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957 lines
22 KiB
957 lines
22 KiB
// SPDX-License-Identifier: GPL-2.0 |
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#define pr_fmt(fmt) "ASYM-TPM: "fmt |
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#include <linux/slab.h> |
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#include <linux/module.h> |
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#include <linux/export.h> |
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#include <linux/kernel.h> |
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#include <linux/seq_file.h> |
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#include <linux/scatterlist.h> |
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#include <linux/tpm.h> |
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#include <linux/tpm_command.h> |
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#include <crypto/akcipher.h> |
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#include <crypto/hash.h> |
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#include <crypto/sha1.h> |
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#include <asm/unaligned.h> |
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#include <keys/asymmetric-subtype.h> |
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#include <keys/trusted_tpm.h> |
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#include <crypto/asym_tpm_subtype.h> |
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#include <crypto/public_key.h> |
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|
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#define TPM_ORD_FLUSHSPECIFIC 186 |
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#define TPM_ORD_LOADKEY2 65 |
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#define TPM_ORD_UNBIND 30 |
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#define TPM_ORD_SIGN 60 |
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|
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#define TPM_RT_KEY 0x00000001 |
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|
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/* |
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* Load a TPM key from the blob provided by userspace |
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*/ |
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static int tpm_loadkey2(struct tpm_buf *tb, |
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uint32_t keyhandle, unsigned char *keyauth, |
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const unsigned char *keyblob, int keybloblen, |
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uint32_t *newhandle) |
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{ |
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unsigned char nonceodd[TPM_NONCE_SIZE]; |
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unsigned char enonce[TPM_NONCE_SIZE]; |
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unsigned char authdata[SHA1_DIGEST_SIZE]; |
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uint32_t authhandle = 0; |
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unsigned char cont = 0; |
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uint32_t ordinal; |
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int ret; |
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ordinal = htonl(TPM_ORD_LOADKEY2); |
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|
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/* session for loading the key */ |
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ret = oiap(tb, &authhandle, enonce); |
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if (ret < 0) { |
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pr_info("oiap failed (%d)\n", ret); |
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return ret; |
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} |
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|
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/* generate odd nonce */ |
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ret = tpm_get_random(NULL, nonceodd, TPM_NONCE_SIZE); |
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if (ret < 0) { |
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pr_info("tpm_get_random failed (%d)\n", ret); |
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return ret; |
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} |
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|
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/* calculate authorization HMAC value */ |
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ret = TSS_authhmac(authdata, keyauth, SHA1_DIGEST_SIZE, enonce, |
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nonceodd, cont, sizeof(uint32_t), &ordinal, |
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keybloblen, keyblob, 0, 0); |
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if (ret < 0) |
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return ret; |
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|
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/* build the request buffer */ |
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tpm_buf_reset(tb, TPM_TAG_RQU_AUTH1_COMMAND, TPM_ORD_LOADKEY2); |
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tpm_buf_append_u32(tb, keyhandle); |
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tpm_buf_append(tb, keyblob, keybloblen); |
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tpm_buf_append_u32(tb, authhandle); |
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tpm_buf_append(tb, nonceodd, TPM_NONCE_SIZE); |
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tpm_buf_append_u8(tb, cont); |
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tpm_buf_append(tb, authdata, SHA1_DIGEST_SIZE); |
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|
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ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE); |
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if (ret < 0) { |
