diff --git a/Makefile b/Makefile index 7bea912e5a..22e4ef3ac5 100644 --- a/Makefile +++ b/Makefile @@ -1417,7 +1417,14 @@ else DC_SHA1 := YesPlease LIB_OBJS += sha1dc/sha1.o LIB_OBJS += sha1dc/ubc_check.o - BASIC_CFLAGS += -DSHA1_DC + BASIC_CFLAGS += \ + -DSHA1_DC \ + -DSHA1DC_NO_STANDARD_INCLUDES \ + -DSHA1DC_INIT_SAFE_HASH_DEFAULT=0 \ + -DSHA1DC_CUSTOM_INCLUDE_SHA1_C="\"cache.h\"" \ + -DSHA1DC_CUSTOM_TRAILING_INCLUDE_SHA1_C="\"sha1dc_git.c\"" \ + -DSHA1DC_CUSTOM_TRAILING_INCLUDE_SHA1_H="\"sha1dc_git.h\"" \ + -DSHA1DC_CUSTOM_INCLUDE_UBC_CHECK_C="\"git-compat-util.h\"" endif endif endif diff --git a/sha1dc/sha1.c b/sha1dc/sha1.c index 35e9dd5bf4..3dff80ac72 100644 --- a/sha1dc/sha1.c +++ b/sha1dc/sha1.c @@ -5,9 +5,23 @@ * https://opensource.org/licenses/MIT ***/ -#include "cache.h" -#include "sha1dc/sha1.h" -#include "sha1dc/ubc_check.h" +#ifndef SHA1DC_NO_STANDARD_INCLUDES +#include +#include +#include +#include +#endif + +#ifdef SHA1DC_CUSTOM_INCLUDE_SHA1_C +#include SHA1DC_CUSTOM_INCLUDE_SHA1_C +#endif + +#ifndef SHA1DC_INIT_SAFE_HASH_DEFAULT +#define SHA1DC_INIT_SAFE_HASH_DEFAULT 1 +#endif + +#include "sha1.h" +#include "ubc_check.h" /* @@ -18,16 +32,31 @@ If you are compiling on a big endian platform and your compiler does not define one of these, you will have to add whatever macros your tool chain defines to indicate Big-Endianness. */ -#if (defined(__BYTE_ORDER) && (__BYTE_ORDER == __BIG_ENDIAN)) || \ - (defined(__BYTE_ORDER__) && (__BYTE_ORDER__ == __BIG_ENDIAN__)) || \ - defined(__BIG_ENDIAN__) || defined(__ARMEB__) || defined(__THUMBEB__) || defined(__AARCH64EB__) || \ - defined(_MIPSEB) || defined(__MIPSEB) || defined(__MIPSEB__) - -#define SHA1DC_BIGENDIAN 1 -#else +#ifdef SHA1DC_BIGENDIAN #undef SHA1DC_BIGENDIAN +#endif +#if (!defined SHA1DC_FORCE_LITTLEENDIAN) && \ + ((defined(__BYTE_ORDER) && (__BYTE_ORDER == __BIG_ENDIAN)) || \ + (defined(__BYTE_ORDER__) && (__BYTE_ORDER__ == __BIG_ENDIAN__)) || \ + defined(_BIG_ENDIAN) || defined(__BIG_ENDIAN__) || defined(__ARMEB__) || defined(__THUMBEB__) || defined(__AARCH64EB__) || \ + defined(_MIPSEB) || defined(__MIPSEB) || defined(__MIPSEB__) || defined(SHA1DC_FORCE_BIGENDIAN)) + +#define SHA1DC_BIGENDIAN + #endif /*ENDIANNESS SELECTION*/ +#if (defined SHA1DC_FORCE_UNALIGNED_ACCESS || \ + defined(__amd64__) || defined(__amd64) || defined(__x86_64__) || defined(__x86_64) || \ + defined(i386) || defined(__i386) || defined(__i386__) || defined(__i486__) || \ + defined(__i586__) || defined(__i686__) || defined(_M_IX86) || defined(__X86__) || \ + defined(_X86_) || defined(__THW_INTEL__) || defined(__I86__) || defined(__INTEL__) || \ + defined(__386) || defined(_M_X64) || defined(_M_AMD64)) + +#define SHA1DC_ALLOW_UNALIGNED_ACCESS + +#endif /*UNALIGNMENT DETECTION*/ + + #define rotate_right(x,n) (((x)>>(n))|((x)<<(32-(n)))) #define rotate_left(x,n) (((x)<<(n))|((x)>>(32-(n)))) @@ -36,11 +65,11 @@ #define sha1_mix(W, t) (rotate_left(W[t - 3] ^ W[t - 8] ^ W[t - 14] ^ W[t - 16], 1)) -#if defined(SHA1DC_BIGENDIAN) +#ifdef