cregit-Linux how code gets into the kernel

Release 4.7 security/integrity/ima/ima_crypto.c

/*
 * Copyright (C) 2005,2006,2007,2008 IBM Corporation
 *
 * Authors:
 * Mimi Zohar <zohar@us.ibm.com>
 * Kylene Hall <kjhall@us.ibm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, version 2 of the License.
 *
 * File: ima_crypto.c
 *      Calculates md5/sha1 file hash, template hash, boot-aggreate hash
 */


#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt

#include <linux/kernel.h>
#include <linux/moduleparam.h>
#include <linux/ratelimit.h>
#include <linux/file.h>
#include <linux/crypto.h>
#include <linux/scatterlist.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <crypto/hash.h>

#include "ima.h"


struct ahash_completion {
	
struct completion completion;
	
int err;
};

/* minimum file size for ahash use */

static unsigned long ima_ahash_minsize;
module_param_named(ahash_minsize, ima_ahash_minsize, ulong, 0644);
MODULE_PARM_DESC(ahash_minsize, "Minimum file size for ahash use");

/* default is 0 - 1 page. */

static int ima_maxorder;

static unsigned int ima_bufsize = PAGE_SIZE;


static int param_set_bufsize(const char *val, const struct kernel_param *kp) { unsigned long long size; int order; size = memparse(val, NULL); order = get_order(size); if (order >= MAX_ORDER) return -EINVAL; ima_maxorder = order; ima_bufsize = PAGE_SIZE << order; return 0; }

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static const struct kernel_param_ops param_ops_bufsize = { .set = param_set_bufsize, .get = param_get_uint, }; #define param_check_bufsize(name, p) __param_check(name, p, unsigned int) module_param_named(ahash_bufsize, ima_bufsize, bufsize, 0644); MODULE_PARM_DESC(ahash_bufsize, "Maximum ahash buffer size"); static struct crypto_shash *ima_shash_tfm; static struct crypto_ahash *ima_ahash_tfm;
int __init ima_init_crypto(void) { long rc; ima_shash_tfm = crypto_alloc_shash(hash_algo_name[ima_hash_algo], 0, 0); if (IS_ERR(ima_shash_tfm)) { rc = PTR_ERR(ima_shash_tfm); pr_err("Can not allocate %s (reason: %ld)\n", hash_algo_name[ima_hash_algo], rc); return rc; } return 0; }

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static struct crypto_shash *ima_alloc_tfm(enum hash_algo algo) { struct crypto_shash *tfm = ima_shash_tfm; int rc; if (algo < 0 || algo >= HASH_ALGO__LAST) algo = ima_hash_algo; if (algo != ima_hash_algo) { tfm = crypto_alloc_shash(hash_algo_name[algo], 0, 0); if (IS_ERR(tfm)) { rc = PTR_ERR(tfm); pr_err("Can not allocate %s (reason: %d)\n", hash_algo_name[algo], rc); } } return tfm; }

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static void ima_free_tfm(struct crypto_shash *tfm) { if (tfm != ima_shash_tfm) crypto_free_shash(tfm); }

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/** * ima_alloc_pages() - Allocate contiguous pages. * @max_size: Maximum amount of memory to allocate. * @allocated_size: Returned size of actual allocation. * @last_warn: Should the min_size allocation warn or not. * * Tries to do opportunistic allocation for memory first trying to allocate * max_size amount of memory and then splitting that until zero order is * reached. Allocation is tried without generating allocation warnings unless * last_warn is set. Last_warn set affects only last allocation of zero order. * * By default, ima_maxorder is 0 and it is equivalent to kmalloc(GFP_KERNEL) * * Return pointer to allocated memory, or NULL on failure. */
static void *ima_alloc_pages(loff_t max_size, size_t *allocated_size, int last_warn) { void *ptr; int order = ima_maxorder; gfp_t gfp_mask = __GFP_RECLAIM | __GFP_NOWARN | __GFP_NORETRY; if (order) order = min(get_order(max_size), order); for (; order; order--) { ptr = (void *)__get_free_pages(gfp_mask, order); if (ptr) { *allocated_size = PAGE_SIZE << order; return ptr; } } /* order is zero - one page */ gfp_mask = GFP_KERNEL; if (!last_warn) gfp_mask |= __GFP_NOWARN; ptr = (void *)__get_free_pages(gfp_mask, 0); if (ptr) { *allocated_size = PAGE_SIZE; return ptr; } *allocated_size = 0; return NULL; }

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/** * ima_free_pages() - Free pages allocated by ima_alloc_pages(). * @ptr: Pointer to allocated pages. * @size: Size of allocated buffer. */
static void ima_free_pages(void *ptr, size_t size) { if (!ptr) return; free_pages((unsigned long)ptr, get_order(size)); }

