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grub/grub-core/commands/verify.c
Vladimir Serbinenko 37ba761b1c commands/verify: Fix sha1 context zeroing-out. 
Current code doesn't zero-out context completely. It's a minor issue
really as sha1 init already takes care of initing the context.
2015-01-24 21:27:10 +01:00

1036 lines
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/*
* GRUB -- GRand Unified Bootloader
* 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
* 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/>.
*/
#include <grub/types.h>
#include <grub/misc.h>
#include <grub/mm.h>
#include <grub/err.h>
#include <grub/dl.h>
#include <grub/file.h>
#include <grub/command.h>
#include <grub/crypto.h>
#include <grub/i18n.h>
#include <grub/gcrypt/gcrypt.h>
#include <grub/pubkey.h>
#include <grub/env.h>
#include <grub/kernel.h>
#include <grub/extcmd.h>
GRUB_MOD_LICENSE ("GPLv3+");
struct grub_verified
{
grub_file_t file;
void *buf;
};
typedef struct grub_verified *grub_verified_t;
enum
{
OPTION_SKIP_SIG = 0
};
static const struct grub_arg_option options[] =
{
{"skip-sig", 's', 0,
N_("Skip signature-checking of the public key file."), 0, ARG_TYPE_NONE},
{0, 0, 0, 0, 0, 0}
};
static grub_err_t
read_packet_header (grub_file_t sig, grub_uint8_t *out_type, grub_size_t *len)
{
grub_uint8_t type;
grub_uint8_t l;
grub_uint16_t l16;
grub_uint32_t l32;
/* New format. */
switch (grub_file_read (sig, &type, sizeof (type)))
{
case 1:
break;
case 0:
{
*out_type = 0xff;
return 0;
}
default:
if (grub_errno)
return grub_errno;
/* TRANSLATORS: it's about GNUPG signatures. */
return grub_error (GRUB_ERR_BAD_SIGNATURE, N_("bad signature"));
}
if (type == 0)
{
*out_type = 0xfe;
return 0;
}
if (!(type & 0x80))
return grub_error (GRUB_ERR_BAD_SIGNATURE, N_("bad signature"));
if (type & 0x40)
{
*out_type = (type & 0x3f);
if (grub_file_read (sig, &l, sizeof (l)) != 1)
return grub_error (GRUB_ERR_BAD_SIGNATURE, N_("bad signature"));
if (l < 192)
{
*len = l;
return 0;
}
if (l < 224)
{
*len = (l - 192) << GRUB_CHAR_BIT;
if (grub_file_read (sig, &l, sizeof (l)) != 1)
return grub_error (GRUB_ERR_BAD_SIGNATURE, N_("bad signature"));
*len |= l;
return 0;
}
if (l == 255)
{
if (grub_file_read (sig, &l32, sizeof (l32)) != sizeof (l32))
return grub_error (GRUB_ERR_BAD_SIGNATURE, N_("bad signature"));
*len = grub_be_to_cpu32 (l32);
return 0;
}
return grub_error (GRUB_ERR_BAD_SIGNATURE, N_("bad signature"));
}
*out_type = ((type >> 2) & 0xf);
switch (type & 0x3)
{
case 0:
if (grub_file_read (sig, &l, sizeof (l)) != sizeof (l))
return grub_error (GRUB_ERR_BAD_SIGNATURE, N_("bad signature"));
*len = l;
return 0;
case 1:
if (grub_file_read (sig, &l16, sizeof (l16)) != sizeof (l16))
return grub_error (GRUB_ERR_BAD_SIGNATURE, N_("bad signature"));
*len = grub_be_to_cpu16 (l16);
return 0;
case 2:
if (grub_file_read (sig, &l32, sizeof (l32)) != sizeof (l32))
return grub_error (GRUB_ERR_BAD_SIGNATURE, N_("bad signature"));
*len = grub_be_to_cpu32 (l32);
return 0;
}
return grub_error (GRUB_ERR_BAD_SIGNATURE, N_("bad signature"));
}
struct signature_v4_header
{
grub_uint8_t type;
