lkml.org 
[lkml]   [2014]   [Sep]   [10]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
Patch in this message
/
SubjectRe: [PATCH 2/6] KEYS: Reinstate EPERM for a key type name beginning with a '.'
From
Date
On Wed, 2014-09-10 at 22:22 +0100, David Howells wrote: 
> Reinstate the generation of EPERM for a key type name beginning with a '.' in
> a userspace call. Types whose name begins with a '.' are internal only.
>
> The test was removed by:
>
> commit a4e3b8d79a5c6d40f4a9703abf7fe3abcc6c3b8d
> Author: Mimi Zohar <zohar@linux.vnet.ibm.com>
> Date: Thu May 22 14:02:23 2014 -0400
> Subject: KEYS: special dot prefixed keyring name bug fix
>

The test was removed, as the patch log description indicates, because
the comparison is against the wrong field. Even the function name
indicates key_get_type_from_user() is about the key type, not the key or
keyring name.

Debugging info:

diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
index e26f860..7a8d9b9 100644
--- a/security/keys/keyctl.c
+++ b/security/keys/keyctl.c
@@ -37,6 +37,7 @@ static int key_get_type_from_user(char *type,
return ret;
if (ret == 0 || ret >= len)
return -EINVAL;
+ printk(KERN_INFO "%s: type %s \n", __func__, type);
type[len - 1] = '\0';
return 0;
}

: [ 7.725429]: key_get_type_from_user: type trusted
: [ 9.007721] key_get_type_from_user: type keyring
: [ 9.011889] key_get_type_from_user: type keyring
: [ 9.068825] key_get_type_from_user: type encrypted
: [ 9.268310] key_get_type_from_user: type asymmetric
: [ 9.290360] key_get_type_from_user: type keyring
: [ 9.354509] key_get_type_from_user: type asymmetric
: [ 9.390396] key_get_type_from_user: type asymmetric
: [ 9.414216] key_get_type_from_user: type asymmetric
: [ 9.437155] key_get_type_from_user: type asymmetric

> I think we want to keep the restriction on type name so that userspace can't
> add keys of a special internal type.

Definitely! Commit a4e3b8d7 added a comparison against the description.

> Note that removal of the test causes several of the tests in the keyutils
> testsuite to fail.

Perhaps the added description test is insufficient, but reverting this
commit won't resolve the underlying problem.

Mimi

> Signed-off-by: David Howells <dhowells@redhat.com>
> Acked-by: Vivek Goyal <vgoyal@redhat.com>
> cc: Mimi Zohar <zohar@linux.vnet.ibm.com>
> ---
>
> security/keys/keyctl.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/security/keys/keyctl.c b/security/keys/keyctl.c
> index e26f860e5f2e..eff88a5f5d40 100644
> --- a/security/keys/keyctl.c
> +++ b/security/keys/keyctl.c
> @@ -37,6 +37,8 @@ static int key_get_type_from_user(char *type,
> return ret;
> if (ret == 0 || ret >= len)
> return -EINVAL;
> + if (type[0] == '.')
> + return -EPERM;
> type[len - 1] = '\0';
> return 0;
> }
>




\
 
 \ /
  Last update: 2014-09-11 02:01    [W:1.763 / U:0.008 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site