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-rw-r--r--security/keys/keyctl.c107
1 files changed, 84 insertions, 23 deletions
diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index 299f0ae11cf0..3d2ebae029c1 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -834,6 +834,17 @@ long keyctl_instantiate_key(key_serial_t id,
if (plen > 32767)
goto error;
+ /* the appropriate instantiation authorisation key must have been
+ * assumed before calling this */
+ ret = -EPERM;
+ instkey = current->request_key_auth;
+ if (!instkey)
+ goto error;
+
+ rka = instkey->payload.data;
+ if (rka->target_key->serial != id)
+ goto error;
+
/* pull the payload in if one was supplied */
payload = NULL;
@@ -848,15 +859,6 @@ long keyctl_instantiate_key(key_serial_t id,
goto error2;
}
- /* find the instantiation authorisation key */
- instkey = key_get_instantiation_authkey(id);
- if (IS_ERR(instkey)) {
- ret = PTR_ERR(instkey);
- goto error2;
- }
-
- rka = instkey->payload.data;
-
/* find the destination keyring amongst those belonging to the
* requesting task */
keyring_ref = NULL;
@@ -865,7 +867,7 @@ long keyctl_instantiate_key(key_serial_t id,
KEY_WRITE);
if (IS_ERR(keyring_ref)) {
ret = PTR_ERR(keyring_ref);
- goto error3;
+ goto error2;
}
}
@@ -874,11 +876,17 @@ long keyctl_instantiate_key(key_serial_t id,
key_ref_to_ptr(keyring_ref), instkey);
key_ref_put(keyring_ref);
- error3:
- key_put(instkey);
- error2:
+
+ /* discard the assumed authority if it's just been disabled by
+ * instantiation of the key */
+ if (ret == 0) {
+ key_put(current->request_key_auth);
+ current->request_key_auth = NULL;
+ }
+
+error2:
kfree(payload);
- error:
+error:
return ret;
} /* end keyctl_instantiate_key() */
@@ -895,14 +903,16 @@ long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
key_ref_t keyring_ref;
long ret;
- /* find the instantiation authorisation key */
- instkey = key_get_instantiation_authkey(id);
- if (IS_ERR(instkey)) {
- ret = PTR_ERR(instkey);
+ /* the appropriate instantiation authorisation key must have been
+ * assumed before calling this */
+ ret = -EPERM;
+ instkey = current->request_key_auth;
+ if (!instkey)
goto error;
- }
rka = instkey->payload.data;
+ if (rka->target_key->serial != id)
+ goto error;
/* find the destination keyring if present (which must also be
* writable) */
@@ -911,7 +921,7 @@ long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
keyring_ref = lookup_user_key(NULL, ringid, 1, 0, KEY_WRITE);
if (IS_ERR(keyring_ref)) {
ret = PTR_ERR(keyring_ref);
- goto error2;
+ goto error;
}
}
@@ -920,9 +930,15 @@ long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid)
key_ref_to_ptr(keyring_ref), instkey);
key_ref_put(keyring_ref);
- error2:
- key_put(instkey);
- error:
+
+ /* discard the assumed authority if it's just been disabled by
+ * instantiation of the key */
+ if (ret == 0) {
+ key_put(current->request_key_auth);
+ current->request_key_auth = NULL;
+ }
+
+error:
return ret;
} /* end keyctl_negate_key() */
@@ -1007,6 +1023,48 @@ error:
/*****************************************************************************/
/*
+ * assume the authority to instantiate the specified key
+ */
+long keyctl_assume_authority(key_serial_t id)
+{
+ struct key *authkey;
+ long ret;
+
+ /* special key IDs aren't permitted */
+ ret = -EINVAL;
+ if (id < 0)
+ goto error;
+
+ /* we divest ourselves of authority if given an ID of 0 */
+ if (id == 0) {
+ key_put(current->request_key_auth);
+ current->request_key_auth = NULL;
+ ret = 0;
+ goto error;
+ }
+
+ /* attempt to assume the authority temporarily granted to us whilst we
+ * instantiate the specified key
+ * - the authorisation key must be in the current task's keyrings
+ * somewhere
+ */
+ authkey = key_get_instantiation_authkey(id);
+ if (IS_ERR(authkey)) {
+ ret = PTR_ERR(authkey);
+ goto error;
+ }
+
+ key_put(current->request_key_auth);
+ current->request_key_auth = authkey;
+ ret = authkey->serial;
+
+error:
+ return ret;
+
+} /* end keyctl_assume_authority() */
+
+/*****************************************************************************/
+/*
* the key control system call
*/
asmlinkage long sys_keyctl(int option, unsigned long arg2, unsigned long arg3,
@@ -1082,6 +1140,9 @@ asmlinkage long sys_keyctl(int option, unsigned long arg2, unsigned long arg3,
return keyctl_set_timeout((key_serial_t) arg2,
(unsigned) arg3);
+ case KEYCTL_ASSUME_AUTHORITY:
+ return keyctl_assume_authority((key_serial_t) arg2);
+
default:
return -EOPNOTSUPP;
}