Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755475Ab2FJJWQ (ORCPT ); Sun, 10 Jun 2012 05:22:16 -0400 Received: from mail-we0-f174.google.com ([74.125.82.174]:33612 "EHLO mail-we0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754344Ab2FJJWN (ORCPT ); Sun, 10 Jun 2012 05:22:13 -0400 Message-ID: <4FD465BF.4060906@gmail.com> Date: Sun, 10 Jun 2012 11:15:43 +0200 From: Marco Stornelli User-Agent: Mozilla/5.0 (X11; Linux i686; rv:12.0) Gecko/20120421 Thunderbird/12.0 MIME-Version: 1.0 To: Linux FS Devel CC: Linux Kernel Subject: [PATCH 11/17] pramfs: ACL operations Content-Type: text/plain; charset=ISO-8859-15 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 12875 Lines: 509 From: Marco Stornelli ACL operations. Signed-off-by: Marco Stornelli --- diff -Nurp linux-3.5-rc2-orig/fs/pramfs/acl.c linux-3.5-rc2/fs/pramfs/acl.c --- linux-3.5-rc2-orig/fs/pramfs/acl.c 1970-01-01 01:00:00.000000000 +0100 +++ linux-3.5-rc2/fs/pramfs/acl.c 2012-06-10 10:08:28.000000000 +0200 @@ -0,0 +1,405 @@ +/* + * BRIEF DESCRIPTION + * + * POSIX ACL operations + * + * Copyright 2010-2011 Marco Stornelli + * + * based on fs/ext2/acl.c with the following copyright: + * + * Copyright (C) 2001-2003 Andreas Gruenbacher, + * + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + */ + +#include +#include +#include +#include +#include +#include "pram.h" +#include "xattr.h" +#include "acl.h" + +/* + * Load ACL information from filesystem. + */ +static struct posix_acl *pram_acl_load(const void *value, size_t size) +{ + const char *end = (char *)value + size; + int n, count; + struct posix_acl *acl; + + if (!value) + return NULL; + if (size < sizeof(struct pram_acl_header)) + return ERR_PTR(-EINVAL); + if (((struct pram_acl_header *)value)->a_version != + cpu_to_be32(PRAM_ACL_VERSION)) + return ERR_PTR(-EINVAL); + value = (char *)value + sizeof(struct pram_acl_header); + count = pram_acl_count(size); + if (count < 0) + return ERR_PTR(-EINVAL); + if (count == 0) + return NULL; + acl = posix_acl_alloc(count, GFP_KERNEL); + if (!acl) + return ERR_PTR(-ENOMEM); + for (n = 0; n < count; n++) { + struct pram_acl_entry *entry = (struct pram_acl_entry *)value; + if ((char *)value + sizeof(struct pram_acl_entry_short) > end) + goto fail; + acl->a_entries[n].e_tag = be16_to_cpu(entry->e_tag); + acl->a_entries[n].e_perm = be16_to_cpu(entry->e_perm); + switch (acl->a_entries[n].e_tag) { + case ACL_USER_OBJ: + case ACL_GROUP_OBJ: + case ACL_MASK: + case ACL_OTHER: + value = (char *)value + + sizeof(struct pram_acl_entry_short); + acl->a_entries[n].e_id = ACL_UNDEFINED_ID; + break; + case ACL_USER: + case ACL_GROUP: + value = (char *)value + sizeof(struct pram_acl_entry); + if ((char *)value > end) + goto fail; + acl->a_entries[n].e_id = + be32_to_cpu(entry->e_id); + break; + default: + goto fail; + } + } + if (value != end) + goto fail; + return acl; + +fail: + posix_acl_release(acl); + return ERR_PTR(-EINVAL); +} + +/* + * Save ACL information into the filesystem. + */ +static void *pram_acl_save(const struct posix_acl *acl, size_t *size) +{ + struct pram_acl_header *ext_acl; + char *e; + size_t n; + + *size = pram_acl_size(acl->a_count); + ext_acl = kmalloc(sizeof(struct pram_acl_header) + acl->a_count * + sizeof(struct pram_acl_entry), GFP_KERNEL); + if (!ext_acl) + return ERR_PTR(-ENOMEM); + ext_acl->a_version = cpu_to_be32(PRAM_ACL_VERSION); + e = (char *)ext_acl + sizeof(struct pram_acl_header); + for (n = 0; n < acl->a_count; n++) { + struct pram_acl_entry *entry = (struct pram_acl_entry *)e; + entry->e_tag = cpu_to_be16(acl->a_entries[n].e_tag); + entry->e_perm = cpu_to_be16(acl->a_entries[n].e_perm); + switch (acl->a_entries[n].e_tag) { + case ACL_USER: + case ACL_GROUP: + entry->e_id = + cpu_to_be32(acl->a_entries[n].e_id); + e += sizeof(struct pram_acl_entry); + break; + case ACL_USER_OBJ: + case ACL_GROUP_OBJ: + case ACL_MASK: + case ACL_OTHER: + e += sizeof(struct pram_acl_entry_short); + break; + default: + goto fail; + } + } + return (char *)ext_acl; + +fail: + kfree(ext_acl); + return ERR_PTR(-EINVAL); +} + +/* + * inode->i_mutex: don't care + */ +struct posix_acl *pram_get_acl(struct inode *inode, int type) +{ + int name_index; + char *value = NULL; + struct posix_acl *acl; + int retval; + + if (!test_opt(inode->i_sb, POSIX_ACL)) + return NULL; + + acl = get_cached_acl(inode, type); + if (acl != ACL_NOT_CACHED) + return acl; + + switch (type) { + case ACL_TYPE_ACCESS: + name_index = PRAM_XATTR_INDEX_POSIX_ACL_ACCESS; + break; + case ACL_TYPE_DEFAULT: + name_index = PRAM_XATTR_INDEX_POSIX_ACL_DEFAULT; + break; + default: + BUG(); + } + retval = pram_xattr_get(inode, name_index, "", NULL, 0); + if (retval > 0) { + value = kmalloc(retval, GFP_KERNEL); + if (!value) + return ERR_PTR(-ENOMEM); + retval = pram_xattr_get(inode, name_index, "", value, retval); + } + if (retval > 0) + acl = pram_acl_load(value, retval); + else if (retval == -ENODATA || retval == -ENOSYS) + acl = NULL; + else + acl = ERR_PTR(retval); + kfree(value); + + if (!IS_ERR(acl)) + set_cached_acl(inode, type, acl); + + return acl; +} + +/* + * inode->i_mutex: down + */ +static int pram_set_acl(struct inode *inode, int type, struct posix_acl *acl) +{ + int name_index; + void *value = NULL; + size_t size = 0; + int error; + + if (S_ISLNK(inode->i_mode)) + return -EOPNOTSUPP; + if (!test_opt(inode->i_sb, POSIX_ACL)) + return 0; + + switch (type) { + case ACL_TYPE_ACCESS: + name_index = PRAM_XATTR_INDEX_POSIX_ACL_ACCESS; + if (acl) { + error = posix_acl_equiv_mode(acl, &inode->i_mode); + if (error < 0) + return error; + else { + inode->i_ctime = CURRENT_TIME_SEC; + mark_inode_dirty(inode); + if (error == 0) + acl = NULL; + } + } + break; + case ACL_TYPE_DEFAULT: + name_index = PRAM_XATTR_INDEX_POSIX_ACL_DEFAULT; + if (!S_ISDIR(inode->i_mode)) + return acl ? -EACCES : 0; + break; + default: + return -EINVAL; + } + if (acl) { + value = pram_acl_save(acl, &size); + if (IS_ERR(value)) + return (int)PTR_ERR(value); + } + + error = pram_xattr_set(inode, name_index, "", value, size, 0); + + kfree(value); + if (!error) + set_cached_acl(inode, type, acl); + return error; +} + +/* + * Initialize the ACLs of a new inode. Called from pram_new_inode. + * + * dir->i_mutex: down + * inode->i_mutex: up (access to inode is still exclusive) + */ +int pram_init_acl(struct inode *inode, struct inode *dir) +{ + struct posix_acl *acl = NULL; + int error = 0; + + if (!S_ISLNK(inode->i_mode)) { + if (test_opt(dir->i_sb, POSIX_ACL)) { + acl = pram_get_acl(dir, ACL_TYPE_DEFAULT); + if (IS_ERR(acl)) + return PTR_ERR(acl); + } + if (!acl) + inode->i_mode &= ~current_umask(); + } + + if (test_opt(inode->i_sb, POSIX_ACL) && acl) { + umode_t mode = inode->i_mode; + if (S_ISDIR(inode->i_mode)) { + error = pram_set_acl(inode, ACL_TYPE_DEFAULT, acl); + if (error) + goto cleanup; + } + error = posix_acl_create(&acl, GFP_KERNEL, &mode); + if (error < 0) + return error; + inode->i_mode = mode; + if (error > 0) { + /* This is an extended ACL */ + error = pram_set_acl(inode, ACL_TYPE_ACCESS, acl); + } + } +cleanup: + posix_acl_release(acl); + return error; +} + +/* + * Does chmod for an inode that may have an Access Control List. The + * inode->i_mode field must be updated to the desired value by the caller + * before calling this function. + * Returns 0 on success, or a negative error number. + * + * We change the ACL rather than storing some ACL entries in the file + * mode permission bits (which would be more efficient), because that + * would break once additional permissions (like ACL_APPEND, ACL_DELETE + * for directories) are added. There are no more bits available in the + * file mode. + * + * inode->i_mutex: down + */ +int pram_acl_chmod(struct inode *inode) +{ + struct posix_acl *acl; + int error; + + if (!test_opt(inode->i_sb, POSIX_ACL)) + return 0; + if (S_ISLNK(inode->i_mode)) + return -EOPNOTSUPP; + acl = pram_get_acl(inode, ACL_TYPE_ACCESS); + if (IS_ERR(acl) || !acl) + return PTR_ERR(acl); + error = posix_acl_chmod(&acl, GFP_KERNEL, inode->i_mode); + if (error) + return error; + error = pram_set_acl(inode, ACL_TYPE_ACCESS, acl); + posix_acl_release(acl); + return error; +} + +/* + * Extended attribut handlers + */ +static size_t pram_xattr_list_acl_access(struct dentry *dentry, char *list, + size_t list_size, const char *name, + size_t name_len, int type) +{ + const size_t size = sizeof(POSIX_ACL_XATTR_ACCESS); + + if (!test_opt(dentry->d_sb, POSIX_ACL)) + return 0; + if (list && size <= list_size) + memcpy(list, POSIX_ACL_XATTR_ACCESS, size); + return size; +} + +static size_t pram_xattr_list_acl_default(struct dentry *dentry, char *list, + size_t list_size, const char *name, + size_t name_len, int type) +{ + const size_t size = sizeof(POSIX_ACL_XATTR_DEFAULT); + + if (!test_opt(dentry->d_sb, POSIX_ACL)) + return 0; + if (list && size <= list_size) + memcpy(list, POSIX_ACL_XATTR_DEFAULT, size); + return size; +} + +static int pram_xattr_get_acl(struct dentry *dentry, const char *name, + void *buffer, size_t size, int type) +{ + struct posix_acl *acl; + int error; + + if (strcmp(name, "") != 0) + return -EINVAL; + if (!test_opt(dentry->d_sb, POSIX_ACL)) + return -EOPNOTSUPP; + + acl = pram_get_acl(dentry->d_inode, type); + if (IS_ERR(acl)) + return PTR_ERR(acl); + if (acl == NULL) + return -ENODATA; + error = posix_acl_to_xattr(acl, buffer, size); + posix_acl_release(acl); + + return error; +} + +static int pram_xattr_set_acl(struct dentry *dentry, const char *name, + const void *value, size_t size, int flags, + int