/* * JFFS2 -- Journalling Flash File System, Version 2. * * Copyright © 2006 NEC Corporation * * Created by KaiGai Kohei <kaigai@ak.jp.nec.com> * * For licensing information, see the file 'LICENCE' in this directory. * */ #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt #include <linux/kernel.h> #include <linux/slab.h> #include <linux/fs.h> #include <linux/sched.h> #include <linux/time.h> #include <linux/crc32.h> #include <linux/jffs2.h> #include <linux/xattr.h> #include <linux/posix_acl_xattr.h> #include <linux/mtd/mtd.h> #include "nodelist.h" static size_t jffs2_acl_size(int count) { if (count <= 4) { return sizeof(struct jffs2_acl_header) + count * sizeof(struct jffs2_acl_entry_short); } else { return sizeof(struct jffs2_acl_header) + 4 * sizeof(struct jffs2_acl_entry_short) + (count - 4) * sizeof(struct jffs2_acl_entry); } } static int jffs2_acl_count(size_t size) { size_t s; size -= sizeof(struct jffs2_acl_header); if (size < 4 * sizeof(struct jffs2_acl_entry_short)) { if (size % sizeof(struct jffs2_acl_entry_short)) return -1; return size / sizeof(struct jffs2_acl_entry_short); } else { s = size - 4 * sizeof(struct jffs2_acl_entry_short); if (s % sizeof(struct jffs2_acl_entry)) return -1; return s / sizeof(struct jffs2_acl_entry) + 4; } } static struct posix_acl *jffs2_acl_from_medium(void *value, size_t size) { void *end = value + size; struct jffs2_acl_header *header = value; struct jffs2_acl_entry *entry; struct posix_acl *acl; uint32_t ver; int i, count; if (!value) return NULL; if (size < sizeof(struct jffs2_acl_header)) return ERR_PTR(-EINVAL); ver = je32_to_cpu(header->a_version); if (ver != JFFS2_ACL_VERSION) { JFFS2_WARNING("Invalid ACL version. (=%u)\n", ver); return ERR_PTR(-EINVAL); } value += sizeof(struct jffs2_acl_header); count = jffs2_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 (i=0; i < count; i++) { entry = value; if (value + sizeof(struct jffs2_acl_entry_short) > end) goto fail; acl->a_entries[i].e_tag = je16_to_cpu(entry->e_tag); acl->a_entries[i].e_perm = je16_to_cpu(entry->e_perm); switch (acl->a_entries[i].e_tag) { case ACL_USER_OBJ: case ACL_GROUP_OBJ: case ACL_MASK: case ACL_OTHER: value += sizeof(struct jffs2_acl_entry_short); break; case ACL_USER: value += sizeof(struct jffs2_acl_entry); if (value > end) goto fail; acl->a_entries[i].e_uid = make_kuid(&init_user_ns, je32_to_cpu(entry->e_id)); break; case ACL_GROUP: value += sizeof(struct jffs2_acl_entry); if (value > end) goto fail; acl->a_entries[i].e_gid = make_kgid(&init_user_ns, je32_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); } static void *jffs2_acl_to_medium(const struct posix_acl *acl, size_t *size) { struct jffs2_acl_header *header; struct jffs2_acl_entry *entry; void *e; size_t i; *size = jffs2_acl_size(acl->a_count); header = kmalloc(struct_size(header, a_entries, acl->a_count), GFP_KERNEL); if (!header) return ERR_PTR(-ENOMEM); header->a_version = cpu_to_je32(JFFS2_ACL_VERSION); e = header + 1; for (i=0; i < acl->a_count; i++) { const struct posix_acl_entry *acl_e = &acl->a_entries[i]; entry = e; entry->e_tag = cpu_to_je16(acl_e->e_tag); entry->e_perm = cpu_to_je16(acl_e->e_perm); switch(acl_e->e_tag) { case ACL_USER: entry->e_id = cpu_to_je32( from_kuid(&init_user_ns, acl_e->e_uid)); e += sizeof(struct jffs2_acl_entry); break; case ACL_GROUP: entry->e_id = cpu_to_je32( from_kgid(&init_user_ns, acl_e->e_gid)); e += sizeof(struct jffs2_acl_entry); break; case ACL_USER_OBJ: case ACL_GROUP_OBJ: case ACL_MASK: case ACL_OTHER: e += sizeof(struct jffs2_acl_entry_short); break; default: goto fail; } } return header; fail: kfree(header); return ERR_PTR(-EINVAL); } struct posix_acl *jffs2_get_acl(struct inode *inode, int type) { struct posix_acl *acl; char *value = NULL; int rc, xprefix; switch (type) { case ACL_TYPE_ACCESS: xprefix = JFFS2_XPREFIX_ACL_ACCESS; break; case ACL_TYPE_DEFAULT: xprefix = JFFS2_XPREFIX_ACL_DEFAULT; break; default: BUG(); } rc = do_jffs2_getxattr(inode, xprefix, "", NULL, 0); if (rc > 0) { value = kmalloc(rc, GFP_KERNEL); if (!value) return ERR_PTR(-ENOMEM); rc = do_jffs2_getxattr(inode, xprefix, "", value, rc); } if (rc > 0) { acl = jffs2_acl_from_medium(value, rc); } else if (rc == -ENODATA || rc == -ENOSYS) { acl = NULL; } else { acl = ERR_PTR(rc); } kfree(value); return acl; } static int __jffs2_set_acl(struct inode *inode, int xprefix, struct posix_acl *acl) { char *value = NULL; size_t size = 0; int rc; if (acl) { value = jffs2_acl_to_medium(acl, &size); if (IS_ERR(value)) return PTR_ERR(value); } rc = do_jffs2_setxattr(inode, xprefix, "", value, size, 0); if (!value && rc == -ENODATA) rc = 0; kfree(value); return rc; } int jffs2_set_acl(struct user_namespace *mnt_userns, struct inode *inode, struct posix_acl *acl, int type) { int rc, xprefix; switch (type) { case ACL_TYPE_ACCESS: xprefix = JFFS2_XPREFIX_ACL_ACCESS; if (acl) { umode_t mode; rc = posix_acl_update_mode(&init_user_ns, inode, &mode, &acl); if (rc) return rc; if (inode->i_mode != mode) { struct iattr attr; attr.ia_valid = ATTR_MODE | ATTR_CTIME; attr.ia_mode = mode; attr.ia_ctime = current_time(inode); rc = jffs2_do_setattr(inode, &attr); if (rc < 0) return rc; } } break; case ACL_TYPE_DEFAULT: xprefix = JFFS2_XPREFIX_ACL_DEFAULT; if (!S_ISDIR(inode->i_mode)) return acl ? -EACCES : 0; break; default: return -EINVAL; } rc = __jffs2_set_acl(inode, xprefix, acl); if (!rc) set_cached_acl(inode, type, acl); return rc; } int jffs2_init_acl_pre(struct inode *dir_i, struct inode *inode, umode_t *i_mode) { struct posix_acl *default_acl, *acl; int rc; cache_no_acl(inode); rc = posix_acl_create(dir_i, i_mode, &default_acl, &acl); if (rc) return rc; if (default_acl) { set_cached_acl(inode, ACL_TYPE_DEFAULT, default_acl); posix_acl_release(default_acl); } if (acl) { set_cached_acl(inode, ACL_TYPE_ACCESS, acl); posix_acl_release(acl); } return 0; } int jffs2_init_acl_post(struct inode *inode) { int rc; if (inode->i_default_acl) { rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_DEFAULT, inode->i_default_acl); if (rc) return rc; } if (inode->i_acl) { rc = __jffs2_set_acl(inode, JFFS2_XPREFIX_ACL_ACCESS, inode->i_acl); if (rc) return rc; } return 0; }