/** @file Random number generators for DCS Copyright (c) 2016. Disk Cryptography Services for EFI (DCS), Alex Kolotnikov This program and the accompanying materials are licensed and made available under the terms and conditions of the GNU Lesser General Public License, version 3.0 (LGPL-3.0). The full text of the license may be found at https://opensource.org/licenses/LGPL-3.0 !NOTE: Very simple! Need to select several sources of random like user input or other. **/ #include #include #include #include #include #include #include DCS_RND* gRnd = NULL; ////////////////////////////////////////////////////////////////////////// // Random data from file ////////////////////////////////////////////////////////////////////////// EFI_STATUS RndFilePrepare( IN DCS_RND* rnd ) { EFI_STATUS res = EFI_NOT_READY; if (rnd != NULL && rnd->Type == RndTypeFile && rnd->State.File.Data != NULL) { rnd->State.File.Pos = 0; res = EFI_SUCCESS; } return res; } EFI_STATUS RndFileGetBytes( IN DCS_RND *rnd, OUT UINT8 *buf, IN UINTN len) { UINTN i; if (rnd != NULL && rnd->Type == RndTypeFile && rnd->State.File.Data != NULL) { for (i = 0; i < len; i++, rnd->State.File.Pos++) { if (rnd->State.File.Pos >= rnd->State.File.Size) { rnd->State.File.Pos = 0; } buf[i] = rnd->State.File.Data[rnd->State.File.Pos]; } } return EFI_SUCCESS; } EFI_STATUS RndFileInit( IN DCS_RND* rnd, IN VOID* Context ) { EFI_STATUS res = EFI_NOT_FOUND; ZeroMem(rnd, sizeof(DCS_RND)); rnd->Type = RndTypeFile; rnd->GetBytes = RndFileGetBytes; rnd->Prepare = RndFilePrepare; if (Context != NULL) { res = FileLoad(NULL, (CHAR16*)Context, &rnd->State.File.Data, &rnd->State.File.Size); if (!EFI_ERROR(res)) { return rnd->Prepare(rnd); } } return res; } ////////////////////////////////////////////////////////////////////////// // Random data from CPU RDRAND ////////////////////////////////////////////////////////////////////////// EFI_STATUS RndRDRandPrepare( IN DCS_RND* rnd ) { UINT64 rndTmp; if (rnd != NULL && rnd->Type == RndTypeRDRand) { if (GetRandomNumber64((UINT64*)&rndTmp)) { return EFI_SUCCESS; } } return EFI_NOT_READY; } EFI_STATUS RndRDRandGetBytes( IN DCS_RND *rnd, OUT UINT8 *buf, IN UINTN len) { UINT8 tmpRnd[8]; UINTN i = 0; UINTN j = 0; if (rnd != NULL && rnd->Type == RndTypeRDRand) { for (i = 0; i < len; ++i, ++j) { j &= 7; if (j == 0) { if (!GetRandomNumber64((UINT64*)tmpRnd)) return EFI_NOT_READY; } buf[i] = tmpRnd[j]; } } else { return EFI_NOT_READY; } return EFI_SUCCESS; } EFI_STATUS RndRDRandInit( IN DCS_RND* rnd, IN VOID* Context ) { ZeroMem(rnd, sizeof(DCS_RND)); rnd->Type = RndTypeRDRand; rnd->GetBytes = RndRDRandGetBytes; rnd->Prepare = RndRDRandPrepare; return rnd->Prepare(rnd); } ////////////////////////////////////////////////////////////////////////// // DRBG HMAC (SHA512) (NIST SP 800-90A) (simplified) ////////////////////////////////////////////////////////////////////////// EFI_STATUS HmacSha512( IN UINT8 *k, /* secret key */ OUT UINT8 *out, /* output buffer */ ... ) { sha512_ctx ctx; char inner[SHA512_DIGEST_SIZE], outer[SHA512_DIGEST_SIZE]; char