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pr_info("authhmac failed (%d)\n", ret); |
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return ret; |
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} |
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|
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ret = TSS_checkhmac1(tb->data, ordinal, nonceodd, keyauth, |
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SHA1_DIGEST_SIZE, 0, 0); |
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if (ret < 0) { |
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pr_info("TSS_checkhmac1 failed (%d)\n", ret); |
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return ret; |
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} |
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*newhandle = LOAD32(tb->data, TPM_DATA_OFFSET); |
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return 0; |
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} |
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/* |
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* Execute the FlushSpecific TPM command |
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*/ |
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static int tpm_flushspecific(struct tpm_buf *tb, uint32_t handle) |
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{ |
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tpm_buf_reset(tb, TPM_TAG_RQU_COMMAND, TPM_ORD_FLUSHSPECIFIC); |
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tpm_buf_append_u32(tb, handle); |
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tpm_buf_append_u32(tb, TPM_RT_KEY); |
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return trusted_tpm_send(tb->data, MAX_BUF_SIZE); |
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} |
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/* |
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* Decrypt a blob provided by userspace using a specific key handle. |
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* The handle is a well known handle or previously loaded by e.g. LoadKey2 |
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*/ |
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static int tpm_unbind(struct tpm_buf *tb, |
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uint32_t keyhandle, unsigned char *keyauth, |
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const unsigned char *blob, uint32_t bloblen, |
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void *out, uint32_t outlen) |
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{ |
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unsigned char nonceodd[TPM_NONCE_SIZE]; |
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unsigned char enonce[TPM_NONCE_SIZE]; |
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unsigned char authdata[SHA1_DIGEST_SIZE]; |
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uint32_t authhandle = 0; |
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unsigned char cont = 0; |
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uint32_t ordinal; |
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uint32_t datalen; |
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int ret; |
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ordinal = htonl(TPM_ORD_UNBIND); |
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datalen = htonl(bloblen); |
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/* session for loading the key */ |
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ret = oiap(tb, &authhandle, enonce); |
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if (ret < 0) { |
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pr_info("oiap failed (%d)\n", ret); |
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return ret; |
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} |
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|
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/* generate odd nonce */ |
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ret = tpm_get_random(NULL, nonceodd, TPM_NONCE_SIZE); |
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if (ret < 0) { |
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pr_info("tpm_get_random failed (%d)\n", ret); |
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return ret; |
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} |
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/* calculate authorization HMAC value */ |
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ret = TSS_authhmac(authdata, keyauth, SHA1_DIGEST_SIZE, enonce, |
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nonceodd, cont, sizeof(uint32_t), &ordinal, |
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sizeof(uint32_t), &datalen, |
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bloblen, blob, 0, 0); |
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if (ret < 0) |
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return ret; |
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|
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/* build the request buffer */ |
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tpm_buf_reset(tb, TPM_TAG_RQU_AUTH1_COMMAND, TPM_ORD_UNBIND); |
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tpm_buf_append_u32(tb, keyhandle); |
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tpm_buf_append_u32(tb, bloblen); |
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tpm_buf_append(tb, blob, bloblen); |
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tpm_buf_append_u32(tb, authhandle); |
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tpm_buf_append(tb, nonceodd, TPM_NONCE_SIZE); |
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tpm_buf_append_u8(tb, cont); |
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tpm_buf_append(tb, authdata, SHA1_DIGEST_SIZE); |
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ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE); |
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if (ret < 0) { |
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pr_info("authhmac failed (%d)\n", ret); |
