diff options
Diffstat (limited to 'fs/jffs2/acl.c')
| -rw-r--r-- | fs/jffs2/acl.c | 483 |
1 files changed, 483 insertions, 0 deletions
diff --git a/fs/jffs2/acl.c b/fs/jffs2/acl.c new file mode 100644 index 000000000000..080bb51e4b65 --- /dev/null +++ b/fs/jffs2/acl.c @@ -0,0 +1,483 @@ +/*-------------------------------------------------------------------------* + * File: fs/jffs2/acl.c + * POSIX ACL support on JFFS2 FileSystem + * + * Implemented by KaiGai Kohei <kaigai@ak.jp.nec.com> + * Copyright (C) 2006 NEC Corporation + * + * For licensing information, see the file 'LICENCE' in the jffs2 directory. + *-------------------------------------------------------------------------*/ +#include <linux/kernel.h> +#include <linux/slab.h> +#include <linux/fs.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(jffs2_acl_header) + + count * sizeof(jffs2_acl_entry_short); + } else { + return sizeof(jffs2_acl_header) + + 4 * sizeof(jffs2_acl_entry_short) + + (count - 4) * sizeof(jffs2_acl_entry); + } +} + +static int jffs2_acl_count(size_t size) +{ + size_t s; + + size -= sizeof(jffs2_acl_header); + s = size - 4 * sizeof(jffs2_acl_entry_short); + if (s < 0) { + if (size % sizeof(jffs2_acl_entry_short)) + return -1; + return size / sizeof(jffs2_acl_entry_short); + } else { + if (s % sizeof(jffs2_acl_entry)) + return -1; + return s / sizeof(jffs2_acl_entry) + 4; + } +} + +static struct posix_acl *jffs2_acl_from_medium(const void *value, size_t size) +{ + const char *end = (char *)value + size; + struct posix_acl *acl; + uint32_t ver; + int i, count; + + if (!value) + return NULL; + if (size < sizeof(jffs2_acl_header)) + return ERR_PTR(-EINVAL); + ver = je32_to_cpu(((jffs2_acl_header *)value)->a_version); + if (ver != JFFS2_ACL_VERSION) { + JFFS2_WARNING("Invalid ACL version. (=%u)\n", ver); + return ERR_PTR(-EINVAL); + } + + value = (char *)value + sizeof(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++) { + jffs2_acl_entry *entry = (jffs2_acl_entry *)value; + if ((char *)value + sizeof(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 = (char *)value + sizeof(jffs2_acl_entry_short); + acl->a_entries[i].e_id = ACL_UNDEFINED_ID; + break; + + case ACL_USER: + case ACL_GROUP: + value = (char *)value + sizeof(jffs2_acl_entry); + if ((char *)value > end) + goto fail; + acl->a_entries[i].e_id = 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) +{ + jffs2_acl_header *jffs2_acl; + char *e; + size_t i; + + *size = jffs2_acl_size(acl->a_count); + jffs2_acl = (jffs2_acl_header *)kmalloc(sizeof(jffs2_acl_header) + + acl->a_count * sizeof(jffs2_acl_entry), + GFP_KERNEL); + if (!jffs2_acl) + return ERR_PTR(-ENOMEM); + jffs2_acl->a_version = cpu_to_je32(JFFS2_ACL_VERSION); + e = (char *)jffs2_acl + sizeof(jffs2_acl_header); + for (i=0; i < acl->a_count; i++) { + jffs2_acl_entry *entry = (jffs2_acl_entry *)e; + entry->e_tag = cpu_to_je16(acl->a_entries[i].e_tag); + entry->e_perm = cpu_to_je16(acl->a_entries[i].e_perm); + switch(acl->a_entries[i].e_tag) { + case ACL_USER: + case ACL_GROUP: + entry->e_id = cpu_to_je32(acl->a_entries[i].e_id); + e += sizeof(jffs2_acl_entry); + break; + + case ACL_USER_OBJ: + case ACL_GROUP_OBJ: + case ACL_MASK: + case ACL_OTHER: + e += sizeof(jffs2_acl_entry_short); + break; + + default: + goto fail; + } + } + return (char *)jffs2_acl; + fail: + kfree(jffs2_acl); + return ERR_PTR(-EINVAL); +} + +static struct posix_acl *jffs2_iget_acl(struct inode *inode, struct posix_acl **i_acl) +{ + struct posix_acl *acl = JFFS2_ACL_NOT_CACHED; + + spin_lock(&inode->i_lock); + if (*i_acl != JFFS2_ACL_NOT_CACHED) + acl = posix_acl_dup(*i_acl); + spin_unlock(&inode->i_lock); + return