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authorMickaël Salaün <mic@linux.microsoft.com>2021-07-12 20:03:12 +0300
committerJarkko Sakkinen <jarkko@kernel.org>2022-05-23 18:47:49 +0300
commit141e523914f72575915dd334fce3cef4fb0f1e91 (patch)
treea1fd9fd869d32125134630d3c3b88c6ae6223f81
parent58d416351e6df1a41d415958ccdd8eb9c2173fed (diff)
downloadlinux-141e523914f72575915dd334fce3cef4fb0f1e91.tar.xz
certs: Factor out the blacklist hash creation
Factor out the blacklist hash creation with the get_raw_hash() helper. This also centralize the "tbs" and "bin" prefixes and make them private, which help to manage them consistently. Cc: David Howells <dhowells@redhat.com> Cc: David S. Miller <davem@davemloft.net> Cc: David Woodhouse <dwmw2@infradead.org> Cc: Eric Snowberg <eric.snowberg@oracle.com> Cc: Herbert Xu <herbert@gondor.apana.org.au> Cc: Jarkko Sakkinen <jarkko@kernel.org> Signed-off-by: Mickaël Salaün <mic@linux.microsoft.com> Link: https://lore.kernel.org/r/20210712170313.884724-5-mic@digikod.net Signed-off-by: Jarkko Sakkinen <jarkko@kernel.org>
-rw-r--r--certs/blacklist.c76
-rw-r--r--crypto/asymmetric_keys/x509_public_key.c3
-rw-r--r--include/keys/system_keyring.h14
-rw-r--r--security/integrity/platform_certs/keyring_handler.c26
4 files changed, 73 insertions, 46 deletions
diff --git a/certs/blacklist.c b/certs/blacklist.c
index c9a435b15af4..1cdf309a5b08 100644
--- a/certs/blacklist.c
+++ b/certs/blacklist.c
@@ -83,11 +83,43 @@ static struct key_type key_type_blacklist = {
.describe = blacklist_describe,
};
+static char *get_raw_hash(const u8 *hash, size_t hash_len,
+ enum blacklist_hash_type hash_type)
+{
+ size_t type_len;
+ const char *type_prefix;
+ char *buffer, *p;
+
+ switch (hash_type) {
+ case BLACKLIST_HASH_X509_TBS:
+ type_len = sizeof(tbs_prefix) - 1;
+ type_prefix = tbs_prefix;
+ break;
+ case BLACKLIST_HASH_BINARY:
+ type_len = sizeof(bin_prefix) - 1;
+ type_prefix = bin_prefix;
+ break;
+ default:
+ WARN_ON_ONCE(1);
+ return ERR_PTR(-EINVAL);
+ }
+ buffer = kmalloc(type_len + 1 + hash_len * 2 + 1, GFP_KERNEL);
+ if (!buffer)
+ return ERR_PTR(-ENOMEM);
+ p = memcpy(buffer, type_prefix, type_len);
+ p += type_len;
+ *p++ = ':';
+ bin2hex(p, hash, hash_len);
+ p += hash_len * 2;
+ *p = '\0';
+ return buffer;
+}
+
/**
- * mark_hash_blacklisted - Add a hash to the system blacklist
+ * mark_raw_hash_blacklisted - Add a hash to the system blacklist
* @hash: The hash as a hex string with a type prefix (eg. "tbs:23aa429783")
*/
-int mark_hash_blacklisted(const char *hash)
+static int mark_raw_hash_blacklisted(const char *hash)
{
key_ref_t key;
@@ -107,29 +139,36 @@ int mark_hash_blacklisted(const char *hash)
return 0;
}
+int mark_hash_blacklisted(const u8 *hash, size_t hash_len,
+ enum blacklist_hash_type hash_type)
+{
+ const char *buffer;
+ int err;
+
+ buffer = get_raw_hash(hash, hash_len, hash_type);
+ if (IS_ERR(buffer))
+ return PTR_ERR(buffer);
+ err = mark_raw_hash_blacklisted(buffer);
+ kfree(buffer);
+ return err;
+}
+
/**
* is_hash_blacklisted - Determine if a hash is blacklisted
* @hash: The hash to be checked as a binary blob
* @hash_len: The length of the binary hash
- * @type: Type of hash
+ * @hash_type: Type of hash
*/
-int is_hash_blacklisted(const u8 *hash, size_t hash_len, const char *type)
+int is_hash_blacklisted(const u8 *hash, size_t hash_len,
+ enum blacklist_hash_type hash_type)
{
key_ref_t kref;
- size_t type_len = strlen(type);
- char *buffer, *p;
+ const char *buffer;
int ret = 0;
- buffer = kmalloc(type_len + 1 + hash_len * 2 + 1, GFP_KERNEL);
- if (!buffer)
- return -ENOMEM;
- p = memcpy(buffer, type, type_len);
- p += type_len;
- *p++ = ':';
- bin2hex(p, hash, hash_len);
- p += hash_len * 2;
- *p = 0;
-
+ buffer = get_raw_hash(hash, hash_len, hash_type);
+ if (IS_ERR(buffer))
