Georg Wicherski (gw@oxff.net) just uploaded a new patch set to gerrit, which you can find at https://review.coreboot.org/14038
-gerrit
commit a197677796180fb7309129f72fbb5594dc983211 Author: Georg Wicherski gw@oxff.net Date: Fri Mar 11 17:53:01 2016 +0100
TPM: add measurement code
WORK IN PROGRESS
Measure ramstage and payload, extend PCRs.
Change-Id: I1c15108e4a27e9929ae02c6409c3cae0bda073a5 --- src/drivers/tpm/lpc/Kconfig | 30 ++++++ src/include/tpm/tspi.h | 14 +++ src/lib/prog_loaders.c | 13 ++- src/lib/tpm/Makefile.inc | 5 + src/lib/tpm/sha1.c | 222 ++++++++++++++++++++++++++++++++++++++++++++ src/lib/tpm/tspi.c | 41 +++++++- 6 files changed, 319 insertions(+), 6 deletions(-)
diff --git a/src/drivers/tpm/lpc/Kconfig b/src/drivers/tpm/lpc/Kconfig index ec17782..6015eca 100644 --- a/src/drivers/tpm/lpc/Kconfig +++ b/src/drivers/tpm/lpc/Kconfig @@ -13,6 +13,36 @@ config LPC_TPM
If unsure, say N.
+config TPM_MEASURE + bool "Enable TPM PCR measurements" + depends on LPC_TPM + default n + help + Add code to compute SHA1 digests on coreboot components and the + payload; extend appropriate PCRs with these digests. + + If unsure, say N. + +config TPM_MEASURE_RAMSTAGE + bool "Measure the coreboot ramstage" + depends on TPM_MEASURE + default n + help + Compute SHA1 digest on the ramstage after loading it. Extend PCR[0] + with the digest. + + If unsure, say N. + +config TPM_MEASURE_PAYLOAD + bool "Measure the coreboot payload" + depends on TPM_MEASURE + default n + help + Compute SHA1 digest on the payload as it is found in memory just + before mirroring it. Extend PCR[4] with the digest. + + If unsure, say N. + config TPM_READ_INIT_PCRS bool "Read PCR values after initialization" depends on LPC_TPM diff --git a/src/include/tpm/tspi.h b/src/include/tpm/tspi.h index ba2f119..26987cf 100644 --- a/src/include/tpm/tspi.h +++ b/src/include/tpm/tspi.h @@ -17,10 +17,24 @@ #ifndef TPM_TSPI_H #define TPM_TSPI_H
+#include <stdint.h> +#include <program_loading.h> + /** * TSPI Implementation for coreboot without vboot2 */ void init_tpm(int s3resume);
+/** + * Compute SHA1 digest on program memory contents and + * extend requested PCR with the digest. + */ +void measure_prog(struct prog *program, int pcr, const char *measured_thing); + + +#define SHA1_BLOCK_LENGTH 64 +#define SHA1_DIGEST_LENGTH 20 +u8 *sha1(const u8 *data, unsigned long len, u8 *buf); +
#endif /* TPM_TSPI_H */ diff --git a/src/lib/prog_loaders.c b/src/lib/prog_loaders.c index 14e1299..c21613e 100644 --- a/src/lib/prog_loaders.c +++ b/src/lib/prog_loaders.c @@ -28,6 +28,7 @@ #include <stage_cache.h> #include <symbols.h> #include <timestamp.h> +#include <tpm/tspi.h>
/* Only can represent up to 1 byte less than size_t. */ const struct mem_region_device addrspace_32bit = MEM_REGION_DEV_INIT(0, ~0UL); @@ -53,7 +54,7 @@ void run_romstage(void)
if (prog_locate(&romstage)) goto fail; - + timestamp_add_now(TS_START_COPYROM);
if (cbfs_prog_stage_load(&romstage)) @@ -115,8 +116,12 @@ void run_ramstage(void) if (prog_locate(&ramstage)) goto fail;
- timestamp_add_now(TS_START_COPYRAM); + if (IS_ENABLED(CONFIG_TPM_MEASURE_RAMSTAGE)) { + measure_prog(&ramstage, 0, __func__); + }
