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Support activation options for error handling modes in dm-verity.

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This patch adds veritysetup support for these Linux kernel dm-verity options:

  --ignore-corruption - dm-verity just logs detected corruption
  --restart-on-corruption - dm-verity restarts the kernel if corruption is detected

  If the options above are not specified, default behaviour for dm-verity remains.
  Default is that I/O operation fails with I/O error if corrupted block is detected.

  --ignore-zero-blocks - Instructs dm-verity to not verify blocks that are expected
   to contain zeroes and always return zeroes directly instead.

NOTE that these options could have serious security or functional impacts,
do not use them without assessing the risks!
This commit is contained in:
Milan Broz
2016-05-04 10:07:47 +02:00
parent 99a254f2f6
commit 4dd703ea6c
7 changed files with 181 additions and 24 deletions
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86
lib/libdevmapper.c
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@@ -3,8 +3,8 @@
*
* Copyright (C) 2004, Jana Saout <jana@saout.de>
* Copyright (C) 2004-2007, Clemens Fruhwirth <clemens@endorphin.org>
* Copyright (C) 2009-2015, Red Hat, Inc. All rights reserved.
* Copyright (C) 2009-2015, Milan Broz
* Copyright (C) 2009-2016, Red Hat, Inc. All rights reserved.
* Copyright (C) 2009-2016, Milan Broz
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License
@@ -159,6 +159,15 @@ static void _dm_set_verity_compat(const char *dm_version, unsigned verity_maj,
{
if (verity_maj > 0)
_dm_crypt_flags |= DM_VERITY_SUPPORTED;
else
return;
/*
* ignore_corruption, restart_on corruption is available since 1.2 (kernel 4.1)
* ignore_zero_blocks since 1.3 (kernel 4.5)
* (but some dm-verity targets 1.2 don't support it)
*/
if (_dm_satisfies_version(1, 3, verity_maj, verity_min))
_dm_crypt_flags |= DM_VERITY_ON_CORRUPTION_SUPPORTED;
log_dbg("Detected dm-verity version %i.%i.%i.",
verity_maj, verity_min, verity_patch);
@@ -357,14 +366,35 @@ out:
/* https://gitlab.com/cryptsetup/cryptsetup/wikis/DMVerity */
static char *get_dm_verity_params(struct crypt_params_verity *vp,
struct crypt_dm_active_device *dmd)
struct crypt_dm_active_device *dmd, uint32_t flags)
{
int max_size, r;
int max_size, r, num_options = 0;
char *params = NULL, *hexroot = NULL, *hexsalt = NULL;
char features[256];
if (!vp || !dmd)
return NULL;
/* These flags are not compatible */
if ((flags & CRYPT_ACTIVATE_IGNORE_CORRUPTION) &&
(flags & CRYPT_ACTIVATE_RESTART_ON_CORRUPTION))
flags &= ~CRYPT_ACTIVATE_IGNORE_CORRUPTION;
if (flags & CRYPT_ACTIVATE_IGNORE_CORRUPTION)
num_options++;
if (flags & CRYPT_ACTIVATE_RESTART_ON_CORRUPTION)
num_options++;
if (flags & CRYPT_ACTIVATE_IGNORE_ZERO_BLOCKS)
num_options++;
if (num_options)
snprintf(features, sizeof(features)-1, " %d%s%s%s", num_options,
(flags & CRYPT_ACTIVATE_IGNORE_CORRUPTION) ? " ignore_corruption" : "",
(flags & CRYPT_ACTIVATE_RESTART_ON_CORRUPTION) ? " restart_on_corruption" : "",
(flags & CRYPT_ACTIVATE_IGNORE_ZERO_BLOCKS) ? " ignore_zero_blocks" : "");
else
*features = '\0';
