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authorDavid Howells <dhowells@redhat.com>2016-01-27 01:02:03 +0000
committerJames Morris <james.l.morris@oracle.com>2016-01-28 10:48:40 +1100
commiteee045021fb22aeac7f5d6f2092430b530c880ee (patch)
tree9175a14f9b0ee8423aa3f9b51cac21bf444dbeda /security
parent03c21cb775a313f1ff19be59c5d02df3e3526471 (diff)
downloadleg-kernel-eee045021fb22aeac7f5d6f2092430b530c880ee.tar.gz
KEYS: Only apply KEY_FLAG_KEEP to a key if a parent keyring has it set
KEY_FLAG_KEEP should only be applied to a key if the keyring it is being linked into has KEY_FLAG_KEEP set. To this end, partially revert the following patch: commit 1d6d167c2efcfe9539d9cffb1a1be9c92e39c2c0 Author: Mimi Zohar <zohar@linux.vnet.ibm.com> Date: Thu Jan 7 07:46:36 2016 -0500 KEYS: refcount bug fix to undo the change that made it unconditional (Mimi got it right the first time). Without undoing this change, it becomes impossible to delete, revoke or invalidate keys added to keyrings through __key_instantiate_and_link() where the keyring has itself been linked to. To test this, run the following command sequence: keyctl newring foo @s keyctl add user a a %:foo keyctl unlink %user:a %:foo keyctl clear %:foo With the commit mentioned above the third and fourth commands fail with EPERM when they should succeed. Reported-by: Stephen Gallager <sgallagh@redhat.com> Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com> cc: Mimi Zohar <zohar@linux.vnet.ibm.com> cc: keyrings@vger.kernel.org cc: stable@vger.kernel.org Signed-off-by: James Morris <james.l.morris@oracle.com>
Diffstat (limited to 'security')
-rw-r--r--security/keys/key.c3
1 files changed, 2 insertions, 1 deletions
diff --git a/security/keys/key.c b/security/keys/key.c
index 07a87311055c..09ef276c4bdc 100644
--- a/security/keys/key.c
+++ b/security/keys/key.c
@@ -430,7 +430,8 @@ static int __key_instantiate_and_link(struct key *key,
/* and link it into the destination keyring */
if (keyring) {
- set_bit(KEY_FLAG_KEEP, &key->flags);
+ if (test_bit(KEY_FLAG_KEEP, &keyring->flags))
+ set_bit(KEY_FLAG_KEEP, &key->flags);
__key_link(key, _edit);
}