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Message-Id: <20200406221439.1469862-11-deven.desai@linux.microsoft.com>
Date: Mon, 6 Apr 2020 15:14:37 -0700
From: deven.desai@...ux.microsoft.com
To: agk@...hat.com, axboe@...nel.dk, snitzer@...hat.com,
jmorris@...ei.org, serge@...lyn.com, zohar@...ux.ibm.com,
linux-integrity@...r.kernel.org,
linux-security-module@...r.kernel.org, dm-devel@...hat.com,
linux-block@...r.kernel.org
Cc: tyhicks@...ux.microsoft.com, pasha.tatashin@...een.com,
sashal@...nel.org, jaskarankhurana@...ux.microsoft.com,
nramas@...ux.microsoft.com, mdsakib@...ux.microsoft.com,
linux-kernel@...r.kernel.org
Subject: [RFC PATCH v2 10/12] ipe: add property for dmverity roothash
From: Deven Bowers <deven.desai@...ux.microsoft.com>
Add a property to allow IPE policy to express rules around a specific
root-hash of a dm-verity volume.
This can be used for revocation, (when combined with the previous dm-verity
property) or the authorization of a single dm-verity volume.
Signed-off-by: Deven Bowers <deven.desai@...ux.microsoft.com>
---
security/ipe/ipe-blobs.c | 10 ++
security/ipe/ipe-engine.h | 3 +
security/ipe/ipe.c | 4 +
security/ipe/properties/Kconfig | 13 +-
security/ipe/properties/Makefile | 1 +
security/ipe/properties/dmverity-roothash.c | 155 ++++++++++++++++++++
security/ipe/properties/prop-entry.h | 9 ++
7 files changed, 194 insertions(+), 1 deletion(-)
create mode 100644 security/ipe/properties/dmverity-roothash.c
diff --git a/security/ipe/ipe-blobs.c b/security/ipe/ipe-blobs.c
index a4ee8df02855..1e054eb13857 100644
--- a/security/ipe/ipe-blobs.c
+++ b/security/ipe/ipe-blobs.c
@@ -45,6 +45,8 @@ void ipe_bdev_free_security(struct block_device *bdev)
{
struct ipe_bdev_blob *bdev_sec = ipe_bdev(bdev);
+ kfree(bdev_sec->dmverity_rh);
+
memset(bdev_sec, 0x0, sizeof(*bdev_sec));
}
@@ -76,5 +78,13 @@ int ipe_bdev_setsecurity(struct block_device *bdev, const char *key,
bdev_sec->dmv_rh_sig_len = len;
}
+ if (!strcmp(key, DM_VERITY_ROOTHASH_SEC_NAME)) {
+ bdev_sec->dmverity_rh = kmemdup(value, len, GFP_KERNEL);
+ if (!bdev_sec->dmverity_rh)
+ return -ENOMEM;
+
+ bdev_sec->rh_size = len;
+ }
+
return 0;
}
diff --git a/security/ipe/ipe-engine.h b/security/ipe/ipe-engine.h
index be17115861cb..d8cdb3cc7af8 100644
--- a/security/ipe/ipe-engine.h
+++ b/security/ipe/ipe-engine.h
@@ -18,6 +18,9 @@
struct ipe_bdev_blob {
u8 *dmverity_rh_sig;
size_t dmv_rh_sig_len;
+
+ u8 *dmverity_rh;
+ size_t rh_size;
};
struct ipe_engine_ctx {
diff --git a/security/ipe/ipe.c b/security/ipe/ipe.c
index 924f535c3d32..b398eafa6049 100644
--- a/security/ipe/ipe.c
+++ b/security/ipe/ipe.c
@@ -49,6 +49,10 @@ static int __init ipe_load_properties(void)
if (rc != 0)
return rc;
+ rc = ipe_init_dm_verity_rh();
+ if (rc != 0)
+ return rc;
+
return rc;
}
diff --git a/security/ipe/properties/Kconfig b/security/ipe/properties/Kconfig
index 2d8866ee456e..57b97b2b3877 100644
--- a/security/ipe/properties/Kconfig
+++ b/security/ipe/properties/Kconfig
@@ -13,8 +13,19 @@ config IPE_BOOT_PROP
if unsure, answer N.
+config IPE_DM_VERITY_ROOTHASH
+ bool "Enable property for authorizing dm-verity volumes via root-hash"
+ depends on DM_VERITY
+ help
+ This option enables IPE's integration with Device-Mapper Verity.
+ This enables the usage of the property "dmverity_roothash" in IPE's
+ policy. This property allows authorization or revocation via a
+ a hex-string representing the roothash of a dmverity volume.
+
+ if unsure, answer Y.
+
config IPE_DM_VERITY_SIGNATURE
- bool "Enable property for signature verified dm-verity volumes"
+ bool "Enable property for verified dm-verity volumes"
depends on DM_VERITY_VERIFY_ROOTHASH_SIG
help
This option enables IPE's integration with Device-Mapper Verity's
diff --git a/security/ipe/properties/Makefile b/security/ipe/properties/Makefile
index 6b67cbe36e31..d9a3807797f4 100644
--- a/security/ipe/properties/Makefile
+++ b/security/ipe/properties/Makefile
@@ -10,3 +10,4 @@ obj-$(CONFIG_SECURITY_IPE) += properties.o
properties-$(CONFIG_IPE_BOOT_PROP) += boot-verified.o
properties-$(CONFIG_IPE_DM_VERITY_SIGNATURE) += dmverity-signature.o
+properties-$(CONFIG_IPE_DM_VERITY_ROOTHASH) += dmverity-roothash.o
diff --git a/security/ipe/properties/dmverity-roothash.c b/security/ipe/properties/dmverity-roothash.c
new file mode 100644
index 000000000000..5c575fc275bc
--- /dev/null
+++ b/security/ipe/properties/dmverity-roothash.c
@@ -0,0 +1,155 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) Microsoft Corporation. All rights reserved.