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static struct crypto_ahash *ima_alloc_atfm(enum hash_algo algo) { struct crypto_ahash *tfm = ima_ahash_tfm; int rc; if (algo < 0 || algo >= HASH_ALGO__LAST) algo = ima_hash_algo; if (algo != ima_hash_algo || !tfm) { tfm = crypto_alloc_ahash(hash_algo_name[algo], 0, 0); if (!IS_ERR(tfm)) { if (algo == ima_hash_algo) ima_ahash_tfm = tfm; } else { rc = PTR_ERR(tfm); pr_err("Can not allocate %s (reason: %d)\n", hash_algo_name[algo], rc); } } return tfm; }

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static void ima_free_atfm(struct crypto_ahash *tfm) { if (tfm != ima_ahash_tfm) crypto_free_ahash(tfm); }

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static void ahash_complete(struct crypto_async_request *req, int err) { struct ahash_completion *res = req->data; if (err == -EINPROGRESS) return; res->err = err; complete(&res->completion); }

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static int ahash_wait(int err, struct ahash_completion *res) { switch (err) { case 0: break; case -EINPROGRESS: case -EBUSY: wait_for_completion(&res->completion); reinit_completion(&res->completion); err = res->err; /* fall through */ default: pr_crit_ratelimited("ahash calculation failed: err: %d\n", err); } return err; }

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static int ima_calc_file_hash_atfm(struct file *file, struct ima_digest_data *hash, struct crypto_ahash *tfm) { loff_t i_size, offset; char *rbuf[2] = { NULL, }; int rc, read = 0, rbuf_len, active = 0, ahash_rc = 0; struct ahash_request *req; struct scatterlist sg[1]; struct ahash_completion res; size_t rbuf_size[2]; hash->length = crypto_ahash_digestsize(tfm); req = ahash_request_alloc(tfm, GFP_KERNEL); if (!req) return -ENOMEM; init_completion(&res.completion); ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, ahash_complete, &res); rc = ahash_wait(crypto_ahash_init(req), &res); if (rc) goto out1; i_size = i_size_read(file_inode(file)); if (i_size == 0) goto out2; /* * Try to allocate maximum size of memory. * Fail if even a single page cannot be allocated. */ rbuf[0] = ima_alloc_pages(i_size, &rbuf_size[0], 1); if (!rbuf[0]) { rc = -ENOMEM; goto out1; } /* Only allocate one buffer if that is enough. */ if (i_size > rbuf_size[0]) { /* * Try to allocate secondary buffer. If that fails fallback to * using single buffering. Use previous memory allocation size * as baseline for possible allocation size. */ rbuf[1] = ima_alloc_pages(i_size - rbuf_size[0], &rbuf_size[1], 0); } if (!(file->f_mode & FMODE_READ)) { file->f_mode |= FMODE_READ; read = 1; } for (offset = 0; offset < i_size; offset += rbuf_len) { if (!rbuf[1] && offset) { /* Not using two buffers, and it is not the first * read/request, wait for the completion of the * previous ahash_update() request. */ rc = ahash_wait(ahash_rc, &res); if (rc) goto out3; } /* read buffer */ rbuf_len = min_t(loff_t, i_size - offset, rbuf_size[active]); rc = integrity_kernel_read(file, offset, rbuf[active], rbuf_len); if (rc != rbuf_len) goto out3; if (rbuf[1] && offset) { /* Using two buffers, and it is not the first * read/request, wait for the completion of the * previous ahash_update() request. */ rc = ahash_wait(ahash_rc, &res); if (rc) goto out3; } sg_init_one(&sg[0], rbuf[active], rbuf_len); ahash_request_set_crypt(req, sg, NULL, rbuf_len); ahash_rc = crypto_ahash_update(req); if (rbuf[1]) active = !active; /* swap buffers, if we use two */ } /* wait for the last update request to complete */ rc = ahash_wait(ahash_rc, &res); out3: if (read) file->f_mode &= ~FMODE_READ; ima_free_pages(rbuf[0], rbuf_size[0]); ima_free_pages(rbuf[1], rbuf_size[1]); out2: if (!rc) { ahash_request_set_crypt(req, NULL, hash->digest, 0); rc = ahash_wait(crypto_ahash_final(req), &res); } out1: ahash_request_free(req); return rc; }

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static int ima_calc_file_ahash(struct file *file, 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 = ima_calc_file_hash_atfm(file, hash, tfm); ima_free_atfm(tfm); return rc; }