+ timestamp_add_now(TS_START_COPYRAM); + if (IS_ENABLED(CONFIG_RELOCATABLE_RAMSTAGE)) { if (load_relocatable_ramstage(&ramstage)) goto fail; @@ -151,6 +156,10 @@ void payload_load(void)
if (prog_locate(payload)) goto out; + + if (IS_ENABLED(CONFIG_TPM_MEASURE_PAYLOAD)) { + measure_prog(payload, 4, __func__); + }
mirror_payload(payload);
diff --git a/src/lib/tpm/Makefile.inc b/src/lib/tpm/Makefile.inc index 81a3eb9..60bdfa2 100644 --- a/src/lib/tpm/Makefile.inc +++ b/src/lib/tpm/Makefile.inc @@ -1,10 +1,15 @@ ifneq ($(CONFIG_CHROMEOS),y) romstage-$(CONFIG_LPC_TPM) += tss.c tspi.c ramstage-$(CONFIG_LPC_TPM) += tss.c tspi.c +bootblock-$(CONFIG_LPC_TPM) += tss.c tspi.c else romstage-$(CONFIG_LPC_TPM) += tspi.c endif
+bootblock-$(CONFIG_TPM_MEASURE) += sha1.c +romstage-$(CONFIG_TPM_MEASURE) += sha1.c +ramstage-$(CONFIG_TPM_MEASURE) += sha1.c + ifeq ($(MOCK_TPM),1) libverstage-y += mocked_tss.c else diff --git a/src/lib/tpm/sha1.c b/src/lib/tpm/sha1.c new file mode 100644 index 0000000..6e649b4 --- /dev/null +++ b/src/lib/tpm/sha1.c @@ -0,0 +1,222 @@ +/* + * This file was copied from the libpayload project. + * + * It has originally been taken from the OpenBSD project. + */ + +/* $OpenBSD: sha1.c,v 1.20 2005/08/08 08:05:35 espie Exp $ */ + +/* + * SHA-1 in C + * By Steve Reid steve@edmweb.com + * 100% Public Domain + * + * Test Vectors (from FIPS PUB 180-1) + * "abc" + * A9993E36 4706816A BA3E2571 7850C26C 9CD0D89D + * "abcdbcdecdefdefgefghfghighijhijkijkljklmklmnlmnomnopnopq" + * 84983E44 1C3BD26E BAAE4AA1 F95129E5 E54670F1 + * A million repetitions of "a" + * 34AA973C D4C4DAA4 F61EEB2B DBAD2731 6534016F + */ + +#include <tpm/tspi.h> +#include <string.h> + +typedef u8 u_int8_t; +typedef u32 u_int32_t; +typedef u64 u_int64_t; +typedef unsigned int u_int; + +typedef struct { + u32 state[5]; + u64 count; + u8 buffer[SHA1_BLOCK_LENGTH]; +} SHA1_CTX; + + +#define LITTLE_ENDIAN 1234 +#define BIG_ENDIAN 4321 + +#if CONFIG_LITTLE_ENDIAN +#define BYTE_ORDER LITTLE_ENDIAN +#else +#define BYTE_ORDER BIG_ENDIAN +#endif + +#define rol(value, bits) (((value) << (bits)) | ((value) >> (32 - (bits)))) + +/* + * blk0() and blk() perform the initial expand. + * I got the idea of expanding during the round function from SSLeay + */ +#if BYTE_ORDER == LITTLE_ENDIAN +# define blk0(i) (block->l[i] = (rol(block->l[i],24)&0xFF00FF00) \ + |(rol(block->l[i],8)&0x00FF00FF)) +#else +# define blk0(i) block->l[i] +#endif +#define blk(i) (block->l[i&15] = rol(block->l[(i+13)&15]^block->l[(i+8)&15] \ + ^block->l[(i+2)&15]^block->l[i&15],1)) + +/* + * (R0+R1), R2, R3, R4 are the different operations (rounds) used in SHA1 + */ +#define R0(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk0(i)+0x5A827999+rol(v,5);w=rol(w,30); +#define R1(v,w,x,y,z,i) z+=((w&(x^y))^y)+blk(i)+0x5A827999+rol(v,5);w=rol(w,30); +#define R2(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0x6ED9EBA1+rol(v,5);w=rol(w,30); +#define R3(v,w,x,y,z,i) z+=(((w|x)&y)|(w&x))+blk(i)+0x8F1BBCDC+rol(v,5);w=rol(w,30); +#define R4(v,w,x,y,z,i) z+=(w^x^y)+blk(i)+0xCA62C1D6+rol(v,5);w=rol(w,30); + +/* + * Hash a single 512-bit block. This