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Date: Tue, 30 Oct 2012 19:22:48 +0000
From: David Howells <dhowells@...hat.com>
To: rusty@...tcorp.com.au
Cc: dhowells@...hat.com, pjones@...hat.com, jwboyer@...hat.com,
mjg@...hat.com, dmitry.kasatkin@...el.com,
zohar@...ux.vnet.ibm.com, keescook@...omium.org,
keyrings@...ux-nfs.org, linux-kernel@...r.kernel.org
Subject: [PATCH 23/23] KEYS: Add a 'trusted' flag and a 'trusted only' flag
Add KEY_FLAG_TRUSTED to indicate that a key either comes from a trusted source
or had a cryptographic signature chain that led back to a trusted key the
kernel already possessed.
Add KEY_FLAGS_TRUSTED_ONLY to indicate that a keyring will only accept links to
keys marked with KEY_FLAGS_TRUSTED.
Signed-off-by: David Howells <dhowells@...hat.com>
---
crypto/asymmetric_keys/pefile_parser.c | 2 +-
crypto/asymmetric_keys/pkcs7_parser.h | 3 ++-
crypto/asymmetric_keys/pkcs7_trust.c | 6 +++++-
include/linux/key-type.h | 1 +
include/linux/key.h | 3 +++
kernel/modsign_pubkey.c | 6 ++++--
security/keys/key.c | 8 ++++++++
security/keys/keyring.c | 4 ++++
security/keys/proc.c | 3 ++-
9 files changed, 30 insertions(+), 6 deletions(-)
diff --git a/crypto/asymmetric_keys/pefile_parser.c b/crypto/asymmetric_keys/pefile_parser.c
index 28be7d3..da2db58 100644
--- a/crypto/asymmetric_keys/pefile_parser.c
+++ b/crypto/asymmetric_keys/pefile_parser.c
@@ -432,7 +432,7 @@ static int pefile_key_preparse(struct key_preparsed_payload *prep)
if (ret < 0)
goto error;
- ret = pkcs7_validate_trust(pkcs7, modsign_keyring);
+ ret = pkcs7_validate_trust(pkcs7, modsign_keyring, &prep->trusted);
if (ret < 0)
goto error;
diff --git a/crypto/asymmetric_keys/pkcs7_parser.h b/crypto/asymmetric_keys/pkcs7_parser.h
index f6df500..ffa72dc 100644
--- a/crypto/asymmetric_keys/pkcs7_parser.h
+++ b/crypto/asymmetric_keys/pkcs7_parser.h
@@ -63,7 +63,8 @@ extern void pkcs7_free_message(struct pkcs7_message *pkcs7);
* pkcs7_trust.c
*/
extern int pkcs7_validate_trust(struct pkcs7_message *pkcs7,
- struct key *trust_keyring);
+ struct key *trust_keyring,
+ bool *_trusted);
/*
* pkcs7_verify.c
diff --git a/crypto/asymmetric_keys/pkcs7_trust.c b/crypto/asymmetric_keys/pkcs7_trust.c
index 9abcb39..cc226f5 100644
--- a/crypto/asymmetric_keys/pkcs7_trust.c
+++ b/crypto/asymmetric_keys/pkcs7_trust.c
@@ -74,11 +74,13 @@ static struct key *pkcs7_request_asymmetric_key(
* keys we already know and trust.
*/
int pkcs7_validate_trust(struct pkcs7_message *pkcs7,
- struct key *trust_keyring)
+ struct key *trust_keyring,
+ bool *_trusted)
{
struct public_key_signature *sig = &pkcs7->sig;
struct x509_certificate *x509, *last = NULL;
struct key *key;
+ bool trusted;
int ret;
kenter("");
@@ -131,6 +133,7 @@ int pkcs7_validate_trust(struct pkcs7_message *pkcs7,
matched:
ret = verify_signature(key, sig);
+ trusted = test_bit(KEY_FLAG_TRUSTED, &key->flags);
key_put(key);
if (ret < 0) {
if (ret == -ENOMEM)
@@ -139,6 +142,7 @@ matched:
return -EKEYREJECTED;
}
+ *_trusted = trusted;
kleave(" = 0");
return 0;
}
diff --git a/include/linux/key-type.h b/include/linux/key-type.h
index 518a53a..f942b2d 100644
--- a/include/linux/key-type.h
+++ b/include/linux/key-type.h
@@ -45,6 +45,7 @@ struct key_preparsed_payload {
const void *data; /* Raw data */
size_t datalen; /* Raw datalen */
size_t quotalen; /* Quota length for proposed payload */
+ bool trusted; /* True if key is trusted */
};
typedef int (*request_key_actor_t)(struct key_construction *key,
diff --git a/include/linux/key.h b/include/linux/key.h
index 2393b1c..cd0b9e9 100644
--- a/include/linux/key.h
+++ b/include/linux/key.h
@@ -162,6 +162,8 @@ struct key {
#define KEY_FLAG_NEGATIVE 5 /* set if key is negative */
#define KEY_FLAG_ROOT_CAN_CLEAR 6 /* set if key can be cleared by root without permission */
#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 */
/* the description string
* - this is used to match a key against search criteria