+ */
+
+#include "../ipe.h"
+#include "../ipe-pin.h"
+#include "../ipe-property.h"
+#include "../utility.h"
+
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/fs.h>
+#include <linux/mount.h>
+#include <linux/audit.h>
+#include <linux/kernel.h>
+
+#define PROPERTY_NAME "dmverity_roothash"
+
+struct counted_array {
+ u8 *arr;
+ size_t len;
+};
+
+static void audit(struct audit_buffer *ab, const void *value)
+{
+ const struct counted_array *a = (const struct counted_array *)value;
+
+ if (!a || a->len == 0)
+ audit_log_format(ab, "NULL");
+ else
+ audit_log_n_hex(ab, a->arr, a->len);
+}
+
+static inline void audit_rule_value(struct audit_buffer *ab,
+ const void *value)
+{
+ audit(ab, value);
+}
+
+static inline void audit_ctx(struct audit_buffer *ab,
+ const struct ipe_engine_ctx *ctx,
+ const void *storage)
+{
+ struct counted_array a;
+
+ if (!has_bdev(ctx->file))
+ return audit(ab, NULL);
+
+ a.arr = ctx->sec_bdev->dmverity_rh;
+ a.len = ctx->sec_bdev->rh_size;
+
+ return audit(ab, &a);
+}
+
+static bool evaluate(const struct ipe_engine_ctx *ctx,
+ const void *value, void **storage)
+{
+ const struct counted_array *a = (const struct counted_array *)value;
+
+ if (!has_bdev(ctx->file))
+ return false;
+
+ if (a->len != ctx->sec_bdev->rh_size)
+ return false;
+
+ return memcmp(a->arr, ctx->sec_bdev->dmverity_rh, a->len) == 0;
+}
+
+static int parse(const char *val_str, void **value)
+{
+ struct counted_array *arr = NULL;
+ int rv = 0;
+
+ arr = kzalloc(sizeof(*arr), GFP_KERNEL);
+ if (!arr) {
+ rv = -ENOMEM;
+ goto err;
+ }
+
+ arr->len = strlen(val_str) / 2;
+
+ arr->arr = kzalloc(arr->len, GFP_KERNEL);
+ if (!arr->arr) {
+ rv = -ENOMEM;
+ goto err;
+ }
+
+ rv = hex2bin(arr->arr, val_str, arr->len);
+ if (rv != 0)
+ goto err;
+
+ *value = arr;
+ return rv;
+err:
+ if (arr)
+ kfree(arr->arr);
+ kfree(arr);
+ return rv;
+}
+
+static int duplicate(const void *src, void **dest)
+{
+ struct counted_array *arr = NULL;
+ const struct counted_array *src_arr = src;
+ int rv = 0;
+
+ arr = kmemdup(src_arr, sizeof(*arr), GFP_KERNEL);
+ if (!arr) {
+ rv = -ENOMEM;
+ goto err;
+ }
+
+ arr->arr = kmemdup(src_arr->arr, src_arr->len, GFP_KERNEL);
+ if (!arr->arr) {
+ rv = -ENOMEM;
+ goto err;
+ }
+
+ *dest = arr;
+ return rv;
+err:
+ if (arr)
+ kfree(arr->arr);
+ kfree(arr);
+
+ return rv;
+}
+
+static void free_val(void **value)
+{
+ struct counted_array *a = (struct counted_array *)*value;
+
+ if (a)
+ kfree(a->arr);
+ kfree(a);
+ *value = NULL;
+}
+
+static const struct ipe_property dmv_roothash = {
+ .property_name = PROPERTY_NAME,
+ .eval = evaluate,
+ .parse = parse,
+ .rule_audit = audit_rule_value,
+ .ctx_audit = audit_ctx,
+ .dup = duplicate,
+ .free_val = free_val,
+ .prealloc = NULL,
+ .free_storage = NULL,
+};
+
+int ipe_init_dm_verity_rh(void)
+{
+ return ipe_register_property(&dmv_roothash);
+}
diff --git a/security/ipe/properties/prop-entry.h b/security/ipe/properties/prop-entry.h
index 85366366ff0d..86a360570f3b 100644
--- a/security/ipe/properties/prop-entry.h
+++ b/security/ipe/properties/prop-entry.h
@@ -26,4 +26,13 @@ static inline int __init ipe_init_dm_verity_signature(void)
int __init ipe_init_dm_verity_signature(void);
#endif /* CONFIG_IPE_DM_VERITY_SIGNATURE */
+#ifndef CONFIG_IPE_DM_VERITY_ROOTHASH
+static inline int __init ipe_init_dm_verity_rh(void)
+{
+ return 0;
+}
+#else
+int __init ipe_init_dm_verity_rh(void);
+#endif /* CONFIG_IPE_DM_VERITY_ROOTHASH */
+
#endif /* IPE_PROP_ENTRY_H */
--
2.26.0
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