is the core of the algorithm. + */ +static void +SHA1Transform(u_int32_t state[5], const u_int8_t buffer[SHA1_BLOCK_LENGTH]) +{ + u_int32_t a, b, c, d, e; + u_int8_t workspace[SHA1_BLOCK_LENGTH]; + typedef union { + u_int8_t c[64]; + u_int32_t l[16]; + } CHAR64LONG16; + CHAR64LONG16 *block = (CHAR64LONG16 *)workspace; + + (void)memcpy(block, buffer, SHA1_BLOCK_LENGTH); + + /* Copy context->state[] to working vars */ + a = state[0]; + b = state[1]; + c = state[2]; + d = state[3]; + e = state[4]; + + /* 4 rounds of 20 operations each. Loop unrolled. */ + R0(a,b,c,d,e, 0); R0(e,a,b,c,d, 1); R0(d,e,a,b,c, 2); R0(c,d,e,a,b, 3); + R0(b,c,d,e,a, 4); R0(a,b,c,d,e, 5); R0(e,a,b,c,d, 6); R0(d,e,a,b,c, 7); + R0(c,d,e,a,b, 8); R0(b,c,d,e,a, 9); R0(a,b,c,d,e,10); R0(e,a,b,c,d,11); + R0(d,e,a,b,c,12); R0(c,d,e,a,b,13); R0(b,c,d,e,a,14); R0(a,b,c,d,e,15); + R1(e,a,b,c,d,16); R1(d,e,a,b,c,17); R1(c,d,e,a,b,18); R1(b,c,d,e,a,19); + R2(a,b,c,d,e,20); R2(e,a,b,c,d,21); R2(d,e,a,b,c,22); R2(c,d,e,a,b,23); + R2(b,c,d,e,a,24); R2(a,b,c,d,e,25); R2(e,a,b,c,d,26); R2(d,e,a,b,c,27); + R2(c,d,e,a,b,28); R2(b,c,d,e,a,29); R2(a,b,c,d,e,30); R2(e,a,b,c,d,31); + R2(d,e,a,b,c,32); R2(c,d,e,a,b,33); R2(b,c,d,e,a,34); R2(a,b,c,d,e,35); + R2(e,a,b,c,d,36); R2(d,e,a,b,c,37); R2(c,d,e,a,b,38); R2(b,c,d,e,a,39); + R3(a,b,c,d,e,40); R3(e,a,b,c,d,41); R3(d,e,a,b,c,42); R3(c,d,e,a,b,43); + R3(b,c,d,e,a,44); R3(a,b,c,d,e,45); R3(e,a,b,c,d,46); R3(d,e,a,b,c,47); + R3(c,d,e,a,b,48); R3(b,c,d,e,a,49); R3(a,b,c,d,e,50); R3(e,a,b,c,d,51); + R3(d,e,a,b,c,52); R3(c,d,e,a,b,53); R3(b,c,d,e,a,54); R3(a,b,c,d,e,55); + R3(e,a,b,c,d,56); R3(d,e,a,b,c,57); R3(c,d,e,a,b,58); R3(b,c,d,e,a,59); + R4(a,b,c,d,e,60); R4(e,a,b,c,d,61); R4(d,e,a,b,c,62); R4(c,d,e,a,b,63); + R4(b,c,d,e,a,64); R4(a,b,c,d,e,65); R4(e,a,b,c,d,66); R4(d,e,a,b,c,67); + R4(c,d,e,a,b,68); R4(b,c,d,e,a,69); R4(a,b,c,d,e,70); R4(e,a,b,c,d,71); + R4(d,e,a,b,c,72); R4(c,d,e,a,b,73); R4(b,c,d,e,a,74); R4(a,b,c,d,e,75); + R4(e,a,b,c,d,76); R4(d,e,a,b,c,77); R4(c,d,e,a,b,78); R4(b,c,d,e,a,79); + + /* Add the working vars back into context.state[] */ + state[0] += a; + state[1] += b; + state[2] += c; + state[3] += d; + state[4] += e; + + /* Wipe variables */ + a = b = c = d = e = 0; +} + + +/* + * SHA1Init - Initialize new context + */ +static void +SHA1Init(SHA1_CTX *context) +{ + + /* SHA1 initialization constants */ + context->count = 0; + context->state[0] = 0x67452301; + context->state[1] = 0xEFCDAB89; + context->state[2] = 0x98BADCFE; + context->state[3] = 0x10325476; + context->state[4] = 0xC3D2E1F0; +} + + +/* + * Run your data through this. + */ +static void +SHA1Update(SHA1_CTX *context, const u_int8_t *data, unsigned long len) +{ + size_t i, j; + + j = (size_t)((context->count >> 3) & 63); + context->count += (len << 3); + if ((j + len) > 63) { + (void)memcpy(&context->buffer[j], data, (i = 64-j)); + SHA1Transform(context->state, context->buffer); + for ( ; i + 63 < len; i += 64) + SHA1Transform(context->state, (u_int8_t *)&data[i]); + j = 0; + } else { + i = 0; + } + (void)memcpy(&context->buffer[j], &data[i], len - i); +} + + +/* + * Add padding and return the