@@ -203,6 +205,7 @@ extern struct key *key_alloc(struct key_type *type,
#define KEY_ALLOC_IN_QUOTA 0x0000 /* add to quota, reject if would overrun */
#define KEY_ALLOC_QUOTA_OVERRUN 0x0001 /* add to quota, permit even if overrun */
#define KEY_ALLOC_NOT_IN_QUOTA 0x0002 /* not in quota */
+#define KEY_ALLOC_TRUSTED 0x0004 /* Key should be flagged as trusted */
extern void key_revoke(struct key *key);
extern void key_invalidate(struct key *key);
diff --git a/kernel/modsign_pubkey.c b/kernel/modsign_pubkey.c
index 602be22..57b0a77 100644
--- a/kernel/modsign_pubkey.c
+++ b/kernel/modsign_pubkey.c
@@ -45,7 +45,7 @@ static __init int module_verify_init(void)
KUIDT_INIT(0), KGIDT_INIT(0),
current_cred(),
(KEY_POS_ALL & ~KEY_POS_SETATTR) |
- KEY_USR_VIEW | KEY_USR_READ,
+ KEY_USR_VIEW | KEY_USR_READ | KEY_USR_WRITE,
KEY_ALLOC_NOT_IN_QUOTA);
if (IS_ERR(modsign_keyring))
panic("Can't allocate module signing keyring\n");
@@ -53,6 +53,7 @@ static __init int module_verify_init(void)
if (key_instantiate_and_link(modsign_keyring, NULL, 0, NULL, NULL) < 0)
panic("Can't instantiate module signing keyring\n");
+ set_bit(KEY_FLAG_TRUSTED_ONLY, &modsign_keyring->flags);
return 0;
}
@@ -95,7 +96,8 @@ static __init int load_module_signing_keys(void)
plen,
(KEY_POS_ALL & ~KEY_POS_SETATTR) |
KEY_USR_VIEW,
- KEY_ALLOC_NOT_IN_QUOTA);
+ KEY_ALLOC_NOT_IN_QUOTA |
+ KEY_ALLOC_TRUSTED);
if (IS_ERR(key))
pr_err("MODSIGN: Problem loading in-kernel X.509 certificate (%ld)\n",
PTR_ERR(key));
diff --git a/security/keys/key.c b/security/keys/key.c
index a15c9da..d0f35d1 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -299,6 +299,8 @@ struct key *key_alloc(struct key_type *type, const char *desc,
if (!(flags & KEY_ALLOC_NOT_IN_QUOTA))
key->flags |= 1 << KEY_FLAG_IN_QUOTA;
+ if (flags & KEY_ALLOC_TRUSTED)
+ key->flags |= 1 << KEY_FLAG_TRUSTED;
memset(&key->type_data, 0, sizeof(key->type_data));
@@ -813,6 +815,7 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref,
prep.data = payload;
prep.datalen = plen;
prep.quotalen = ktype->def_datalen;
+ prep.trusted = flags & KEY_ALLOC_TRUSTED;
if (ktype->preparse) {
ret = ktype->preparse(&prep);
if (ret < 0) {
@@ -826,6 +829,11 @@ key_ref_t key_create_or_update(key_ref_t keyring_ref,
goto error_free_prep;
}
+ key_ref = ERR_PTR(-EPERM);
+ if (!prep.trusted && test_bit(KEY_FLAG_TRUSTED_ONLY, &keyring->flags))
+ goto error_free_prep;
+ flags |= prep.trusted ? KEY_ALLOC_TRUSTED : 0;
+
ret = __key_link_begin(keyring, ktype, description, &prealloc);
if (ret < 0) {
key_ref = ERR_PTR(ret);
diff --git a/security/keys/keyring.c b/security/keys/keyring.c
index 6e42df1..af90786 100644
--- a/security/keys/keyring.c
+++ b/security/keys/keyring.c
@@ -1008,6 +1008,10 @@ int key_link(struct key *keyring, struct key *key)
key_check(keyring);
key_check(key);
+ if (test_bit(KEY_FLAG_TRUSTED_ONLY, &keyring->flags) &&
+ !test_bit(KEY_FLAG_TRUSTED, &key->flags))
+ return -EPERM;
+
ret = __key_link_begin(keyring, key->type, key->description, &prealloc);
if (ret == 0) {
ret = __key_link_check_live_key(keyring, key);
diff --git a/security/keys/proc.c b/security/keys/proc.c
index 217b685..d0ca948 100644
--- a/security/keys/proc.c
+++ b/security/keys/proc.c
@@ -242,7 +242,7 @@ static int proc_keys_show(struct seq_file *m, void *v)
#define showflag(KEY, LETTER, FLAG) \
(test_bit(FLAG, &(KEY)->flags) ? LETTER : '-')
- seq_printf(m, "%08x %c%c%c%c%c%c%c %5d %4s %08x %5d %5d %-9.9s ",
+ seq_printf(m, "%08x %c%c%c%c%c%c%c%c %5d %4s %08x %5d %5d %-9.9s ",
key->serial,
showflag(key, 'I', KEY_FLAG_INSTANTIATED),
showflag(key, 'R', KEY_FLAG_REVOKED),
@@ -251,6 +251,7 @@ static int proc_keys_show(struct seq_file *m, void *v)
showflag(key, 'U', KEY_FLAG_USER_CONSTRUCT),
showflag(key, 'N', KEY_FLAG_NEGATIVE),
showflag(key, 'i', KEY_FLAG_INVALIDATED),
+ showflag(key, 'T', KEY_FLAG_TRUSTED),
atomic_read(&key->usage),
xbuf,
key->perm,
--
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