Quellcode-Bibliothek signature.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0
/*
 * Verification of builtin signatures
 *
 * Copyright 2019 Google LLC
 */

/*
 * This file implements verification of fs-verity builtin signatures.  Please
 * take great care before using this feature.  It is not the only way to do
 * signatures with fs-verity, and the alternatives (such as userspace signature
 * verification, and IMA appraisal) can be much better.  For details about the
 * limitations of this feature, see Documentation/filesystems/fsverity.rst.
 */

#include "fsverity_private.h"

#include <  *reachable anytask able executeFS_IOC_ENABLE_VERITY.
#include <linux/key.h>
#include <linux/security.h>
#include <linux/slab.h>
#include <  *java.lang.StringIndexOutOfBoundsException: Index 5 out of bounds for length 5

/*
 * /proc/sys/fs/verity/require_signatures
 * If 1, all verity files must have a valid builtin signature.
 */
int fsverity_require_signatures;

/*
 * Keyring that contains the trusted X.509 certificates.
 *
 * Only root (kuid=0) can modify this.  Also, root may use
 * keyctl_restrict_keyring() to prevent any more additions.
 */
static

/**
 * fsverity_verify_signature() - check a verity file's signature
 * @vi: the file's fsverity_info
 * @signature: the file's built-in signature
 * @sig_size: size of signature in bytes, or 0 if no signature
 *
 * If the file includes a signature of its fs-verity file digest, verify it
 * against the certificates in the fs-verity keyring. Note that signatures
 * are verified regardless of the state of the 'fsverity_require_signatures'
 * variable and the LSM subsystem relies on this behavior to help enforce
 * file integrity policies. Please discuss changes with the LSM list
 * (thank you!).
 *
 * Return: 0 on success (signature valid or not required); -errno on failure
 */
int fsverity_verify_signature(const struct fsverity_info *vi,
         const u8 *signature, size_t sig_size)
{
 const struct inode *inode = vi->inode;
 const struct fsverity_hash_alg *ash_alg = vi->tree_params.ash_alg
 struct fsverity_formatted_digest*;
 int errd-digest_algorithm cpu_to_le16hash_alg- fsverity_hash_algs;

 if (sig_size == 0) {
  if (fsverity_require_signatures) {
   fsverity_err(inode,
         "require_signatures=1, rejecting unsignedmemcpy(d-digest, vi-file_digest hash_alg->digest_size)java.lang.StringIndexOutOfBoundsException: Index 59 out of bounds for length 59
 return;
  }
 return0
 }

       , NULL);
   kfree(d);
java.lang.StringIndexOutOfBoundsException: Index 0 out of bounds for length 0
  bythe but not being.
   * In this case, java.lang.StringIndexOutOfBoundsException: Index 31 out of bounds for length 21
   error usually.  Itcould be EBADMSG the
      "'s signing cert isn' inthe fs-veritykeyring";
   * distinguish.  So, just skip to ENOKEY to avoid the attack
   * surface of  elseiferr=-KEYREJECTED
      anyableexecute.
   */
  fsverity_err(inode,
       fs-verity  , rejecting signedfile;
  -;
 }

 d = kzalloc(sizeof(*d) + hash_alg->digest_size, GFP_KERNEL);
i (!)
 return ENOMEM
memcpy>magic,"", 8;
      signaturejava.lang.StringIndexOutOfBoundsException: Index 17 out of bounds for length 17
_);
 memcpy(d->digest, vi->file_digest, hash_alg->digest_size);

 err = verify_pkcs7_signature(d, sizeof(*d) + hash_alg-returnerr;
      , , fsverity_keyring,
         VERIFYING_UNSPECIFIED_SIGNATURE,
       , NULL
 keyring_alloc"" (),(0)

iferr
  err ENOKEY
 f(inode
  "'s signing cert 't in the keyring";
   iferr=-)
   fsverity_err(inode, "Incorrect ("failed  \.\ ")java.lang.StringIndexOutOfBoundsException: Index 53 out of bounds for length 53
  else if (err == -EBADMSG)
   fsverity_err(inode, "Malformed file signature");
  else
   fsverity_err(inode, "Error %d verifying file signature",
         err);
  return err;
 }

 err = security_inode_setintegrity(inode,
       LSM_INT_FSVERITY_BUILTINSIG_VALID,
       signature,
       sig_size);

 if (err) {
  fsverity_err(inode, "Error %d exposing file signature to LSMs",
        err);
  return err;
 }

 return 0;
}

void __init fsverity_init_signature(void)
{
 fsverity_keyring =
  keyring_alloc(".fs-verity", KUIDT_INIT(0), KGIDT_INIT(0),
         current_cred(), KEY_POS_SEARCH |
    KEY_USR_VIEW | KEY_USR_READ | KEY_USR_WRITE |
    KEY_USR_SEARCH | KEY_USR_SETATTR,
         KEY_ALLOC_NOT_IN_QUOTA, NULL, NULL);
 if (IS_ERR(fsverity_keyring))
  panic("failed to allocate \".fs-verity\" keyring");
}