grub_uint8_t pkeyalgo;
grub_uint8_t hash;
grub_uint16_t hashed_sub;
} GRUB_PACKED;
const char *hashes[] = {
[0x01] = "md5",
[0x02] = "sha1",
[0x03] = "ripemd160",
[0x08] = "sha256",
[0x09] = "sha384",
[0x0a] = "sha512",
[0x0b] = "sha224"
};
struct gcry_pk_spec *grub_crypto_pk_dsa;
struct gcry_pk_spec *grub_crypto_pk_ecdsa;
struct gcry_pk_spec *grub_crypto_pk_rsa;
static int
dsa_pad (gcry_mpi_t *hmpi, grub_uint8_t *hval,
const gcry_md_spec_t *hash, struct grub_public_subkey *sk);
static int
rsa_pad (gcry_mpi_t *hmpi, grub_uint8_t *hval,
const gcry_md_spec_t *hash, struct grub_public_subkey *sk);
struct
{
const char *name;
grub_size_t nmpisig;
grub_size_t nmpipub;
struct gcry_pk_spec **algo;
int (*pad) (gcry_mpi_t *hmpi, grub_uint8_t *hval,
const gcry_md_spec_t *hash, struct grub_public_subkey *sk);
const char *module;
} pkalgos[] =
{
[1] = { "rsa", 1, 2, &grub_crypto_pk_rsa, rsa_pad, "gcry_rsa" },
[3] = { "rsa", 1, 2, &grub_crypto_pk_rsa, rsa_pad, "gcry_rsa" },
[17] = { "dsa", 2, 4, &grub_crypto_pk_dsa, dsa_pad, "gcry_dsa" },
};
struct grub_public_key
{
struct grub_public_key *next;
struct grub_public_subkey *subkeys;
};
struct grub_public_subkey
{
struct grub_public_subkey *next;
grub_uint8_t type;
grub_uint32_t fingerprint[5];
gcry_mpi_t mpis[10];
};
static void
free_pk (struct grub_public_key *pk)
{
struct grub_public_subkey *nsk, *sk;
for (sk = pk->subkeys; sk; sk = nsk)
{
grub_size_t i;
for (i = 0; i < ARRAY_SIZE (sk->mpis); i++)
if (sk->mpis[i])
gcry_mpi_release (sk->mpis[i]);
nsk = sk->next;
grub_free (sk);
}
grub_free (pk);
}
#define READBUF_SIZE 4096
struct grub_public_key *
grub_load_public_key (grub_file_t f)
{
grub_err_t err;
struct grub_public_key *ret;
struct grub_public_subkey **last = 0;
void *fingerprint_context = NULL;
grub_uint8_t *buffer = NULL;
ret = grub_zalloc (sizeof (*ret));
if (!ret)
{
grub_free (fingerprint_context);
return NULL;
}
buffer = grub_zalloc (READBUF_SIZE);
fingerprint_context = grub_zalloc (GRUB_MD_SHA1->contextsize);
if (!buffer || !fingerprint_context)
goto fail;
last = &ret->subkeys;
while (1)
{
grub_uint8_t type;
grub_size_t len;
grub_uint8_t v, pk;
grub_uint32_t creation_time;
grub_off_t pend;
struct grub_public_subkey *sk;
grub_size_t i;
grub_uint16_t len_be;
err = read_packet_header (f, &type, &len);
if (err)
goto fail;
if (type == 0xfe)
continue;
if (type == 0xff)
{
grub_free (fingerprint_context);
grub_free (buffer);
return ret;
}
grub_dprintf ("crypt", "len = %x\n", (int) len);
pend = grub_file_tell (f) + len;
if (type != 6 && type != 14
&& type != 5 && type != 7)
{
grub_file_seek (f, pend);
continue;
}
if (grub_file_read (f, &v, sizeof (v)) != sizeof (v))
{
grub_error (GRUB_ERR_BAD_SIGNATURE, N_("bad signature"));
goto fail;
}
grub_dprintf ("crypt", "v = %x\n", v);
if (v != 4)
{
grub_error (GRUB_ERR_BAD_SIGNATURE, N_("bad signature"));
goto fail;
}
if (grub_file_read (f, &creation_time, sizeof (creation_time)) != sizeof (creation_time))
{
grub_error (GRUB_ERR_BAD_SIGNATURE, N_("bad signature"));
goto fail;
}
grub_dprintf ("crypt", "time = %x\n", creation_time);
if (grub_file_read (f, &pk, sizeof (pk)) != sizeof (pk))
