From fdd1b94581782a2ddf9124414e5b7a5f48ce2f9c Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 7 Mar 2011 15:06:09 +0000 Subject: KEYS: Add a new keyctl op to reject a key with a specified error code Add a new keyctl op to reject a key with a specified error code. This works much the same as negating a key, and so keyctl_negate_key() is made a special case of keyctl_reject_key(). The difference is that keyctl_negate_key() selects ENOKEY as the error to be reported. Typically the key would be rejected with EKEYEXPIRED, EKEYREVOKED or EKEYREJECTED, but this is not mandatory. Signed-off-by: David Howells Signed-off-by: James Morris --- security/keys/compat.c | 3 +++ security/keys/internal.h | 1 + security/keys/key.c | 19 +++++++++++-------- security/keys/keyctl.c | 40 ++++++++++++++++++++++++++++++++++++++-- security/keys/keyring.c | 4 ++-- security/keys/request_key.c | 2 +- 6 files changed, 56 insertions(+), 13 deletions(-) (limited to 'security/keys') diff --git a/security/keys/compat.c b/security/keys/compat.c index 07a5f35e3970..17c99d0149ec 100644 --- a/security/keys/compat.c +++ b/security/keys/compat.c @@ -85,6 +85,9 @@ asmlinkage long compat_sys_keyctl(u32 option, case KEYCTL_SESSION_TO_PARENT: return keyctl_session_to_parent(); + case KEYCTL_REJECT: + return keyctl_reject_key(arg2, arg3, arg4, arg5); + default: return -EOPNOTSUPP; } diff --git a/security/keys/internal.h b/security/keys/internal.h index a52aa7c88b41..286c0959ee51 100644 --- a/security/keys/internal.h +++ b/security/keys/internal.h @@ -214,6 +214,7 @@ extern long keyctl_assume_authority(key_serial_t); extern long keyctl_get_security(key_serial_t keyid, char __user *buffer, size_t buflen); extern long keyctl_session_to_parent(void); +extern long keyctl_reject_key(key_serial_t, unsigned, unsigned, key_serial_t); /* * Debugging key validation diff --git a/security/keys/key.c b/security/keys/key.c index 8e315ef2e88e..f7f9d93f08d9 100644 --- a/security/keys/key.c +++ b/security/keys/key.c @@ -511,26 +511,29 @@ int key_instantiate_and_link(struct key *key, EXPORT_SYMBOL(key_instantiate_and_link); /** - * key_negate_and_link - Negatively instantiate a key and link it into the keyring. + * key_reject_and_link - Negatively instantiate a key and link it into the keyring. * @key: The key to instantiate. * @timeout: The timeout on the negative key. + * @error: The error to return when the key is hit. * @keyring: Keyring to create a link in on success (or NULL). * @authkey: The authorisation token permitting instantiation. * * Negatively instantiate a key that's in the uninstantiated state and, if - * successful, set its timeout and link it in to the destination keyring if one - * is supplied. The key and any links to the key will be automatically garbage - * collected after the timeout expires. + * successful, set its timeout and stored error and link it in to the + * destination keyring if one is supplied. The key and any links to the key + * will be automatically garbage collected after the timeout expires. * * Negative keys are used to rate limit repeated request_key() calls by causing - * them to return -ENOKEY until the negative key expires. + * them to return the stored error code (typically ENOKEY) until the negative + * key expires. * * If successful, 0 is returned, the authorisation token is revoked and anyone * waiting for the key is woken up. If the key was already instantiated, * -EBUSY will be returned. */ -int key_negate_and_link(struct key *key, +int key_reject_and_link(struct key *key, unsigned timeout, + unsigned error, struct key *keyring, struct key *authkey) { @@ -556,6 +559,7 @@ int key_negate_and_link(struct key *key, atomic_inc(&key->user->nikeys); set_bit(KEY_FLAG_NEGATIVE, &key->flags); set_bit(KEY_FLAG_INSTANTIATED, &key->flags); + key->type_data.reject_error = -error; now = current_kernel_time(); key->expiry = now.tv_sec + timeout; key_schedule_gc(key->expiry + key_gc_delay); @@ -585,8 +589,7 @@ int key_negate_and_link(struct key *key, return ret == 0 ? link_ret : ret; } - -EXPORT_SYMBOL(key_negate_and_link); +EXPORT_SYMBOL(key_reject_and_link); /* * Garbage collect keys in process context so that we don't have to disable diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c index 31a0fd8189f1..0d7b1946ff94 100644 --- a/security/keys/keyctl.c +++ b/security/keys/keyctl.c @@ -1012,13 +1012,43 @@ error: * If successful, 0 will be returned. */ long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid) +{ + return keyctl_reject_key(id, timeout, ENOKEY, ringid); +} + +/* + * Negatively instantiate the key with the given timeout (in seconds) and error + * code and link the key into the destination keyring if one is given. + * + * The caller must have the appropriate instantiation permit set for this to + * work (see keyctl_assume_authority). No other permissions are required. + * + * The key and any links to the key will be automatically garbage collected + * after the timeout expires. + * + * Negative keys are used to rate limit repeated request_key() calls by causing + * them to return the specified error code until the negative key expires. + * + * If successful, 0 will be returned. + */ +long keyctl_reject_key(key_serial_t id, unsigned timeout, unsigned error, + key_serial_t ringid) { const struct cred *cred = current_cred(); struct request_key_auth *rka; struct key *instkey, *dest_keyring; long ret; - kenter("%d,%u,%d", id, timeout, ringid); + kenter("%d,%u,%u,%d", id, timeout, error, ringid); + + /* must be a valid error code and mustn't be a kernel special */ + if (error <= 0 || + error >= MAX_ERRNO || + error == ERESTARTSYS || + error == ERESTARTNOINTR || + error == ERESTARTNOHAND || + error == ERESTART_RESTARTBLOCK) + return -EINVAL; /* the appropriate instantiation authorisation key must have been * assumed before calling this */ @@ -1038,7 +1068,7 @@ long keyctl_negate_key(key_serial_t id, unsigned timeout, key_serial_t ringid) goto error; /* instantiate the key and link it into a keyring */ - ret = key_negate_and_link(rka->target_key, timeout, + ret = key_reject_and_link(rka->target_key, timeout, error, dest_keyring, instkey); key_put(dest_keyring); @@ -1492,6 +1522,12 @@ SYSCALL_DEFINE5(keyctl, int, option, unsigned long, arg2, unsigned long, arg3, case KEYCTL_SESSION_TO_PARENT: return keyctl_session_to_parent(); + case KEYCTL_REJECT: + return keyctl_reject_key((key_serial_t) arg2, + (unsigned) arg3, + (unsigned) arg4, + (key_serial_t) arg5); + default: return -EOPNOTSUPP; } diff --git a/security/keys/keyring.c b/security/keys/keyring.c index 5620f084dede..cdd2f3f88c88 100644 --- a/security/keys/keyring.c +++ b/security/keys/keyring.c @@ -352,7 +352,7 @@ key_ref_t keyring_search_aux(key_ref_t keyring_ref, goto error_2; if (key->expiry && now.tv_sec >= key->expiry) goto error_2; - key_ref = ERR_PTR(-ENOKEY); + key_ref = ERR_PTR(key->type_data.reject_error); if (kflags & (1 << KEY_FLAG_NEGATIVE)) goto error_2; goto found; @@ -401,7 +401,7 @@ descend: /* we set a different error code if we pass a negative key */ if (kflags & (1 << KEY_FLAG_NEGATIVE)) { - err = -ENOKEY; + err = key->type_data.reject_error; continue; } diff --git a/security/keys/request_key.c b/security/keys/request_key.c index a3dc0d460def..df3c0417ee40 100644 --- a/security/keys/request_key.c +++ b/security/keys/request_key.c @@ -585,7 +585,7 @@ int wait_for_key_construction(struct key *key, bool intr) if (ret < 0) return ret; if (test_bit(KEY_FLAG_NEGATIVE, &key->flags)) - return -ENOKEY; + return key->type_data.reject_error; return key_validate(key); } EXPORT_SYMBOL(wait_for_key_construction); -- cgit v1.2.3