+ return PTR_ERR(buffer);
kref = keyring_search(make_key_ref(blacklist_keyring, true),
&key_type_blacklist, buffer, false);
if (!IS_ERR(kref)) {
@@ -144,7 +183,8 @@ EXPORT_SYMBOL_GPL(is_hash_blacklisted);
int is_binary_blacklisted(const u8 *hash, size_t hash_len)
{
- if (is_hash_blacklisted(hash, hash_len, "bin") == -EKEYREJECTED)
+ if (is_hash_blacklisted(hash, hash_len, BLACKLIST_HASH_BINARY) ==
+ -EKEYREJECTED)
return -EPERM;
return 0;
@@ -217,7 +257,7 @@ static int __init blacklist_init(void)
panic("Can't allocate system blacklist keyring\n");
for (bl = blacklist_hashes; *bl; bl++)
- if (mark_hash_blacklisted(*bl) < 0)
+ if (mark_raw_hash_blacklisted(*bl) < 0)
pr_err("- blacklisting failed\n");
return 0;
}
diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c
index 91a4ad50dea2..77ed4e93ad56 100644
--- a/crypto/asymmetric_keys/x509_public_key.c
+++ b/crypto/asymmetric_keys/x509_public_key.c
@@ -69,7 +69,8 @@ int x509_get_sig_params(struct x509_certificate *cert)
if (ret < 0)
goto error_2;
- ret = is_hash_blacklisted(sig->digest, sig->digest_size, "tbs");
+ ret = is_hash_blacklisted(sig->digest, sig->digest_size,
+ BLACKLIST_HASH_X509_TBS);
if (ret == -EKEYREJECTED) {
pr_err("Cert %*phN is blacklisted\n",
sig->digest_size, sig->digest);
diff --git a/include/keys/system_keyring.h b/include/keys/system_keyring.h
index 2419a735420f..91e080efb918 100644
--- a/include/keys/system_keyring.h
+++ b/include/keys/system_keyring.h
@@ -10,6 +10,13 @@
#include <linux/key.h>
+enum blacklist_hash_type {
+ /* TBSCertificate hash */
+ BLACKLIST_HASH_X509_TBS = 1,
+ /* Raw data hash */
+ BLACKLIST_HASH_BINARY = 2,
+};
+
#ifdef CONFIG_SYSTEM_TRUSTED_KEYRING
extern int restrict_link_by_builtin_trusted(struct key *keyring,
@@ -54,13 +61,14 @@ static inline void __init set_machine_trusted_keys(struct key *keyring)
extern struct pkcs7_message *pkcs7;
#ifdef CONFIG_SYSTEM_BLACKLIST_KEYRING
-extern int mark_hash_blacklisted(const char *hash);
+extern int mark_hash_blacklisted(const u8 *hash, size_t hash_len,
+ enum blacklist_hash_type hash_type);
extern int is_hash_blacklisted(const u8 *hash, size_t hash_len,
- const char *type);
+ enum blacklist_hash_type hash_type);
extern int is_binary_blacklisted(const u8 *hash, size_t hash_len);
#else
static inline int is_hash_blacklisted(const u8 *hash, size_t hash_len,
- const char *type)
+ enum blacklist_hash_type hash_type)
{
return 0;
}
diff --git a/security/integrity/platform_certs/keyring_handler.c b/security/integrity/platform_certs/keyring_handler.c
index 1db4d3b4356d..a2464f3e66cc 100644
--- a/security/integrity/platform_certs/keyring_handler.c
+++ b/security/integrity/platform_certs/keyring_handler.c
@@ -17,34 +17,12 @@ static efi_guid_t efi_cert_x509_sha256_guid __initdata =
static efi_guid_t efi_cert_sha256_guid __initdata = EFI_CERT_SHA256_GUID;
/*
- * Blacklist a hash.
- */
-static __init void uefi_blacklist_hash(const char *source, const void *data,
- size_t len, const char *type,
- size_t type_len)
-{
- char *hash, *p;
-
- hash = kmalloc(type_len + len * 2 + 1, GFP_KERNEL);
- if (!hash)
- return;
- p = memcpy(hash, type, type_len);
- p += type_len;
- bin2hex(p, data, len);
- p += len * 2;
- *p = 0;
-
- mark_hash_blacklisted(hash);
- kfree(hash);
-}
-
-/*
* Blacklist an X509 TBS hash.
*/
static __init void uefi_blacklist_x509_tbs(const char *source,
const void *data, size_t len)
{
- uefi_blacklist_hash(source, data, len, "tbs:", 4);
+ mark_hash_blacklisted(data, len, BLACKLIST_HASH_X509_TBS);
}
/*
@@ -53,7 +31,7 @@ static __init void uefi_blacklist_x509_tbs(const char *source,
static __init void uefi_blacklist_binary(const char *source,
const void *data, size_t len)
{
- uefi_blacklist_hash(source, data, len, "bin:", 4);
+ mark_hash_blacklisted(data, len, BLACKLIST_HASH_BINARY);
}
/*