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return ret; |
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} |
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datalen = LOAD32(tb->data, TPM_DATA_OFFSET); |
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ret = TSS_checkhmac1(tb->data, ordinal, nonceodd, |
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keyauth, SHA1_DIGEST_SIZE, |
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sizeof(uint32_t), TPM_DATA_OFFSET, |
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datalen, TPM_DATA_OFFSET + sizeof(uint32_t), |
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0, 0); |
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if (ret < 0) { |
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pr_info("TSS_checkhmac1 failed (%d)\n", ret); |
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return ret; |
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} |
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memcpy(out, tb->data + TPM_DATA_OFFSET + sizeof(uint32_t), |
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min(outlen, datalen)); |
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return datalen; |
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} |
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/* |
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* Sign a blob provided by userspace (that has had the hash function applied) |
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* using a specific key handle. The handle is assumed to have been previously |
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* loaded by e.g. LoadKey2. |
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* |
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* Note that the key signature scheme of the used key should be set to |
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* TPM_SS_RSASSAPKCS1v15_DER. This allows the hashed input to be of any size |
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* up to key_length_in_bytes - 11 and not be limited to size 20 like the |
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* TPM_SS_RSASSAPKCS1v15_SHA1 signature scheme. |
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*/ |
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static int tpm_sign(struct tpm_buf *tb, |
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uint32_t keyhandle, unsigned char *keyauth, |
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const unsigned char *blob, uint32_t bloblen, |
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void *out, uint32_t outlen) |
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{ |
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unsigned char nonceodd[TPM_NONCE_SIZE]; |
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unsigned char enonce[TPM_NONCE_SIZE]; |
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unsigned char authdata[SHA1_DIGEST_SIZE]; |
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uint32_t authhandle = 0; |
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unsigned char cont = 0; |
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uint32_t ordinal; |
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uint32_t datalen; |
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int ret; |
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ordinal = htonl(TPM_ORD_SIGN); |
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datalen = htonl(bloblen); |
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/* session for loading the key */ |
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ret = oiap(tb, &authhandle, enonce); |
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if (ret < 0) { |
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pr_info("oiap failed (%d)\n", ret); |
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return ret; |
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} |
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/* generate odd nonce */ |
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ret = tpm_get_random(NULL, nonceodd, TPM_NONCE_SIZE); |
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if (ret < 0) { |
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pr_info("tpm_get_random failed (%d)\n", ret); |
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return ret; |
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} |
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/* calculate authorization HMAC value */ |
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ret = TSS_authhmac(authdata, keyauth, SHA1_DIGEST_SIZE, enonce, |
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nonceodd, cont, sizeof(uint32_t), &ordinal, |
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sizeof(uint32_t), &datalen, |
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bloblen, blob, 0, 0); |
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if (ret < 0) |
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return ret; |
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/* build the request buffer */ |
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tpm_buf_reset(tb, TPM_TAG_RQU_AUTH1_COMMAND, TPM_ORD_SIGN); |
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tpm_buf_append_u32(tb, keyhandle); |
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tpm_buf_append_u32(tb, bloblen); |
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tpm_buf_append(tb, blob, bloblen); |
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tpm_buf_append_u32(tb, authhandle); |
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tpm_buf_append(tb, nonceodd, TPM_NONCE_SIZE); |
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tpm_buf_append_u8(tb, cont); |
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tpm_buf_append(tb, authdata, SHA1_DIGEST_SIZE); |
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ret = trusted_tpm_send(tb->data, MAX_BUF_SIZE); |
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if (ret < 0) { |
