From mboxrd@z Thu Jan 1 00:00:00 1970 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,DKIMWL_WL_HIGH, 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 2D7B9C433E0 for ; Mon, 15 Feb 2021 16:23:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E960664E26 for ; Mon, 15 Feb 2021 16:23:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231522AbhBOQWi (ORCPT ); Mon, 15 Feb 2021 11:22:38 -0500 Received: from mail.kernel.org ([198.145.29.99]:49638 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231165AbhBOPfh (ORCPT ); Mon, 15 Feb 2021 10:35:37 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 9CE8164E70; Mon, 15 Feb 2021 15:31:36 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1613403097; bh=Ffhyf60erkGDMmC/z5vAbbYWcKe61yWtQ4zdQlyeutA=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=0iQ6lsfSrfoTQHrqJnZCeQ6B3EocuCVj1eKn0YCl4FhdtBa/ZnBP1+yz6K3Bps6Qd EqVt1+2iUGBc+c4mbtBA8dAhVWBf4rjXpeJMHULg5KEqLwxFX6kvZBk7cU2TSG/jK9 wWNxM4uwoM4hPzmqvTy0+EwSc8xg2HvUThCaLkbY= From: Greg Kroah-Hartman To: linux-kernel@vger.kernel.org Cc: Greg Kroah-Hartman , stable@vger.kernel.org, Miklos Szeredi , "Eric W. Biederman" , Sasha Levin Subject: [PATCH 5.10 026/104] cap: fix conversions on getxattr Date: Mon, 15 Feb 2021 16:26:39 +0100 Message-Id: <20210215152720.320621411@linuxfoundation.org> X-Mailer: git-send-email 2.30.1 In-Reply-To: <20210215152719.459796636@linuxfoundation.org> References: <20210215152719.459796636@linuxfoundation.org> User-Agent: quilt/0.66 MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Miklos Szeredi [ Upstream commit f2b00be488730522d0fb7a8a5de663febdcefe0a ] If a capability is stored on disk in v2 format cap_inode_getsecurity() will currently return in v2 format unconditionally. This is wrong: v2 cap should be equivalent to a v3 cap with zero rootid, and so the same conversions performed on it. If the rootid cannot be mapped, v3 is returned unconverted. Fix this so that both v2 and v3 return -EOVERFLOW if the rootid (or the owner of the fs user namespace in case of v2) cannot be mapped into the current user namespace. Signed-off-by: Miklos Szeredi Acked-by: "Eric W. Biederman" Signed-off-by: Sasha Levin --- security/commoncap.c | 67 ++++++++++++++++++++++++++++---------------- 1 file changed, 43 insertions(+), 24 deletions(-) diff --git a/security/commoncap.c b/security/commoncap.c index 59bf3c1674c8b..a6c9bb4441d54 100644 --- a/security/commoncap.c +++ b/security/commoncap.c @@ -371,10 +371,11 @@ int cap_inode_getsecurity(struct inode *inode, const char *name, void **buffer, { int size, ret; kuid_t kroot; + u32 nsmagic, magic; uid_t root, mappedroot; char *tmpbuf = NULL; struct vfs_cap_data *cap; - struct vfs_ns_cap_data *nscap; + struct vfs_ns_cap_data *nscap = NULL; struct dentry *dentry; struct user_namespace *fs_ns; @@ -396,46 +397,61 @@ int cap_inode_getsecurity(struct inode *inode, const char *name, void **buffer, fs_ns = inode->i_sb->s_user_ns; cap = (struct vfs_cap_data *) tmpbuf; if (is_v2header((size_t) ret, cap)) { - /* If this is sizeof(vfs_cap_data) then we're ok with the - * on-disk value, so return that. */ - if (alloc) - *buffer = tmpbuf; - else - kfree(tmpbuf); - return ret; - } else if (!is_v3header((size_t) ret, cap)) { - kfree(tmpbuf); - return -EINVAL; + root = 0; + } else if (is_v3header((size_t) ret, cap)) { + nscap = (struct vfs_ns_cap_data *) tmpbuf; + root = le32_to_cpu(nscap->rootid); + } else { + size = -EINVAL; + goto out_free; } - nscap = (struct vfs_ns_cap_data *) tmpbuf; - root = le32_to_cpu(nscap->rootid); kroot = make_kuid(fs_ns, root); /* If the root kuid maps to a valid uid in current ns, then return * this as a nscap. */ mappedroot = from_kuid(current_user_ns(), kroot); if (mappedroot != (uid_t)-1 && mappedroot != (uid_t)0) { + size = sizeof(struct vfs_ns_cap_data); if (alloc) { - *buffer = tmpbuf; + if (!nscap) { + /* v2 -> v3 conversion */ + nscap = kzalloc(size, GFP_ATOMIC); + if (!nscap) { + size = -ENOMEM; + goto out_free; + } + nsmagic = VFS_CAP_REVISION_3; + magic = le32_to_cpu(cap->magic_etc); + if (magic & VFS_CAP_FLAGS_EFFECTIVE) + nsmagic |= VFS_CAP_FLAGS_EFFECTIVE; + memcpy(&nscap->data, &cap->data, sizeof(__le32) * 2 * VFS_CAP_U32); + nscap->magic_etc = cpu_to_le32(nsmagic); + } else { + /* use allocated v3 buffer */ + tmpbuf = NULL; + } nscap->rootid = cpu_to_le32(mappedroot); - } else - kfree(tmpbuf); - return size; + *buffer = nscap; + } + goto out_free; } if (!rootid_owns_currentns(kroot)) { - kfree(tmpbuf); - return -EOPNOTSUPP; + size = -EOVERFLOW; + goto out_free; } /* This comes from a parent namespace. Return as a v2 capability */ size = sizeof(struct vfs_cap_data); if (alloc) { - *buffer = kmalloc(size, GFP_ATOMIC); - if (*buffer) { - struct vfs_cap_data *cap = *buffer; - __le32 nsmagic, magic; + if (nscap) { + /* v3 -> v2 conversion */ + cap = kzalloc(size, GFP_ATOMIC); + if (!cap) { + size = -ENOMEM; + goto out_free; + } magic = VFS_CAP_REVISION_2; nsmagic = le32_to_cpu(nscap->magic_etc); if (nsmagic & VFS_CAP_FLAGS_EFFECTIVE) @@ -443,9 +459,12 @@ int cap_inode_getsecurity(struct inode *inode, const char *name, void **buffer, memcpy(&cap->data, &nscap->data, sizeof(__le32) * 2 * VFS_CAP_U32); cap->magic_etc = cpu_to_le32(magic); } else { - size = -ENOMEM; + /* use unconverted v2 */ + tmpbuf = NULL; } + *buffer = cap; } +out_free: kfree(tmpbuf); return size; } -- 2.27.0