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From: Andy Lutomirski <luto@amacapital.net>
To: Will Drewry <wad@chromium.org>, linux-kernel@vger.kernel.org
Cc: Casey Schaufler <casey@schaufler-ca.com>,
	Linus Torvalds <torvalds@linux-foundation.org>,
	Jamie Lokier <jamie@shareable.org>,
	keescook@chromium.org, john.johansen@canonical.com,
	serge.hallyn@canonical.com, coreyb@linux.vnet.ibm.com,
	pmoore@redhat.com, eparis@redhat.com, djm@mindrot.org,
	segoon@openwall.com, rostedt@goodmis.org, jmorris@namei.org,
	scarybeasts@gmail.com, avi@redhat.com, penberg@cs.helsinki.fi,
	viro@zeniv.linux.org.uk, mingo@elte.hu,
	akpm@linux-foundation.org, khilman@ti.com,
	borislav.petkov@amd.com, amwang@redhat.com, oleg@redhat.com,
	ak@linux.intel.com, eric.dumazet@gmail.com, gregkh@suse.de,
	dhowells@redhat.com, daniel.lezcano@free.fr,
	linux-fsdevel@vger.kernel.org,
	linux-security-module@vger.kernel.org, olofj@chromium.org,
	mhalcrow@google.com, dlaor@redhat.com, corbet@lwn.net,
	alan@lxorguk.ukuu.org.uk, Al Viro <viro@zeniv.linux.org.uk>,
	Andy Lutomirski <luto@amacapital.net>
Subject: [PATCH v3 2/4] Fix apparmor for PR_{GET,SET}_NO_NEW_PRIVS
Date: Mon, 30 Jan 2012 08:17:27 -0800	[thread overview]
Message-ID: <fb49711a1ec532c2f2bc7a5f4c1f70df60e27973.1327858005.git.luto@amacapital.net> (raw)
In-Reply-To: <cover.1327858005.git.luto@amacapital.net>
In-Reply-To: <cover.1327858005.git.luto@amacapital.net>

From: John Johansen <john.johansen@canonical.com>

Signed-off-by: John Johansen <john.johansen@canonical.com>
Signed-off-by: Andy Lutomirski <luto@amacapital.net>
---
 security/apparmor/domain.c |   39 +++++++++++++++++++++++++++++++++++----
 1 files changed, 35 insertions(+), 4 deletions(-)

diff --git a/security/apparmor/domain.c b/security/apparmor/domain.c
index fcfb610..7316d77 100644
--- a/security/apparmor/domain.c
+++ b/security/apparmor/domain.c
@@ -360,10 +360,6 @@ int apparmor_bprm_set_creds(struct linux_binprm *bprm)
 	if (bprm->cred_prepared)
 		return 0;
 
-	/* XXX: no_new_privs is not usable with AppArmor yet */
-	if (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS)
-		return -EPERM;
-
 	cxt = bprm->cred->security;
 	BUG_ON(!cxt);
 
@@ -399,6 +395,11 @@ int apparmor_bprm_set_creds(struct linux_binprm *bprm)
 			new_profile = find_attach(ns, &ns->base.profiles, name);
 		if (!new_profile)
 			goto cleanup;
+		/*
+		 * NOTE: Domain transitions from unconfined are allowed
+		 * even when no_new_privs is set because this aways results
+		 * in a further reduction of permissions.
+		 */
 		goto apply;
 	}
 
@@ -459,6 +460,16 @@ int apparmor_bprm_set_creds(struct linux_binprm *bprm)
 		/* fail exec */
 		error = -EACCES;
 
+	/*
+	 * Policy has specified a domain transition, if no_new_privs then
+	 * fail the exec.
+	 */
+	if (bprm->unsafe & LSM_UNSAFE_NO_NEW_PRIVS) {
+		aa_put_profile(new_profile);
+		error = -EPERM;
+		goto cleanup;
+	}
+
 	if (!new_profile)
 		goto audit;
 
@@ -613,6 +624,14 @@ int aa_change_hat(const char *hats[], int count, u64 token, bool permtest)
 	const char *target = NULL, *info = NULL;
 	int error = 0;
 
+	/*
+	 * Fail explicitly requested domain transitions if no_new_privs.
+	 * There is no exception for unconfined as change_hat is not
+	 * available.
+	 */
+	if (current->no_new_privs)
+		return -EPERM;
+
 	/* released below */
 	cred = get_current_cred();
 	cxt = cred->security;
@@ -754,6 +773,18 @@ int aa_change_profile(const char *ns_name, const char *hname, bool onexec,
 	cxt = cred->security;
 	profile = aa_cred_profile(cred);
 
+	/*
+	 * Fail explicitly requested domain transitions if no_new_privs
+	 * and not unconfined.
+	 * Domain transitions from unconfined are allowed even when
+	 * no_new_privs is set because this aways results in a reduction
+	 * of permissions.
+	 */
+	if (current->no_new_privs && !unconfined(profile)) {
+		put_cred(cred);
+		return -EPERM;
+	}
+
 	if (ns_name) {
 		/* released below */
 		ns = aa_find_namespace(profile->ns, ns_name);
-- 
1.7.7.6


  parent reply	other threads:[~2012-01-30 16:18 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-01-30 16:17 [PATCH v3 0/4] PR_SET_NO_NEW_PRIVS, unshare, and chroot Andy Lutomirski
2012-01-30 16:17 ` [PATCH v3 1/4] Add PR_{GET,SET}_NO_NEW_PRIVS to prevent execve from granting privs Andy Lutomirski
2012-02-01 18:14   ` Kees Cook
2012-01-30 16:17 ` Andy Lutomirski [this message]
2012-01-30 16:17 ` [PATCH v3 3/4] Allow unprivileged CLONE_NEWUTS and CLONE_NEWIPC with no_new_privs Andy Lutomirski
2012-02-01 19:02   ` Kees Cook
2012-02-01 20:35     ` Andy Lutomirski
2012-01-30 16:17 ` [PATCH v3 4/4] Allow unprivileged chroot when safe Andy Lutomirski
2012-01-30 21:58   ` Colin Walters
2012-01-30 22:10     ` Andy Lutomirski
2012-01-30 22:41       ` Colin Walters
2012-01-30 22:43         ` Andy Lutomirski
2012-01-30 23:10           ` Colin Walters
2012-01-30 23:15             ` Andy Lutomirski
2012-01-30 23:55               ` Colin Walters
2012-01-31  0:13                 ` Andy Lutomirski
2012-01-30 22:18     ` Steven Rostedt
2012-01-30 22:28       ` Andy Lutomirski
2012-01-30 22:38       ` Will Drewry
2012-01-30 22:48         ` Colin Walters
2012-01-30 22:51         ` Andy Lutomirski
2012-02-09  9:35           ` Vasiliy Kulikov

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