{
grub_error (GRUB_ERR_BAD_SIGNATURE, N_("bad signature"));
goto fail;
}
grub_dprintf ("crypt", "pk = %x\n", pk);
if (pk >= ARRAY_SIZE (pkalgos) || pkalgos[pk].name == NULL)
{
grub_file_seek (f, pend);
continue;
}
sk = grub_zalloc (sizeof (struct grub_public_subkey));
if (!sk)
goto fail;
grub_memset (fingerprint_context, 0, GRUB_MD_SHA1->contextsize);
GRUB_MD_SHA1->init (fingerprint_context);
GRUB_MD_SHA1->write (fingerprint_context, "\x99", 1);
len_be = grub_cpu_to_be16 (len);
GRUB_MD_SHA1->write (fingerprint_context, &len_be, sizeof (len_be));
GRUB_MD_SHA1->write (fingerprint_context, &v, sizeof (v));
GRUB_MD_SHA1->write (fingerprint_context, &creation_time, sizeof (creation_time));
GRUB_MD_SHA1->write (fingerprint_context, &pk, sizeof (pk));
for (i = 0; i < pkalgos[pk].nmpipub; i++)
{
grub_uint16_t l;
grub_size_t lb;
if (grub_file_read (f, &l, sizeof (l)) != sizeof (l))
{
grub_error (GRUB_ERR_BAD_SIGNATURE, N_("bad signature"));
goto fail;
}
lb = (grub_be_to_cpu16 (l) + GRUB_CHAR_BIT - 1) / GRUB_CHAR_BIT;
if (lb > READBUF_SIZE - sizeof (grub_uint16_t))
{
grub_error (GRUB_ERR_BAD_SIGNATURE, N_("bad signature"));
goto fail;
}
if (grub_file_read (f, buffer + sizeof (grub_uint16_t), lb) != (grub_ssize_t) lb)
{
grub_error (GRUB_ERR_BAD_SIGNATURE, N_("bad signature"));
goto fail;
}
grub_memcpy (buffer, &l, sizeof (l));
GRUB_MD_SHA1->write (fingerprint_context, buffer, lb + sizeof (grub_uint16_t));
if (gcry_mpi_scan (&sk->mpis[i], GCRYMPI_FMT_PGP,
buffer, lb + sizeof (grub_uint16_t), 0))
{
grub_error (GRUB_ERR_BAD_SIGNATURE, N_("bad signature"));
goto fail;
}
}
GRUB_MD_SHA1->final (fingerprint_context);
grub_memcpy (sk->fingerprint, GRUB_MD_SHA1->read (fingerprint_context), 20);
*last = sk;
last = &sk->next;
grub_dprintf ("crypt", "actual pos: %x, expected: %x\n", (int)grub_file_tell (f), (int)pend);
grub_file_seek (f, pend);
}
fail:
free_pk (ret);
grub_free (fingerprint_context);
grub_free (buffer);
return NULL;
}
struct grub_public_key *grub_pk_trusted;
struct grub_public_subkey *
grub_crypto_pk_locate_subkey (grub_uint64_t keyid, struct grub_public_key *pkey)
{
struct grub_public_subkey *sk;
for (sk = pkey->subkeys; sk; sk = sk->next)
if (grub_memcmp (sk->fingerprint + 3, &keyid, 8) == 0)
return sk;
return 0;
}
struct grub_public_subkey *
grub_crypto_pk_locate_subkey_in_trustdb (grub_uint64_t keyid)
{
struct grub_public_key *pkey;
struct grub_public_subkey *sk;
for (pkey = grub_pk_trusted; pkey; pkey = pkey->next)
{
sk = grub_crypto_pk_locate_subkey (keyid, pkey);
if (sk)
return sk;
}
return 0;
}
static int
dsa_pad (gcry_mpi_t *hmpi, grub_uint8_t *hval,
const gcry_md_spec_t *hash, struct grub_public_subkey *sk)
{
unsigned nbits = gcry_mpi_get_nbits (sk->mpis[1]);
grub_dprintf ("crypt", "must be %u bits got %d bits\n", nbits,
(int)(8 * hash->mdlen));
return gcry_mpi_scan (hmpi, GCRYMPI_FMT_USG, hval,
nbits / 8 < (unsigned) hash->mdlen ? nbits / 8
: (unsigned) hash->mdlen, 0);
}
static int
rsa_pad (gcry_mpi_t *hmpi, grub_uint8_t *hval,
const gcry_md_spec_t *hash, struct grub_public_subkey *sk)
{
grub_size_t tlen, emlen, fflen;
grub_uint8_t *em, *emptr;
