From 879669961b11e7f40b518784863a259f735a72bf Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 17 Jun 2011 11:25:59 +0100 Subject: 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 Acked-by: Eric Paris Tested-by: Jeff Layton Signed-off-by: Linus Torvalds --- security/keys/request_key.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) (limited to 'security/keys/request_key.c') 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); -- cgit v1.2.3-59-g8ed1b