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Diffstat (limited to 'lib/libtpm/sha.c')
| -rw-r--r-- | lib/libtpm/sha.c | 205 |
1 files changed, 205 insertions, 0 deletions
diff --git a/lib/libtpm/sha.c b/lib/libtpm/sha.c new file mode 100644 index 0000000..43de658 --- /dev/null +++ b/lib/libtpm/sha.c @@ -0,0 +1,205 @@ +/***************************************************************************** + * Copyright (c) 2015-2021 IBM Corporation + * All rights reserved. + * This program and the accompanying materials + * are made available under the terms of the BSD License + * which accompanies this distribution, and is available at + * http://www.opensource.org/licenses/bsd-license.php + * + * Contributors: + * IBM Corporation - initial implementation + *****************************************************************************/ + +/* + * See: NIST standard for SHA-1 in FIPS PUB 180-4 + */ + +#include "byteorder.h" +#include "sha.h" +#include "string.h" + +typedef struct _sha1_ctx { + uint32_t h[5]; +} sha1_ctx; + +#define rol(VAL, N) \ +({ \ + uint32_t res; \ + __asm__ ( \ + "rotlwi %0, %1, %2\n\t" \ + : "=r" (res) \ + : "r" (VAL), "i" (N) \ + ); \ + res; \ +}) + +static void sha1_block(uint32_t *w, sha1_ctx *ctx) +{ + uint32_t i; + uint32_t a,b,c,d,e,f; + uint32_t tmp; + uint32_t idx; + + /* + * FIPS 180-4 4.2.1: SHA1 Constants + */ + static const uint32_t sha_ko[4] = { + 0x5a827999, 0x6ed9eba1, 0x8f1bbcdc, 0xca62c1d6 + }; + + /* + * FIPS 180-4 6.1.2: step 1 + * + * 0 <= i <= 15: + * W(t) = M(t) + * 16 <= i <= 79: + * W(t) = ROTL(W(t-3) XOR W(t-8) XOR W(t-14) XOR W(t-16), 1) + */ + + /* w(0)..w(15) are in big endian format */ + for (i = 0; i <= 15; i++) + w[i] = be32_to_cpu(w[i]); + + for (i = 16; i <= 79; i++) { + tmp = w[i-3] ^ w[i-8] ^ w[i-14] ^ w[i-16]; + w[i] = rol(tmp, 1); + } + + /* + * step 2: a = H0, b = H1, c = H2, d = H3, e = H4. + */ + a = ctx->h[0]; + b = ctx->h[1]; + c = ctx->h[2]; + d = ctx->h[3]; + e = ctx->h[4]; + + /* + * step 3: For i = 0 to 79: + * T = ROTL(a, 5) + f(i; b,c,d) + e + W(t) + K(t); + */ + for (i = 0; i <= 79; i++) { + /* + * FIPS 180-4: 4.1.1 : definition of f(i; b,c,d) + */ + if (i <= 19) { + /* + * 0 <= i <= 19: + * f(i; b,c,d) = (b AND c) OR ((NOT b) AND d) + */ + f = (b & c) | ((b ^ 0xffffffff) & d); + idx = 0; + } else if (i <= 39) { + /* + * 20 <= i <= 39: + * f(i; b,c,d) = b XOR c XOR d + */ + f = b ^ c ^ d; + idx = 1; + } else if (i <= 59) { + /* + * 40 <= i <= 59: + * f(i; b,c,d) = (b AND c) OR (b AND d) OR (c AND d) + */ + f = (b & c) | (b & d) | (c & d); + idx = 2; + } else { + /* + * 60 <= i <= 79: + * f(i; b,c,d) = b XOR c XOR d + */ + f = b ^ c ^ d; + idx = 3; + } + + /* + * step 3: + * t = ROTL(a, 5) + f(t;b,c,d) + e + K(t) + W(t); + * e = d; d = c; c = ROTL(b, 30); b = a; a = t; + */ + tmp = rol(a, 5) + + f + + e + + sha_ko[idx] + + w[i]; + e = d; + d = c; + c = rol(b, 30); + b = a; + a = tmp; + } + + /* + * step 4: + * H0 = a + H0, H1 = b + H1, H2 = c + H2, H3 = d + H3, H4 = e + H4 + */ + ctx->h[0] += a; + ctx->h[1] += b; + ctx->h[2] += c; + ctx->h[3] += d; + ctx->h[4] += e; +} + +static void sha1_do(sha1_ctx *ctx, const uint8_t *data32, uint32_t length) +{ + uint32_t offset = 0; + uint16_t num; + uint64_t bits = 0; + uint32_t w[80]; + uint64_t tmp; + + /* treat data in 64-byte chunks */ + for (offset = 0; length - offset >= 64; offset += 64) { + memcpy(w, data32 + offset, 64); + sha1_block((uint32_t *)w, ctx); + bits += (64 * 8); + } + + /* last block with less than 64 bytes */ + num = length - offset; + bits += (num << 3); + + memcpy(w, data32 + offset, num); + /* + * FIPS 180-4 5.1: Padding the Message + */ + ((uint8_t *)w)[num] = 0x80; + if (64 - (num + 1) > 0) + memset( &((uint8_t *)w)[num + 1], 0, 64 - (num + 1)); + + if (num >= 56) { + /* cannot append number of bits here */ + sha1_block((uint32_t *)w, ctx); + memset(w, 0, 60); + } + + /* write number of bits to end of block */ + tmp = cpu_to_be64(bits); + memcpy(&w[14], &tmp, 8); + + sha1_block(w, ctx); + + /* need to switch result's endianness */ + for (num = 0; num < 5; num++) + ctx->h[num] = cpu_to_be32(ctx->h[num]); +} + +void sha1(const uint8_t *data, uint32_t length, uint8_t *hash) +{ + sha1_ctx ctx = { + .h = { + /* + * FIPS 180-4: 6.1.1 + * -> 5.3.1: initial hash value + */ + 0x67452301, + 0xefcdab89, + 0x98badcfe, + 0x10325476, + 0xc3d2e1f0, + } + }; + + sha1_do(&ctx, data, length); + memcpy(hash, &ctx.h[0], 20); +} |