message digest. + */ +static void +SHA1Pad(SHA1_CTX *context) +{ + u_int8_t finalcount[8]; + u_int i; + + for (i = 0; i < 8; i++) { + finalcount[i] = (u_int8_t)((context->count >> + ((7 - (i & 7)) * 8)) & 255); /* Endian independent */ + } + SHA1Update(context, (u_int8_t *)"\200", 1); + while ((context->count & 504) != 448) + SHA1Update(context, (u_int8_t *)"\0", 1); + SHA1Update(context, finalcount, 8); /* Should cause a SHA1Transform() */ +} + +static void +SHA1Final(u_int8_t digest[SHA1_DIGEST_LENGTH], SHA1_CTX *context) +{ + u_int i; + + SHA1Pad(context); + if (digest) { + for (i = 0; i < SHA1_DIGEST_LENGTH; i++) { + digest[i] = (u_int8_t) + ((context->state[i>>2] >> ((3-(i & 3)) * 8) ) & 255); + } + memset(context, 0, sizeof(*context)); + } +} + +/** + * Compute the SHA-1 hash of the given data as specified by the 'data' and + * 'len' arguments, and place the result -- 160 bits (20 bytes) -- into the + * specified output buffer 'buf'. + * + * @param data Pointer to the input data that shall be hashed. + * @param len Length of the input data (in bytes). + * @param buf Buffer which will hold the resulting hash (must be at + * least 20 bytes in size). + * @return Pointer to the output buffer where the hash is stored. + */ +u8 *sha1(const u8 *data, unsigned long len, u8 *buf) +{ + SHA1_CTX ctx; + + SHA1Init(&ctx); + SHA1Update(&ctx, data, len); + SHA1Final(buf, &ctx); + + return buf; +} diff --git a/src/lib/tpm/tspi.c b/src/lib/tpm/tspi.c index 0d9c6aa..1f2c579 100644 --- a/src/lib/tpm/tspi.c +++ b/src/lib/tpm/tspi.c @@ -19,14 +19,13 @@ #include <reset.h>
#include <tpm/tss.h> -#define TPM_PCR_DIGEST_LENGTH 20 #include <tpm/tspi.h>
static inline void _debug_init_pcrs(void) { uint32_t result; int pcr_index; - uint8_t digest[TPM_PCR_DIGEST_LENGTH]; + uint8_t digest[SHA1_DIGEST_LENGTH];
for (pcr_index = 0; pcr_index < 24; ++pcr_index) { int digest_offset; @@ -43,11 +42,11 @@ static inline void _debug_init_pcrs(void) printk(BIOS_SPEW, "TPM: PCR %i value is ", pcr_index); for (digest_offset = 0; - digest_offset < TPM_PCR_DIGEST_LENGTH; + digest_offset < SHA1_DIGEST_LENGTH; ++digest_offset) { printk(BIOS_SPEW, "%02x%c", digest[digest_offset], - digest_offset < TPM_PCR_DIGEST_LENGTH - 1 ? + digest_offset < SHA1_DIGEST_LENGTH - 1 ? ':' : '\n'); } } @@ -125,3 +124,37 @@ void init_tpm(int s3resume) hard_reset(); } } + + +void measure_prog(struct prog *program, int pcr, const char *measured_thing) +{ + uint8_t digest[SHA1_DIGEST_LENGTH]; + const uint8_t * start; + size_t size; + + start = prog_start(program); + size = prog_size(program); + + sha1(start, size, digest); + + printk(BIOS_DEBUG, "TPM: Digest for program "%s" " + "at %p (%lx bytes): ", + measured_thing, start, size); + for(size = 0; size < SHA1_DIGEST_LENGTH; ++size) { + printk(BIOS_SPEW, "%02x%c", + digest[size], + size < SHA1_DIGEST_LENGTH - 1 ? + ':' : '\n'); + } + + if (tlcl_extend(pcr, digest, digest) == TPM_SUCCESS) { + printk(BIOS_DEBUG, "TPM: PCR[%i] after extension: ", pcr); + + for(size = 0; size < SHA1_DIGEST_LENGTH; ++size) { + printk(BIOS_SPEW, "%02x%c", + digest[size], + size < SHA1_DIGEST_LENGTH - 1 ? + ':' : '\n'); + } + } +}