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static int ima_calc_file_hash_tfm(struct file *file, struct ima_digest_data *hash, struct crypto_shash *tfm) { loff_t i_size, offset = 0; char *rbuf; int rc, read = 0; SHASH_DESC_ON_STACK(shash, tfm); shash->tfm = tfm; shash->flags = 0; hash->length = crypto_shash_digestsize(tfm); rc = crypto_shash_init(shash); if (rc != 0) return rc; i_size = i_size_read(file_inode(file)); if (i_size == 0) goto out; rbuf = kzalloc(PAGE_SIZE, GFP_KERNEL); if (!rbuf) return -ENOMEM; if (!(file->f_mode & FMODE_READ)) { file->f_mode |= FMODE_READ; read = 1; } while (offset < i_size) { int rbuf_len; rbuf_len = integrity_kernel_read(file, offset, rbuf, PAGE_SIZE); if (rbuf_len < 0) { rc = rbuf_len; break; } if (rbuf_len == 0) break; offset += rbuf_len; rc = crypto_shash_update(shash, rbuf, rbuf_len); if (rc) break; } if (read) file->f_mode &= ~FMODE_READ; kfree(rbuf); out: if (!rc) rc = crypto_shash_final(shash, hash->digest); return rc; }

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static int ima_calc_file_shash(struct file *file, 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 = ima_calc_file_hash_tfm(file, hash, tfm); ima_free_tfm(tfm); return rc; }

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/* * ima_calc_file_hash - calculate file hash * * Asynchronous hash (ahash) allows using HW acceleration for calculating * a hash. ahash performance varies for different data sizes on different * crypto accelerators. shash performance might be better for smaller files. * The 'ima.ahash_minsize' module parameter allows specifying the best * minimum file size for using ahash on the system. * * If the ima.ahash_minsize parameter is not specified, this function uses * shash for the hash calculation. If ahash fails, it falls back to using * shash. */
int ima_calc_file_hash(struct file *file, struct ima_digest_data *hash) { loff_t i_size; int rc; i_size = i_size_read(file_inode(file)); if (ima_ahash_minsize && i_size >= ima_ahash_minsize) { rc = ima_calc_file_ahash(file, hash); if (!rc) return 0; } return ima_calc_file_shash(file, hash); }

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/* * Calculate the hash of template data */
static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data, struct ima_template_desc *td, int num_fields, struct ima_digest_data *hash, struct crypto_shash *tfm) { SHASH_DESC_ON_STACK(shash, tfm); int rc, i; shash->tfm = tfm; shash->flags = 0; hash->length = crypto_shash_digestsize(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; if (strcmp(td->name, IMA_TEMPLATE_IMA_NAME) != 0) { rc = crypto_shash_update(shash, (const u8 *) &field_data[i].len, sizeof(field_data[i].len)); 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, hash->digest); return rc; }

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int ima_calc_field_array_hash(struct ima_field_data *field_data, struct ima_template_desc *desc, int num_fields, 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 = ima_calc_field_array_hash_tfm(field_data, desc, num_fields, hash, tfm); ima_free_tfm(tfm); return rc; }

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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 ahash_completion res; int rc, ahash_rc = 0; hash->length = crypto_ahash_digestsize(tfm); req = ahash_request_alloc(tfm, GFP_KERNEL); if (!req) return -ENOMEM; init_completion(&res.completion); ahash_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG | CRYPTO_TFM_REQ_MAY_SLEEP, ahash_complete, &res); rc = ahash_wait(crypto_ahash_init(req), &res); 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, &res); if (!rc) { ahash_request_set_crypt(req, NULL, hash->digest, 0); rc = ahash_wait(crypto_ahash_final(req), &res); } out: ahash_request_free(req); return rc; }

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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; }

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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; shash->flags = 0; 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; }

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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; }

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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); }

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static void __init ima_pcrread(int idx, u8 *pcr) { if (!ima_used_chip) return; if (tpm_pcr_read(TPM_ANY_NUM, idx, pcr) != 0) pr_err("Error Communicating to TPM chip\n"); }

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/* * Calculate the boot aggregate hash */
static int __init ima_calc_boot_aggregate_tfm(char *digest, struct crypto_shash *tfm) { u8 pcr_i[TPM_DIGEST_SIZE]; int rc, i; SHASH_DESC_ON_STACK(shash, tfm); shash->tfm = tfm; shash->flags = 0; rc = crypto_shash_init(shash); if (rc != 0) return rc; /* cumulative sha1 over tpm registers 0-7 */ for (i = TPM_PCR0; i < TPM_PCR8; i++) { ima_pcrread(i, pcr_i); /* now accumulate with current aggregate */ rc = crypto_shash_update(shash, pcr_i, TPM_DIGEST_SIZE); } if (!rc) crypto_shash_final(shash, digest); return rc; }

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eric pariseric paris10.89%116.67%
Total112100.00%6100.00%


int __init ima_calc_boot_aggregate(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); hash->length = crypto_shash_digestsize(tfm); rc = ima_calc_boot_aggregate_tfm(hash->digest, tfm); ima_free_tfm(tfm); return rc; }

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behan websterbehan webster180.64%13.23%
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eric pariseric paris20.07%13.23%
mel gormanmel gorman10.04%13.23%
luis r. rodriguezluis r. rodriguez10.04%13.23%
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