Commit 5b841bfa authored Oct 17, 2018 by Zoran Markovic Committed by Casey Schaufler Dec 03, 2018

smack: fix access permissions for keyring



Function smack_key_permission() only issues smack requests for the
following operations:
 - KEY_NEED_READ (issues MAY_READ)
 - KEY_NEED_WRITE (issues MAY_WRITE)
 - KEY_NEED_LINK (issues MAY_WRITE)
 - KEY_NEED_SETATTR (issues MAY_WRITE)
A blank smack request is issued in all other cases, resulting in
smack access being granted if there is any rule defined between
subject and object, or denied with -EACCES otherwise.

Request MAY_READ access for KEY_NEED_SEARCH and KEY_NEED_VIEW.
Fix the logic in the unlikely case when both MAY_READ and
MAY_WRITE are needed. Validate access permission field for valid
contents.

Signed-off-by: Zoran Markovic <zmarkovic@sierrawireless.com>
Signed-off-by: Casey Schaufler <casey@schaufler-ca.com>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Cc: James Morris <jmorris@namei.org>
Cc: "Serge E. Hallyn" <serge@hallyn.com>

parent 26b76320

security/smack/smack_lsm.c

+9 −3

Original line number	Diff line number	Diff line
		@@ -4333,6 +4333,12 @@ static int smack_key_permission(key_ref_t key_ref,
		int request = 0;
		int rc;

		/*
		* Validate requested permissions
		*/
		if (perm & ~KEY_NEED_ALL)
		return -EINVAL;

		keyp = key_ref_to_ptr(key_ref);
		if (keyp == NULL)
		return -EINVAL;
		@@ -4356,10 +4362,10 @@ static int smack_key_permission(key_ref_t key_ref,
		ad.a.u.key_struct.key = keyp->serial;
		ad.a.u.key_struct.key_desc = keyp->description;
		#endif
		if (perm & KEY_NEED_READ)
		request = MAY_READ;
		if (perm & (KEY_NEED_READ \| KEY_NEED_SEARCH \| KEY_NEED_VIEW))
		request \|= MAY_READ;
		if (perm & (KEY_NEED_WRITE \| KEY_NEED_LINK \| KEY_NEED_SETATTR))
		request = MAY_WRITE;
		request \|= MAY_WRITE;
		rc = smk_access(tkp, keyp->security, request, &ad);
		rc = smk_bu_note("key access", tkp, keyp->security, request, rc);
		return rc;