From patchwork Tue Apr 26 19:36:26 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Seth Forshee X-Patchwork-Id: 8943811 Return-Path: X-Original-To: patchwork-linux-fsdevel@patchwork.kernel.org Delivered-To: patchwork-parsemail@patchwork2.web.kernel.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.136]) by patchwork2.web.kernel.org (Postfix) with ESMTP id E8287BF29F for ; Tue, 26 Apr 2016 19:43:54 +0000 (UTC) Received: from mail.kernel.org (localhost [127.0.0.1]) by mail.kernel.org (Postfix) with ESMTP id CA3A0201C7 for ; Tue, 26 Apr 2016 19:43:53 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 94A4A20166 for ; Tue, 26 Apr 2016 19:43:52 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753132AbcDZTn2 (ORCPT ); Tue, 26 Apr 2016 15:43:28 -0400 Received: from mail-io0-f175.google.com ([209.85.223.175]:36228 "EHLO mail-io0-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752783AbcDZThH (ORCPT ); Tue, 26 Apr 2016 15:37:07 -0400 Received: by mail-io0-f175.google.com with SMTP id u185so30182620iod.3 for ; Tue, 26 Apr 2016 12:37:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=canonical-com.20150623.gappssmtp.com; s=20150623; h=from:to:cc:subject:date:message-id:in-reply-to:references; bh=2E0VoJF/ExWKPUkUD6OQauklR/etRVxTBqNKD6CAktw=; b=1H5wXsGjIgNnaq2YI6mxvZSLjhcUqbHV82szmeRm8Ipn2tJFaqxcqezCkBOd71RxDf DPhreKosFwYhlpJ8Lk5UCQexNP56ScpDdPSG6otktkIBANmjb84wqYepfFk6WpmtYiuC RKRC+SNsBAj25Ikffp+9ft0CrXPw+kgSJU3jP//Td1ad5duJH49pD4HWsiEAkzl9nz9o JCKjGqt58iMSvuLwBDuYL/79Ol6Y8A2gSbAKhM9MQV6RW4SG2aqkO8Zv/Ar93s/huQVJ pljIyofpWN1Gzx6L95OrRNJknbz++0PsXW1IhC8n/IQ6h8dMT0YPnYPWfgebvkkzvmq8 e1WA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20130820; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references; bh=2E0VoJF/ExWKPUkUD6OQauklR/etRVxTBqNKD6CAktw=; b=fW4BwJ3QN9XOsJ0KECZQEHu8UbwN0M4nRKnoGrWTxf6slMd8l0WMtd/3b/X9BqgYQY QWX3BDtu6e7XAscvB129kW9G/47CD/b+0B2OFh9AS/UzRpw3zUisryiJbGTrzFna2LGy uqUP2bsqArNWrUPx1b+pQxfDx7cqs8cMSCeC9o4sNvwAzsasjiXExPRGWmTg1LLtTQki xB6hsf1egBszVnTGz0AATSwvnxzXpVsBHQ+9jhVmFLgwDRXlbeP9OVr5yLoJU3gilbRr dR8imhdhQ3RGFSyJO1Q3xvNNyudNVoLfrTzeoaDoinEjJPu72l89m+gQL52lnPKeWpSd ctNQ== X-Gm-Message-State: AOPr4FVGhPaHxL60cyV14bap3zK335EinWj0fVOQ0POdo+3TfoknwJKSwcUxV81e3KZO3TDr X-Received: by 10.107.17.19 with SMTP id z19mr6524987ioi.43.1461699426775; Tue, 26 Apr 2016 12:37:06 -0700 (PDT) Received: from localhost ([2605:a601:aab:f920:39a1:5bcf:aa:5b00]) by smtp.gmail.com with ESMTPSA id b9sm4080444igv.6.2016.04.26.12.37.06 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Tue, 26 Apr 2016 12:37:06 -0700 (PDT) From: Seth Forshee To: "Eric W. Biederman" , Alexander Viro Cc: Serge Hallyn , Richard Weinberger , Austin S Hemmelgarn , Miklos Szeredi , Pavel Tikhomirov , linux-kernel@vger.kernel.org, linux-bcache@vger.kernel.org, dm-devel@redhat.com, linux-raid@vger.kernel.org, linux-mtd@lists.infradead.org, linux-fsdevel@vger.kernel.org, fuse-devel@lists.sourceforge.net, linux-security-module@vger.kernel.org, selinux@tycho.nsa.gov, cgroups@vger.kernel.org, Seth Forshee Subject: [PATCH v4 13/21] fs: Update posix_acl support to handle user namespace mounts Date: Tue, 26 Apr 2016 14:36:26 -0500 Message-Id: <1461699396-33000-14-git-send-email-seth.forshee@canonical.