key[SHA512_DIGEST_SIZE]; char buf[SHA512_BLOCK_SIZE]; int32 i; int32 lk = SHA512_DIGEST_SIZE; /* length of the key in bytes */ VA_LIST args; UINT8* data; UINTN len; /**** Inner Digest ****/ sha512_begin(&ctx); /* Pad the key for inner digest */ for (i = 0; i < lk; ++i) buf[i] = (char)(k[i] ^ 0x36); for (i = lk; i < SHA512_BLOCK_SIZE; ++i) buf[i] = 0x36; sha512_hash((unsigned char *)buf, SHA512_BLOCK_SIZE, &ctx); VA_START(args, out); while ((data = VA_ARG(args, UINT8 *)) != NULL) { len = VA_ARG(args, UINTN); sha512_hash(data, (UINT32)len, &ctx); } VA_END(args); sha512_end((unsigned char *)inner, &ctx); /**** Outer Digest ****/ sha512_begin(&ctx); for (i = 0; i < lk; ++i) buf[i] = (char)(k[i] ^ 0x5C); for (i = lk; i < SHA512_BLOCK_SIZE; ++i) buf[i] = 0x5C; sha512_hash((unsigned char *)buf, SHA512_BLOCK_SIZE, &ctx); sha512_hash((unsigned char *)inner, SHA512_DIGEST_SIZE, &ctx); sha512_end((unsigned char *)out, &ctx); /* Prevent possible leaks. */ burn(&ctx, sizeof(ctx)); burn(outer, sizeof(outer)); burn(inner, sizeof(inner)); burn(buf, sizeof(buf)); burn(key, sizeof(key)); return EFI_SUCCESS; } EFI_STATUS RndDtrmHmacSha512Update( RND_DTRM_HMAC_SHA512_STATE *state, UINT8 *seed, UINTN seedLen, BOOLEAN reseed ) { EFI_STATUS res = EFI_NOT_READY; int i = 0; if (!reseed) { /* 10.1.2.3 */ memset(state->V, 1, SHA512_DIGEST_SIZE); memset(state->C, 0, SHA512_DIGEST_SIZE); } /* we execute two rounds of V/K massaging */ for (i = 2; 0 < i; i--) { /* first round uses 0x0, second 0x1 */ unsigned char prefix = 0; if (1 == i) prefix = 1; /* 10.1.2.2 step 1 and 4 -- concatenation and HMAC for key */ res = HmacSha512(state->C, state->C, state->V, SHA512_DIGEST_SIZE, &prefix, 1, seed, seedLen, NULL ); if (EFI_ERROR(res)) return res; /* 10.1.2.2 step 2 and 5 -- HMAC for V */ res = HmacSha512(state->C, state->V, state->V, SHA512_DIGEST_SIZE, NULL); if (EFI_ERROR(res)) return res; /* 10.1.2.2 step 3 */ if (!seed || 0 == seedLen) return res; } return EFI_SUCCESS; } /* generate function of HMAC DRBG as defined in 10.1.2.5 */ EFI_STATUS RndDtrmHmacSha512Generate( RND_DTRM_HMAC_SHA512_STATE *state, OUT UINT8 *buf, IN UINTN buflen, IN UINT8 *seed, IN UINTN seedLen ) { EFI_STATUS res = EFI_SUCCESS; UINTN len = 0; /* 10.1.2.5 step 2 */ if (seed && 0 < seedLen) { res = RndDtrmHmacSha512Update(state, seed, seedLen, 1); if (EFI_ERROR(res)) return res; } while (len < buflen) { UINTN outlen = 0; /* 10.1.2.5 step 4.1 */ res = HmacSha512(state->C, state->V, state->V, SHA512_DIGEST_SIZE, NULL ); if (EFI_ERROR(res)) return res; outlen = (SHA512_DIGEST_SIZE < (buflen - len)) ? SHA512_DIGEST_SIZE : (buflen - len); /* 10.1.2.5 step 4.2 */ memcpy(buf + len, state->V, outlen); len += outlen; } /* 10.1.2.5 step 6 */ res = RndDtrmHmacSha512Update(state, seed, seedLen, 1); return res; } EFI_STATUS RndDtrmHmacSha512Prepare( IN DCS_RND* rnd ) { if (rnd != NULL && rnd->Type == RndTypeDtrmHmacSha512) { return EFI_SUCCESS; } return EFI_NOT_READY; } EFI_STATUS RndDtrmHmacSha512GetBytes( IN DCS_RND* rnd, UINT8 *buf, UINTN len ) { EFI_TIME seed; EFI_STATUS res = EFI_NOT_READY; RND_DTRM_HMAC_SHA512_STATE *state = &rnd->State.HMacSha512; if (state->ReseedCtr < (1LL << 48)) { gST->RuntimeServices->GetTime(&seed, NULL); res = RndDtrmHmacSha512Generate(state, buf, len, (UINT8*)&seed, sizeof(seed)); state->ReseedCtr++; } return res; } EFI_STATUS RndDtrmHmacSha512Init( IN DCS_RND* rnd, IN VOID* Context ) { EFI_STATUS res = EFI_SUCCESS; ZeroMem(rnd, sizeof(DCS_RND)); rnd->Type = RndTypeDtrmHmacSha512; rnd->GetBytes = RndDtrmHmacSha512GetBytes; rnd->Prepare = RndDtrmHmacSha512Prepare; if (Context != NULL) { CHAR16* type = (CHAR16*)Context; if (*type == '_') { UINT8* data; UINTN size; type++; res = FileLoad(NULL, (CHAR16*)type, &data, &size); if (EFI_ERROR(res)) { rnd->Type = RndTypeNone; } res = RndDtrmHmacSha512Update(&rnd->State.HMacSha512, data, size, 0); if (EFI_ERROR(res)) { rnd->Type = RndTypeNone; } } } return rnd->Prepare(rnd); } ////////////////////////////////////////////////////////////////////////// // Random API ////////////////////////////////////////////////////////////////////////// EFI_STATUS RndInit( IN UINTN rndType, IN VOID* Context, OUT DCS_RND **rnd) { if (rnd != NULL) { DCS_RND *rndTemp; rndTemp = (DCS_RND*)MEM_ALLOC(sizeof(DCS_RND)); if (rndTemp != NULL) { EFI_STATUS res = EFI_NOT_FOUND; rndTemp->Type = (UINT32)rndType; switch (rndType) { case RndTypeFile: res = RndFileInit(rndTemp, Context); break; case RndTypeRDRand: res = RndRDRandInit(rndTemp, Context); break; case RndTypeDtrmHmacSha512: res = RndDtrmHmacSha512Init(rndTemp, Context); break; } if (EFI_ERROR(res)) { MEM_FREE(rndTemp); return res; } *rnd = rndTemp; return res; } } return EFI_NOT_READY; } EFI_STATUS RndGetBytes( UINT8 *buf, UINTN len) { if (gRnd != NULL) { return gRnd->GetBytes(gRnd, buf, len); } return EFI_NOT_READY; } EFI_STATUS RndPreapare() { if (gRnd != NULL) { return gRnd->Prepare(gRnd); } return EFI_NOT_READY; } UINT64 gRndHeaderSign = RND_HEADER_SIGN; EFI_STATUS RndSave( IN DCS_RND *rnd, OUT DCS_RND_SAVED **rndSaved ) { EFI_STATUS res = EFI_NOT_READY; DCS_RND_SAVED *RndSaved; UINT32 crc; if (rnd != NULL && rndSaved != NULL && rnd->Type != RndTypeFile) { RndSaved = MEM_ALLOC(sizeof(DCS_RND_SAVED)); if (RndSaved != NULL) { RndSaved->Size = sizeof(DCS_RND_SAVED); CopyMem(&RndSaved->State, &rnd->State, sizeof(DCS_RND_STATE)); RndSaved->Type = rnd->Type; RndSaved->Sign = gRndHeaderSign; gST->RuntimeServices->GetTime(&RndSaved->SavedAt, NULL); res = gBS->CalculateCrc32(RndSaved, sizeof(DCS_RND_SAVED), &crc); if (EFI_ERROR(res)) { MEM_FREE(RndSaved); return res; } RndSaved->CRC = crc; *rndSaved = RndSaved; } } return res; } EFI_STATUS RndLoad( IN DCS_RND_SAVED *rndSaved, OUT DCS_RND **rndOut ) { EFI_STATUS res = EFI_SUCCESS; UINT32 crc; UINT32 crcSaved; crcSaved = rndSaved->CRC; rndSaved->CRC = 0; res = gBS->CalculateCrc32(rndSaved, sizeof(DCS_RND_SAVED), &crc); if (EFI_ERROR(res) || crc != crcSaved || rndSaved->Sign != gRndHeaderSign) { return EFI_CRC_ERROR; } res = RndInit(rndSaved->Type, NULL, rndOut); if (!EFI_ERROR(res)) { CopyMem(&((*rndOut)->State), &rndSaved->State, sizeof(DCS_RND_STATE)); } return res; }