unsigned nbits = gcry_mpi_get_nbits (sk->mpis[0]);
int ret;
tlen = hash->mdlen + hash->asnlen;
emlen = (nbits + 7) / 8;
if (emlen < tlen + 11)
return 1;
em = grub_malloc (emlen);
if (!em)
return 1;
em[0] = 0x00;
em[1] = 0x01;
fflen = emlen - tlen - 3;
for (emptr = em + 2; emptr < em + 2 + fflen; emptr++)
*emptr = 0xff;
*emptr++ = 0x00;
grub_memcpy (emptr, hash->asnoid, hash->asnlen);
emptr += hash->asnlen;
grub_memcpy (emptr, hval, hash->mdlen);
ret = gcry_mpi_scan (hmpi, GCRYMPI_FMT_USG, em, emlen, 0);
grub_free (em);
return ret;
}
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;
grub_uint8_t h;
grub_uint8_t t;
grub_uint8_t pk;
const gcry_md_spec_t *hash;
struct signature_v4_header v4;
grub_err_t err;
grub_size_t i;
gcry_mpi_t mpis[10];
grub_uint8_t type;
err = read_packet_header (sig, &type, &len);
if (err)
return err;
if (type != 0x2)
return grub_error (GRUB_ERR_BAD_SIGNATURE, N_("bad signature"));
if (grub_file_read (sig, &v, sizeof (v)) != sizeof (v))
return grub_error (GRUB_ERR_BAD_SIGNATURE, N_("bad signature"));
if (v != 4)
return grub_error (GRUB_ERR_BAD_SIGNATURE, N_("bad signature"));
if (grub_file_read (sig, &v4, sizeof (v4)) != sizeof (v4))
return grub_error (GRUB_ERR_BAD_SIGNATURE, N_("bad signature"));
h = v4.hash;
t = v4.type;
pk = v4.pkeyalgo;
if (t != 0)
return grub_error (GRUB_ERR_BAD_SIGNATURE, N_("bad signature"));
if (h >= ARRAY_SIZE (hashes) || hashes[h] == NULL)
return grub_error (GRUB_ERR_BAD_SIGNATURE, "unknown hash");
if (pk >= ARRAY_SIZE (pkalgos) || pkalgos[pk].name == NULL)
return grub_error (GRUB_ERR_BAD_SIGNATURE, N_("bad signature"));
hash = grub_crypto_lookup_md_by_name (hashes[h]);
if (!hash)
return grub_error (GRUB_ERR_BAD_SIGNATURE, "hash `%s' not loaded", hashes[h]);
grub_dprintf ("crypt", "alive\n");
{
void *context = NULL;
unsigned char *hval;
grub_ssize_t rem = grub_be_to_cpu16 (v4.hashed_sub);
grub_uint32_t headlen = grub_cpu_to_be32 (rem + 6);
grub_uint8_t s;
grub_uint16_t unhashed_sub;
grub_ssize_t r;
grub_uint8_t hash_start[2];
gcry_mpi_t hmpi;
grub_uint64_t keyid = 0;
struct grub_public_subkey *sk;
grub_uint8_t *readbuf = NULL;
context = grub_zalloc (hash->contextsize);
readbuf = grub_zalloc (READBUF_SIZE);
if (!context || !readbuf)
goto fail;
hash->init (context);
if (buf)
hash->write (context, buf, size);
else
while (1)
{
r = grub_file_read (f, readbuf, READBUF_SIZE);
if (r < 0)
goto fail;
if (r == 0)
break;
hash->write (context, readbuf, r);
}
hash->write (context, &v, sizeof (v));
hash->write (context, &v4, sizeof (v4));
while (rem)
{
r = grub_file_read (sig, readbuf,
rem < READBUF_SIZE ? rem : READBUF_SIZE);
if (r < 0)
goto fail;
if (r == 0)
break;
hash->write (context, readbuf, r);
rem -= r;
}
hash->write (context, &v, sizeof (v));
s = 0xff;
hash->write (context, &s, sizeof (s));
hash->write (context, &headlen, sizeof (headlen));
r = grub_file_read (sig, &unhashed_sub, sizeof (unhashed_sub));
if (r != sizeof (unhashed_sub))
goto fail;
{
grub_uint8_t *ptr;
grub_uint32_t l;
rem = grub_be_to_cpu16 (unhashed_sub);
if (rem > READBUF_SIZE)
goto fail;
r = grub_file_read (sig, readbuf, rem);
if (r != rem)
