Commit 017679c4 authored by David Howells's avatar David Howells Committed by Linus Torvalds

[PATCH] keys: Permit key expiry time to be set

Add a new keyctl function that allows the expiry time to be set on a key or
removed from a key, provided the caller has attribute modification access.
Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
Cc: Trond Myklebust <trond.myklebust@fys.uio.no>
Cc: Alexander Zangerl <az@bond.edu.au>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent cd140a5c
......@@ -498,7 +498,7 @@ The keyctl syscall functions are:
keyring is full, error ENFILE will result.
The link procedure checks the nesting of the keyrings, returning ELOOP if
it appears to deep or EDEADLK if the link would introduce a cycle.
it appears too deep or EDEADLK if the link would introduce a cycle.
(*) Unlink a key or keyring from another keyring:
......@@ -628,6 +628,19 @@ The keyctl syscall functions are:
there is one, otherwise the user default session keyring.
(*) Set the timeout on a key.
long keyctl(KEYCTL_SET_TIMEOUT, key_serial_t key, unsigned timeout);
This sets or clears the timeout on a key. The timeout can be 0 to clear
the timeout or a number of seconds to set the expiry time that far into
the future.
The process must have attribute modification access on a key to set its
timeout. Timeouts may not be set with this function on negative, revoked
or expired keys.
===============
KERNEL SERVICES
===============
......
......@@ -46,5 +46,6 @@
#define KEYCTL_INSTANTIATE 12 /* instantiate a partially constructed key */
#define KEYCTL_NEGATE 13 /* negate a partially constructed key */
#define KEYCTL_SET_REQKEY_KEYRING 14 /* set default request-key keyring */
#define KEYCTL_SET_TIMEOUT 15 /* set key timeout */
#endif /* _LINUX_KEYCTL_H */
......@@ -74,6 +74,9 @@ asmlinkage long compat_sys_keyctl(u32 option,
case KEYCTL_SET_REQKEY_KEYRING:
return keyctl_set_reqkey_keyring(arg2);
case KEYCTL_SET_TIMEOUT:
return keyctl_set_timeout(arg2, arg3);
default:
return -EOPNOTSUPP;
}
......
......@@ -136,6 +136,7 @@ extern long keyctl_instantiate_key(key_serial_t, const void __user *,
size_t, key_serial_t);
extern long keyctl_negate_key(key_serial_t, unsigned, key_serial_t);
extern long keyctl_set_reqkey_keyring(int);
extern long keyctl_set_timeout(key_serial_t, unsigned);
/*
......
......@@ -965,6 +965,46 @@ long keyctl_set_reqkey_keyring(int reqkey_defl)
} /* end keyctl_set_reqkey_keyring() */
/*****************************************************************************/
/*
* set or clear the timeout for a key
*/
long keyctl_set_timeout(key_serial_t id, unsigned timeout)
{
struct timespec now;
struct key *key;
key_ref_t key_ref;
time_t expiry;
long ret;
key_ref = lookup_user_key(NULL, id, 1, 1, KEY_SETATTR);
if (IS_ERR(key_ref)) {
ret = PTR_ERR(key_ref);
goto error;
}
key = key_ref_to_ptr(key_ref);
/* make the changes with the locks held to prevent races */
down_write(&key->sem);
expiry = 0;
if (timeout > 0) {
now = current_kernel_time();
expiry = now.tv_sec + timeout;
}
key->expiry = expiry;
up_write(&key->sem);
key_put(key);
ret = 0;
error:
return ret;
} /* end keyctl_set_timeout() */
/*****************************************************************************/
/*
* the key control system call
......@@ -1038,6 +1078,10 @@ asmlinkage long sys_keyctl(int option, unsigned long arg2, unsigned long arg3,
case KEYCTL_SET_REQKEY_KEYRING:
return keyctl_set_reqkey_keyring(arg2);
case KEYCTL_SET_TIMEOUT:
return keyctl_set_timeout((key_serial_t) arg2,
(unsigned) arg3);
default:
return -EOPNOTSUPP;
}
......
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