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/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2017 Free Software Foundation, Inc.
*
* GRUB 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, either version 3 of the License, or
* (at your option) any later version.
*
* GRUB is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License
* along with GRUB. If not, see <http://www.gnu.org/licenses/>.
*
* Verifiers helper.
*/
#include <grub/file.h>
#include <grub/verify.h>
#include <grub/dl.h>
GRUB_MOD_LICENSE ("GPLv3+");
struct grub_file_verifier *grub_file_verifiers;
struct grub_verified
{
grub_file_t file;
void *buf;
};
typedef struct grub_verified *grub_verified_t;
static void
verified_free (grub_verified_t verified)
{
if (verified)
{
grub_free (verified->buf);
grub_free (verified);
}
}
static grub_ssize_t
verified_read (struct grub_file *file, char *buf, grub_size_t len)
{
grub_verified_t verified = file->data;
grub_memcpy (buf, (char *) verified->buf + file->offset, len);
return len;
}
static grub_err_t
verified_close (struct grub_file *file)
{
grub_verified_t verified = file->data;
grub_file_close (verified->file);
verified_free (verified);
file->data = 0;
/* Device and name are freed by parent. */
file->device = 0;
file->name = 0;
return grub_errno;
}
struct grub_fs verified_fs =
{
.name = "verified_read",
.fs_read = verified_read,
.fs_close = verified_close
};
static grub_file_t
grub_verifiers_open (grub_file_t io, enum grub_file_type type)
{
grub_verified_t verified = NULL;
struct grub_file_verifier *ver;
void *context;
grub_file_t ret = 0;
grub_err_t err;
int defer = 0;
grub_dprintf ("verify", "file: %s type: %d\n", io->name, type);
if ((type & GRUB_FILE_TYPE_MASK) == GRUB_FILE_TYPE_SIGNATURE
|| (type & GRUB_FILE_TYPE_MASK) == GRUB_FILE_TYPE_VERIFY_SIGNATURE
|| (type & GRUB_FILE_TYPE_SKIP_SIGNATURE))
return io;
if (io->device->disk &&
(io->device->disk->dev->id == GRUB_DISK_DEVICE_MEMDISK_ID
|| io->device->disk->dev->id == GRUB_DISK_DEVICE_PROCFS_ID))
return io;
FOR_LIST_ELEMENTS(ver, grub_file_verifiers)
{
enum grub_verify_flags flags = 0;
err = ver->init (io, type, &context, &flags);
if (err)
goto fail_noclose;
if (flags & GRUB_VERIFY_FLAGS_DEFER_AUTH)
{
defer = 1;
continue;
}
if (!(flags & GRUB_VERIFY_FLAGS_SKIP_VERIFICATION))
break;
}
if (!ver)
{
if (defer)
{
grub_error (GRUB_ERR_ACCESS_DENIED,
N_("verification requested but nobody cares: %s"), io->name);
goto fail_noclose;
}
/* No verifiers wanted to verify. Just return underlying file. */
return io;
}
ret = grub_malloc (sizeof (*ret));
if (!ret)
{
goto fail;
}
*ret = *io;
ret->fs = &verified_fs;
ret->not_easily_seekable = 0;
if (ret->size >> (sizeof (grub_size_t) * GRUB_CHAR_BIT - 1))
{
grub_error (GRUB_ERR_NOT_IMPLEMENTED_YET,
N_("big file signature isn't implemented yet"));
goto fail;
}
verified = grub_malloc (sizeof (*verified));
if (!verified)
{
goto fail;
}
verified->buf = grub_malloc (ret->size);
if (!verified->buf)
{
goto fail;
}
if (grub_file_read (io, verified->buf, ret->size) != (grub_ssize_t) ret->size)
{
if (!grub_errno)
grub_error (GRUB_ERR_FILE_READ_ERROR, N_("premature end of file %s"),
io->name);
goto fail;
}
err = ver->write (context, verified->buf, ret->size);
if (err)
goto fail;
err = ver->fini ? ver->fini (context) : GRUB_ERR_NONE;
if (err)
goto fail;
if (ver->close)
ver->close (context);
FOR_LIST_ELEMENTS_NEXT(ver, grub_file_verifiers)
{
enum grub_verify_flags flags = 0;
err = ver->init (io, type, &context, &flags);
if (err)
goto fail_noclose;
if (flags & GRUB_VERIFY_FLAGS_SKIP_VERIFICATION ||
/* Verification done earlier. So, we are happy here. */
flags & GRUB_VERIFY_FLAGS_DEFER_AUTH)
continue;
err = ver->write (context, verified->buf, ret->size);
if (err)
goto fail;
err = ver->fini ? ver->fini (context) : GRUB_ERR_NONE;
if (err)
goto fail;
if (ver->close)
ver->close (context);
}
verified->file = io;
ret->data = verified;
return ret;
fail:
if (ver->close)
ver->close (context);
fail_noclose:
verified_free (verified);
grub_free (ret);
return NULL;
}
grub_err_t
grub_verify_string (char *str, enum grub_verify_string_type type)
{
struct grub_file_verifier *ver;
grub_dprintf ("verify", "string: %s, type: %d\n", str, type);
FOR_LIST_ELEMENTS(ver, grub_file_verifiers)
{
grub_err_t err;
err = ver->verify_string ? ver->verify_string (str, type) : GRUB_ERR_NONE;
if (err)
return err;
}
return GRUB_ERR_NONE;
}
void
grub_verifiers_init (void)
{
grub_file_filter_register (GRUB_FILE_FILTER_VERIFY, grub_verifiers_open);
}
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