SHA1DC_BIGENDIAN #define sha1_load(m, t, temp) { temp = m[t]; } #else #define sha1_load(m, t, temp) { temp = m[t]; sha1_bswap32(temp); } -#endif /* !defined(SHA1DC_BIGENDIAN) */ +#endif #define sha1_store(W, t, x) *(volatile uint32_t *)&W[t] = x @@ -869,6 +898,11 @@ static void sha1recompress_fast_ ## t (uint32_t ihvin[5], uint32_t ihvout[5], co ihvout[0] = ihvin[0] + a; ihvout[1] = ihvin[1] + b; ihvout[2] = ihvin[2] + c; ihvout[3] = ihvin[3] + d; ihvout[4] = ihvin[4] + e; \ } +#ifdef _MSC_VER +#pragma warning(push) +#pragma warning(disable: 4127) /* Complier complains about the checks in the above macro being constant. */ +#endif + #ifdef DOSTORESTATE0 SHA1_RECOMPRESS(0) #endif @@ -1189,6 +1223,10 @@ SHA1_RECOMPRESS(78) SHA1_RECOMPRESS(79) #endif +#ifdef _MSC_VER +#pragma warning(pop) +#endif + static void sha1_recompression_step(uint32_t step, uint32_t ihvin[5], uint32_t ihvout[5], const uint32_t me2[80], const uint32_t state[5]) { switch (step) @@ -1662,7 +1700,7 @@ void SHA1DCInit(SHA1_CTX* ctx) ctx->ihv[3] = 0x10325476; ctx->ihv[4] = 0xC3D2E1F0; ctx->found_collision = 0; - ctx->safe_hash = 0; + ctx->safe_hash = SHA1DC_INIT_SAFE_HASH_DEFAULT; ctx->ubc_check = 1; ctx->detect_coll = 1; ctx->reduced_round_coll = 0; @@ -1710,6 +1748,7 @@ void SHA1DCSetCallback(SHA1_CTX* ctx, collision_block_callback callback) void SHA1DCUpdate(SHA1_CTX* ctx, const char* buf, size_t len) { unsigned left, fill; + if (len == 0) return; @@ -1728,7 +1767,13 @@ void SHA1DCUpdate(SHA1_CTX* ctx, const char* buf, size_t len) while (len >= 64) { ctx->total += 64; + +#if defined(SHA1DC_ALLOW_UNALIGNED_ACCESS) sha1_process(ctx, (uint32_t*)(buf)); +#else + memcpy(ctx->buffer, buf, 64); + sha1_process(ctx, (uint32_t*)(ctx->buffer)); +#endif /* defined(SHA1DC_ALLOW_UNALIGNED_ACCESS) */ buf += 64; len -= 64; } @@ -1788,22 +1833,6 @@ int SHA1DCFinal(unsigned char output[20], SHA1_CTX *ctx) return ctx->found_collision; } -void git_SHA1DCFinal(unsigned char hash[20], SHA1_CTX *ctx) -{ - if (!SHA1DCFinal(hash, ctx)) - return; - die("SHA-1 appears to be part of a collision attack: %s", - sha1_to_hex(hash)); -} - -void git_SHA1DCUpdate(SHA1_CTX *ctx, const void *vdata, unsigned long len) -{ - const char *data = vdata; - /* We expect an unsigned long, but sha1dc only takes an int */ - while (len > INT_MAX) { - SHA1DCUpdate(ctx, data, INT_MAX); - data += INT_MAX; - len -= INT_MAX; - } - SHA1DCUpdate(ctx, data, len); -} +#ifdef SHA1DC_CUSTOM_TRAILING_INCLUDE_SHA1_C +#include SHA1DC_CUSTOM_TRAILING_INCLUDE_SHA1_C +#endif diff --git a/sha1dc/sha1.h b/sha1dc/sha1.h index bd8bd928fb..a0ff5d1305 100644 --- a/sha1dc/sha1.h +++ b/sha1dc/sha1.h @@ -4,6 +4,7 @@ * See accompanying file LICENSE.txt or copy at * https://opensource.org/licenses/MIT ***/ + #ifndef SHA1DC_SHA1_H #define SHA1DC_SHA1_H @@ -11,36 +12,30 @@ extern "C" { #endif -/* uses SHA-1 message expansion to expand the first 16 words of W[] to 80 words */ -/* void sha1_message_expansion(uint32_t W[80]); */ +#ifndef SHA1DC_NO_STANDARD_INCLUDES +#include +#endif -/* sha-1 compression function; first version takes a message block pre-parsed as 16 32-bit integers, second version takes an already expanded message) */ -/* void sha1_compression(uint32_t ihv[5], const uint32_t m[16]); -void sha1_compression_W(uint32_t ihv[5], const uint32_t W[80]); */ - -/* same as sha1_compression_W, but additionally store intermediate states */ +/* sha-1 compression function that takes an already expanded message, and additionally store intermediate states */ /* only stores states ii (the state between step ii-1 and step ii) when DOSTORESTATEii is defined in ubc_check.h */ void sha1_compression_states(uint32_t[5], const uint32_t[16], uint32_t[80], uint32_t[80][5]); /* -// function type for sha1_recompression_step_T (uint32_t ihvin[5], uint32_t ihvout[5], const uint32_t me2[80], const uint32_t state[5]) -// where 0 <= T < 80 -// me2 is an expanded message (the expansion of an original message block XOR'ed with a disturbance vector's message block difference) -// state is the internal state (a,b,c,d,e) before step T of the SHA-1 compression function while processing the original message block -// the function will return: -// ihvin: the reconstructed input chaining value -// ihvout: the reconstructed output chaining value +// Function type for sha1_recompression_step_T (uint32_t ihvin[5], uint32_t ihvout[5], const uint32_t me2[80], const uint32_t state[5]). +// Where 0 <= T < 80 +// me2 is an expanded message (the expansion of an original message block XOR'ed with a disturbance vector's message block difference.) +// state is the internal state (a,b,c,d,e) before step T of the SHA-1 compression function while processing the original message block. +// The function will return: +// ihvin: The reconstructed input chaining value. +// ihvout: The reconstructed output chaining value. */ typedef void(*sha1_recompression_type)(uint32_t*, uint32_t*, const uint32_t*, const uint32_t*); -/* table of sha1_recompression_step_0, ... , sha1_recompression_step_79 */ -/* extern sha1_recompression_type sha1_recompression_step[80];*/ - -/* a callback function type that can be set to be called when a collision block has been found: */ +/* A callback function type that can be set to be called when a collision block has been found: */ /* void collision_block_callback(uint64_t byteoffset, const uint32_t ihvin1[5], const uint32_t ihvin2[5], const uint32_t m1[80], const uint32_t m2[80]) */ typedef void(*collision_block_callback)(uint64_t, const uint32_t*, const uint32_t*, const uint32_t*, const uint32_t*); -/* the SHA-1 context */ +/* The SHA-1 context. */ typedef struct { uint64_t total; uint32_t ihv[5]; @@ -59,30 +54,34 @@ typedef struct { uint32_t states[80][5]; } SHA1_CTX; -/* initialize SHA-1 context */ +/* Initialize SHA-1 context. */ void SHA1DCInit(SHA1_CTX*); /* -// function to enable safe SHA-1 hashing: -// collision attacks are thwarted by hashing a detected near-collision block 3 times -// think of it as extending SHA-1 from 80-steps to 240-steps for such