hexroot = crypt_safe_alloc(dmd->u.verity.root_hash_size * 2 + 1);
if (!hexroot)
goto out;
@@ -388,12 +418,12 @@ static char *get_dm_verity_params(struct crypt_params_verity *vp,
goto out;
r = snprintf(params, max_size,
"%u %s %s %u %u %" PRIu64 " %" PRIu64 " %s %s %s",
"%u %s %s %u %u %" PRIu64 " %" PRIu64 " %s %s %s %s",
vp->hash_type, device_block_path(dmd->data_device),
device_block_path(dmd->u.verity.hash_device),
vp->data_block_size, vp->hash_block_size,
vp->data_size, dmd->u.verity.hash_offset,
vp->hash_name, hexroot, hexsalt);
vp->hash_name, hexroot, hexsalt, features);
if (r < 0 || r >= max_size) {
crypt_safe_free(params);
params = NULL;
@@ -676,7 +706,7 @@ int dm_create_device(struct crypt_device *cd, const char *name,
if (dmd->target == DM_CRYPT)
table_params = get_dm_crypt_params(dmd, dmd_flags);
else if (dmd->target == DM_VERITY)
table_params = get_dm_verity_params(dmd->u.verity.vp, dmd);
table_params = get_dm_verity_params(dmd->u.verity.vp, dmd, dmd_flags);
r = _dm_create_device(name, type, dmd->data_device, dmd_flags,
dmd->uuid, dmd->size, table_params, reload);
@@ -696,7 +726,13 @@ int dm_create_device(struct crypt_device *cd, const char *name,
if (r == -EINVAL &&
dmd_flags & (CRYPT_ACTIVATE_SAME_CPU_CRYPT|CRYPT_ACTIVATE_SUBMIT_FROM_CRYPT_CPUS) &&
!(dm_flags() & (DM_SAME_CPU_CRYPT_SUPPORTED|DM_SUBMIT_FROM_CRYPT_CPUS_SUPPORTED)))
log_err(cd, _("Requested dmcrypt performance options are not supported.\n"));
log_err(cd, _("Requested dm-crypt performance options are not supported.\n"));
if (r == -EINVAL && dmd_flags & (CRYPT_ACTIVATE_IGNORE_CORRUPTION|
CRYPT_ACTIVATE_RESTART_ON_CORRUPTION|
CRYPT_ACTIVATE_IGNORE_ZERO_BLOCKS) &&
!(dm_flags() & DM_VERITY_ON_CORRUPTION_SUPPORTED))
log_err(cd, _("Requested dm-verity data corruption handling options are not supported.\n"));
crypt_safe_free(table_params);
dm_exit_context();
@@ -893,7 +929,7 @@ static int _dm_query_crypt(uint32_t get_flags,
return -EINVAL;
}
/* All parameters shold be processed */
/* All parameters should be processed */
if (params)
return -EINVAL;
}
@@ -936,7 +972,8 @@ static int _dm_query_verity(uint32_t get_flags,
uint32_t val32;
uint64_t val64;
ssize_t len;
char *str, *str2;
char *str, *str2, *arg;
unsigned int i;
int r;
if (get_flags & DM_ACTIVE_VERITY_PARAMS)
@@ -1032,8 +1069,6 @@ static int _dm_query_verity(uint32_t get_flags,
/* salt */
str = strsep(&params, " ");
if (params)
return -EINVAL;
if (vp) {
if (!strcmp(str, "-")) {
vp->salt_size = 0;
@@ -1047,6 +1082,33 @@ static int _dm_query_verity(uint32_t get_flags,
}
}
/* Features section, available since verity target version 1.3 */
if (params) {
/* Number of arguments */
val64 = strtoull(params, &params, 10);
if (*params != ' ')
return -EINVAL;
params++;
for (i = 0; i < val64; i++) {
if (!params)
return -EINVAL;
arg = strsep(&params, " ");
if (!strcasecmp(arg, "ignore_corruption"))
dmd->flags |= CRYPT_ACTIVATE_IGNORE_CORRUPTION;
else if (!strcasecmp(arg, "restart_on_corruption"))
dmd->flags |= CRYPT_ACTIVATE_RESTART_ON_CORRUPTION;
else if (!strcasecmp(arg, "ignore_zero_blocks"))
dmd->flags |= CRYPT_ACTIVATE_IGNORE_ZERO_BLOCKS;
else /* unknown option */
return -EINVAL;
}
/* All parameters should be processed */
if (params)
return -EINVAL;
}
return 0;
}