* [PATCH] Don't leak a key reference if request_key() tries to use a revoked keyring
@ 2015-02-11 21:26 David Jeffery
2015-02-12 16:46 ` David Howells
0 siblings, 1 reply; 4+ messages in thread
From: David Jeffery @ 2015-02-11 21:26 UTC (permalink / raw)
To: keyrings; +Cc: David Howells, linux-kernel
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 <djeffery@redhat.com>
---
The basic way to trigger this is to use keyctl to revoke a session's keyring,
then do an action which will trigger request_key(). request_key() will fail
and a key will leak.
diff --git a/security/keys/request_key.c b/security/keys/request_key.c
index 0c7aea4..486ef6f 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;
^ permalink raw reply related [flat|nested] 4+ messages in thread
* [PATCH] Don't leak a key reference if request_key() tries to use a revoked keyring
@ 2015-02-12 16:45 David Howells
2015-02-16 2:27 ` James Morris
0 siblings, 1 reply; 4+ messages in thread
From: David Howells @ 2015-02-12 16:45 UTC (permalink / raw)
To: jmorris
Cc: dhowells, linux-security-module, keyrings, David Jeffery,
linux-kernel
From: David Jeffery <djeffery@redhat.com>
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 <djeffery@redhat.com>
Signed-off-by: David Howells <dhowells@redhat.com>
---
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;
^ permalink raw reply related [flat|nested] 4+ messages in thread
* Re: [PATCH] Don't leak a key reference if request_key() tries to use a revoked keyring
2015-02-11 21:26 [PATCH] Don't leak a key reference if request_key() tries to use a revoked keyring David Jeffery
@ 2015-02-12 16:46 ` David Howells
0 siblings, 0 replies; 4+ messages in thread
From: David Howells @ 2015-02-12 16:46 UTC (permalink / raw)
To: David Jeffery; +Cc: dhowells, keyrings, linux-kernel
David Jeffery <djeffery@redhat.com> wrote:
> 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.
Applied.
^ permalink raw reply [flat|nested] 4+ messages in thread
* Re: [PATCH] Don't leak a key reference if request_key() tries to use a revoked keyring
2015-02-12 16:45 David Howells
@ 2015-02-16 2:27 ` James Morris
0 siblings, 0 replies; 4+ messages in thread
From: James Morris @ 2015-02-16 2:27 UTC (permalink / raw)
To: David Howells
Cc: linux-security-module, keyrings, David Jeffery, linux-kernel
On Thu, 12 Feb 2015, David Howells wrote:
> From: David Jeffery <djeffery@redhat.com>
>
> 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 <djeffery@redhat.com>
> Signed-off-by: David Howells <dhowells@redhat.com>
Applied.
--
James Morris
<jmorris@namei.org>
^ permalink raw reply [flat|nested] 4+ messages in thread
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