acl; +} + +static void jffs2_iset_acl(struct inode *inode, struct posix_acl **i_acl, struct posix_acl *acl) +{ + spin_lock(&inode->i_lock); + if (*i_acl != JFFS2_ACL_NOT_CACHED) + posix_acl_release(*i_acl); + *i_acl = posix_acl_dup(acl); + spin_unlock(&inode->i_lock); +} + +static struct posix_acl *jffs2_get_acl(struct inode *inode, int type) +{ + struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); + struct posix_acl *acl; + char *value = NULL; + int rc, xprefix; + + switch (type) { + case ACL_TYPE_ACCESS: + acl = jffs2_iget_acl(inode, &f->i_acl_access); + if (acl != JFFS2_ACL_NOT_CACHED) + return acl; + xprefix = JFFS2_XPREFIX_ACL_ACCESS; + break; + case ACL_TYPE_DEFAULT: + acl = jffs2_iget_acl(inode, &f->i_acl_default); + if (acl != JFFS2_ACL_NOT_CACHED) + return acl; + xprefix = JFFS2_XPREFIX_ACL_DEFAULT; + break; + default: + return ERR_PTR(-EINVAL); + } + 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); + } + if (value) + kfree(value); + if (!IS_ERR(acl)) { + switch (type) { + case ACL_TYPE_ACCESS: + jffs2_iset_acl(inode, &f->i_acl_access, acl); + break; + case ACL_TYPE_DEFAULT: + jffs2_iset_acl(inode, &f->i_acl_default, acl); + break; + } + } + return acl; +} + +static int jffs2_set_acl(struct inode *inode, int type, struct posix_acl *acl) +{ + struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); + size_t size = 0; + char *value = NULL; + int rc, xprefix; + + if (S_ISLNK(inode->i_mode)) + return -EOPNOTSUPP; + + switch (type) { + case ACL_TYPE_ACCESS: + xprefix = JFFS2_XPREFIX_ACL_ACCESS; + if (acl) { + mode_t mode = inode->i_mode; + rc = posix_acl_equiv_mode(acl, &mode); + if (rc < 0) + return rc; + if (inode->i_mode != mode) { + inode->i_mode = mode; + jffs2_dirty_inode(inode); + } + if (rc == 0) + acl = NULL; + } + break; + case ACL_TYPE_DEFAULT: + xprefix = JFFS2_XPREFIX_ACL_DEFAULT; + if (!S_ISDIR(inode->i_mode)) + return acl ? -EACCES : 0; + break; + default: + return -EINVAL; + } + 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) + kfree(value); + if (!rc) { + switch(type) { + case ACL_TYPE_ACCESS: + jffs2_iset_acl(inode, &f->i_acl_access, acl); + break; + case ACL_TYPE_DEFAULT: + jffs2_iset_acl(inode, &f->i_acl_default, acl); + break; + } + } + return rc; +} + +static int jffs2_check_acl(struct inode *inode, int mask) +{ + struct posix_acl *acl; + int rc; + + acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS); + if (IS_ERR(acl)) + return PTR_ERR(acl); + if (acl) { + rc = posix_acl_permission(inode, acl, mask); + posix_acl_release(acl); + return rc; + } + return -EAGAIN; +} + +int jffs2_permission(struct inode *inode, int mask, struct nameidata *nd) +{ + return generic_permission(inode, mask, jffs2_check_acl); +} + +int jffs2_init_acl(struct inode *inode, struct inode *dir) +{ + struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); + struct posix_acl *acl = NULL, *clone; + mode_t mode; + int rc = 0; + + f->i_acl_access = JFFS2_ACL_NOT_CACHED; + f->i_acl_default = JFFS2_ACL_NOT_CACHED; + if (!S_ISLNK(inode->i_mode)) { + acl = jffs2_get_acl(dir, ACL_TYPE_DEFAULT); + if (IS_ERR(acl)) + return PTR_ERR(acl); + if (!acl) + inode->i_mode &= ~current->fs->umask; + } + if (acl) { + if (S_ISDIR(inode->i_mode)) { + rc = jffs2_set_acl(inode, ACL_TYPE_DEFAULT, acl); + if (rc) + goto cleanup; + } + clone = posix_acl_clone(acl, GFP_KERNEL); + rc = -ENOMEM; + if (!clone) + goto cleanup; + mode = inode->i_mode; + rc = posix_acl_create_masq(clone, &mode); + if (rc >= 0) { + inode->i_mode = mode; + if (rc > 0) + rc = jffs2_set_acl(inode, ACL_TYPE_ACCESS, clone); + } + posix_acl_release(clone); + } + cleanup: + posix_acl_release(acl); + return rc; +} + +void