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881 lines
20 KiB
881 lines
20 KiB
// SPDX-License-Identifier: GPL-2.0-only |
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/* |
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* Copyright (C) 2005,2006,2007,2008 IBM Corporation |
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* |
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* Authors: |
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* Mimi Zohar <[email protected]> |
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* Kylene Hall <[email protected]> |
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* |
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* File: ima_crypto.c |
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* Calculates md5/sha1 file hash, template hash, boot-aggreate hash |
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*/ |
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|
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#include <linux/kernel.h> |
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#include <linux/moduleparam.h> |
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#include <linux/ratelimit.h> |
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#include <linux/file.h> |
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#include <linux/crypto.h> |
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#include <linux/scatterlist.h> |
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#include <linux/err.h> |
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#include <linux/slab.h> |
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#include <crypto/hash.h> |
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|
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#include "ima.h" |
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|
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/* minimum file size for ahash use */ |
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static unsigned long ima_ahash_minsize; |
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module_param_named(ahash_minsize, ima_ahash_minsize, ulong, 0644); |
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MODULE_PARM_DESC(ahash_minsize, "Minimum file size for ahash use"); |
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|
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/* default is 0 - 1 page. */ |
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static int ima_maxorder; |
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static unsigned int ima_bufsize = PAGE_SIZE; |
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|
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static int param_set_bufsize(const char *val, const struct kernel_param *kp) |
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{ |
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unsigned long long size; |
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int order; |
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|
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size = memparse(val, NULL); |
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order = get_order(size); |
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if (order >= MAX_ORDER) |
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return -EINVAL; |
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ima_maxorder = order; |
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ima_bufsize = PAGE_SIZE << order; |
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return 0; |
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} |
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static const struct kernel_param_ops param_ops_bufsize = { |
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.set = param_set_bufsize, |
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.get = param_get_uint, |
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}; |
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#define param_check_bufsize(name, p) __param_check(name, p, unsigned int) |
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|
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module_param_named(ahash_bufsize, ima_bufsize, bufsize, 0644); |
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MODULE_PARM_DESC(ahash_bufsize, "Maximum ahash buffer size"); |
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static struct crypto_shash *ima_shash_tfm; |
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static struct crypto_ahash *ima_ahash_tfm; |
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struct ima_algo_desc { |
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struct crypto_shash *tfm; |
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enum hash_algo algo; |
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}; |
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int ima_sha1_idx __ro_after_init; |
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int ima_hash_algo_idx __ro_after_init; |
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/* |
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* Additional number of slots reserved, as needed, for SHA1 |
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* and IMA default algo. |
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*/ |
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int ima_extra_slots __ro_after_init; |
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|
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static struct ima_algo_desc *ima_algo_array; |
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static int __init ima_init_ima_crypto(void) |
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{ |
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long rc; |
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ima_shash_tfm = crypto_alloc_shash(hash_algo_name[ima_hash_algo], 0, 0); |
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if (IS_ERR(ima_shash_tfm)) { |
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rc = PTR_ERR(ima_shash_tfm); |
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pr_err("Can not allocate %s (reason: %ld)\n", |
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hash_algo_name[ima_hash_algo], rc); |
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return rc; |
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} |
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pr_info("Allocated hash algorithm: %s\n", |
