linux-stable/security/integrity/ima/ima_crypto.c
Linus Torvalds d895cb1af1 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull vfs pile (part one) from Al Viro:
 "Assorted stuff - cleaning namei.c up a bit, fixing ->d_name/->d_parent
  locking violations, etc.

  The most visible changes here are death of FS_REVAL_DOT (replaced with
  "has ->d_weak_revalidate()") and a new helper getting from struct file
  to inode.  Some bits of preparation to xattr method interface changes.

  Misc patches by various people sent this cycle *and* ocfs2 fixes from
  several cycles ago that should've been upstream right then.

  PS: the next vfs pile will be xattr stuff."

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs: (46 commits)
  saner proc_get_inode() calling conventions
  proc: avoid extra pde_put() in proc_fill_super()
  fs: change return values from -EACCES to -EPERM
  fs/exec.c: make bprm_mm_init() static
  ocfs2/dlm: use GFP_ATOMIC inside a spin_lock
  ocfs2: fix possible use-after-free with AIO
  ocfs2: Fix oops in ocfs2_fast_symlink_readpage() code path
  get_empty_filp()/alloc_file() leave both ->f_pos and ->f_version zero
  target: writev() on single-element vector is pointless
  export kernel_write(), convert open-coded instances
  fs: encode_fh: return FILEID_INVALID if invalid fid_type
  kill f_vfsmnt
  vfs: kill FS_REVAL_DOT by adding a d_weak_revalidate dentry op
  nfsd: handle vfs_getattr errors in acl protocol
  switch vfs_getattr() to struct path
  default SET_PERSONALITY() in linux/elf.h
  ceph: prepopulate inodes only when request is aborted
  d_hash_and_lookup(): export, switch open-coded instances
  9p: switch v9fs_set_create_acl() to inode+fid, do it before d_instantiate()
  9p: split dropping the acls from v9fs_set_create_acl()
  ...
2013-02-26 20:16:07 -08:00

148 lines
3 KiB
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
*/
#include <linux/kernel.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"
static struct crypto_shash *ima_shash_tfm;
int ima_init_crypto(void)
{
long rc;
ima_shash_tfm = crypto_alloc_shash(ima_hash, 0, 0);
if (IS_ERR(ima_shash_tfm)) {
rc = PTR_ERR(ima_shash_tfm);
pr_err("Can not allocate %s (reason: %ld)\n", ima_hash, rc);
return rc;
}
return 0;
}
/*
* Calculate the MD5/SHA1 file digest
*/
int ima_calc_file_hash(struct file *file, char *digest)
{
loff_t i_size, offset = 0;
char *rbuf;
int rc, read = 0;
struct {
struct shash_desc shash;
char ctx[crypto_shash_descsize(ima_shash_tfm)];
} desc;
desc.shash.tfm = ima_shash_tfm;
desc.shash.flags = 0;
rc = crypto_shash_init(&desc.shash);
if (rc != 0)
return rc;
rbuf = kzalloc(PAGE_SIZE, GFP_KERNEL);
if (!rbuf) {
rc = -ENOMEM;
goto out;
}
if (!(file->f_mode & FMODE_READ)) {
file->f_mode |= FMODE_READ;
read = 1;
}
i_size = i_size_read(file_inode(file));
while (offset < i_size) {
int rbuf_len;
rbuf_len = 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(&desc.shash, rbuf, rbuf_len);
if (rc)
break;
}
kfree(rbuf);
if (!rc)
rc = crypto_shash_final(&desc.shash, digest);
if (read)
file->f_mode &= ~FMODE_READ;
out:
return rc;
}
/*
* Calculate the hash of a given buffer
*/
int ima_calc_buffer_hash(const void *data, int len, char *digest)
{
struct {
struct shash_desc shash;
char ctx[crypto_shash_descsize(ima_shash_tfm)];
} desc;
desc.shash.tfm = ima_shash_tfm;
desc.shash.flags = 0;
return crypto_shash_digest(&desc.shash, data, len, digest);
}
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("IMA: Error Communicating to TPM chip\n");
}
/*
* Calculate the boot aggregate hash
*/
int __init ima_calc_boot_aggregate(char *digest)
{
u8 pcr_i[IMA_DIGEST_SIZE];
int rc, i;
struct {
struct shash_desc shash;
char ctx[crypto_shash_descsize(ima_shash_tfm)];
} desc;
desc.shash.tfm = ima_shash_tfm;
desc.shash.flags = 0;
rc = crypto_shash_init(&desc.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(&desc.shash, pcr_i, IMA_DIGEST_SIZE);
}
if (!rc)
crypto_shash_final(&desc.shash, digest);
return rc;
}