 8;
 		ptr = (unsigned int *)&ctx->sha_block[60];
 		*ptr = htonl(ctx->running_total);
 		sctp_sha1_process_a_block(ctx, (unsigned int *)ctx->sha_block);
 	}
 	/* transfer the digest back to the user */
 	digest[3] = (ctx->H0 & 0xff);
 	digest[2] = ((ctx->H0 >> 8) & 0xff);
 	digest[1] = ((ctx->H0 >> 16) & 0xff);
 	digest[0] = ((ctx->H0 >> 24) & 0xff);
 	digest[7] = (ctx->H1 & 0xff);
 	digest[6] = ((ctx->H1 >> 8) & 0xff);
 	digest[5] = ((ctx->H1 >> 16) & 0xff);
 	digest[4] = ((ctx->H1 >> 24) & 0xff);
 	digest[11] = (ctx->H2 & 0xff);
 	digest[10] = ((ctx->H2 >> 8) & 0xff);
 	digest[9] = ((ctx->H2 >> 16) & 0xff);
 	digest[8] = ((ctx->H2 >> 24) & 0xff);
 	digest[15] = (ctx->H3 & 0xff);
 	digest[14] = ((ctx->H3 >> 8) & 0xff);
 	digest[13] = ((ctx->H3 >> 16) & 0xff);
 	digest[12] = ((ctx->H3 >> 24) & 0xff);
 	digest[19] = (ctx->H4 & 0xff);
 	digest[18] = ((ctx->H4 >> 8) & 0xff);
 	digest[17] = ((ctx->H4 >> 16) & 0xff);
 	digest[16] = ((ctx->H4 >> 24) & 0xff);
 }
 #endif

The Tor Browser / annotate

netwerk/sctp/src/netinet/sctp_sha1.c@97036ab72558 (annotated)

netwerk/sctp/src/netinet/sctp_sha1.c