jffs2_clear_acl(struct inode *inode) +{ + struct jffs2_inode_info *f = JFFS2_INODE_INFO(inode); + + if (f->i_acl_access && f->i_acl_access != JFFS2_ACL_NOT_CACHED) { + posix_acl_release(f->i_acl_access); + f->i_acl_access = JFFS2_ACL_NOT_CACHED; + } + if (f->i_acl_default && f->i_acl_default != JFFS2_ACL_NOT_CACHED) { + posix_acl_release(f->i_acl_default); + f->i_acl_default = JFFS2_ACL_NOT_CACHED; + } +} + +int jffs2_acl_chmod(struct inode *inode) +{ + struct posix_acl *acl, *clone; + int rc; + + if (S_ISLNK(inode->i_mode)) + return -EOPNOTSUPP; + acl = jffs2_get_acl(inode, ACL_TYPE_ACCESS); + if (IS_ERR(acl) || !acl) + return PTR_ERR(acl); + clone = posix_acl_clone(acl, GFP_KERNEL); + posix_acl_release(acl); + if (!clone) + return -ENOMEM; + rc = posix_acl_chmod_masq(clone, inode->i_mode); + if (!rc) + rc = jffs2_set_acl(inode, ACL_TYPE_ACCESS, clone); + posix_acl_release(clone); + return rc; +} + +static size_t jffs2_acl_access_listxattr(struct inode *inode, char *list, size_t list_size, + const char *name, size_t name_len) +{ + const int retlen = sizeof(POSIX_ACL_XATTR_ACCESS); + + if (list && retlen <= list_size) + strcpy(list, POSIX_ACL_XATTR_ACCESS); + return retlen; +} + +static size_t jffs2_acl_default_listxattr(struct inode *inode, char *list, size_t list_size, + const char *name, size_t name_len) +{ + const int retlen = sizeof(POSIX_ACL_XATTR_DEFAULT); + + if (list && retlen <= list_size) + strcpy(list, POSIX_ACL_XATTR_DEFAULT); + return retlen; +} + +static int jffs2_acl_getxattr(struct inode *inode, int type, void *buffer, size_t size) +{ + struct posix_acl *acl; + int rc; + + acl = jffs2_get_acl(inode, type); + if (IS_ERR(acl)) + return PTR_ERR(acl); + if (!acl) + return -ENODATA; + rc = posix_acl_to_xattr(acl, buffer, size); + posix_acl_release(acl); + + return rc; +} + +static int jffs2_acl_access_getxattr(struct inode *inode, const char *name, void *buffer, size_t size) +{ + if (name[0] != '\0') + return -EINVAL; + return jffs2_acl_getxattr(inode, ACL_TYPE_ACCESS, buffer, size); +} + +static int jffs2_acl_default_getxattr(struct inode *inode, const char *name, void *buffer, size_t size) +{ + if (name[0] != '\0') + return -EINVAL; + return jffs2_acl_getxattr(inode, ACL_TYPE_DEFAULT, buffer, size); +} + +static int jffs2_acl_setxattr(struct inode *inode, int type, const void *value, size_t size) +{ + struct posix_acl *acl; + int rc; + + if ((current->fsuid != inode->i_uid) && !capable(CAP_FOWNER)) + return -EPERM; + + if (value) { + acl = posix_acl_from_xattr(value, size); + if (IS_ERR(acl)) + return PTR_ERR(acl); + if (acl) { + rc = posix_acl_valid(acl); + if (rc) + goto out; + } + } else { + acl = NULL; + } + rc = jffs2_set_acl(inode, type, acl); + out: + posix_acl_release(acl); + return rc; +} + +static int jffs2_acl_access_setxattr(struct inode *inode, const char *name, + const void *buffer, size_t size, int flags) +{ + if (name[0] != '\0') + return -EINVAL; + return jffs2_acl_setxattr(inode, ACL_TYPE_ACCESS, buffer, size); +} + +static int jffs2_acl_default_setxattr(struct inode *inode, const char *name, + const void *buffer, size_t size, int flags) +{ + if (name[0] != '\0') + return -EINVAL; + return jffs2_acl_setxattr(inode, ACL_TYPE_DEFAULT, buffer, size); +} + +struct xattr_handler jffs2_acl_access_xattr_handler = { + .prefix = POSIX_ACL_XATTR_ACCESS, + .list = jffs2_acl_access_listxattr, + .get = jffs2_acl_access_getxattr, + .set = jffs2_acl_access_setxattr, +}; + +struct xattr_handler jffs2_acl_default_xattr_handler = { + .prefix = POSIX_ACL_XATTR_DEFAULT, + .list = jffs2_acl_default_listxattr, + .get = jffs2_acl_default_getxattr, + .set = jffs2_acl_default_setxattr, +}; |