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hash_algo_name[ima_hash_algo]); |
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return 0; |
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} |
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static struct crypto_shash *ima_alloc_tfm(enum hash_algo algo) |
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{ |
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struct crypto_shash *tfm = ima_shash_tfm; |
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int rc, i; |
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if (algo < 0 || algo >= HASH_ALGO__LAST) |
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algo = ima_hash_algo; |
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if (algo == ima_hash_algo) |
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return tfm; |
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for (i = 0; i < NR_BANKS(ima_tpm_chip) + ima_extra_slots; i++) |
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if (ima_algo_array[i].tfm && ima_algo_array[i].algo == algo) |
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return ima_algo_array[i].tfm; |
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tfm = crypto_alloc_shash(hash_algo_name[algo], 0, 0); |
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if (IS_ERR(tfm)) { |
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rc = PTR_ERR(tfm); |
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pr_err("Can not allocate %s (reason: %d)\n", |
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hash_algo_name[algo], rc); |
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} |
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return tfm; |
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} |
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int __init ima_init_crypto(void) |
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{ |
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enum hash_algo algo; |
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long rc; |
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int i; |
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rc = ima_init_ima_crypto(); |
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if (rc) |
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return rc; |
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ima_sha1_idx = -1; |
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ima_hash_algo_idx = -1; |
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for (i = 0; i < NR_BANKS(ima_tpm_chip); i++) { |
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algo = ima_tpm_chip->allocated_banks[i].crypto_id; |
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if (algo == HASH_ALGO_SHA1) |
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ima_sha1_idx = i; |
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if (algo == ima_hash_algo) |
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ima_hash_algo_idx = i; |
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} |
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if (ima_sha1_idx < 0) { |
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ima_sha1_idx = NR_BANKS(ima_tpm_chip) + ima_extra_slots++; |
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if (ima_hash_algo == HASH_ALGO_SHA1) |
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ima_hash_algo_idx = ima_sha1_idx; |
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} |
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if (ima_hash_algo_idx < 0) |
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ima_hash_algo_idx = NR_BANKS(ima_tpm_chip) + ima_extra_slots++; |
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ima_algo_array = kcalloc(NR_BANKS(ima_tpm_chip) + ima_extra_slots, |
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sizeof(*ima_algo_array), GFP_KERNEL); |
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if (!ima_algo_array) { |
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rc = -ENOMEM; |
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goto out; |
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} |
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for (i = 0; i < NR_BANKS(ima_tpm_chip); i++) { |
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algo = ima_tpm_chip->allocated_banks[i].crypto_id; |
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ima_algo_array[i].algo = algo; |
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/* unknown TPM algorithm */ |
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if (algo == HASH_ALGO__LAST) |
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continue; |
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if (algo == ima_hash_algo) { |
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ima_algo_array[i].tfm = ima_shash_tfm; |
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continue; |
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} |
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ima_algo_array[i].tfm = ima_alloc_tfm(algo); |
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if (IS_ERR(ima_algo_array[i].tfm)) { |
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if (algo == HASH_ALGO_SHA1) { |
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rc = PTR_ERR(ima_algo_array[i].tfm); |
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ima_algo_array[i].tfm = NULL; |
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goto out_array; |
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} |
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ima_algo_array[i].tfm = NULL; |
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} |
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} |
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if (ima_sha1_idx >= NR_BANKS(ima_tpm_chip)) { |
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if (ima_hash_algo == HASH_ALGO_SHA1) { |
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ima_algo_array[ima_sha1_idx].tfm = ima_shash_tfm; |
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} else { |
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ima_algo_array[ima_sha1_idx].tfm = |
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ima_alloc_tfm(HASH_ALGO_SHA1); |
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if (IS_ERR(ima_algo_array[ima_sha1_idx].tfm)) { |
