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-rw-r--r--certs/Kconfig9
-rw-r--r--certs/system_keyring.c139
2 files changed, 122 insertions, 26 deletions
diff --git a/certs/Kconfig b/certs/Kconfig
index f0f8a4433685..fc5955f5fc8a 100644
--- a/certs/Kconfig
+++ b/certs/Kconfig
@@ -17,6 +17,7 @@ config MODULE_SIG_KEY
config SYSTEM_TRUSTED_KEYRING
bool "Provide system-wide ring of trusted keys"
depends on KEYS
+ depends on ASYMMETRIC_KEY_TYPE
help
Provide a system keyring to which trusted keys can be added. Keys in
the keyring are considered to be trusted. Keys may be added at will
@@ -55,4 +56,12 @@ config SYSTEM_EXTRA_CERTIFICATE_SIZE
This is the number of bytes reserved in the kernel image for a
certificate to be inserted.
+config SECONDARY_TRUSTED_KEYRING
+ bool "Provide a keyring to which extra trustable keys may be added"
+ depends on SYSTEM_TRUSTED_KEYRING
+ help
+ If set, provide a keyring to which extra keys may be added, provided
+ those keys are not blacklisted and are vouched for by a key built
+ into the kernel or already in the secondary trusted keyring.
+
endmenu
diff --git a/certs/system_keyring.c b/certs/system_keyring.c
index f4180326c2e1..50979d6dcecd 100644
--- a/certs/system_keyring.c
+++ b/certs/system_keyring.c
@@ -18,29 +18,88 @@
#include <keys/system_keyring.h>
#include <crypto/pkcs7.h>
-struct key *system_trusted_keyring;
-EXPORT_SYMBOL_GPL(system_trusted_keyring);
+static struct key *builtin_trusted_keys;
+#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
+static struct key *secondary_trusted_keys;
+#endif
extern __initconst const u8 system_certificate_list[];
extern __initconst const unsigned long system_certificate_list_size;
+/**
+ * restrict_link_to_builtin_trusted - Restrict keyring addition by built in CA
+ *
+ * Restrict the addition of keys into a keyring based on the key-to-be-added
+ * being vouched for by a key in the built in system keyring.
+ */
+int restrict_link_by_builtin_trusted(struct key *keyring,
+ const struct key_type *type,
+ const union key_payload *payload)
+{
+ return restrict_link_by_signature(builtin_trusted_keys, type, payload);
+}
+
+#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
+/**
+ * restrict_link_by_builtin_and_secondary_trusted - Restrict keyring
+ * addition by both builtin and secondary keyrings
+ *
+ * Restrict the addition of keys into a keyring based on the key-to-be-added
+ * being vouched for by a key in either the built-in or the secondary system
+ * keyrings.
+ */
+int restrict_link_by_builtin_and_secondary_trusted(
+ struct key *keyring,
+ const struct key_type *type,
+ const union key_payload *payload)
+{
+ /* If we have a secondary trusted keyring, then that contains a link
+ * through to the builtin keyring and the search will follow that link.
+ */
+ if (type == &key_type_keyring &&
+ keyring == secondary_trusted_keys &&
+ payload == &builtin_trusted_keys->payload)
+ /* Allow the builtin keyring to be added to the secondary */
+ return 0;
+
+ return restrict_link_by_signature(secondary_trusted_keys, type, payload);
+}
+#endif
+
/*
- * Load the compiled-in keys
+ * Create the trusted keyrings
*/
static __init int system_trusted_keyring_init(void)
{
- pr_notice("Initialise system trusted keyring\n");
+ pr_notice("Initialise system trusted keyrings\n");
- system_trusted_keyring =
- keyring_alloc(".system_keyring",
+ builtin_trusted_keys =
+ keyring_alloc(".builtin_trusted_keys",
KUIDT_INIT(0), KGIDT_INIT(0), current_cred(),
((KEY_POS_ALL & ~KEY_POS_SETATTR) |
KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH),
- KEY_ALLOC_NOT_IN_QUOTA, NULL);
- if (IS_ERR(system_trusted_keyring))
- panic("Can't allocate system trusted keyring\n");
+ KEY_ALLOC_NOT_IN_QUOTA,
+ NULL, NULL);
+ if (IS_ERR(builtin_trusted_keys))
+ panic("Can't allocate builtin trusted keyring\n");
+
+#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
+ secondary_trusted_keys =
+ keyring_alloc(".secondary_trusted_keys",
+ KUIDT_INIT(0), KGIDT_INIT(0), current_cred(),
+ ((KEY_POS_ALL & ~KEY_POS_SETATTR) |
+ KEY_USR_VIEW | KEY_USR_READ | KEY_USR_SEARCH |
+ KEY_USR_WRITE),
+ KEY_ALLOC_NOT_IN_QUOTA,
+ restrict_link_by_builtin_and_secondary_trusted,
+ NULL);
+ if (IS_ERR(secondary_trusted_keys))
+ panic("Can't allocate secondary trusted keyring\n");
+
+ if (key_link(secondary_trusted_keys, builtin_trusted_keys) < 0)
+ panic("Can't link trusted keyrings\n");
+#endif
- set_bit(KEY_FLAG_TRUSTED_ONLY, &system_trusted_keyring->flags);
return 0;
}
@@ -76,7 +135,7 @@ static __init int load_system_certificate_list(void)
if (plen > end - p)
goto dodgy_cert;
- key = key_create_or_update(make_key_ref(system_trusted_keyring, 1),
+ key = key_create_or_update(make_key_ref(builtin_trusted_keys, 1),
"asymmetric",
NULL,
p,
@@ -84,8 +143,8 @@ static __init int load_system_certificate_list(void)
((KEY_POS_ALL & ~KEY_POS_SETATTR) |
KEY_USR_VIEW | KEY_USR_READ),
KEY_ALLOC_NOT_IN_QUOTA |
- KEY_ALLOC_TRUSTED |
- KEY_ALLOC_BUILT_IN);
+ KEY_ALLOC_BUILT_IN |
+ KEY_ALLOC_BYPASS_RESTRICTION);
if (IS_ERR(key)) {
pr_err("Problem loading in-kernel X.509 certificate (%ld)\n",
PTR_ERR(key));
@@ -108,19 +167,27 @@ late_initcall(load_system_certificate_list);
#ifdef CONFIG_SYSTEM_DATA_VERIFICATION
/**
- * Verify a PKCS#7-based signature on system data.