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pr_info("authhmac failed (%d)\n", ret); |
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return ret; |
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} |
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datalen = LOAD32(tb->data, TPM_DATA_OFFSET); |
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ret = TSS_checkhmac1(tb->data, ordinal, nonceodd, |
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keyauth, SHA1_DIGEST_SIZE, |
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sizeof(uint32_t), TPM_DATA_OFFSET, |
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datalen, TPM_DATA_OFFSET + sizeof(uint32_t), |
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0, 0); |
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if (ret < 0) { |
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pr_info("TSS_checkhmac1 failed (%d)\n", ret); |
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return ret; |
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} |
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memcpy(out, tb->data + TPM_DATA_OFFSET + sizeof(uint32_t), |
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min(datalen, outlen)); |
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return datalen; |
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} |
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/* Room to fit two u32 zeros for algo id and parameters length. */ |
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#define SETKEY_PARAMS_SIZE (sizeof(u32) * 2) |
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/* |
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* Maximum buffer size for the BER/DER encoded public key. The public key |
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* is of the form SEQUENCE { INTEGER n, INTEGER e } where n is a maximum 2048 |
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* bit key and e is usually 65537 |
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* The encoding overhead is: |
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* - max 4 bytes for SEQUENCE |
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* - max 4 bytes for INTEGER n type/length |
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* - 257 bytes of n |
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* - max 2 bytes for INTEGER e type/length |
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* - 3 bytes of e |
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* - 4+4 of zeros for set_pub_key parameters (SETKEY_PARAMS_SIZE) |
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*/ |
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#define PUB_KEY_BUF_SIZE (4 + 4 + 257 + 2 + 3 + SETKEY_PARAMS_SIZE) |
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/* |
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* Provide a part of a description of the key for /proc/keys. |
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*/ |
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static void asym_tpm_describe(const struct key *asymmetric_key, |
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struct seq_file *m) |
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{ |
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struct tpm_key *tk = asymmetric_key->payload.data[asym_crypto]; |
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if (!tk) |
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return; |
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seq_printf(m, "TPM1.2/Blob"); |
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} |
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static void asym_tpm_destroy(void *payload0, void *payload3) |
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{ |
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struct tpm_key *tk = payload0; |
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if (!tk) |
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return; |
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kfree(tk->blob); |
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tk->blob_len = 0; |
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kfree(tk); |
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} |
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/* How many bytes will it take to encode the length */ |
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static inline uint32_t definite_length(uint32_t len) |
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{ |
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if (len <= 127) |
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return 1; |
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if (len <= 255) |
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return 2; |
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return 3; |
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} |
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static inline uint8_t *encode_tag_length(uint8_t *buf, uint8_t tag, |
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uint32_t len) |
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{ |
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*buf++ = tag; |
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if (len <= 127) { |
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buf[0] = len; |
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return buf + 1; |
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} |
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if (len <= 255) { |
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buf[0] = 0x81; |
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buf[1] = len; |
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return buf + 2; |
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} |
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buf[0] = 0x82; |
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put_unaligned_be16(len, buf + 1); |
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return buf + 3; |
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} |
