From patchwork Mon Dec 28 12:49:33 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Greg Kroah-Hartman X-Patchwork-Id: 354467 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-18.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID, DKIM_VALID_AU, HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER, INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3784EC43333 for ; Mon, 28 Dec 2020 15:59:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1C54C224D2 for ; Mon, 28 Dec 2020 15:59:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387863AbgL1NdP (ORCPT ); Mon, 28 Dec 2020 08:33:15 -0500 Received: from mail.kernel.org ([198.145.29.99]:33496 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2387855AbgL1NdO (ORCPT ); Mon, 28 Dec 2020 08:33:14 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 0747C205CB; Mon, 28 Dec 2020 13:32:57 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1609162378; bh=WwdSu1cG6CLU8EYZ1nQEUZzBfnFvqLD1stcDgrJK7CE=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=NmsoFCtxRwYCjdsb9VqWWdMSex9H7S2sEbeLc3FFfBvwsnNP5W2HpmOSfuSzSFbF6 c1RHMVQTLEdMWOPucU/j7xmxPD46gIwrZylkmb9rXJoifYUD/QrfdJ3RNoGu820ByV ISvjxUhASsAUu0q25mqE090qw30BA+Hdg/fajnGk= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, =?utf-8?q?Herv=C3=A9_Guillemet?= , Casey Schaufler , Serge Hallyn , "Andrew G. Morgan" , James Morris , Sasha Levin Subject: [PATCH 4.19 254/346] [SECURITY] fix namespaced fscaps when !CONFIG_SECURITY Date: Mon, 28 Dec 2020 13:49:33 +0100 Message-Id: <20201228124932.060888289@linuxfoundation.org> X-Mailer: git-send-email 2.29.2 In-Reply-To: <20201228124919.745526410@linuxfoundation.org> References: <20201228124919.745526410@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: stable@vger.kernel.org From: Serge Hallyn [ Upstream commit ed9b25d1970a4787ac6a39c2091e63b127ecbfc1 ] Namespaced file capabilities were introduced in 8db6c34f1dbc . When userspace reads an xattr for a namespaced capability, a virtualized representation of it is returned if the caller is in a user namespace owned by the capability's owning rootid. The function which performs this virtualization was not hooked up if CONFIG_SECURITY=n. Therefore in that case the original xattr was shown instead of the virtualized one. To test this using libcap-bin (*1), $ v=$(mktemp) $ unshare -Ur setcap cap_sys_admin-eip $v $ unshare -Ur setcap -v cap_sys_admin-eip $v /tmp/tmp.lSiIFRvt8Y: OK "setcap -v" verifies the values instead of setting them, and will check whether the rootid value is set. Therefore, with this bug un-fixed, and with CONFIG_SECURITY=n, setcap -v will fail: $ v=$(mktemp) $ unshare -Ur setcap cap_sys_admin=eip $v $ unshare -Ur setcap -v cap_sys_admin=eip $v nsowner[got=1000, want=0],/tmp/tmp.HHDiOOl9fY differs in [] Fix this bug by calling cap_inode_getsecurity() in security_inode_getsecurity() instead of returning -EOPNOTSUPP, when CONFIG_SECURITY=n. *1 - note, if libcap is too old for getcap to have the '-n' option, then use verify-caps instead. Bugzilla: https://bugzilla.kernel.org/show_bug.cgi?id=209689 Cc: Hervé Guillemet Acked-by: Casey Schaufler Signed-off-by: Serge Hallyn Signed-off-by: Andrew G. Morgan Signed-off-by: James Morris Signed-off-by: Sasha Levin --- include/linux/security.h | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff --git a/include/linux/security.h b/include/linux/security.h index d2240605edc46..454cc963d1457 100644 --- a/include/linux/security.h +++ b/include/linux/security.h @@ -787,7 +787,7 @@ static inline int security_inode_killpriv(struct dentry *dentry) static inline int security_inode_getsecurity(struct inode *inode, const char *name, void **buffer, bool alloc) { - return -EOPNOTSUPP; + return cap_inode_getsecurity(inode, name, buffer, alloc); } static inline int security_inode_setsecurity(struct inode *inode, const char *name, const void *value, size_t size, int flags)