2015-02-12 16:45:49

by David Howells

Subject: [PATCH] Don't leak a key reference if request_key() tries to use a revoked keyring

From: David Jeffery <[email protected]>

If a request_key() call to allocate and fill out a key attempts to insert the
key structure into a revoked keyring, the key will leak, using memory and part
of the user's key quota until the system reboots. This is from a failure of
construct_alloc_key() to decrement the key's reference count after the attempt
to insert into the requested keyring is rejected.

key_put() needs to be called in the link_prealloc_failed callpath to ensure
the unused key is released.

Signed-off-by: David Jeffery <[email protected]>
Signed-off-by: David Howells <[email protected]>
---

security/keys/request_key.c | 1 +
1 file changed, 1 insertion(+)

diff --git a/security/keys/request_key.c b/security/keys/request_key.c
index 0c7aea4dea54..486ef6fa393b 100644
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -414,6 +414,7 @@ link_check_failed:

link_prealloc_failed:
mutex_unlock(&user->cons_lock);
+ key_put(key);
kleave(" = %d [prelink]", ret);
return ret;

2015-02-16 02:27:41

by James Morris

Subject: Re: [PATCH] Don't leak a key reference if request_key() tries to use a revoked keyring

On Thu, 12 Feb 2015, David Howells wrote:

> From: David Jeffery <[email protected]>
>
> If a request_key() call to allocate and fill out a key attempts to insert the
> key structure into a revoked keyring, the key will leak, using memory and part
> of the user's key quota until the system reboots. This is from a failure of
> construct_alloc_key() to decrement the key's reference count after the attempt
> to insert into the requested keyring is rejected.
>
> key_put() needs to be called in the link_prealloc_failed callpath to ensure
> the unused key is released.
>
> Signed-off-by: David Jeffery <[email protected]>
> Signed-off-by: David Howells <[email protected]>

Applied.


--
James Morris
<[email protected]>