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static uint32_t derive_pub_key(const void *pub_key, uint32_t len, uint8_t *buf) |
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{ |
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uint8_t *cur = buf; |
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uint32_t n_len = definite_length(len) + 1 + len + 1; |
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uint32_t e_len = definite_length(3) + 1 + 3; |
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uint8_t e[3] = { 0x01, 0x00, 0x01 }; |
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/* SEQUENCE */ |
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cur = encode_tag_length(cur, 0x30, n_len + e_len); |
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/* INTEGER n */ |
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cur = encode_tag_length(cur, 0x02, len + 1); |
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cur[0] = 0x00; |
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memcpy(cur + 1, pub_key, len); |
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cur += len + 1; |
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cur = encode_tag_length(cur, 0x02, sizeof(e)); |
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memcpy(cur, e, sizeof(e)); |
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cur += sizeof(e); |
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/* Zero parameters to satisfy set_pub_key ABI. */ |
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memzero_explicit(cur, SETKEY_PARAMS_SIZE); |
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return cur - buf; |
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} |
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/* |
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* Determine the crypto algorithm name. |
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*/ |
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static int determine_akcipher(const char *encoding, const char *hash_algo, |
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char alg_name[CRYPTO_MAX_ALG_NAME]) |
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{ |
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if (strcmp(encoding, "pkcs1") == 0) { |
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if (!hash_algo) { |
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strcpy(alg_name, "pkcs1pad(rsa)"); |
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return 0; |
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} |
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if (snprintf(alg_name, CRYPTO_MAX_ALG_NAME, "pkcs1pad(rsa,%s)", |
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hash_algo) >= CRYPTO_MAX_ALG_NAME) |
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return -EINVAL; |
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return 0; |
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} |
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if (strcmp(encoding, "raw") == 0) { |
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strcpy(alg_name, "rsa"); |
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return 0; |
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} |
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return -ENOPKG; |
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} |
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/* |
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* Query information about a key. |
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*/ |
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static int tpm_key_query(const struct kernel_pkey_params *params, |
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struct kernel_pkey_query *info) |
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{ |
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struct tpm_key *tk = params->key->payload.data[asym_crypto]; |
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int ret; |
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char alg_name[CRYPTO_MAX_ALG_NAME]; |
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struct crypto_akcipher *tfm; |
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uint8_t der_pub_key[PUB_KEY_BUF_SIZE]; |
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uint32_t der_pub_key_len; |
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int len; |
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/* TPM only works on private keys, public keys still done in software */ |
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ret = determine_akcipher(params->encoding, params->hash_algo, alg_name); |
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if (ret < 0) |
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return ret; |
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tfm = crypto_alloc_akcipher(alg_name, 0, 0); |
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if (IS_ERR(tfm)) |
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return PTR_ERR(tfm); |
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der_pub_key_len = derive_pub_key(tk->pub_key, tk->pub_key_len, |
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der_pub_key); |
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ret = crypto_akcipher_set_pub_key(tfm, der_pub_key, der_pub_key_len); |
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if (ret < 0) |
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goto error_free_tfm; |
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len = crypto_akcipher_maxsize(tfm); |
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info->key_size = tk->key_len; |
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info->max_data_size = tk->key_len / 8; |
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info->max_sig_size = len; |
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info->max_enc_size = len; |
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info->max_dec_size = tk->key_len / 8; |
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info->supported_ops = KEYCTL_SUPPORTS_ENCRYPT | |
