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authorFredrik Tolf <fredrik@dolda2000.com>2006-06-26 00:24:51 -0700
committerLinus Torvalds <torvalds@g5.osdl.org>2006-06-26 09:58:18 -0700
commit5801649d8b83e7cb9b15839761bdee594653c294 (patch)
tree4534b606908596651a533b2f51418444b5a1e705 /security
parent31204ed925b067d2bb65adb89501656f8274a32a (diff)
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[PATCH] keys: let keyctl_chown() change a key's owner
Let keyctl_chown() change a key's owner, including attempting to transfer the quota burden to the new user. Signed-off-by: David Howells <dhowells@redhat.com> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'security')
-rw-r--r--security/keys/keyctl.c56
1 files changed, 48 insertions, 8 deletions
diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index d74458522e9..329411cf876 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -673,6 +673,7 @@ long keyctl_read_key(key_serial_t keyid, char __user *buffer, size_t buflen)
*/
long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid)
{
+ struct key_user *newowner, *zapowner = NULL;
struct key *key;
key_ref_t key_ref;
long ret;
@@ -696,19 +697,50 @@ long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid)
if (!capable(CAP_SYS_ADMIN)) {
/* only the sysadmin can chown a key to some other UID */
if (uid != (uid_t) -1 && key->uid != uid)
- goto no_access;
+ goto error_put;
/* only the sysadmin can set the key's GID to a group other
* than one of those that the current process subscribes to */
if (gid != (gid_t) -1 && gid != key->gid && !in_group_p(gid))
- goto no_access;
+ goto error_put;
}
- /* change the UID (have to update the quotas) */
+ /* change the UID */
if (uid != (uid_t) -1 && uid != key->uid) {
- /* don't support UID changing yet */
- ret = -EOPNOTSUPP;
- goto no_access;
+ ret = -ENOMEM;
+ newowner = key_user_lookup(uid);
+ if (!newowner)
+ goto error_put;
+
+ /* transfer the quota burden to the new user */
+ if (test_bit(KEY_FLAG_IN_QUOTA, &key->flags)) {
+ spin_lock(&newowner->lock);
+ if (newowner->qnkeys + 1 >= KEYQUOTA_MAX_KEYS ||
+ newowner->qnbytes + key->quotalen >=
+ KEYQUOTA_MAX_BYTES)
+ goto quota_overrun;
+
+ newowner->qnkeys++;
+ newowner->qnbytes += key->quotalen;
+ spin_unlock(&newowner->lock);
+
+ spin_lock(&key->user->lock);
+ key->user->qnkeys--;
+ key->user->qnbytes -= key->quotalen;
+ spin_unlock(&key->user->lock);
+ }
+
+ atomic_dec(&key->user->nkeys);
+ atomic_inc(&newowner->nkeys);
+
+ if (test_bit(KEY_FLAG_INSTANTIATED, &key->flags)) {
+ atomic_dec(&key->user->nikeys);
+ atomic_inc(&newowner->nikeys);
+ }
+
+ zapowner = key->user;
+ key->user = newowner;
+ key->uid = uid;
}
/* change the GID */
@@ -717,12 +749,20 @@ long keyctl_chown_key(key_serial_t id, uid_t uid, gid_t gid)
ret = 0;
- no_access:
+error_put:
up_write(&key->sem);
key_put(key);
- error:
+ if (zapowner)
+ key_user_put(zapowner);
+error:
return ret;
+quota_overrun:
+ spin_unlock(&newowner->lock);
+ zapowner = newowner;
+ ret = -EDQUOT;
+ goto error_put;
+
} /* end keyctl_chown_key() */
/*****************************************************************************/