133 lines
4.7 KiB
C
133 lines
4.7 KiB
C
/* ====================================================================
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* Copyright (c) 2010 The OpenSSL Project. All rights reserved.
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*
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* Redistribution and use is governed by OpenSSL license.
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* ====================================================================
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*/
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#include <openssl/modes.h>
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#if (defined(_WIN32) || defined(_WIN64)) && !defined(__MINGW32__)
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typedef __int64 i64;
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typedef unsigned __int64 u64;
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#define U64(C) C##UI64
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#elif defined(__arch64__)
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typedef long i64;
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typedef unsigned long u64;
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#define U64(C) C##UL
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#else
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typedef long long i64;
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typedef unsigned long long u64;
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#define U64(C) C##ULL
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#endif
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typedef unsigned int u32;
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typedef unsigned char u8;
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#define STRICT_ALIGNMENT 1
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#if defined(__i386) || defined(__i386__) || \
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defined(__x86_64) || defined(__x86_64__) || \
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defined(_M_IX86) || defined(_M_AMD64) || defined(_M_X64) || \
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defined(__s390__) || defined(__s390x__)
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# undef STRICT_ALIGNMENT
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#endif
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#if !defined(PEDANTIC) && !defined(OPENSSL_NO_ASM) && !defined(OPNESSL_NO_INLINE_ASM)
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#if defined(__GNUC__) && __GNUC__>=2
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# if defined(__x86_64) || defined(__x86_64__)
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# define BSWAP8(x) ({ u64 ret=(x); \
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asm volatile ("bswapq %0" \
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: "+r"(ret)); ret; })
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# define BSWAP4(x) ({ u32 ret=(x); \
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asm volatile ("bswapl %0" \
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: "+r"(ret)); ret; })
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# elif (defined(__i386) || defined(__i386__))
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# define BSWAP8(x) ({ u32 lo=(u64)(x)>>32,hi=(x); \
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asm volatile ("bswapl %0; bswapl %1" \
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: "+r"(hi),"+r"(lo)); \
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(u64)hi<<32|lo; })
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# define BSWAP4(x) ({ u32 ret=(x); \
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asm volatile ("bswapl %0" \
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: "+r"(ret)); ret; })
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# endif
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#elif defined(_MSC_VER)
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# if _MSC_VER>=1300
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# pragma intrinsic(_byteswap_uint64,_byteswap_ulong)
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# define BSWAP8(x) _byteswap_uint64((u64)(x))
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# define BSWAP4(x) _byteswap_ulong((u32)(x))
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# elif defined(_M_IX86)
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__inline u32 _bswap4(u32 val) {
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_asm mov eax,val
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_asm bswap eax
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}
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# define BSWAP4(x) _bswap4(x)
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# endif
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#endif
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#endif
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#if defined(BSWAP4) && !defined(STRICT_ALIGNMENT)
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#define GETU32(p) BSWAP4(*(const u32 *)(p))
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#define PUTU32(p,v) *(u32 *)(p) = BSWAP4(v)
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#else
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#define GETU32(p) ((u32)(p)[0]<<24|(u32)(p)[1]<<16|(u32)(p)[2]<<8|(u32)(p)[3])
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#define PUTU32(p,v) ((p)[0]=(u8)((v)>>24),(p)[1]=(u8)((v)>>16),(p)[2]=(u8)((v)>>8),(p)[3]=(u8)(v))
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#endif
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/* GCM definitions */
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typedef struct { u64 hi,lo; } u128;
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#ifdef TABLE_BITS
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#undef TABLE_BITS
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#endif
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/*
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* Even though permitted values for TABLE_BITS are 8, 4 and 1, it should
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* never be set to 8. 8 is effectively reserved for testing purposes.
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* TABLE_BITS>1 are lookup-table-driven implementations referred to as
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* "Shoup's" in GCM specification. In other words OpenSSL does not cover
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* whole spectrum of possible table driven implementations. Why? In
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* non-"Shoup's" case memory access pattern is segmented in such manner,
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* that it's trivial to see that cache timing information can reveal
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* fair portion of intermediate hash value. Given that ciphertext is
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* always available to attacker, it's possible for him to attempt to
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* deduce secret parameter H and if successful, tamper with messages
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* [which is nothing but trivial in CTR mode]. In "Shoup's" case it's
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* not as trivial, but there is no reason to believe that it's resistant
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* to cache-timing attack. And the thing about "8-bit" implementation is
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* that it consumes 16 (sixteen) times more memory, 4KB per individual
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* key + 1KB shared. Well, on pros side it should be twice as fast as
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* "4-bit" version. And for gcc-generated x86[_64] code, "8-bit" version
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* was observed to run ~75% faster, closer to 100% for commercial
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* compilers... Yet "4-bit" procedure is preferred, because it's
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* believed to provide better security-performance balance and adequate
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* all-round performance. "All-round" refers to things like:
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*
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* - shorter setup time effectively improves overall timing for
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* handling short messages;
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* - larger table allocation can become unbearable because of VM
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* subsystem penalties (for example on Windows large enough free
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* results in VM working set trimming, meaning that consequent
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* malloc would immediately incur working set expansion);
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* - larger table has larger cache footprint, which can affect
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* performance of other code paths (not necessarily even from same
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* thread in Hyper-Threading world);
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*/
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#define TABLE_BITS 4
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struct gcm128_context {
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/* Following 6 names follow names in GCM specification */
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union { u64 u[2]; u32 d[4]; u8 c[16]; } Yi,EKi,EK0,
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Xi,H,len;
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/* Pre-computed table used by gcm_gmult_* */
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#if TABLE_BITS==8
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u128 Htable[256];
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#else
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u128 Htable[16];
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void (*gmult)(u64 Xi[2],const u128 Htable[16]);
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void (*ghash)(u64 Xi[2],const u128 Htable[16],const u8 *inp,size_t len);
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#endif
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unsigned int mres, ares;
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block128_f block;
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void *key;
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};
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