diff options
Diffstat (limited to 'fs/jffs2/acl.c')
| -rw-r--r-- | fs/jffs2/acl.c | 312 |
1 files changed, 312 insertions, 0 deletions
diff --git a/fs/jffs2/acl.c b/fs/jffs2/acl.c new file mode 100644 index 000000000..e945e3484 --- /dev/null +++ b/fs/jffs2/acl.c @@ -0,0 +1,312 @@ +/* + * 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, bool rcu) +{ + struct posix_acl *acl; + char *value = NULL; + int rc, xprefix; + + if (rcu) + return ERR_PTR(-ECHILD); + + 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; +} |