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authorDavid Howells <dhowells@redhat.com>2014-07-17 20:45:08 +0100
committerDavid Howells <dhowells@redhat.com>2014-07-17 20:45:08 +0100
commit0c7774abb41bd00d5836d9ba098825a40fa94133 (patch)
treed3c6cb9e81dd798b7383ed47a5fd5499b772a3ea /security/keys/keyctl.c
parentMerge branch 'stable-3.16' of git://git.infradead.org/users/pcmoore/selinux into next (diff)
downloadlinux-dev-0c7774abb41bd00d5836d9ba098825a40fa94133.tar.xz
linux-dev-0c7774abb41bd00d5836d9ba098825a40fa94133.zip
KEYS: Allow special keys (eg. DNS results) to be invalidated by CAP_SYS_ADMIN
Special kernel keys, such as those used to hold DNS results for AFS, CIFS and NFS and those used to hold idmapper results for NFS, used to be 'invalidateable' with key_revoke(). However, since the default permissions for keys were reduced: Commit: 96b5c8fea6c0861621051290d705ec2e971963f1 KEYS: Reduce initial permissions on keys it has become impossible to do this. Add a key flag (KEY_FLAG_ROOT_CAN_INVAL) that will permit a key to be invalidated by root. This should not be used for system keyrings as the garbage collector will try and remove any invalidate key. For system keyrings, KEY_FLAG_ROOT_CAN_CLEAR can be used instead. After this, from userspace, keyctl_invalidate() and "keyctl invalidate" can be used by any possessor of CAP_SYS_ADMIN (typically root) to invalidate DNS and idmapper keys. Invalidated keys are immediately garbage collected and will be immediately rerequested if needed again. Signed-off-by: David Howells <dhowells@redhat.com> Tested-by: Steve Dickson <steved@redhat.com>
Diffstat (limited to 'security/keys/keyctl.c')
-rw-r--r--security/keys/keyctl.c15
1 files changed, 14 insertions, 1 deletions
diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index cd5bd0cef25d..609f8d326ddc 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -404,12 +404,25 @@ long keyctl_invalidate_key(key_serial_t id)
key_ref = lookup_user_key(id, 0, KEY_NEED_SEARCH);
if (IS_ERR(key_ref)) {
ret = PTR_ERR(key_ref);
+
+ /* Root is permitted to invalidate certain special keys */
+ if (capable(CAP_SYS_ADMIN)) {
+ key_ref = lookup_user_key(id, 0, 0);
+ if (IS_ERR(key_ref))
+ goto error;
+ if (test_bit(KEY_FLAG_ROOT_CAN_INVAL,
+ &key_ref_to_ptr(key_ref)->flags))
+ goto invalidate;
+ goto error_put;
+ }
+
goto error;
}
+invalidate:
key_invalidate(key_ref_to_ptr(key_ref));
ret = 0;
-
+error_put:
key_ref_put(key_ref);
error:
kleave(" = %ld", ret);