Replaced the use of a Variable Length Array In Struct (VLAIS) with a C99 compliant equivalent. This patch allocates the appropriate amount of memory using a char array using the SHASH_DESC_ON_STACK macro. The new code can be compiled with both gcc and clang. Signed-off-by: Behan Webster <behanw@converseincode.com> Reviewed-by: Mark Charlebois <charlebm@gmail.com> Reviewed-by: Jan-Simon Möller <dl9pf@gmx.de> Acked-by: Herbert Xu <herbert@gondor.apana.org.au> Acked-by: Dmitry Kasatkin <d.kasatkin@samsung.com> Cc: tglx@linutronix.de
604 lines
14 KiB
C
604 lines
14 KiB
C
/*
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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 <zohar@us.ibm.com>
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* Kylene Hall <kjhall@us.ibm.com>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation, version 2 of the License.
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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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#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
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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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#include <crypto/hash_info.h>
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#include "ima.h"
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struct ahash_completion {
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struct completion completion;
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int err;
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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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/* 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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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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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 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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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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/**
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* ima_kernel_read - read file content
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*
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* This is a function for reading file content instead of kernel_read().
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* It does not perform locking checks to ensure it cannot be blocked.
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* It does not perform security checks because it is irrelevant for IMA.
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*
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*/
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static int ima_kernel_read(struct file *file, loff_t offset,
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char *addr, unsigned long count)
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{
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mm_segment_t old_fs;
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char __user *buf = addr;
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ssize_t ret = -EINVAL;
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if (!(file->f_mode & FMODE_READ))
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return -EBADF;
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old_fs = get_fs();
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set_fs(get_ds());
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if (file->f_op->read)
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ret = file->f_op->read(file, buf, count, &offset);
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else if (file->f_op->aio_read)
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ret = do_sync_read(file, buf, count, &offset);
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else if (file->f_op->read_iter)
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ret = new_sync_read(file, buf, count, &offset);
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set_fs(old_fs);
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return ret;
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}
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int __init ima_init_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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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;
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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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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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}
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return tfm;
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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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if (tfm != ima_shash_tfm)
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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_WAIT | __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 void ahash_complete(struct crypto_async_request *req, int err)
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{
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struct ahash_completion *res = req->data;
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if (err == -EINPROGRESS)
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return;
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res->err = err;
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complete(&res->completion);
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}
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static int ahash_wait(int err, struct ahash_completion *res)
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{
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switch (err) {
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case 0:
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break;
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case -EINPROGRESS:
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case -EBUSY:
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wait_for_completion(&res->completion);
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reinit_completion(&res->completion);
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err = res->err;
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/* fall through */
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default:
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pr_crit_ratelimited("ahash calculation failed: err: %d\n", err);
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}
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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, read = 0, 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 ahash_completion res;
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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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init_completion(&res.completion);
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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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ahash_complete, &res);
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rc = ahash_wait(crypto_ahash_init(req), &res);
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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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if (!(file->f_mode & FMODE_READ)) {
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file->f_mode |= FMODE_READ;
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read = 1;
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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, &res);
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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 = ima_kernel_read(file, offset, rbuf[active], rbuf_len);
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if (rc != rbuf_len)
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goto out3;
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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, &res);
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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, &res);
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out3:
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if (read)
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file->f_mode &= ~FMODE_READ;
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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), &res);
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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, read = 0;
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SHASH_DESC_ON_STACK(shash, tfm);
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shash->tfm = tfm;
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shash->flags = 0;
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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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if (!(file->f_mode & FMODE_READ)) {
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file->f_mode |= FMODE_READ;
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read = 1;
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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 = ima_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)
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break;
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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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if (read)
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file->f_mode &= ~FMODE_READ;
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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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rc = ima_calc_file_hash_tfm(file, hash, tfm);
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ima_free_tfm(tfm);
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return rc;
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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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i_size = i_size_read(file_inode(file));
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if (ima_ahash_minsize && i_size >= ima_ahash_minsize) {
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rc = ima_calc_file_ahash(file, hash);
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if (!rc)
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return 0;
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}
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return ima_calc_file_shash(file, hash);
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}
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/*
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* Calculate the hash of template data
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*/
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static int ima_calc_field_array_hash_tfm(struct ima_field_data *field_data,
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struct ima_template_desc *td,
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int num_fields,
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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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SHASH_DESC_ON_STACK(shash, tfm);
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int rc, i;
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shash->tfm = tfm;
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shash->flags = 0;
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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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for (i = 0; i < num_fields; i++) {
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u8 buffer[IMA_EVENT_NAME_LEN_MAX + 1] = { 0 };
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u8 *data_to_hash = field_data[i].data;
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u32 datalen = field_data[i].len;
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if (strcmp(td->name, IMA_TEMPLATE_IMA_NAME) != 0) {
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rc = crypto_shash_update(shash,
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(const u8 *) &field_data[i].len,
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sizeof(field_data[i].len));
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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;
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
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");
|
|
}
|
|
|
|
/*
|
|
* 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;
|
|
}
|
|
|
|
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;
|
|
}
|