- * @data: The data to be verified.
+ * verify_pkcs7_signature - Verify a PKCS#7-based signature on system data.
+ * @data: The data to be verified (NULL if expecting internal data).
* @len: Size of @data.
* @raw_pkcs7: The PKCS#7 message that is the signature.
* @pkcs7_len: The size of @raw_pkcs7.
+ * @trusted_keys: Trusted keys to use (NULL for builtin trusted keys only,
+ * (void *)1UL for all trusted keys).
* @usage: The use to which the key is being put.
+ * @view_content: Callback to gain access to content.
+ * @ctx: Context for callback.
*/
-int system_verify_data(const void *data, unsigned long len,
- const void *raw_pkcs7, size_t pkcs7_len,
- enum key_being_used_for usage)
+int verify_pkcs7_signature(const void *data, size_t len,
+ const void *raw_pkcs7, size_t pkcs7_len,
+ struct key *trusted_keys,
+ enum key_being_used_for usage,
+ int (*view_content)(void *ctx,
+ const void *data, size_t len,
+ size_t asn1hdrlen),
+ void *ctx)
{
struct pkcs7_message *pkcs7;
- bool trusted;
int ret;
pkcs7 = pkcs7_parse_message(raw_pkcs7, pkcs7_len);
@@ -128,7 +195,7 @@ int system_verify_data(const void *data, unsigned long len,
return PTR_ERR(pkcs7);
/* The data should be detached - so we need to supply it. */
- if (pkcs7_supply_detached_data(pkcs7, data, len) < 0) {
+ if (data && pkcs7_supply_detached_data(pkcs7, data, len) < 0) {
pr_err("PKCS#7 signature with non-detached data\n");
ret = -EBADMSG;
goto error;
@@ -138,13 +205,33 @@ int system_verify_data(const void *data, unsigned long len,
if (ret < 0)
goto error;
- ret = pkcs7_validate_trust(pkcs7, system_trusted_keyring, &trusted);
- if (ret < 0)
+ if (!trusted_keys) {
+ trusted_keys = builtin_trusted_keys;
+ } else if (trusted_keys == (void *)1UL) {
+#ifdef CONFIG_SECONDARY_TRUSTED_KEYRING
+ trusted_keys = secondary_trusted_keys;
+#else
+ trusted_keys = builtin_trusted_keys;
+#endif
+ }
+ ret = pkcs7_validate_trust(pkcs7, trusted_keys);
+ if (ret < 0) {
+ if (ret == -ENOKEY)
+ pr_err("PKCS#7 signature not signed with a trusted key\n");
goto error;
+ }
+
+ if (view_content) {
+ size_t asn1hdrlen;
+
+ ret = pkcs7_get_content_data(pkcs7, &data, &len, &asn1hdrlen);
+ if (ret < 0) {
+ if (ret == -ENODATA)
+ pr_devel("PKCS#7 message does not contain data\n");
+ goto error;
+ }
- if (!trusted) {
- pr_err("PKCS#7 signature not signed with a trusted key\n");
- ret = -ENOKEY;
+ ret = view_content(ctx, data, len, asn1hdrlen);
}
error:
@@ -152,6 +239,6 @@ error:
pr_devel("<==%s() = %d\n", __func__, ret);
return ret;
}
-EXPORT_SYMBOL_GPL(system_verify_data);
+EXPORT_SYMBOL_GPL(verify_pkcs7_signature);
#endif /* CONFIG_SYSTEM_DATA_VERIFICATION */
generated by cgit v1.2.3-58-ga151 (git 2.39.0) at 2024-12-30 18:48:54 +0000