type) +{ + struct posix_acl *acl; + int error; + + if (strcmp(name, "") != 0) + return -EINVAL; + if (!test_opt(dentry->d_sb, POSIX_ACL)) + return -EOPNOTSUPP; + if (!inode_owner_or_capable(dentry->d_inode)) + return -EPERM; + + if (value) { + acl = posix_acl_from_xattr(value, size); + if (IS_ERR(acl)) + return PTR_ERR(acl); + else if (acl) { + error = posix_acl_valid(acl); + if (error) + goto release_and_out; + } + } else + acl = NULL; + + error = pram_set_acl(dentry->d_inode, type, acl); + +release_and_out: + posix_acl_release(acl); + return error; +} + +const struct xattr_handler pram_xattr_acl_access_handler = { + .prefix = POSIX_ACL_XATTR_ACCESS, + .flags = ACL_TYPE_ACCESS, + .list = pram_xattr_list_acl_access, + .get = pram_xattr_get_acl, + .set = pram_xattr_set_acl, +}; + +const struct xattr_handler pram_xattr_acl_default_handler = { + .prefix = POSIX_ACL_XATTR_DEFAULT, + .flags = ACL_TYPE_DEFAULT, + .list = pram_xattr_list_acl_default, + .get = pram_xattr_get_acl, + .set = pram_xattr_set_acl, +}; diff -Nurp linux-3.5-rc2-orig/fs/pramfs/acl.h linux-3.5-rc2/fs/pramfs/acl.h --- linux-3.5-rc2-orig/fs/pramfs/acl.h 1970-01-01 01:00:00.000000000 +0100 +++ linux-3.5-rc2/fs/pramfs/acl.h 2012-06-10 10:08:28.000000000 +0200 @@ -0,0 +1,85 @@ +/* + * BRIEF DESCRIPTION + * + * POSIX ACL operations + * + * Copyright 2010-2011 Marco Stornelli + * This file is licensed under the terms of the GNU General Public + * License version 2. This program is licensed "as is" without any + * warranty of any kind, whether express or implied. + * + * Based on fs/ext2/acl.h with the following copyright: + * + * Copyright (C) 2001-2003 Andreas Gruenbacher, + * + */ + +#include + +#define PRAM_ACL_VERSION 0x0001 + +struct pram_acl_entry { + __be16 e_tag; + __be16 e_perm; + __be32 e_id; +}; + +struct pram_acl_entry_short { + __be16 e_tag; + __be16 e_perm; +}; + +struct pram_acl_header { + __be32 a_version; +}; + +static inline size_t pram_acl_size(int count) +{ + if (count <= 4) { + return sizeof(struct pram_acl_header) + + count * sizeof(struct pram_acl_entry_short); + } else { + return sizeof(struct pram_acl_header) + + 4 * sizeof(struct pram_acl_entry_short) + + (count - 4) * sizeof(struct pram_acl_entry); + } +} + +static inline int pram_acl_count(size_t size) +{ + ssize_t s; + size -= sizeof(struct pram_acl_header); + s = size - 4 * sizeof(struct pram_acl_entry_short); + if (s < 0) { + if (size % sizeof(struct pram_acl_entry_short)) + return -1; + return size / sizeof(struct pram_acl_entry_short); + } else { + if (s % sizeof(struct pram_acl_entry)) + return -1; + return s / sizeof(struct pram_acl_entry) + 4; + } +} + +#ifdef CONFIG_PRAMFS_POSIX_ACL + +/* acl.c */ +extern struct posix_acl *pram_get_acl(struct inode *inode, int type); +extern int pram_acl_chmod(struct inode *); +extern int pram_init_acl(struct inode *, struct inode *); + +#else +#include +#define pram_get_acl NULL +#define pram_set_acl NULL + +static inline int pram_acl_chmod(struct inode *inode) +{ + return 0; +} + +static inline int pram_init_acl(struct inode *inode, struct inode *dir) +{ + return 0; +} +#endif -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/