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KEYCTL_SUPPORTS_DECRYPT | |
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KEYCTL_SUPPORTS_VERIFY | |
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KEYCTL_SUPPORTS_SIGN; |
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ret = 0; |
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error_free_tfm: |
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crypto_free_akcipher(tfm); |
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pr_devel("<==%s() = %d\n", __func__, ret); |
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return ret; |
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} |
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/* |
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* Encryption operation is performed with the public key. Hence it is done |
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* in software |
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*/ |
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static int tpm_key_encrypt(struct tpm_key *tk, |
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struct kernel_pkey_params *params, |
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const void *in, void *out) |
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{ |
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char alg_name[CRYPTO_MAX_ALG_NAME]; |
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struct crypto_akcipher *tfm; |
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struct akcipher_request *req; |
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struct crypto_wait cwait; |
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struct scatterlist in_sg, out_sg; |
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uint8_t der_pub_key[PUB_KEY_BUF_SIZE]; |
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uint32_t der_pub_key_len; |
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int ret; |
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pr_devel("==>%s()\n", __func__); |
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ret = determine_akcipher(params->encoding, params->hash_algo, alg_name); |
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if (ret < 0) |
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return ret; |
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tfm = crypto_alloc_akcipher(alg_name, 0, 0); |
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if (IS_ERR(tfm)) |
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return PTR_ERR(tfm); |
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der_pub_key_len = derive_pub_key(tk->pub_key, tk->pub_key_len, |
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der_pub_key); |
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ret = crypto_akcipher_set_pub_key(tfm, der_pub_key, der_pub_key_len); |
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if (ret < 0) |
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goto error_free_tfm; |
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ret = -ENOMEM; |
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req = akcipher_request_alloc(tfm, GFP_KERNEL); |
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if (!req) |
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goto error_free_tfm; |
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sg_init_one(&in_sg, in, params->in_len); |
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sg_init_one(&out_sg, out, params->out_len); |
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akcipher_request_set_crypt(req, &in_sg, &out_sg, params->in_len, |
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params->out_len); |
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crypto_init_wait(&cwait); |
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akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG | |
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CRYPTO_TFM_REQ_MAY_SLEEP, |
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crypto_req_done, &cwait); |
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ret = crypto_akcipher_encrypt(req); |
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ret = crypto_wait_req(ret, &cwait); |
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if (ret == 0) |
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ret = req->dst_len; |
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akcipher_request_free(req); |
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error_free_tfm: |
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crypto_free_akcipher(tfm); |
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pr_devel("<==%s() = %d\n", __func__, ret); |
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return ret; |
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} |
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|
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/* |
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* Decryption operation is performed with the private key in the TPM. |
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*/ |
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static int tpm_key_decrypt(struct tpm_key *tk, |
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struct kernel_pkey_params *params, |
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const void *in, void *out) |
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{ |
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struct tpm_buf tb; |
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uint32_t keyhandle; |
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uint8_t srkauth[SHA1_DIGEST_SIZE]; |
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uint8_t keyauth[SHA1_DIGEST_SIZE]; |
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int r; |
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pr_devel("==>%s()\n", __func__); |
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|
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if (params->hash_algo) |
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return -ENOPKG; |