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1461699396-33000-1-git-send-email-seth.forshee@canonical.com> References: <1461699396-33000-1-git-send-email-seth.forshee@canonical.com> Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Spam-Status: No, score=-7.8 required=5.0 tests=BAYES_00,DKIM_SIGNED, RCVD_IN_DNSWL_HI,RP_MATCHES_RCVD,T_DKIM_INVALID,UNPARSEABLE_RELAY autolearn=unavailable version=3.3.1 X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on mail.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP ids in on-disk ACLs should be converted to s_user_ns instead of init_user_ns as is done now. This introduces the possibility for id mappings to fail, and when this happens syscalls will return EOVERFLOW. Signed-off-by: Seth Forshee Acked-by: Serge Hallyn --- fs/posix_acl.c | 67 ++++++++++++++++++++++++++--------------- fs/xattr.c | 19 +++++++++--- include/linux/posix_acl_xattr.h | 17 ++++++++--- 3 files changed, 70 insertions(+), 33 deletions(-) diff --git a/fs/posix_acl.c b/fs/posix_acl.c index 711dd5170376..dac2842dd4cb 100644 --- a/fs/posix_acl.c +++ b/fs/posix_acl.c @@ -595,59 +595,77 @@ EXPORT_SYMBOL_GPL(posix_acl_create); /* * Fix up the uids and gids in posix acl extended attributes in place. */ -static void posix_acl_fix_xattr_userns( +static int posix_acl_fix_xattr_userns( struct user_namespace *to, struct user_namespace *from, void *value, size_t size) { posix_acl_xattr_header *header = (posix_acl_xattr_header *)value; posix_acl_xattr_entry *entry = (posix_acl_xattr_entry *)(header+1), *end; int count; - kuid_t uid; - kgid_t gid; + kuid_t kuid; + uid_t uid; + kgid_t kgid; + gid_t gid; if (!value) - return; + return 0; if (size < sizeof(posix_acl_xattr_header)) - return; + return 0; if (header->a_version != cpu_to_le32(POSIX_ACL_XATTR_VERSION)) - return; + return 0; count = posix_acl_xattr_count(size); if (count < 0) - return; + return 0; if (count == 0) - return; + return 0; for (end = entry + count; entry != end; entry++) { switch(le16_to_cpu(entry->e_tag)) { case ACL_USER: - uid = make_kuid(from, le32_to_cpu(entry->e_id)); - entry->e_id = cpu_to_le32(from_kuid(to, uid)); + kuid = make_kuid(from, le32_to_cpu(entry->e_id)); + if (!uid_valid(kuid)) + return -EOVERFLOW; + uid = from_kuid(to, kuid); + if (uid == (uid_t)-1) + return -EOVERFLOW; + entry->e_id = cpu_to_le32(uid); break; case ACL_GROUP: - gid = make_kgid(from, le32_to_cpu(entry->e_id)); - entry->e_id = cpu_to_le32(from_kgid(to, gid)); + kgid = make_kgid(from, le32_to_cpu(entry->e_id)); + if (!gid_valid(kgid)) + return -EOVERFLOW; + gid = from_kgid(to, kgid); + if (gid == (gid_t)-1) + return -EOVERFLOW; + entry->e_id = cpu_to_le32(gid); break; default: break; } } + + return 0; } -void posix_acl_fix_xattr_from_user(void *value, size_t size) +int +posix_acl_fix_xattr_from_user(struct user_namespace *target_ns, void *value, + size_t size) { - struct user_namespace *user_ns = current_user_ns(); - if (user_ns == &init_user_ns) - return; - posix_acl_fix_xattr_userns(&init_user_ns, user_ns, value, size); + struct user_namespace *source_ns = current_user_ns(); + if (source_ns == target_ns) + return 0; + return posix_acl_fix_xattr_userns(target_ns, source_ns, value, size); } -void posix_acl_fix_xattr_to_user(void *value, size_t size) +int +posix_acl_fix_xattr_to_user(struct user_namespace *source_ns, void *value, + size_t size) { - struct user_namespace *user_ns = current_user_ns(); - if (user_ns == &init_user_ns) - return; - posix_acl_fix_xattr_userns(user_ns, &init_user_ns, value, size); + struct user_namespace *target_ns = current_user_ns(); + if (target_ns == source_ns) + return 0; + return posix_acl_fix_xattr_userns(target_ns, source_ns, value, size); } /* @@ -780,7 +798,7 @@ posix_acl_xattr_get(const struct xattr_handler *handler, if (acl == NULL) return -ENODATA; - error = posix_acl_to_xattr(&init_user_ns, acl, value, size); + error = posix_acl_to_xattr(dentry->d_sb->s_user_ns, acl, value, size); posix_acl_release(acl); return error; @@ -806,7 +824,8 @@ posix_acl_xattr_set(const struct xattr_handler *handler, return -EPERM; if (value) { - acl = posix_acl_from_xattr(&init_user_ns, value, size); + acl = posix_acl_from_xattr(dentry->d_sb->s_user_ns, value, + size); if (IS_ERR(acl)) return PTR_ERR(acl); diff --git a/fs/xattr.c b/fs/xattr.c index 4861322e28e8..c541121945cd 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -330,8 +330,12 @@ setxattr(struct dentry *d, const char __user *name, const void __user *value, goto out; } if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) || - (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)) - posix_acl_fix_xattr_from_user(kvalue, size); + (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)) { + error = posix_acl_fix_xattr_from_user(d->d_sb->s_user_ns, + kvalue, size); + if (error) + goto out; + } } error = vfs_setxattr(d, kname, kvalue, size, flags); @@ -427,9 +431,14 @@ getxattr(struct dentry *d, const char __user *name, void __user *value, error = vfs_getxattr(d, kname, kvalue, size); if (error > 0) { if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) || - (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)) - posix_acl_fix_xattr_to_user(kvalue, size); - if (size && copy_to_user(value, kvalue, error)) + (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)) { + int ret; + ret = posix_acl_fix_xattr_to_user(d->d_sb->s_user_ns, + kvalue, size); + if (ret) + error = ret; + } + if (error > 0 && size && copy_to_user(value, kvalue, error)) error = -EFAULT; } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) { /* The file system tried to returned a value bigger diff --git a/include/linux/posix_acl_xattr.h b/include/linux/posix_acl_xattr.h index e5e8ec40278d..5dec6b10951a 100644 --- a/include/linux/posix_acl_xattr.h +++ b/include/linux/posix_acl_xattr.h @@ -49,14 +49,23 @@ posix_acl_xattr_count(size_t size) } #ifdef CONFIG_FS_POSIX_ACL -void posix_acl_fix_xattr_from_user(void *value, size_t size); -void posix_acl_fix_xattr_to_user(void *value, size_t size); +int posix_acl_fix_xattr_from_user(struct user_namespace *target_ns, + void *value, size_t size); +int posix_acl_fix_xattr_to_user(struct user_namespace *source_ns, void *value, + size_t size); #else -static inline void posix_acl_fix_xattr_from_user(void *value, size_t size) +static inline int +posix_acl_fix_xattr_from_user(struct user_namespace *target_ns, void *value, + size_t size) { + return 0; } -static inline void posix_acl_fix_xattr_to_user(void *value, size_t size) + +static inline int +posix_acl_fix_xattr_to_user(struct user_namespace *source_ns, void *value, + size_t size) { + return 0; } #endif