* grub-core/commands/verify.c: Save verified file to avoid it being

tampered with after verification was done.
This commit is contained in:
Vladimir 'phcoder' Serbinenko 2013-04-03 17:32:33 +02:00
parent db8ff59f61
commit 1a78d573c7
3 changed files with 88 additions and 17 deletions

View file

@ -1,3 +1,8 @@
2013-04-03 Vladimir Serbinenko <phcoder@gmail.com>
* grub-core/commands/verify.c: Save verified file to avoid it being
tampered with after verification was done.
2013-04-03 Vladimir Serbinenko <phcoder@gmail.com>
* grub-core/term/i386/pc/console.c (grub_console_getwh): Decrease

View file

@ -1,6 +1,6 @@
/*
* GRUB -- GRand Unified Bootloader
* Copyright (C) 2011 Free Software Foundation, Inc.
* Copyright (C) 2013 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
@ -338,9 +338,10 @@ grub_crypto_pk_locate_subkey_in_trustdb (grub_uint64_t keyid)
return 0;
}
grub_err_t
grub_verify_signature (grub_file_t f, grub_file_t sig,
struct grub_public_key *pkey)
static grub_err_t
grub_verify_signature_real (char *buf, grub_size_t size,
grub_file_t f, grub_file_t sig,
struct grub_public_key *pkey)
{
grub_size_t len;
grub_uint8_t v;
@ -404,16 +405,19 @@ grub_verify_signature (grub_file_t f, grub_file_t sig,
grub_memset (context, 0, sizeof (context));
hash->init (context);
while (1)
{
grub_uint8_t readbuf[4096];
r = grub_file_read (f, readbuf, sizeof (readbuf));
if (r < 0)
return grub_errno;
if (r == 0)
break;
hash->write (context, readbuf, r);
}
if (buf)
hash->write (context, buf, size);
else
while (1)
{
grub_uint8_t readbuf[4096];
r = grub_file_read (f, readbuf, sizeof (readbuf));
if (r < 0)
return grub_errno;
if (r == 0)
break;
hash->write (context, readbuf, r);
}
hash->write (context, &v, sizeof (v));
hash->write (context, &v4, sizeof (v4));
@ -532,6 +536,13 @@ grub_verify_signature (grub_file_t f, grub_file_t sig,
return GRUB_ERR_NONE;
}
grub_err_t
grub_verify_signature (grub_file_t f, grub_file_t sig,
struct grub_public_key *pkey)
{
return grub_verify_signature_real (0, 0, f, sig, pkey);
}
static grub_err_t
grub_cmd_trust (grub_command_t cmd __attribute__ ((unused)),
int argc, char **args)
@ -665,6 +676,28 @@ grub_cmd_verify_signature (grub_command_t cmd __attribute__ ((unused)),
static int sec = 0;
static grub_ssize_t
verified_read (struct grub_file *file, char *buf, grub_size_t len)
{
grub_memcpy (buf, (char *) file->data + file->offset, len);
return len;
}
static grub_err_t
verified_close (struct grub_file *file)
{
grub_free (file->data);
file->data = 0;
return GRUB_ERR_NONE;
}
struct grub_fs verified_fs =
{
.name = "verified_read",
.read = verified_read,
.close = verified_close
};
static grub_file_t
grub_pubkey_open (grub_file_t io, const char *filename)
{
@ -672,9 +705,12 @@ grub_pubkey_open (grub_file_t io, const char *filename)
char *fsuf, *ptr;
grub_err_t err;
grub_file_filter_t curfilt[GRUB_FILE_FILTER_MAX];
grub_file_t ret;
if (!sec)
return io;
if (io->device->disk && io->device->disk->id == GRUB_DISK_DEVICE_MEMDISK_ID)
return io;
fsuf = grub_malloc (grub_strlen (filename) + sizeof (".sig"));
if (!fsuf)
return NULL;
@ -691,12 +727,40 @@ grub_pubkey_open (grub_file_t io, const char *filename)
if (!sig)
return NULL;
err = grub_verify_signature (io, sig, NULL);
ret = grub_malloc (sizeof (*ret));
if (!ret)
return NULL;
*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,
"big file signature isn't implemented yet");
return NULL;
}
ret->data = grub_malloc (ret->size);
if (!ret->data)
{
grub_free (ret);
return NULL;
}
if (grub_file_read (io, ret->data, ret->size) != (grub_ssize_t) ret->size)
{
if (!grub_errno)
grub_error (GRUB_ERR_FILE_READ_ERROR, N_("premature end of file %s"),
filename);
return NULL;
}
err = grub_verify_signature_real (ret->data, ret->size, 0, sig, NULL);
grub_file_close (sig);
if (err)
return NULL;
grub_file_seek (io, 0);
return io;
io->device = 0;
grub_file_close (io);
return ret;
}
static char *

View file

@ -481,4 +481,6 @@ void EXPORT_FUNC(grub_real_boot_time) (const char *file,
#define grub_max(a, b) (((a) > (b)) ? (a) : (b))
#define grub_min(a, b) (((a) < (b)) ? (a) : (b))
#define GRUB_CHAR_BIT 8
#endif /* ! GRUB_MISC_HEADER */