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if (strcmp(params->encoding, "pkcs1")) |
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return -ENOPKG; |
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r = tpm_buf_init(&tb, 0, 0); |
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if (r) |
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return r; |
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/* TODO: Handle a non-all zero SRK authorization */ |
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memset(srkauth, 0, sizeof(srkauth)); |
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|
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r = tpm_loadkey2(&tb, SRKHANDLE, srkauth, |
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tk->blob, tk->blob_len, &keyhandle); |
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if (r < 0) { |
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pr_devel("loadkey2 failed (%d)\n", r); |
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goto error; |
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} |
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|
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/* TODO: Handle a non-all zero key authorization */ |
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memset(keyauth, 0, sizeof(keyauth)); |
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r = tpm_unbind(&tb, keyhandle, keyauth, |
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in, params->in_len, out, params->out_len); |
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if (r < 0) |
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pr_devel("tpm_unbind failed (%d)\n", r); |
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|
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if (tpm_flushspecific(&tb, keyhandle) < 0) |
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pr_devel("flushspecific failed (%d)\n", r); |
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|
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error: |
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tpm_buf_destroy(&tb); |
|
pr_devel("<==%s() = %d\n", __func__, r); |
|
return r; |
|
} |
|
|
|
/* |
|
* Hash algorithm OIDs plus ASN.1 DER wrappings [RFC4880 sec 5.2.2]. |
|
*/ |
|
static const u8 digest_info_md5[] = { |
|
0x30, 0x20, 0x30, 0x0c, 0x06, 0x08, |
|
0x2a, 0x86, 0x48, 0x86, 0xf7, 0x0d, 0x02, 0x05, /* OID */ |
|
0x05, 0x00, 0x04, 0x10 |
|
}; |
|
|
|
static const u8 digest_info_sha1[] = { |
|
0x30, 0x21, 0x30, 0x09, 0x06, 0x05, |
|
0x2b, 0x0e, 0x03, 0x02, 0x1a, |
|
0x05, 0x00, 0x04, 0x14 |
|
}; |
|
|
|
static const u8 digest_info_rmd160[] = { |
|
0x30, 0x21, 0x30, 0x09, 0x06, 0x05, |
|
0x2b, 0x24, 0x03, 0x02, 0x01, |
|
0x05, 0x00, 0x04, 0x14 |
|
}; |
|
|
|
static const u8 digest_info_sha224[] = { |
|
0x30, 0x2d, 0x30, 0x0d, 0x06, 0x09, |
|
0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x04, |
|
0x05, 0x00, 0x04, 0x1c |
|
}; |
|
|
|
static const u8 digest_info_sha256[] = { |
|
0x30, 0x31, 0x30, 0x0d, 0x06, 0x09, |
|
0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x01, |
|
0x05, 0x00, 0x04, 0x20 |
|
}; |
|
|
|
static const u8 digest_info_sha384[] = { |
|
0x30, 0x41, 0x30, 0x0d, 0x06, 0x09, |
|
0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x02, |
|
0x05, 0x00, 0x04, 0x30 |
|
}; |
|
|
|
static const u8 digest_info_sha512[] = { |
|
0x30, 0x51, 0x30, 0x0d, 0x06, 0x09, |
|
0x60, 0x86, 0x48, 0x01, 0x65, 0x03, 0x04, 0x02, 0x03, |
|
0x05, 0x00, 0x04, 0x40 |
|
}; |
|
|
|
static const struct asn1_template { |
|
const char *name; |
|
const u8 *data; |
|
size_t size; |
|
} asn1_templates[] = { |
|
#define _(X) { #X, digest_info_##X, sizeof(digest_info_##X) } |
|
_(md5), |
|
_(sha1), |
|
_(rmd160), |
|
_(sha256), |
|
_(sha384), |
|
_(sha512), |
|
_(sha224), |
|
{ NULL } |
|
#undef _ |
|
}; |
|
|
|
static const struct asn1_template *lookup_asn1(const char *name) |
|
{ |
|
const struct asn1_template *p; |
|
|
|
for (p = asn1_templates; p->name; p++) |
|
if (strcmp(name, p->name) == 0) |
|
return p; |
|
return NULL; |
|
} |
|
|
|
/* |
|
* Sign operation is performed with the private key in the TPM. |
|
*/ |
|
static int tpm_key_sign(struct tpm_key *tk, |
|
struct kernel_pkey_params *params, |
|
const void *in, void *out) |
|
{ |
|
struct tpm_buf tb; |
|
uint32_t keyhandle; |
|
uint8_t srkauth[SHA1_DIGEST_SIZE]; |
|
uint8_t keyauth[SHA1_DIGEST_SIZE]; |
|
void *asn1_wrapped = NULL; |
|
uint32_t in_len = params->in_len; |
|
int r; |
|
|
|
pr_devel("==>%s()\n", __func__); |
|
|
|
if (strcmp(params->encoding, "pkcs1")) |
|
return -ENOPKG; |
|
|
|
if (params->hash_algo) { |
|
const struct asn1_template *asn1 = |
|
lookup_asn1(params->hash_algo); |
|
|
|
if (!asn1) |
|
return -ENOPKG; |
|
|
|
/* request enough space for the ASN.1 template + input hash */ |
|
asn1_wrapped = kzalloc(in_len + asn1->size, GFP_KERNEL); |
|
if (!asn1_wrapped) |
|
return -ENOMEM; |
|
|
|
/* Copy ASN.1 template, then the input */ |
|
memcpy(asn1_wrapped, asn1->data, asn1->size); |
|
memcpy(asn1_wrapped + asn1->size, in, in_len); |
|
|
|
in = asn1_wrapped; |
|
in_len += asn1->size; |
|
} |
|
|
|
if (in_len > tk->key_len / 8 - 11) { |
|
r = -EOVERFLOW; |
|
goto error_free_asn1_wrapped; |
|
} |
|
|
|
r = tpm_buf_init(&tb, 0, 0); |
|
if (r) |
|
goto error_free_asn1_wrapped; |
|
|
|
/* TODO: Handle a non-all zero SRK authorization */ |
|
memset(srkauth, 0, sizeof(srkauth)); |
|
|
|
r = tpm_loadkey2(&tb, SRKHANDLE, srkauth, |
|
tk->blob, tk->blob_len, &keyhandle); |
|
if (r < 0) { |
|
pr_devel("loadkey2 failed (%d)\n", r); |
|
goto error_free_tb; |
|
} |
|
|
|
/* TODO: Handle a non-all zero key authorization */ |
|
memset(keyauth, 0, sizeof(keyauth)); |
|
|
|
r = tpm_sign(&tb, keyhandle, keyauth, in, in_len, out, params->out_len); |
|
if (r < 0) |
|
pr_devel("tpm_sign failed (%d)\n", r); |
|
|
|
if (tpm_flushspecific(&tb, keyhandle) < 0) |
|
pr_devel("flushspecific failed (%d)\n", r); |
|
|
|
error_free_tb: |
|
tpm_buf_destroy(&tb); |
|
error_free_asn1_wrapped: |
|
kfree(asn1_wrapped); |
|
pr_devel("<==%s() = %d\n", __func__, r); |
|
return r; |
|
} |
|
|
|
/* |
|
* Do encryption, decryption and signing ops. |