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rc = PTR_ERR(ima_algo_array[ima_sha1_idx].tfm); |
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goto out_array; |
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} |
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} |
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ima_algo_array[ima_sha1_idx].algo = HASH_ALGO_SHA1; |
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} |
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if (ima_hash_algo_idx >= NR_BANKS(ima_tpm_chip) && |
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ima_hash_algo_idx != ima_sha1_idx) { |
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ima_algo_array[ima_hash_algo_idx].tfm = ima_shash_tfm; |
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ima_algo_array[ima_hash_algo_idx].algo = ima_hash_algo; |
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} |
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return 0; |
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out_array: |
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for (i = 0; i < NR_BANKS(ima_tpm_chip) + ima_extra_slots; i++) { |
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if (!ima_algo_array[i].tfm || |
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ima_algo_array[i].tfm == ima_shash_tfm) |
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continue; |
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crypto_free_shash(ima_algo_array[i].tfm); |
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} |
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out: |
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crypto_free_shash(ima_shash_tfm); |
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return rc; |
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} |
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static void ima_free_tfm(struct crypto_shash *tfm) |
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{ |
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int i; |
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if (tfm == ima_shash_tfm) |
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return; |
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for (i = 0; i < NR_BANKS(ima_tpm_chip) + ima_extra_slots; i++) |
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if (ima_algo_array[i].tfm == tfm) |
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return; |
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crypto_free_shash(tfm); |
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} |
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/** |
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* ima_alloc_pages() - Allocate contiguous pages. |
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* @max_size: Maximum amount of memory to allocate. |
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* @allocated_size: Returned size of actual allocation. |
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* @last_warn: Should the min_size allocation warn or not. |
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* |
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* Tries to do opportunistic allocation for memory first trying to allocate |
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* max_size amount of memory and then splitting that until zero order is |
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* reached. Allocation is tried without generating allocation warnings unless |
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* last_warn is set. Last_warn set affects only last allocation of zero order. |
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* |
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* By default, ima_maxorder is 0 and it is equivalent to kmalloc(GFP_KERNEL) |
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* |
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* Return pointer to allocated memory, or NULL on failure. |
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*/ |
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static void *ima_alloc_pages(loff_t max_size, size_t *allocated_size, |
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int last_warn) |
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{ |
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void *ptr; |
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int order = ima_maxorder; |
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gfp_t gfp_mask = __GFP_RECLAIM | __GFP_NOWARN | __GFP_NORETRY; |
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if (order) |
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order = min(get_order(max_size), order); |
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for (; order; order--) { |
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ptr = (void *)__get_free_pages(gfp_mask, order); |
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if (ptr) { |
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*allocated_size = PAGE_SIZE << order; |
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return ptr; |
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} |
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} |
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/* order is zero - one page */ |
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gfp_mask = GFP_KERNEL; |
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if (!last_warn) |
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gfp_mask |= __GFP_NOWARN; |
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ptr = (void *)__get_free_pages(gfp_mask, 0); |
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if (ptr) { |
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*allocated_size = PAGE_SIZE; |
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return ptr; |
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} |
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*allocated_size = 0; |
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return NULL; |
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} |
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/** |
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* ima_free_pages() - Free pages allocated by ima_alloc_pages(). |
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* @ptr: Pointer to allocated pages. |
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* @size: Size of allocated buffer. |