goto fail;
for (ptr = readbuf; ptr < readbuf + rem; ptr += l)
{
if (*ptr < 192)
l = *ptr++;
else if (*ptr < 255)
{
if (ptr + 1 >= readbuf + rem)
break;
l = (((ptr[0] & ~192) << GRUB_CHAR_BIT) | ptr[1]) + 192;
ptr += 2;
}
else
{
if (ptr + 5 >= readbuf + rem)
break;
l = grub_be_to_cpu32 (grub_get_unaligned32 (ptr + 1));
ptr += 5;
}
if (*ptr == 0x10 && l >= 8)
keyid = grub_get_unaligned64 (ptr + 1);
}
}
hash->final (context);
grub_dprintf ("crypt", "alive\n");
hval = hash->read (context);
if (grub_file_read (sig, hash_start, sizeof (hash_start)) != sizeof (hash_start))
goto fail;
if (grub_memcmp (hval, hash_start, sizeof (hash_start)) != 0)
goto fail;
grub_dprintf ("crypt", "@ %x\n", (int)grub_file_tell (sig));
for (i = 0; i < pkalgos[pk].nmpisig; i++)
{
grub_uint16_t l;
grub_size_t lb;
grub_dprintf ("crypt", "alive\n");
if (grub_file_read (sig, &l, sizeof (l)) != sizeof (l))
goto fail;
grub_dprintf ("crypt", "alive\n");
lb = (grub_be_to_cpu16 (l) + 7) / 8;
grub_dprintf ("crypt", "l = 0x%04x\n", grub_be_to_cpu16 (l));
if (lb > READBUF_SIZE - sizeof (grub_uint16_t))
goto fail;
grub_dprintf ("crypt", "alive\n");
if (grub_file_read (sig, readbuf + sizeof (grub_uint16_t), lb) != (grub_ssize_t) lb)
goto fail;
grub_dprintf ("crypt", "alive\n");
grub_memcpy (readbuf, &l, sizeof (l));
grub_dprintf ("crypt", "alive\n");
if (gcry_mpi_scan (&mpis[i], GCRYMPI_FMT_PGP,
readbuf, lb + sizeof (grub_uint16_t), 0))
goto fail;
grub_dprintf ("crypt", "alive\n");
}
if (pkey)
sk = grub_crypto_pk_locate_subkey (keyid, pkey);
else
sk = grub_crypto_pk_locate_subkey_in_trustdb (keyid);
if (!sk)
{
/* TRANSLATORS: %08x is 32-bit key id. */
grub_error (GRUB_ERR_BAD_SIGNATURE, N_("public key %08x not found"),
keyid);
goto fail;
}
if (pkalgos[pk].pad (&hmpi, hval, hash, sk))
goto fail;
if (!*pkalgos[pk].algo)
{
grub_dl_load (pkalgos[pk].module);
grub_errno = GRUB_ERR_NONE;
}
if (!*pkalgos[pk].algo)
{
grub_error (GRUB_ERR_BAD_SIGNATURE, N_("module `%s' isn't loaded"),
pkalgos[pk].module);
goto fail;
}
if ((*pkalgos[pk].algo)->verify (0, hmpi, mpis, sk->mpis, 0, 0))
goto fail;
grub_free (context);
grub_free (readbuf);
return GRUB_ERR_NONE;
fail:
grub_free (context);
grub_free (readbuf);
if (!grub_errno)
return grub_error (GRUB_ERR_BAD_SIGNATURE, N_("bad signature"));
return grub_errno;
}
}
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_extcmd_context_t ctxt,
int argc, char **args)
{
grub_file_t pkf;
struct grub_public_key *pk = NULL;
if (argc < 1)
return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("one argument expected"));
grub_file_filter_disable_compression ();
if (ctxt->state[OPTION_SKIP_SIG].set)
grub_file_filter_disable_pubkey ();
pkf = grub_file_open (args[0]);
if (!pkf)
return grub_errno;
pk = grub_load_public_key (pkf);
if (!pk)
{
grub_file_close (pkf);
return grub_errno;
}
grub_file_close (pkf);
pk->next = grub_pk_trusted;
grub_pk_trusted = pk;
return GRUB_ERR_NONE;
}
static grub_err_t
grub_cmd_list (grub_command_t cmd __attribute__ ((unused)),
int argc __attribute__ ((unused)),
char **args __attribute__ ((unused)))
{
struct grub_public_key *pk = NULL;