|
*/ |
|
static int tpm_key_eds_op(struct kernel_pkey_params *params, |
|
const void *in, void *out) |
|
{ |
|
struct tpm_key *tk = params->key->payload.data[asym_crypto]; |
|
int ret = -EOPNOTSUPP; |
|
|
|
/* Perform the encryption calculation. */ |
|
switch (params->op) { |
|
case kernel_pkey_encrypt: |
|
ret = tpm_key_encrypt(tk, params, in, out); |
|
break; |
|
case kernel_pkey_decrypt: |
|
ret = tpm_key_decrypt(tk, params, in, out); |
|
break; |
|
case kernel_pkey_sign: |
|
ret = tpm_key_sign(tk, params, in, out); |
|
break; |
|
default: |
|
BUG(); |
|
} |
|
|
|
return ret; |
|
} |
|
|
|
/* |
|
* Verify a signature using a public key. |
|
*/ |
|
static int tpm_key_verify_signature(const struct key *key, |
|
const struct public_key_signature *sig) |
|
{ |
|
const struct tpm_key *tk = key->payload.data[asym_crypto]; |
|
struct crypto_wait cwait; |
|
struct crypto_akcipher *tfm; |
|
struct akcipher_request *req; |
|
struct scatterlist src_sg[2]; |
|
char alg_name[CRYPTO_MAX_ALG_NAME]; |
|
uint8_t der_pub_key[PUB_KEY_BUF_SIZE]; |
|
uint32_t der_pub_key_len; |
|
int ret; |
|
|
|
pr_devel("==>%s()\n", __func__); |
|
|
|
BUG_ON(!tk); |
|
BUG_ON(!sig); |
|
BUG_ON(!sig->s); |
|
|
|
if (!sig->digest) |
|
return -ENOPKG; |
|
|
|
ret = determine_akcipher(sig->encoding, sig->hash_algo, alg_name); |
|
if (ret < 0) |
|
return ret; |
|
|
|
tfm = crypto_alloc_akcipher(alg_name, 0, 0); |
|
if (IS_ERR(tfm)) |
|
return PTR_ERR(tfm); |
|
|
|
der_pub_key_len = derive_pub_key(tk->pub_key, tk->pub_key_len, |
|
der_pub_key); |
|
|
|
ret = crypto_akcipher_set_pub_key(tfm, der_pub_key, der_pub_key_len); |
|
if (ret < 0) |
|
goto error_free_tfm; |
|
|
|
ret = -ENOMEM; |
|
req = akcipher_request_alloc(tfm, GFP_KERNEL); |
|
if (!req) |
|
goto error_free_tfm; |
|
|
|
sg_init_table(src_sg, 2); |
|
sg_set_buf(&src_sg[0], sig->s, sig->s_size); |
|
sg_set_buf(&src_sg[1], sig->digest, sig->digest_size); |
|
akcipher_request_set_crypt(req, src_sg, NULL, sig->s_size, |
|
sig->digest_size); |
|
crypto_init_wait(&cwait); |
|
akcipher_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG | |
|
CRYPTO_TFM_REQ_MAY_SLEEP, |
|
crypto_req_done, &cwait); |
|
ret = crypto_wait_req(crypto_akcipher_verify(req), &cwait); |
|
|
|
akcipher_request_free(req); |
|
error_free_tfm: |
|
crypto_free_akcipher(tfm); |
|
pr_devel("<==%s() = %d\n", __func__, ret); |
|
if (WARN_ON_ONCE(ret > 0)) |
|
ret = -EINVAL; |
|
return ret; |
|
} |
|
|
|
/* |
|
* Parse enough information out of TPM_KEY structure: |
|
* TPM_STRUCT_VER -> 4 bytes |
|
* TPM_KEY_USAGE -> 2 bytes |
|
* TPM_KEY_FLAGS -> 4 bytes |
|
* TPM_AUTH_DATA_USAGE -> 1 byte |
|
* TPM_KEY_PARMS -> variable |
|
* UINT32 PCRInfoSize -> 4 bytes |
|
* BYTE* -> PCRInfoSize bytes |
|
* TPM_STORE_PUBKEY |
|
* UINT32 encDataSize; |
|
* BYTE* -> encDataSize; |
|
* |
|
* TPM_KEY_PARMS: |
|
* TPM_ALGORITHM_ID -> 4 bytes |
|
* TPM_ENC_SCHEME -> 2 bytes |
|
* TPM_SIG_SCHEME -> 2 bytes |
|
* UINT32 parmSize -> 4 bytes |
|
* BYTE* -> variable |
|
*/ |
|
static int extract_key_parameters(struct tpm_key *tk) |
|
{ |
|
const void *cur = tk->blob; |
|
uint32_t len = tk->blob_len; |
|
const void *pub_key; |
|
uint32_t sz; |
|
uint32_t key_len; |
|
|
|
if (len < 11) |
|
return -EBADMSG; |
|
|
|
/* Ensure this is a legacy key */ |
|
if (get_unaligned_be16(cur + 4) != 0x0015) |
|
return -EBADMSG; |
|
|
|
/* Skip to TPM_KEY_PARMS */ |
|
cur += 11; |
|
len -= 11; |
|
|
|
if (len < 12) |
|
return -EBADMSG; |
|
|
|
/* Make sure this is an RSA key */ |
|
if (get_unaligned_be32(cur) != 0x00000001) |
|
return -EBADMSG; |
|
|
|
/* Make sure this is TPM_ES_RSAESPKCSv15 encoding scheme */ |
|
if (get_unaligned_be16(cur + 4) != 0x0002) |
|
return -EBADMSG; |
|
|
|
/* Make sure this is TPM_SS_RSASSAPKCS1v15_DER signature scheme */ |
|
if (get_unaligned_be16(cur + 6) != 0x0003) |
|
return -EBADMSG; |
|
|
|
sz = get_unaligned_be32(cur + 8); |
|
if (len < sz + 12) |
|
return -EBADMSG; |
|
|
|
/* Move to TPM_RSA_KEY_PARMS */ |
|
len -= 12; |
|
cur += 12; |
|
|
|
/* Grab the RSA key length */ |
|
key_len = get_unaligned_be32(cur); |
|
|
|
switch (key_len) { |
|
case 512: |
|
case 1024: |
|
case 1536: |
|
case 2048: |
|
break; |
|
default: |
|
return -EINVAL; |
|
} |
|
|
|
/* Move just past TPM_KEY_PARMS */ |
|
cur += sz; |
|
len -= sz; |
|
|
|
if (len < 4) |
|
return -EBADMSG; |
|
|
|
sz = get_unaligned_be32(cur); |
|
if (len < 4 + sz) |
|
return -EBADMSG; |
|
|
|
/* Move to TPM_STORE_PUBKEY */ |
|
cur += 4 + sz; |
|
len -= 4 + sz; |
|
|
|
/* Grab the size of the public key, it should jive with the key size */ |
|
sz = get_unaligned_be32(cur); |
|
if (sz > 256) |
|
return -EINVAL; |
|
|
|
pub_key = cur + 4; |
|
|
|
tk->key_len = key_len; |
|
tk->pub_key = pub_key; |
|
tk->pub_key_len = sz; |
|
|
|
return 0; |
|
} |
|
|
|
/* Given the blob, parse it and load it into the TPM */ |
|
struct tpm_key *tpm_key_create(const void *blob, uint32_t blob_len) |
|
{ |
|
int r; |
|
struct tpm_key *tk; |
|
|
|
r = tpm_is_tpm2(NULL); |
|
if (r < 0) |
|
goto error; |
|
|
|
/* We don't support TPM2 yet */ |
|
if (r > 0) { |
|
r = -ENODEV; |
|
goto error; |
|
} |
|
|
|
r = -ENOMEM; |
|
tk = kzalloc(sizeof(struct tpm_key), GFP_KERNEL); |
|
if (!tk) |
|
goto error; |
|
|
|
tk->blob = kmemdup(blob, blob_len, GFP_KERNEL); |
|
if (!tk->blob) |
|
goto error_memdup; |
|
|
|
tk->blob_len = blob_len; |
|
|
|
r = extract_key_parameters(tk); |
|
if (r < 0) |
|
goto error_extract; |
|
|
|
return tk; |
|
|
|
error_extract: |
|
kfree(tk->blob); |
|
tk->blob_len = 0; |
|
error_memdup: |
|
kfree(tk); |
|
error: |
|
return ERR_PTR(r); |
|
} |
|
EXPORT_SYMBOL_GPL(tpm_key_create); |
|
|
|
/* |
|
* TPM-based asymmetric key subtype |
|
*/ |
|
struct asymmetric_key_subtype asym_tpm_subtype = { |
|
.owner = THIS_MODULE, |
|
.name = "asym_tpm", |
|
.name_len = sizeof("asym_tpm") - 1, |
|
.describe = asym_tpm_describe, |
|
.destroy = asym_tpm_destroy, |
|
.query = tpm_key_query, |
|
.eds_op = tpm_key_eds_op, |
|
.verify_signature = tpm_key_verify_signature, |
|
}; |
|
EXPORT_SYMBOL_GPL(asym_tpm_subtype); |
|
|
|
MODULE_DESCRIPTION("TPM based asymmetric key subtype"); |
|
MODULE_AUTHOR("Intel Corporation"); |
|
MODULE_LICENSE("GPL v2");
|
|
|