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*/ |
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static void ima_free_pages(void *ptr, size_t size) |
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{ |
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if (!ptr) |
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return; |
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free_pages((unsigned long)ptr, get_order(size)); |
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} |
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static struct crypto_ahash *ima_alloc_atfm(enum hash_algo algo) |
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{ |
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struct crypto_ahash *tfm = ima_ahash_tfm; |
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int rc; |
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if (algo < 0 || algo >= HASH_ALGO__LAST) |
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algo = ima_hash_algo; |
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if (algo != ima_hash_algo || !tfm) { |
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tfm = crypto_alloc_ahash(hash_algo_name[algo], 0, 0); |
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if (!IS_ERR(tfm)) { |
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if (algo == ima_hash_algo) |
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ima_ahash_tfm = tfm; |
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} else { |
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rc = PTR_ERR(tfm); |
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pr_err("Can not allocate %s (reason: %d)\n", |
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hash_algo_name[algo], rc); |
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} |
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} |
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return tfm; |
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} |
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static void ima_free_atfm(struct crypto_ahash *tfm) |
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{ |
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if (tfm != ima_ahash_tfm) |
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crypto_free_ahash(tfm); |
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} |
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static inline int ahash_wait(int err, struct crypto_wait *wait) |
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{ |
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err = crypto_wait_req(err, wait); |
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if (err) |
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pr_crit_ratelimited("ahash calculation failed: err: %d\n", err); |
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return err; |
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} |
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static int ima_calc_file_hash_atfm(struct file *file, |
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struct ima_digest_data *hash, |
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struct crypto_ahash *tfm) |
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{ |
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loff_t i_size, offset; |
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char *rbuf[2] = { NULL, }; |
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int rc, rbuf_len, active = 0, ahash_rc = 0; |
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struct ahash_request *req; |
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struct scatterlist sg[1]; |
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struct crypto_wait wait; |
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size_t rbuf_size[2]; |
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hash->length = crypto_ahash_digestsize(tfm); |
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req = ahash_request_alloc(tfm, GFP_KERNEL); |
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if (!req) |
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return -ENOMEM; |
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crypto_init_wait(&wait); |
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ahash_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, &wait); |
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rc = ahash_wait(crypto_ahash_init(req), &wait); |
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if (rc) |
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goto out1; |
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i_size = i_size_read(file_inode(file)); |
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if (i_size == 0) |
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goto out2; |
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/* |
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* Try to allocate maximum size of memory. |
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* Fail if even a single page cannot be allocated. |
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*/ |
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rbuf[0] = ima_alloc_pages(i_size, &rbuf_size[0], 1); |
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if (!rbuf[0]) { |
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rc = -ENOMEM; |
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goto out1; |
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} |
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/* Only allocate one buffer if that is enough. */ |
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if (i_size > rbuf_size[0]) { |
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/* |
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* Try to allocate secondary buffer. If that fails fallback to |
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* using single buffering. Use previous memory allocation size |
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* as baseline for possible allocation size. |
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*/ |
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rbuf[1] = ima_alloc_pages(i_size - rbuf_size[0], |
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&rbuf_size[1], 0); |
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} |
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for (offset = 0; offset < i_size; offset += rbuf_len) { |
