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Diffstat (limited to 'roms/ipxe/src/crypto/sha256.c')
-rw-r--r-- | roms/ipxe/src/crypto/sha256.c | 256 |
1 files changed, 256 insertions, 0 deletions
diff --git a/roms/ipxe/src/crypto/sha256.c b/roms/ipxe/src/crypto/sha256.c new file mode 100644 index 000000000..36e02b3c2 --- /dev/null +++ b/roms/ipxe/src/crypto/sha256.c @@ -0,0 +1,256 @@ +/* + * Copyright (C) 2012 Michael Brown <mbrown@fensystems.co.uk>. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation; either version 2 of the + * License, or any later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA + * 02110-1301, USA. + */ + +FILE_LICENCE ( GPL2_OR_LATER ); + +/** @file + * + * SHA-256 algorithm + * + */ + +#include <stdint.h> +#include <string.h> +#include <byteswap.h> +#include <assert.h> +#include <ipxe/rotate.h> +#include <ipxe/crypto.h> +#include <ipxe/asn1.h> +#include <ipxe/sha256.h> + +/** SHA-256 variables */ +struct sha256_variables { + /* This layout matches that of struct sha256_digest_data, + * allowing for efficient endianness-conversion, + */ + uint32_t a; + uint32_t b; + uint32_t c; + uint32_t d; + uint32_t e; + uint32_t f; + uint32_t g; + uint32_t h; + uint32_t w[64]; +} __attribute__ (( packed )); + +/** SHA-256 constants */ +static const uint32_t k[64] = { + 0x428a2f98, 0x71374491, 0xb5c0fbcf, 0xe9b5dba5, 0x3956c25b, 0x59f111f1, + 0x923f82a4, 0xab1c5ed5, 0xd807aa98, 0x12835b01, 0x243185be, 0x550c7dc3, + 0x72be5d74, 0x80deb1fe, 0x9bdc06a7, 0xc19bf174, 0xe49b69c1, 0xefbe4786, + 0x0fc19dc6, 0x240ca1cc, 0x2de92c6f, 0x4a7484aa, 0x5cb0a9dc, 0x76f988da, + 0x983e5152, 0xa831c66d, 0xb00327c8, 0xbf597fc7, 0xc6e00bf3, 0xd5a79147, + 0x06ca6351, 0x14292967, 0x27b70a85, 0x2e1b2138, 0x4d2c6dfc, 0x53380d13, + 0x650a7354, 0x766a0abb, 0x81c2c92e, 0x92722c85, 0xa2bfe8a1, 0xa81a664b, + 0xc24b8b70, 0xc76c51a3, 0xd192e819, 0xd6990624, 0xf40e3585, 0x106aa070, + 0x19a4c116, 0x1e376c08, 0x2748774c, 0x34b0bcb5, 0x391c0cb3, 0x4ed8aa4a, + 0x5b9cca4f, 0x682e6ff3, 0x748f82ee, 0x78a5636f, 0x84c87814, 0x8cc70208, + 0x90befffa, 0xa4506ceb, 0xbef9a3f7, 0xc67178f2 +}; + +/** + * Initialise SHA-256 algorithm + * + * @v ctx SHA-256 context + */ +static void sha256_init ( void *ctx ) { + struct sha256_context *context = ctx; + + context->ddd.dd.digest.h[0] = cpu_to_be32 ( 0x6a09e667 ); + context->ddd.dd.digest.h[1] = cpu_to_be32 ( 0xbb67ae85 ); + context->ddd.dd.digest.h[2] = cpu_to_be32 ( 0x3c6ef372 ); + context->ddd.dd.digest.h[3] = cpu_to_be32 ( 0xa54ff53a ); + context->ddd.dd.digest.h[4] = cpu_to_be32 ( 0x510e527f ); + context->ddd.dd.digest.h[5] = cpu_to_be32 ( 0x9b05688c ); + context->ddd.dd.digest.h[6] = cpu_to_be32 ( 0x1f83d9ab ); + context->ddd.dd.digest.h[7] = cpu_to_be32 ( 0x5be0cd19 ); + context->len = 0; +} + +/** + * Calculate SHA-256 digest of accumulated data + * + * @v context SHA-256 context + */ +static void sha256_digest ( struct sha256_context *context ) { + union { + union sha256_digest_data_dwords ddd; + struct sha256_variables v; + } u; + uint32_t *a = &u.v.a; + uint32_t *b = &u.v.b; + uint32_t *c = &u.v.c; + uint32_t *d = &u.v.d; + uint32_t *e = &u.v.e; + uint32_t *f = &u.v.f; + uint32_t *g = &u.v.g; + uint32_t *h = &u.v.h; + uint32_t *w = u.v.w; + uint32_t s0; + uint32_t s1; + uint32_t maj; + uint32_t t1; + uint32_t t2; + uint32_t ch; + unsigned int i; + + /* Sanity checks */ + assert ( ( context->len % sizeof ( context->ddd.dd.data ) ) == 0 ); + linker_assert ( &u.ddd.dd.digest.h[0] == a, sha256_bad_layout ); + linker_assert ( &u.ddd.dd.digest.h[1] == b, sha256_bad_layout ); + linker_assert ( &u.ddd.dd.digest.h[2] == c, sha256_bad_layout ); + linker_assert ( &u.ddd.dd.digest.h[3] == d, sha256_bad_layout ); + linker_assert ( &u.ddd.dd.digest.h[4] == e, sha256_bad_layout ); + linker_assert ( &u.ddd.dd.digest.h[5] == f, sha256_bad_layout ); + linker_assert ( &u.ddd.dd.digest.h[6] == g, sha256_bad_layout ); + linker_assert ( &u.ddd.dd.digest.h[7] == h, sha256_bad_layout ); + linker_assert ( &u.ddd.dd.data.dword[0] == w, sha256_bad_layout ); + + DBGC ( context, "SHA256 digesting:\n" ); + DBGC_HDA ( context, 0, &context->ddd.dd.digest, + sizeof ( context->ddd.dd.digest ) ); + DBGC_HDA ( context, context->len, &context->ddd.dd.data, + sizeof ( context->ddd.dd.data ) ); + + /* Convert h[0..7] to host-endian, and initialise a, b, c, d, + * e, f, g, h, and w[0..15] + */ + for ( i = 0 ; i < ( sizeof ( u.ddd.dword ) / + sizeof ( u.ddd.dword[0] ) ) ; i++ ) { + be32_to_cpus ( &context->ddd.dword[i] ); + u.ddd.dword[i] = context->ddd.dword[i]; + } + + /* Initialise w[16..63] */ + for ( i = 16 ; i < 64 ; i++ ) { + s0 = ( ror32 ( w[i-15], 7 ) ^ ror32 ( w[i-15], 18 ) ^ + ( w[i-15] >> 3 ) ); + s1 = ( ror32 ( w[i-2], 17 ) ^ ror32 ( w[i-2], 19 ) ^ + ( w[i-2] >> 10 ) ); + w[i] = ( w[i-16] + s0 + w[i-7] + s1 ); + } + + /* Main loop */ + for ( i = 0 ; i < 64 ; i++ ) { + s0 = ( ror32 ( *a, 2 ) ^ ror32 ( *a, 13 ) ^ ror32 ( *a, 22 ) ); + maj = ( ( *a & *b ) ^ ( *a & *c ) ^ ( *b & *c ) ); + t2 = ( s0 + maj ); + s1 = ( ror32 ( *e, 6 ) ^ ror32 ( *e, 11 ) ^ ror32 ( *e, 25 ) ); + ch = ( ( *e & *f ) ^ ( (~*e) & *g ) ); + t1 = ( *h + s1 + ch + k[i] + w[i] ); + *h = *g; + *g = *f; + *f = *e; + *e = ( *d + t1 ); + *d = *c; + *c = *b; + *b = *a; + *a = ( t1 + t2 ); + DBGC2 ( context, "%2d : %08x %08x %08x %08x %08x %08x %08x " + "%08x\n", i, *a, *b, *c, *d, *e, *f, *g, *h ); + } + + /* Add chunk to hash and convert back to big-endian */ + for ( i = 0 ; i < 8 ; i++ ) { + context->ddd.dd.digest.h[i] = + cpu_to_be32 ( context->ddd.dd.digest.h[i] + + u.ddd.dd.digest.h[i] ); + } + + DBGC ( context, "SHA256 digested:\n" ); + DBGC_HDA ( context, 0, &context->ddd.dd.digest, + sizeof ( context->ddd.dd.digest ) ); +} + +/** + * Accumulate data with SHA-256 algorithm + * + * @v ctx SHA-256 context + * @v data Data + * @v len Length of data + */ +static void sha256_update ( void *ctx, const void *data, size_t len ) { + struct sha256_context *context = ctx; + const uint8_t *byte = data; + size_t offset; + + /* Accumulate data a byte at a time, performing the digest + * whenever we fill the data buffer + */ + while ( len-- ) { + offset = ( context->len % sizeof ( context->ddd.dd.data ) ); + context->ddd.dd.data.byte[offset] = *(byte++); + context->len++; + if ( ( context->len % sizeof ( context->ddd.dd.data ) ) == 0 ) + sha256_digest ( context ); + } +} + +/** + * Generate SHA-256 digest + * + * @v ctx SHA-256 context + * @v out Output buffer + */ +static void sha256_final ( void *ctx, void *out ) { + struct sha256_context *context = ctx; + uint64_t len_bits; + uint8_t pad; + + /* Record length before pre-processing */ + len_bits = cpu_to_be64 ( ( ( uint64_t ) context->len ) * 8 ); + + /* Pad with a single "1" bit followed by as many "0" bits as required */ + pad = 0x80; + do { + sha256_update ( ctx, &pad, sizeof ( pad ) ); + pad = 0x00; + } while ( ( context->len % sizeof ( context->ddd.dd.data ) ) != + offsetof ( typeof ( context->ddd.dd.data ), final.len ) ); + + /* Append length (in bits) */ + sha256_update ( ctx, &len_bits, sizeof ( len_bits ) ); + assert ( ( context->len % sizeof ( context->ddd.dd.data ) ) == 0 ); + + /* Copy out final digest */ + memcpy ( out, &context->ddd.dd.digest, + sizeof ( context->ddd.dd.digest ) ); +} + +/** SHA-256 algorithm */ +struct digest_algorithm sha256_algorithm = { + .name = "sha256", + .ctxsize = sizeof ( struct sha256_context ), + .blocksize = sizeof ( union sha256_block ), + .digestsize = sizeof ( struct sha256_digest ), + .init = sha256_init, + .update = sha256_update, + .final = sha256_final, +}; + +/** "sha256" object identifier */ +static uint8_t oid_sha256[] = { ASN1_OID_SHA256 }; + +/** "sha256" OID-identified algorithm */ +struct asn1_algorithm oid_sha256_algorithm __asn1_algorithm = { + .name = "sha256", + .digest = &sha256_algorithm, + .oid = ASN1_OID_CURSOR ( oid_sha256 ), +}; |