blocks: -// the best collision attacks against SHA-1 have complexity about 2^60, -// thus for 240-steps an immediate lower-bound for the best cryptanalytic attacks would 2^180 -// an attacker would be better off using a generic birthday search of complexity 2^80 -// -// enabling safe SHA-1 hashing will result in the correct SHA-1 hash for messages where no collision attack was detected -// but it will result in a different SHA-1 hash for messages where a collision attack was detected -// this will automatically invalidate SHA-1 based digital signature forgeries -// enabled by default + Function to enable safe SHA-1 hashing: + Collision attacks are thwarted by hashing a detected near-collision block 3 times. + Think of it as extending SHA-1 from 80-steps to 240-steps for such blocks: + The best collision attacks against SHA-1 have complexity about 2^60, + thus for 240-steps an immediate lower-bound for the best cryptanalytic attacks would be 2^180. + An attacker would be better off using a generic birthday search of complexity 2^80. + + Enabling safe SHA-1 hashing will result in the correct SHA-1 hash for messages where no collision attack was detected, + but it will result in a different SHA-1 hash for messages where a collision attack was detected. + This will automatically invalidate SHA-1 based digital signature forgeries. + Enabled by default. */ void SHA1DCSetSafeHash(SHA1_CTX*, int); -/* function to disable or enable the use of Unavoidable Bitconditions (provides a significant speed up) */ -/* enabled by default */ +/* + Function to disable or enable the use of Unavoidable Bitconditions (provides a significant speed up). + Enabled by default + */ void SHA1DCSetUseUBC(SHA1_CTX*, int); -/* function to disable or enable the use of Collision Detection */ -/* enabled by default */ +/* + Function to disable or enable the use of Collision Detection. + Enabled by default. + */ void SHA1DCSetUseDetectColl(SHA1_CTX*, int); /* function to disable or enable the detection of reduced-round SHA-1 collisions */ @@ -100,23 +99,12 @@ void SHA1DCUpdate(SHA1_CTX*, const char*, size_t); /* returns: 0 = no collision detected, otherwise = collision found => warn user for active attack */ int SHA1DCFinal(unsigned char[20], SHA1_CTX*); -/* - * Same as SHA1DCFinal, but convert collision attack case into a verbose die(). - */ -void git_SHA1DCFinal(unsigned char [20], SHA1_CTX *); - -/* - * Same as SHA1DCUpdate, but adjust types to match git's usual interface. - */ -void git_SHA1DCUpdate(SHA1_CTX *ctx, const void *data, unsigned long len); - -#define platform_SHA_CTX SHA1_CTX -#define platform_SHA1_Init SHA1DCInit -#define platform_SHA1_Update git_SHA1DCUpdate -#define platform_SHA1_Final git_SHA1DCFinal - #if defined(__cplusplus) } #endif -#endif /* SHA1DC_SHA1_H */ +#ifdef SHA1DC_CUSTOM_TRAILING_INCLUDE_SHA1_H +#include SHA1DC_CUSTOM_TRAILING_INCLUDE_SHA1_H +#endif + +#endif diff --git a/sha1dc/ubc_check.c b/sha1dc/ubc_check.c index 089dd4743d..b3beff2afb 100644 --- a/sha1dc/ubc_check.c +++ b/sha1dc/ubc_check.c @@ -24,8 +24,13 @@ // ubc_check has been verified against ubc_check_verify using the 'ubc_check_test' program in the tools section */ -#include "git-compat-util.h" -#include "sha1dc/ubc_check.h" +#ifndef SHA1DC_NO_STANDARD_INCLUDES +#include +#endif +#ifdef SHA1DC_CUSTOM_INCLUDE_UBC_CHECK_C +#include SHA1DC_CUSTOM_INCLUDE_UBC_CHECK_C +#endif +#include "ubc_check.h" static const uint32_t DV_I_43_0_bit = (uint32_t)(1) << 0; static const uint32_t DV_I_44_0_bit = (uint32_t)(1) << 1; @@ -361,3 +366,7 @@ if (mask) { dvmask[0]=mask; } + +#ifdef SHA1DC_CUSTOM_TRAILING_INCLUDE_UBC_CHECK_C +#include SHA1DC_CUSTOM_TRAILING_INCLUDE_UBC_CHECK_C +#endif diff --git a/sha1dc/ubc_check.h b/sha1dc/ubc_check.h index b64c306d77..d7e17dc734 100644 --- a/sha1dc/ubc_check.h +++ b/sha1dc/ubc_check.h @@ -20,13 +20,17 @@ // thus one needs to do the recompression check for each DV that has its bit set */ -#ifndef UBC_CHECK_H -#define UBC_CHECK_H +#ifndef SHA1DC_UBC_CHECK_H +#define SHA1DC_UBC_CHECK_H #if defined(__cplusplus) extern "C" { #endif +#ifndef SHA1DC_NO_STANDARD_INCLUDES +#include +#endif + #define DVMASKSIZE 1 typedef struct { int dvType; int dvK; int dvB; int testt; int maski; int maskb; uint32_t dm[80]; } dv_info_t; extern dv_info_t sha1_dvs[]; @@ -41,4 +45,8 @@ void ubc_check(const uint32_t W[80], uint32_t dvmask[DVMASKSIZE]); } #endif -#endif /* UBC_CHECK_H */ +#ifdef SHA1DC_CUSTOM_TRAILING_INCLUDE_UBC_CHECK_H +#include SHA1DC_CUSTOM_TRAILING_INCLUDE_UBC_CHECK_H +#endif + +#endif diff --git a/sha1dc_git.c b/sha1dc_git.c new file mode 100644 index 0000000000..4d32b4f77e --- /dev/null +++ b/sha1dc_git.c @@ -0,0 +1,24 @@ +/* + * This code is included at the end of sha1dc/sha1.c with the + * SHA1DC_CUSTOM_TRAILING_INCLUDE_SHA1_C macro. + */ + +void git_SHA1DCFinal(unsigned char hash[20], SHA1_CTX *ctx) +{ + if (!SHA1DCFinal(hash, ctx)) + return; + die("SHA-1 appears to be part of a collision attack: %s", + sha1_to_hex(hash)); +} + +void git_SHA1DCUpdate(SHA1_CTX *ctx, const void *vdata, unsigned long len) +{ + const char *data = vdata; + /* We expect an unsigned long, but sha1dc only takes an int */ + while (len > INT_MAX) { + SHA1DCUpdate(ctx, data, INT_MAX); + data += INT_MAX; + len -= INT_MAX; + } + SHA1DCUpdate(ctx, data, len); +} diff --git a/sha1dc_git.h b/sha1dc_git.h new file mode 100644 index 0000000000..a8a5c1da16 --- /dev/null +++ b/sha1dc_git.h @@ -0,0 +1,19 @@ +/* + * This code is included at the end of sha1dc/sha1.h with the + * SHA1DC_CUSTOM_TRAILING_INCLUDE_SHA1_H macro. + */ + +/* + * Same as SHA1DCFinal, but convert collision attack case into a verbose die(). + */ +void git_SHA1DCFinal(unsigned char [20], SHA1_CTX *); + +/* + * Same as SHA1DCUpdate, but adjust types to match git's usual interface. + */ +void git_SHA1DCUpdate(SHA1_CTX *ctx, const void *data, unsigned long len); + +#define platform_SHA_CTX SHA1_CTX +#define platform_SHA1_Init SHA1DCInit +#define platform_SHA1_Update git_SHA1DCUpdate +#define platform_SHA1_Final git_SHA1DCFinal