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if (!rbuf[1] && offset) { |
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/* Not using two buffers, and it is not the first |
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* read/request, wait for the completion of the |
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* previous ahash_update() request. |
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*/ |
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rc = ahash_wait(ahash_rc, &wait); |
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if (rc) |
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goto out3; |
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} |
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/* read buffer */ |
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rbuf_len = min_t(loff_t, i_size - offset, rbuf_size[active]); |
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rc = integrity_kernel_read(file, offset, rbuf[active], |
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rbuf_len); |
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if (rc != rbuf_len) { |
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if (rc >= 0) |
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rc = -EINVAL; |
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/* |
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* Forward current rc, do not overwrite with return value |
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* from ahash_wait() |
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*/ |
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ahash_wait(ahash_rc, &wait); |
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goto out3; |
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} |
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if (rbuf[1] && offset) { |
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/* Using two buffers, and it is not the first |
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* read/request, wait for the completion of the |
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* previous ahash_update() request. |
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*/ |
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rc = ahash_wait(ahash_rc, &wait); |
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if (rc) |
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goto out3; |
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} |
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sg_init_one(&sg[0], rbuf[active], rbuf_len); |
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ahash_request_set_crypt(req, sg, NULL, rbuf_len); |
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ahash_rc = crypto_ahash_update(req); |
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if (rbuf[1]) |
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active = !active; /* swap buffers, if we use two */ |
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} |
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/* wait for the last update request to complete */ |
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rc = ahash_wait(ahash_rc, &wait); |
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out3: |
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ima_free_pages(rbuf[0], rbuf_size[0]); |
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ima_free_pages(rbuf[1], rbuf_size[1]); |
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out2: |
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if (!rc) { |
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ahash_request_set_crypt(req, NULL, hash->digest, 0); |
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rc = ahash_wait(crypto_ahash_final(req), &wait); |
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} |
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out1: |
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ahash_request_free(req); |
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return rc; |
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} |
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static int ima_calc_file_ahash(struct file *file, struct ima_digest_data *hash) |
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{ |
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struct crypto_ahash *tfm; |
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int rc; |
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tfm = ima_alloc_atfm(hash->algo); |
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if (IS_ERR(tfm)) |
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return PTR_ERR(tfm); |
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rc = ima_calc_file_hash_atfm(file, hash, tfm); |
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ima_free_atfm(tfm); |
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return rc; |
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} |
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static int ima_calc_file_hash_tfm(struct file *file, |
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struct ima_digest_data *hash, |
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struct crypto_shash *tfm) |
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{ |
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loff_t i_size, offset = 0; |
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char *rbuf; |
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int rc; |
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SHASH_DESC_ON_STACK(shash, tfm); |
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shash->tfm = tfm; |
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hash->length = crypto_shash_digestsize(tfm); |
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rc = crypto_shash_init(shash); |
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if (rc != 0) |
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return rc; |
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i_size = i_size_read(file_inode(file)); |
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if (i_size == 0) |
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goto out; |
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rbuf = kzalloc(PAGE_SIZE, GFP_KERNEL); |
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if (!rbuf) |
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return -ENOMEM; |
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|
