Return-Path: Received: from mail-wi0-f173.google.com ([209.85.212.173]:33714 "EHLO mail-wi0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932603AbbDXLFU (ORCPT ); Fri, 24 Apr 2015 07:05:20 -0400 From: Andreas Gruenbacher To: linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-nfs@vger.kernel.org Subject: [RFC v3 21/45] richacl: xattr mapping functions Date: Fri, 24 Apr 2015 13:04:18 +0200 Message-Id: In-Reply-To: References: In-Reply-To: References: Sender: linux-nfs-owner@vger.kernel.org List-ID: Map between "system.richacl" xattrs and the in-kernel representation. Signed-off-by: Andreas Gruenbacher --- fs/Makefile | 2 +- fs/richacl_xattr.c | 210 ++++++++++++++++++++++++++++++++++++++++++ fs/xattr.c | 34 +++++-- include/linux/richacl_xattr.h | 52 +++++++++++ include/uapi/linux/xattr.h | 2 + 5 files changed, 293 insertions(+), 7 deletions(-) create mode 100644 fs/richacl_xattr.c create mode 100644 include/linux/richacl_xattr.h diff --git a/fs/Makefile b/fs/Makefile index bb96ad7..6155cc4 100644 --- a/fs/Makefile +++ b/fs/Makefile @@ -48,7 +48,7 @@ obj-$(CONFIG_SYSCTL) += drop_caches.o obj-$(CONFIG_FHANDLE) += fhandle.o obj-$(CONFIG_FS_RICHACL) += richacl.o -richacl-y := richacl_base.o richacl_inode.o +richacl-y := richacl_base.o richacl_inode.o richacl_xattr.o obj-y += quota/ diff --git a/fs/richacl_xattr.c b/fs/richacl_xattr.c new file mode 100644 index 0000000..1fb5b36 --- /dev/null +++ b/fs/richacl_xattr.c @@ -0,0 +1,210 @@ +/* + * Copyright (C) 2006, 2010 Novell, Inc. + * Copyright (C) 2015 Red Hat, Inc. + * Written by Andreas Gruenbacher + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2, or (at your option) any + * later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + */ + +#include +#include +#include +#include +#include + +MODULE_LICENSE("GPL"); + +/** + * richacl_from_xattr - convert a richacl xattr into the in-memory representation + */ +struct richacl * +richacl_from_xattr(struct user_namespace *user_ns, + const void *value, size_t size) +{ + const struct richacl_xattr *xattr_acl = value; + const struct richace_xattr *xattr_ace = (void *)(xattr_acl + 1); + struct richacl *acl; + struct richace *ace; + int count; + + if (size < sizeof(*xattr_acl) || + xattr_acl->a_version != RICHACL_XATTR_VERSION || + (xattr_acl->a_flags & ~RICHACL_VALID_FLAGS) || + xattr_acl->a_unused != 0) + return ERR_PTR(-EINVAL); + size -= sizeof(*xattr_acl); + if (size % sizeof(*xattr_ace)) + return ERR_PTR(-EINVAL); + count = size / sizeof(*xattr_ace); + if (count > RICHACL_XATTR_MAX_COUNT) + return ERR_PTR(-EINVAL); + + acl = richacl_alloc(count, GFP_NOFS); + if (!acl) + return ERR_PTR(-ENOMEM); + + acl->a_flags = xattr_acl->a_flags; + acl->a_owner_mask = le32_to_cpu(xattr_acl->a_owner_mask); + if (acl->a_owner_mask & ~RICHACE_VALID_MASK) + goto fail_einval; + acl->a_group_mask = le32_to_cpu(xattr_acl->a_group_mask); + if (acl->a_group_mask & ~RICHACE_VALID_MASK) + goto fail_einval; + acl->a_other_mask = le32_to_cpu(xattr_acl->a_other_mask); + if (acl->a_other_mask & ~RICHACE_VALID_MASK) + goto fail_einval; + + richacl_for_each_entry(ace, acl) { + ace->e_type = le16_to_cpu(xattr_ace->e_type); + ace->e_flags = le16_to_cpu(xattr_ace->e_flags); + ace->e_mask = le32_to_cpu(xattr_ace->e_mask); + + if (ace->e_flags & ~RICHACE_VALID_FLAGS) + goto fail_einval; + if (ace->e_flags & RICHACE_SPECIAL_WHO) { + ace->e_id.special = le32_to_cpu(xattr_ace->e_id); + if (ace->e_id.special > RICHACE_EVERYONE_SPECIAL_ID) + goto fail_einval; + } else if (ace->e_flags & RICHACE_IDENTIFIER_GROUP) { + ace->e_id.gid = make_kgid(user_ns, le32_to_cpu(xattr_ace->e_id)); + if (!gid_valid(ace->e_id.gid)) + goto fail_einval; + } else { + ace->e_id.uid = make_kuid(user_ns, le32_to_cpu(xattr_ace->e_id)); + if (!uid_valid(ace->e_id.uid)) + goto fail_einval; + } + if (ace->e_type > RICHACE_ACCESS_DENIED_ACE_TYPE || + (ace->e_mask & ~RICHACE_VALID_MASK)) + goto fail_einval; + + xattr_ace++; + } + + return acl; + +fail_einval: + richacl_put(acl); + return ERR_PTR(-EINVAL); +} +EXPORT_SYMBOL_GPL(richacl_from_xattr); + +/** + * richacl_xattr_size - compute the size of the xattr representation of @acl + */ +size_t +richacl_xattr_size(const struct richacl *acl) +{ + size_t size = sizeof(struct richacl_xattr); + + size += sizeof(struct richace_xattr) * acl->a_count; + return size; +} +EXPORT_SYMBOL_GPL(richacl_xattr_size); + +/** + * richacl_to_xattr - convert @acl into its xattr representation + * @acl: the richacl to convert + * @buffer: buffer for the result + * @size: size of @buffer + */ +int +richacl_to_xattr(struct user_namespace *user_ns, + const struct richacl *acl, void *buffer, size_t size) +{ + struct richacl_xattr *xattr_acl = buffer; + struct richace_xattr *xattr_ace; + const struct richace *ace; + size_t real_size; + + real_size = richacl_xattr_size(acl); + if (!buffer) + return real_size; + if (real_size > size) + return -ERANGE; + + xattr_acl->a_version = RICHACL_XATTR_VERSION; + xattr_acl->a_flags = acl->a_flags; + xattr_acl->a_unused = 0; + + xattr_acl->a_owner_mask = cpu_to_le32(acl->a_owner_mask); + xattr_acl->a_group_mask = cpu_to_le32(acl->a_group_mask); + xattr_acl->a_other_mask = cpu_to_le32(acl->a_other_mask); + + xattr_ace = (void *)(xattr_acl + 1); + richacl_for_each_entry(ace, acl) { + xattr_ace->e_type = cpu_to_le16(ace->e_type); + xattr_ace->e_flags = cpu_to_le16(ace->e_flags); + xattr_ace->e_mask = cpu_to_le32(ace->e_mask); + if (ace->e_flags & RICHACE_SPECIAL_WHO) + xattr_ace->e_id = cpu_to_le32(ace->e_id.special); + else if (ace->e_flags & RICHACE_IDENTIFIER_GROUP) + xattr_ace->e_id = + cpu_to_le32(from_kgid(user_ns, ace->e_id.gid)); + else + xattr_ace->e_id = + cpu_to_le32(from_kuid(user_ns, ace->e_id.uid)); + xattr_ace++; + } + return real_size; +} +EXPORT_SYMBOL_GPL(richacl_to_xattr); + +/* + * Fix up the uids and gids in richacl extended attributes in place. + */ +static void richacl_fix_xattr_userns( + struct user_namespace *to, struct user_namespace *from, + void *value, size_t size) +{ + struct richacl_xattr *xattr_acl = value; + struct richace_xattr *xattr_ace = + (struct richace_xattr *)(xattr_acl + 1); + unsigned int count; + + if (!value) + return; + if (size < sizeof(*xattr_acl)) + return; + if (xattr_acl->a_version != cpu_to_le32(RICHACL_XATTR_VERSION)) + return; + size -= sizeof(*xattr_acl); + if (size % sizeof(*xattr_ace)) + return; + count = size / sizeof(*xattr_ace); + for (; count; count--, xattr_ace++) { + if (xattr_ace->e_flags & cpu_to_le16(RICHACE_SPECIAL_WHO)) + continue; + if (xattr_ace->e_flags & cpu_to_le16(RICHACE_IDENTIFIER_GROUP)) { + kgid_t gid = make_kgid(from, le32_to_cpu(xattr_ace->e_id)); + xattr_ace->e_id = cpu_to_le32(from_kgid(to, gid)); + } else { + kuid_t uid = make_kuid(from, le32_to_cpu(xattr_ace->e_id)); + xattr_ace->e_id = cpu_to_le32(from_kuid(to, uid)); + } + } +} + +void richacl_fix_xattr_from_user(void *value, size_t size) +{ + struct user_namespace *user_ns = current_user_ns(); + if (user_ns == &init_user_ns) + return; + richacl_fix_xattr_userns(&init_user_ns, user_ns, value, size); +} + +void richacl_fix_xattr_to_user(void *value, size_t size) +{ + struct user_namespace *user_ns = current_user_ns(); + if (user_ns == &init_user_ns) + return; + richacl_fix_xattr_userns(user_ns, &init_user_ns, value, size); +} diff --git a/fs/xattr.c b/fs/xattr.c index 4ef6985..a09e654 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -21,6 +21,7 @@ #include #include #include +#include #include @@ -314,6 +315,18 @@ vfs_removexattr(struct dentry *dentry, const char *name) } EXPORT_SYMBOL_GPL(vfs_removexattr); +static void +fix_xattr_from_user(const char *kname, void *kvalue, size_t size) +{ + if (strncmp(kname, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) + return; + kname += XATTR_SYSTEM_PREFIX_LEN; + if (!strcmp(kname, XATTR_POSIX_ACL_ACCESS) || + !strcmp(kname, XATTR_POSIX_ACL_DEFAULT)) + posix_acl_fix_xattr_from_user(kvalue, size); + else if (!strcmp(kname, XATTR_RICHACL)) + richacl_fix_xattr_from_user(kvalue, size); +} /* * Extended attribute SET operations @@ -350,9 +363,7 @@ setxattr(struct dentry *d, const char __user *name, const void __user *value, error = -EFAULT; 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); + fix_xattr_from_user(kname, kvalue, size); } error = vfs_setxattr(d, kname, kvalue, size, flags); @@ -419,6 +430,19 @@ SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name, return error; } +static void +fix_xattr_to_user(const char *kname, void *kvalue, size_t size) +{ + if (strncmp(kname, XATTR_SYSTEM_PREFIX, XATTR_SYSTEM_PREFIX_LEN)) + return; + kname += XATTR_SYSTEM_PREFIX_LEN; + if (!strcmp(kname, XATTR_POSIX_ACL_ACCESS) || + !strcmp(kname, XATTR_POSIX_ACL_DEFAULT)) + posix_acl_fix_xattr_to_user(kvalue, size); + else if (!strcmp(kname, XATTR_RICHACL)) + richacl_fix_xattr_to_user(kvalue, size); +} + /* * Extended attribute GET operations */ @@ -451,9 +475,7 @@ 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); + fix_xattr_to_user(kname, kvalue, size); if (size && copy_to_user(value, kvalue, error)) error = -EFAULT; } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) { diff --git a/include/linux/richacl_xattr.h b/include/linux/richacl_xattr.h new file mode 100644 index 0000000..13cf746 --- /dev/null +++ b/include/linux/richacl_xattr.h @@ -0,0 +1,52 @@ +/* + * Copyright (C) 2006, 2010 Novell, Inc. + * Copyright (C) 2015 Red Hat, Inc. + * Written by Andreas Gruenbacher + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License as published by the + * Free Software Foundation; either version 2, or (at your option) any + * later version. + * + * This program is distributed in the hope that it will be useful, but + * WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + * General Public License for more details. + */ + +#ifndef __RICHACL_XATTR_H +#define __RICHACL_XATTR_H + +#include + +#define RICHACL_XATTR "system.richacl" + +struct richace_xattr { + __le16 e_type; + __le16 e_flags; + __le32 e_mask; + __le32 e_id; +}; + +struct richacl_xattr { + unsigned char a_version; + unsigned char a_flags; + __le16 a_unused; + __le32 a_owner_mask; + __le32 a_group_mask; + __le32 a_other_mask; +}; + +#define RICHACL_XATTR_VERSION 0 +#define RICHACL_XATTR_MAX_COUNT \ + ((XATTR_SIZE_MAX - sizeof(struct richacl_xattr)) / \ + sizeof(struct richace_xattr)) + +extern struct richacl *richacl_from_xattr(struct user_namespace *, const void *, size_t); +extern size_t richacl_xattr_size(const struct richacl *); +extern int richacl_to_xattr(struct user_namespace *, const struct richacl *, void *, size_t); + +extern void richacl_fix_xattr_from_user(void *, size_t); +extern void richacl_fix_xattr_to_user(void *, size_t); + +#endif /* __RICHACL_XATTR_H */ diff --git a/include/uapi/linux/xattr.h b/include/uapi/linux/xattr.h index 1590c49..1996903 100644 --- a/include/uapi/linux/xattr.h +++ b/include/uapi/linux/xattr.h @@ -73,5 +73,7 @@ #define XATTR_POSIX_ACL_DEFAULT "posix_acl_default" #define XATTR_NAME_POSIX_ACL_DEFAULT XATTR_SYSTEM_PREFIX XATTR_POSIX_ACL_DEFAULT +#define XATTR_RICHACL "richacl" +#define XATTR_NAME_RICHACL XATTR_SYSTEM_PREFIX XATTR_RICHACL #endif /* _UAPI_LINUX_XATTR_H */ -- 2.1.0