struct grub_public_subkey *sk = NULL;
for (pk = grub_pk_trusted; pk; pk = pk->next)
for (sk = pk->subkeys; sk; sk = sk->next)
{
unsigned i;
for (i = 0; i < 20; i += 2)
grub_printf ("%02x%02x ", ((grub_uint8_t *) sk->fingerprint)[i],
((grub_uint8_t *) sk->fingerprint)[i + 1]);
grub_printf ("\n");
}
return GRUB_ERR_NONE;
}
static grub_err_t
grub_cmd_distrust (grub_command_t cmd __attribute__ ((unused)),
int argc, char **args)
{
grub_uint32_t keyid, keyid_be;
struct grub_public_key **pkey;
struct grub_public_subkey *sk;
if (argc < 1)
return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("one argument expected"));
keyid = grub_strtoull (args[0], 0, 16);
if (grub_errno)
return grub_errno;
keyid_be = grub_cpu_to_be32 (keyid);
for (pkey = &grub_pk_trusted; *pkey; pkey = &((*pkey)->next))
{
struct grub_public_key *next;
for (sk = (*pkey)->subkeys; sk; sk = sk->next)
if (grub_memcmp (sk->fingerprint + 4, &keyid_be, 4) == 0)
break;
if (!sk)
continue;
next = (*pkey)->next;
free_pk (*pkey);
*pkey = next;
return GRUB_ERR_NONE;
}
/* TRANSLATORS: %08x is 32-bit key id. */
return grub_error (GRUB_ERR_BAD_SIGNATURE, N_("public key %08x not found"), keyid);
}
static grub_err_t
grub_cmd_verify_signature (grub_extcmd_context_t ctxt,
int argc, char **args)
{
grub_file_t f = NULL, sig = NULL;
grub_err_t err = GRUB_ERR_NONE;
struct grub_public_key *pk = NULL;
grub_dprintf ("crypt", "alive\n");
if (argc < 2)
return grub_error (GRUB_ERR_BAD_ARGUMENT, N_("two arguments expected"));
grub_dprintf ("crypt", "alive\n");
if (argc > 2)
{
grub_file_t pkf;
grub_file_filter_disable_compression ();
if (ctxt->state[OPTION_SKIP_SIG].set)
grub_file_filter_disable_pubkey ();
pkf = grub_file_open (args[2]);
if (!pkf)
return grub_errno;
pk = grub_load_public_key (pkf);
if (!pk)
{
grub_file_close (pkf);
return grub_errno;
}
grub_file_close (pkf);
}
grub_file_filter_disable_all ();
f = grub_file_open (args[0]);
if (!f)
{
err = grub_errno;
goto fail;
}
grub_file_filter_disable_all ();
sig = grub_file_open (args[1]);
if (!sig)
{
err = grub_errno;
goto fail;
}
err = grub_verify_signature (f, sig, pk);
fail:
if (sig)
grub_file_close (sig);
if (f)
grub_file_close (f);
if (pk)
free_pk (pk);
return err;
}
static int sec = 0;
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",
.read = verified_read,
.close = verified_close
};
static grub_file_t
grub_pubkey_open (grub_file_t io, const char *filename)
{
grub_file_t sig;
char *fsuf, *ptr;
grub_err_t err;
grub_file_filter_t curfilt[GRUB_FILE_FILTER_MAX];
grub_file_t ret;
grub_verified_t verified;
if (!sec)
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;
fsuf = grub_malloc (grub_strlen (filename) + sizeof (".sig"));
if (!fsuf)
return NULL;
ptr = grub_stpcpy (fsuf, filename);
grub_memcpy (ptr, ".sig", sizeof (".sig"));
grub_memcpy (curfilt, grub_file_filters_enabled,
sizeof (curfilt));
grub_file_filter_disable_all ();
sig = grub_file_open (fsuf);
grub_memcpy (grub_file_filters_enabled, curfilt,
sizeof (curfilt));
grub_free (fsuf);
if (!sig)
return NULL;
ret = grub_malloc (sizeof (*ret));
if (!ret)
{
grub_file_close (sig);
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");