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while (offset < i_size) { |
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int rbuf_len; |
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rbuf_len = integrity_kernel_read(file, offset, rbuf, PAGE_SIZE); |
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if (rbuf_len < 0) { |
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rc = rbuf_len; |
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break; |
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} |
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if (rbuf_len == 0) { /* unexpected EOF */ |
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rc = -EINVAL; |
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break; |
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} |
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offset += rbuf_len; |
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rc = crypto_shash_update(shash, rbuf, rbuf_len); |
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if (rc) |
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break; |
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} |
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kfree(rbuf); |
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out: |
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if (!rc) |
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rc = crypto_shash_final(shash, hash->digest); |
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return rc; |
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} |
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static int ima_calc_file_shash(struct file *file, struct ima_digest_data *hash) |
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{ |
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struct crypto_shash *tfm; |
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int rc; |
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tfm = ima_alloc_tfm(hash->algo); |
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if (IS_ERR(tfm)) |
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return PTR_ERR(tfm); |
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|
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rc = ima_calc_file_hash_tfm(file, hash, tfm); |
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ima_free_tfm(tfm); |
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|
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return rc; |
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} |
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|
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/* |
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* ima_calc_file_hash - calculate file hash |
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* |
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* Asynchronous hash (ahash) allows using HW acceleration for calculating |
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* a hash. ahash performance varies for different data sizes on different |
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* crypto accelerators. shash performance might be better for smaller files. |
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* The 'ima.ahash_minsize' module parameter allows specifying the best |
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* minimum file size for using ahash on the system. |
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* |
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* If the ima.ahash_minsize parameter is not specified, this function uses |
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* shash for the hash calculation. If ahash fails, it falls back to using |
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* shash. |
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*/ |
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int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash) |
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{ |
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loff_t i_size; |
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int rc; |
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struct file *f = file; |
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bool new_file_instance = false; |
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|
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/* |
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* For consistency, fail file's opened with the O_DIRECT flag on |
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* filesystems mounted with/without DAX option. |
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*/ |
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if (file->f_flags & O_DIRECT) { |
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hash->length = hash_digest_size[ima_hash_algo]; |
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hash->algo = ima_hash_algo; |
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return -EINVAL; |
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} |
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|
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/* Open a new file instance in O_RDONLY if we cannot read */ |
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if (!(file->f_mode & FMODE_READ)) { |
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int flags = file->f_flags & ~(O_WRONLY | O_APPEND | |
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O_TRUNC | O_CREAT | O_NOCTTY | O_EXCL); |
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flags |= O_RDONLY; |
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f = dentry_open(&file->f_path, flags, file->f_cred); |
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if (IS_ERR(f)) |
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return PTR_ERR(f); |
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|
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new_file_instance = true; |
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} |
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|
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i_size = i_size_read(file_inode(f)); |
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|
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if (ima_ahash_minsize && i_size >= ima_ahash_minsize) { |
|
rc = ima_calc_file_ahash(f, hash); |
|
if (!rc) |
|
goto out; |
|
} |
|
|
