Messages in this thread Patch in this message | | | From | Mimi Zohar <> | Subject | [PATCH v6 5/6] KEYS: validate certificate trust only with builtin keys | Date | Tue, 24 Jun 2014 10:40:51 -0400 |
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From: Dmitry Kasatkin <d.kasatkin@samsung.com>
Instead of allowing public keys, with certificates signed by any key on the system trusted keyring, to be added to a trusted keyring, this patch further restricts the certificates to those signed only by builtin keys on the system keyring.
This patch defines a new option 'builtin' for the kernel parameter 'keys_ownerid' to allow trust validation using builtin keys.
Simplified Mimi's "KEYS: define an owner trusted keyring" patch
Signed-off-by: Dmitry Kasatkin <d.kasatkin@samsung.com> --- Documentation/kernel-parameters.txt | 2 +- crypto/asymmetric_keys/x509_public_key.c | 8 +++++--- include/linux/key.h | 1 + kernel/system_keyring.c | 1 + 4 files changed, 8 insertions(+), 4 deletions(-)
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index b0cc47d..a0c155c 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -1495,7 +1495,7 @@ bytes respectively. Such letter suffixes can also be entirely omitted. keys_ownerid=[KEYS] This parameter identifies a specific key(s) on the system trusted keyring to be used for certificate trust validation. - format: id:<keyid> + format: { id:<keyid> | builtin } kgdbdbgp= [KGDB,HW] kgdb over EHCI usb debug port. Format: <Controller#>[,poll interval] diff --git a/crypto/asymmetric_keys/x509_public_key.c b/crypto/asymmetric_keys/x509_public_key.c index 44850f2..541329d 100644 --- a/crypto/asymmetric_keys/x509_public_key.c +++ b/crypto/asymmetric_keys/x509_public_key.c @@ -24,6 +24,7 @@ #include "public_key.h" #include "x509_parser.h" +static bool builtin_keys; static char *owner_keyid; #ifndef MODULE @@ -34,6 +35,8 @@ static int __init default_owner_keyid_set(char *str) if (strncmp(str, "id:", 3) == 0) owner_keyid = str; /* owner local key 'id:xxxxxx' */ + else if (strcmp(str, "builtin") == 0) + builtin_keys = true; return 1; } @@ -180,7 +183,6 @@ EXPORT_SYMBOL_GPL(x509_check_signature); static int x509_validate_trust(struct x509_certificate *cert, struct key *trust_keyring) { - const struct public_key *pk; struct key *key; int ret = 1; @@ -196,8 +198,8 @@ static int x509_validate_trust(struct x509_certificate *cert, cert->authority, strlen(cert->authority)); if (!IS_ERR(key)) { - pk = key->payload.data; - ret = x509_check_signature(pk, cert); + if (!builtin_keys || test_bit(KEY_FLAG_BUILTIN, &key->flags)) + ret = x509_check_signature(key->payload.data, cert); key_put(key); } return ret; diff --git a/include/linux/key.h b/include/linux/key.h index 017b082..65316f7 100644 --- a/include/linux/key.h +++ b/include/linux/key.h @@ -170,6 +170,7 @@ struct key { #define KEY_FLAG_INVALIDATED 7 /* set if key has been invalidated */ #define KEY_FLAG_TRUSTED 8 /* set if key is trusted */ #define KEY_FLAG_TRUSTED_ONLY 9 /* set if keyring only accepts links to trusted keys */ +#define KEY_FLAG_BUILTIN 10 /* set if key is builtin */ /* the key type and key description string * - the desc is used to match a key against search criteria diff --git a/kernel/system_keyring.c b/kernel/system_keyring.c index 52ebc70..875f64e 100644 --- a/kernel/system_keyring.c +++ b/kernel/system_keyring.c @@ -89,6 +89,7 @@ static __init int load_system_certificate_list(void) pr_err("Problem loading in-kernel X.509 certificate (%ld)\n", PTR_ERR(key)); } else { + set_bit(KEY_FLAG_BUILTIN, &key_ref_to_ptr(key)->flags); pr_notice("Loaded X.509 cert '%s'\n", key_ref_to_ptr(key)->description); key_ref_put(key); -- 1.8.1.4
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