grub_file_close (sig);
grub_free (ret);
return NULL;
}
verified = grub_malloc (sizeof (*verified));
if (!verified)
{
grub_file_close (sig);
grub_free (ret);
return NULL;
}
verified->buf = grub_malloc (ret->size);
if (!verified->buf)
{
grub_file_close (sig);
grub_free (verified);
grub_free (ret);
return NULL;
}
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"),
filename);
grub_file_close (sig);
verified_free (verified);
grub_free (ret);
return NULL;
}
err = grub_verify_signature_real (verified->buf, ret->size, 0, sig, NULL);
grub_file_close (sig);
if (err)
{
verified_free (verified);
grub_free (ret);
return NULL;
}
verified->file = io;
ret->data = verified;
return ret;
}
static char *
grub_env_write_sec (struct grub_env_var *var __attribute__ ((unused)),
const char *val)
{
sec = (*val == '1') || (*val == 'e');
return grub_strdup (sec ? "enforce" : "no");
}
static grub_ssize_t
pseudo_read (struct grub_file *file, char *buf, grub_size_t len)
{
grub_memcpy (buf, (grub_uint8_t *) file->data + file->offset, len);
return len;
}
/* Filesystem descriptor. */
struct grub_fs pseudo_fs =
{
.name = "pseudo",
.read = pseudo_read
};
static grub_extcmd_t cmd, cmd_trust;
static grub_command_t cmd_distrust, cmd_list;
GRUB_MOD_INIT(verify)
{
const char *val;
struct grub_module_header *header;
val = grub_env_get ("check_signatures");
if (val && (val[0] == '1' || val[0] == 'e'))
sec = 1;
else
sec = 0;
grub_file_filter_register (GRUB_FILE_FILTER_PUBKEY, grub_pubkey_open);
grub_register_variable_hook ("check_signatures", 0, grub_env_write_sec);
grub_env_export ("check_signatures");
grub_pk_trusted = 0;
FOR_MODULES (header)
{
struct grub_file pseudo_file;
struct grub_public_key *pk = NULL;
grub_memset (&pseudo_file, 0, sizeof (pseudo_file));
/* Not an ELF module, skip. */
if (header->type != OBJ_TYPE_PUBKEY)
continue;
pseudo_file.fs = &pseudo_fs;
pseudo_file.size = (header->size - sizeof (struct grub_module_header));
pseudo_file.data = (char *) header + sizeof (struct grub_module_header);
pk = grub_load_public_key (&pseudo_file);
if (!pk)
grub_fatal ("error loading initial key: %s\n", grub_errmsg);
pk->next = grub_pk_trusted;
grub_pk_trusted = pk;
}
if (!val)
grub_env_set ("check_signatures", grub_pk_trusted ? "enforce" : "no");
cmd = grub_register_extcmd ("verify_detached", grub_cmd_verify_signature, 0,
N_("[-s|--skip-sig] FILE SIGNATURE_FILE [PUBKEY_FILE]"),
N_("Verify detached signature."),
options);
cmd_trust = grub_register_extcmd ("trust", grub_cmd_trust, 0,
N_("[-s|--skip-sig] PUBKEY_FILE"),
N_("Add PUBKEY_FILE to trusted keys."),
options);
cmd_list = grub_register_command ("list_trusted", grub_cmd_list,
0,
N_("Show the list of trusted keys."));
cmd_distrust = grub_register_command ("distrust", grub_cmd_distrust,
N_("PUBKEY_ID"),
N_("Remove PUBKEY_ID from trusted keys."));
}
GRUB_MOD_FINI(verify)
{
grub_file_filter_unregister (GRUB_FILE_FILTER_PUBKEY);
grub_unregister_extcmd (cmd);
grub_unregister_extcmd (cmd_trust);
grub_unregister_command (cmd_list);
grub_unregister_command (cmd_distrust);
}
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