path: root/security
diff options
authorDavid Howells <dhowells@redhat.com>2011-06-17 11:25:59 +0100
committerLinus Torvalds <torvalds@linux-foundation.org>2011-06-17 09:40:48 -0700
commit879669961b11e7f40b518784863a259f735a72bf (patch)
tree9bff5392e365caf656c9dd9be38f7471c182278c /security
parenteb96c925152fc289311e5d7e956b919e9b60ab53 (diff)
KEYS/DNS: Fix ____call_usermodehelper() to not lose the session keyring
____call_usermodehelper() now erases any credentials set by the subprocess_inf::init() function. The problem is that commit 17f60a7da150 ("capabilites: allow the application of capability limits to usermode helpers") creates and commits new credentials with prepare_kernel_cred() after the call to the init() function. This wipes all keyrings after umh_keys_init() is called. The best way to deal with this is to put the init() call just prior to the commit_creds() call, and pass the cred pointer to init(). That means that umh_keys_init() and suchlike can modify the credentials _before_ they are published and potentially in use by the rest of the system. This prevents request_key() from working as it is prevented from passing the session keyring it set up with the authorisation token to /sbin/request-key, and so the latter can't assume the authority to instantiate the key. This causes the in-kernel DNS resolver to fail with ENOKEY unconditionally. Signed-off-by: David Howells <dhowells@redhat.com> Acked-by: Eric Paris <eparis@redhat.com> Tested-by: Jeff Layton <jlayton@redhat.com> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'security')
1 files changed, 1 insertions, 2 deletions
diff --git a/security/keys/request_key.c b/security/keys/request_key.c
index d31862e0aa1c..8e319a416eec 100644
--- a/security/keys/request_key.c
+++ b/security/keys/request_key.c
@@ -71,9 +71,8 @@ EXPORT_SYMBOL(complete_request_key);
* This is called in context of freshly forked kthread before kernel_execve(),
* so we can simply install the desired session_keyring at this point.
-static int umh_keys_init(struct subprocess_info *info)
+static int umh_keys_init(struct subprocess_info *info, struct cred *cred)
- struct cred *cred = (struct cred*)current_cred();
struct key *keyring = info->data;
return install_session_keyring_to_cred(cred, keyring);