diff options
Diffstat (limited to 'security/integrity/ima/ima_crypto.c')
-rw-r--r-- | security/integrity/ima/ima_crypto.c | 65 |
1 files changed, 50 insertions, 15 deletions
diff --git a/security/integrity/ima/ima_crypto.c b/security/integrity/ima/ima_crypto.c index 73044fc6a952..d5ad7b2539c7 100644 --- a/security/integrity/ima/ima_crypto.c +++ b/security/integrity/ima/ima_crypto.c @@ -411,7 +411,7 @@ int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash) loff_t i_size; int rc; struct file *f = file; - bool new_file_instance = false, modified_flags = false; + bool new_file_instance = false, modified_mode = false; /* * For consistency, fail file's opened with the O_DIRECT flag on @@ -431,13 +431,13 @@ int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash) f = dentry_open(&file->f_path, flags, file->f_cred); if (IS_ERR(f)) { /* - * Cannot open the file again, lets modify f_flags + * Cannot open the file again, lets modify f_mode * of original and continue */ pr_info_ratelimited("Unable to reopen file for reading.\n"); f = file; - f->f_flags |= FMODE_READ; - modified_flags = true; + f->f_mode |= FMODE_READ; + modified_mode = true; } else { new_file_instance = true; } @@ -455,8 +455,8 @@ int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash) out: if (new_file_instance) fput(f); - else if (modified_flags) - f->f_flags &= ~FMODE_READ; + else if (modified_mode) + f->f_mode &= ~FMODE_READ; return rc; } @@ -645,7 +645,7 @@ int ima_calc_buffer_hash(const void *buf, loff_t len, return calc_buffer_shash(buf, len, hash); } -static void __init ima_pcrread(u32 idx, struct tpm_digest *d) +static void ima_pcrread(u32 idx, struct tpm_digest *d) { if (!ima_tpm_chip) return; @@ -655,18 +655,29 @@ static void __init ima_pcrread(u32 idx, struct tpm_digest *d) } /* - * Calculate the boot aggregate hash + * The boot_aggregate is a cumulative hash over TPM registers 0 - 7. With + * TPM 1.2 the boot_aggregate was based on reading the SHA1 PCRs, but with + * TPM 2.0 hash agility, TPM chips could support multiple TPM PCR banks, + * allowing firmware to configure and enable different banks. + * + * Knowing which TPM bank is read to calculate the boot_aggregate digest + * needs to be conveyed to a verifier. For this reason, use the same + * hash algorithm for reading the TPM PCRs as for calculating the boot + * aggregate digest as stored in the measurement list. */ -static int __init ima_calc_boot_aggregate_tfm(char *digest, - struct crypto_shash *tfm) +static int ima_calc_boot_aggregate_tfm(char *digest, u16 alg_id, + struct crypto_shash *tfm) { - struct tpm_digest d = { .alg_id = TPM_ALG_SHA1, .digest = {0} }; + struct tpm_digest d = { .alg_id = alg_id, .digest = {0} }; int rc; u32 i; SHASH_DESC_ON_STACK(shash, tfm); shash->tfm = tfm; + pr_devel("calculating the boot-aggregate based on TPM bank: %04x\n", + d.alg_id); + rc = crypto_shash_init(shash); if (rc != 0) return rc; @@ -675,24 +686,48 @@ static int __init ima_calc_boot_aggregate_tfm(char *digest, for (i = TPM_PCR0; i < TPM_PCR8; i++) { ima_pcrread(i, &d); /* now accumulate with current aggregate */ - rc = crypto_shash_update(shash, d.digest, TPM_DIGEST_SIZE); + rc = crypto_shash_update(shash, d.digest, + crypto_shash_digestsize(tfm)); } if (!rc) crypto_shash_final(shash, digest); return rc; } -int __init ima_calc_boot_aggregate(struct ima_digest_data *hash) +int ima_calc_boot_aggregate(struct ima_digest_data *hash) { struct crypto_shash *tfm; - int rc; + u16 crypto_id, alg_id; + int rc, i, bank_idx = -1; + + for (i = 0; i < ima_tpm_chip->nr_allocated_banks; i++) { + crypto_id = ima_tpm_chip->allocated_banks[i].crypto_id; + if (crypto_id == hash->algo) { + bank_idx = i; + break; + } + + if (crypto_id == HASH_ALGO_SHA256) + bank_idx = i; + + if (bank_idx == -1 && crypto_id == HASH_ALGO_SHA1) + bank_idx = i; + } + + if (bank_idx == -1) { + pr_err("No suitable TPM algorithm for boot aggregate\n"); + return 0; + } + + hash->algo = ima_tpm_chip->allocated_banks[bank_idx].crypto_id; tfm = ima_alloc_tfm(hash->algo); if (IS_ERR(tfm)) return PTR_ERR(tfm); hash->length = crypto_shash_digestsize(tfm); - rc = ima_calc_boot_aggregate_tfm(hash->digest, tfm); + alg_id = ima_tpm_chip->allocated_banks[bank_idx].alg_id; + rc = ima_calc_boot_aggregate_tfm(hash->digest, alg_id, tfm); ima_free_tfm(tfm); |