|
rc = ima_calc_file_shash(f, hash); |
|
out: |
|
if (new_file_instance) |
|
fput(f); |
|
return rc; |
|
} |
|
|
|
/* |
|
* Calculate the hash of template data |
|
*/ |
|
static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data, |
|
struct ima_template_entry *entry, |
|
int tfm_idx) |
|
{ |
|
SHASH_DESC_ON_STACK(shash, ima_algo_array[tfm_idx].tfm); |
|
struct ima_template_desc *td = entry->template_desc; |
|
int num_fields = entry->template_desc->num_fields; |
|
int rc, i; |
|
|
|
shash->tfm = ima_algo_array[tfm_idx].tfm; |
|
|
|
rc = crypto_shash_init(shash); |
|
if (rc != 0) |
|
return rc; |
|
|
|
for (i = 0; i < num_fields; i++) { |
|
u8 buffer[IMA_EVENT_NAME_LEN_MAX + 1] = { 0 }; |
|
u8 *data_to_hash = field_data[i].data; |
|
u32 datalen = field_data[i].len; |
|
u32 datalen_to_hash = !ima_canonical_fmt ? |
|
datalen : (__force u32)cpu_to_le32(datalen); |
|
|
|
if (strcmp(td->name, IMA_TEMPLATE_IMA_NAME) != 0) { |
|
rc = crypto_shash_update(shash, |
|
(const u8 *) &datalen_to_hash, |
|
sizeof(datalen_to_hash)); |
|
if (rc) |
|
break; |
|
} else if (strcmp(td->fields[i]->field_id, "n") == 0) { |
|
memcpy(buffer, data_to_hash, datalen); |
|
data_to_hash = buffer; |
|
datalen = IMA_EVENT_NAME_LEN_MAX + 1; |
|
} |
|
rc = crypto_shash_update(shash, data_to_hash, datalen); |
|
if (rc) |
|
break; |
|
} |
|
|
|
if (!rc) |
|
rc = crypto_shash_final(shash, entry->digests[tfm_idx].digest); |
|
|
|
return rc; |
|
} |
|
|
|
int ima_calc_field_array_hash(struct ima_field_data *field_data, |
|
struct ima_template_entry *entry) |
|
{ |
|
u16 alg_id; |
|
int rc, i; |
|
|
|
rc = ima_calc_field_array_hash_tfm(field_data, entry, ima_sha1_idx); |
|
if (rc) |
|
return rc; |
|
|
|
entry->digests[ima_sha1_idx].alg_id = TPM_ALG_SHA1; |
|
|
|
for (i = 0; i < NR_BANKS(ima_tpm_chip) + ima_extra_slots; i++) { |
|
if (i == ima_sha1_idx) |
|
continue; |
|
|
|
if (i < NR_BANKS(ima_tpm_chip)) { |
|
alg_id = ima_tpm_chip->allocated_banks[i].alg_id; |
|
entry->digests[i].alg_id = alg_id; |
|
} |
|
|
|
/* for unmapped TPM algorithms digest is still a padded SHA1 */ |
|
if (!ima_algo_array[i].tfm) { |
|
memcpy(entry->digests[i].digest, |
|
entry->digests[ima_sha1_idx].digest, |
|
TPM_DIGEST_SIZE); |
|
continue; |
|
} |
|
|
|
rc = ima_calc_field_array_hash_tfm(field_data, entry, i); |
|
if (rc) |
|
return rc; |
|
} |
|
return rc; |
|
} |
|
|
|
static int calc_buffer_ahash_atfm(const void *buf, loff_t len, |
|
struct ima_digest_data *hash, |
|
struct crypto_ahash *tfm) |
|
{ |
|
struct ahash_request *req; |
|
struct scatterlist sg; |
|
struct crypto_wait wait; |
|
int rc, ahash_rc = 0; |
|
|
|
hash->length = crypto_ahash_digestsize(tfm); |
|
|
|
req = ahash_request_alloc(tfm, GFP_KERNEL); |
|
if (!req) |
|
return -ENOMEM; |
|
|
|
crypto_init_wait(&wait); |
|
ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG | |
|
CRYPTO_TFM_REQ_MAY_SLEEP, |
|
crypto_req_done, &wait); |
|
|
|
rc = ahash_wait(crypto_ahash_init(req), &wait); |
|
if (rc) |
|
goto out; |
|
|
|
sg_init_one(&sg, buf, len); |
|
ahash_request_set_crypt(req, &sg, NULL, len); |
|
|
|
ahash_rc = crypto_ahash_update(req); |
|
|
|
/* wait for the update request to complete */ |
|
rc = ahash_wait(ahash_rc, &wait); |
|
if (!rc) { |
|
ahash_request_set_crypt(req, NULL, hash->digest, 0); |
|
rc = ahash_wait(crypto_ahash_final(req), &wait); |
|
} |
|
out: |
|
ahash_request_free(req); |
|
return rc; |
|
} |
|
|
|
static int calc_buffer_ahash(const void *buf, loff_t len, |
|
struct ima_digest_data *hash) |
|
{ |
|
struct crypto_ahash *tfm; |
|
int rc; |
|
|
|
tfm = ima_alloc_atfm(hash->algo); |
|
if (IS_ERR(tfm)) |
|
return PTR_ERR(tfm); |
|
|
|
rc = calc_buffer_ahash_atfm(buf, len, hash, tfm); |
|
|
|
ima_free_atfm(tfm); |
|
|
|
return rc; |
|
} |
|
|
|
static int calc_buffer_shash_tfm(const void *buf, loff_t size, |
|
struct ima_digest_data *hash, |
|
struct crypto_shash *tfm) |
|
{ |
|
SHASH_DESC_ON_STACK(shash, tfm); |
|
unsigned int len; |
|
int rc; |
|
|
|
shash->tfm = tfm; |
|
|
|
hash->length = crypto_shash_digestsize(tfm); |
|
|
|
rc = crypto_shash_init(shash); |
|
if (rc != 0) |
|
return rc; |
|
|
|
while (size) { |
|
len = size < PAGE_SIZE ? size : PAGE_SIZE; |
|
rc = crypto_shash_update(shash, buf, len); |
|
if (rc) |
|
break; |
|
buf += len; |
|
size -= len; |
|
} |
|
|
|
if (!rc) |
|
rc = crypto_shash_final(shash, hash->digest); |
|
return rc; |
|
} |
|
|
|
static int calc_buffer_shash(const void *buf, loff_t len, |
|
struct ima_digest_data *hash) |
|
{ |
|
struct crypto_shash *tfm; |
|
int rc; |
|
|
|
tfm = ima_alloc_tfm(hash->algo); |
|
if (IS_ERR(tfm)) |
|
return PTR_ERR(tfm); |
|
|
|
rc = calc_buffer_shash_tfm(buf, len, hash, tfm); |
|
|
|
ima_free_tfm(tfm); |
|
return rc; |
|
} |
|
|
|
int ima_calc_buffer_hash(const void *buf, loff_t len, |
|
struct ima_digest_data *hash) |
|
{ |
|
int rc; |
|
|
|
if (ima_ahash_minsize && len >= ima_ahash_minsize) { |
|
rc = calc_buffer_ahash(buf, len, hash); |
|
if (!rc) |
|
return 0; |
|
} |
|
|
|
return calc_buffer_shash(buf, len, hash); |
|
} |
|
|
|
static void ima_pcrread(u32 idx, struct tpm_digest *d) |
|
{ |
|
if (!ima_tpm_chip) |
|
return; |
|
|
|
if (tpm_pcr_read(ima_tpm_chip, idx, d) != 0) |
|
pr_err("Error Communicating to TPM chip\n"); |
|
} |
|
|
|
/* |
|
* 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 ima_calc_boot_aggregate_tfm(char *digest, u16 alg_id, |
|
struct crypto_shash *tfm) |
|
{ |
|
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; |
|
|
|
/* cumulative digest over TPM registers 0-7 */ |
|
for (i = TPM_PCR0; i < TPM_PCR8; i++) { |
|
ima_pcrread(i, &d); |
|
/* now accumulate with current aggregate */ |
|
rc = crypto_shash_update(shash, d.digest, |
|
crypto_shash_digestsize(tfm)); |
|
if (rc != 0) |
|
return rc; |
|
} |
|
/* |
|
* Extend cumulative digest over TPM registers 8-9, which contain |
|
* measurement for the kernel command line (reg. 8) and image (reg. 9) |
|
* in a typical PCR allocation. Registers 8-9 are only included in |
|
* non-SHA1 boot_aggregate digests to avoid ambiguity. |
|
*/ |
|
if (alg_id != TPM_ALG_SHA1) { |
|
for (i = TPM_PCR8; i < TPM_PCR10; i++) { |
|
ima_pcrread(i, &d); |
|
rc = crypto_shash_update(shash, d.digest, |
|
crypto_shash_digestsize(tfm)); |
|
} |
|
} |
|
if (!rc) |
|
crypto_shash_final(shash, digest); |
|
return rc; |
|
} |
|
|
|
int ima_calc_boot_aggregate(struct ima_digest_data *hash) |
|
{ |
|
struct crypto_shash *tfm; |
|
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); |
|
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); |
|
|
|
return rc; |
|
}
|
|
|