diff options
| -rw-r--r-- | fs/posix_acl.c | 129 | ||||
| -rw-r--r-- | include/linux/posix_acl.h | 9 | ||||
| -rw-r--r-- | include/linux/posix_acl_xattr.h | 10 |
3 files changed, 141 insertions, 7 deletions
diff --git a/fs/posix_acl.c b/fs/posix_acl.c index 970250506f07..af04e177f019 100644 --- a/fs/posix_acl.c +++ b/fs/posix_acl.c @@ -111,7 +111,9 @@ void forget_all_cached_acls(struct inode *inode) } EXPORT_SYMBOL(forget_all_cached_acls); -struct posix_acl *get_inode_acl(struct inode *inode, int type) +static struct posix_acl *__get_acl(struct user_namespace *mnt_userns, + struct dentry *dentry, struct inode *inode, + int type) { void *sentinel; struct posix_acl **p; @@ -144,19 +146,21 @@ struct posix_acl *get_inode_acl(struct inode *inode, int type) cmpxchg(p, ACL_NOT_CACHED, sentinel); /* - * Normally, the ACL returned by ->get_inode_acl will be cached. + * Normally, the ACL returned by ->get{_inode}_acl will be cached. * A filesystem can prevent that by calling - * forget_cached_acl(inode, type) in ->get_inode_acl. + * forget_cached_acl(inode, type) in ->get{_inode}_acl. * - * If the filesystem doesn't have a get_inode_acl() function at all, + * If the filesystem doesn't have a get{_inode}_ acl() function at all, * we'll just create the negative cache entry. */ - if (!inode->i_op->get_inode_acl) { + if (dentry && inode->i_op->get_acl) { + acl = inode->i_op->get_acl(mnt_userns, dentry, type); + } else if (inode->i_op->get_inode_acl) { + acl = inode->i_op->get_inode_acl(inode, type, false); + } else { set_cached_acl(inode, type, NULL); return NULL; } - acl = inode->i_op->get_inode_acl(inode, type, false); - if (IS_ERR(acl)) { /* * Remove our sentinel so that we don't block future attempts @@ -174,6 +178,11 @@ struct posix_acl *get_inode_acl(struct inode *inode, int type) posix_acl_release(acl); return acl; } + +struct posix_acl *get_inode_acl(struct inode *inode, int type) +{ + return __get_acl(&init_user_ns, NULL, inode, type); +} EXPORT_SYMBOL(get_inode_acl); /* @@ -1120,6 +1129,67 @@ posix_acl_to_xattr(struct user_namespace *user_ns, const struct posix_acl *acl, } EXPORT_SYMBOL (posix_acl_to_xattr); +/** + * vfs_posix_acl_to_xattr - convert from kernel to userspace representation + * @mnt_userns: user namespace of the mount + * @inode: inode the posix acls are set on + * @acl: the posix acls as represented by the vfs + * @buffer: the buffer into which to convert @acl + * @size: size of @buffer + * + * This converts @acl from the VFS representation in the filesystem idmapping + * to the uapi form reportable to userspace. And mount and caller idmappings + * are handled appropriately. + * + * Return: On success, the size of the stored uapi posix acls, on error a + * negative errno. + */ +ssize_t vfs_posix_acl_to_xattr(struct user_namespace *mnt_userns, + struct inode *inode, const struct posix_acl *acl, + void *buffer, size_t size) + +{ + struct posix_acl_xattr_header *ext_acl = buffer; + struct posix_acl_xattr_entry *ext_entry; + struct user_namespace *fs_userns, *caller_userns; + ssize_t real_size, n; + vfsuid_t vfsuid; + vfsgid_t vfsgid; + + real_size = posix_acl_xattr_size(acl->a_count); + if (!buffer) + return real_size; + if (real_size > size) + return -ERANGE; + + ext_entry = (void *)(ext_acl + 1); + ext_acl->a_version = cpu_to_le32(POSIX_ACL_XATTR_VERSION); + + fs_userns = i_user_ns(inode); + caller_userns = current_user_ns(); + for (n=0; n < acl->a_count; n++, ext_entry++) { + const struct posix_acl_entry *acl_e = &acl->a_entries[n]; + ext_entry->e_tag = cpu_to_le16(acl_e->e_tag); + ext_entry->e_perm = cpu_to_le16(acl_e->e_perm); + switch(acl_e->e_tag) { + case ACL_USER: + vfsuid = make_vfsuid(mnt_userns, fs_userns, acl_e->e_uid); + ext_entry->e_id = cpu_to_le32(from_kuid( + caller_userns, vfsuid_into_kuid(vfsuid))); + break; + case ACL_GROUP: + vfsgid = make_vfsgid(mnt_userns, fs_userns, acl_e->e_gid); + ext_entry->e_id = cpu_to_le32(from_kgid( + caller_userns, vfsgid_into_kgid(vfsgid))); + break; + default: + ext_entry->e_id = cpu_to_le32(ACL_UNDEFINED_ID); + break; + } + } + return real_size; +} + static int posix_acl_xattr_get(const struct xattr_handler *handler, struct dentry *unused, struct inode *inode, @@ -1364,3 +1434,48 @@ out_inode_unlock: return error; } EXPORT_SYMBOL_GPL(vfs_set_acl); + +/** + * vfs_get_acl - get posix acls + * @mnt_userns: user namespace of the mount + * @dentry: the dentry based on which to retrieve the posix acls + * @acl_name: the name of the posix acl + * + * This function retrieves @kacl from the filesystem. The caller must all + * posix_acl_release() on @kacl. + * + * Return: On success POSIX ACLs in VFS format, on error negative errno. + */ +struct posix_acl *vfs_get_acl(struct user_namespace *mnt_userns, + struct dentry *dentry, const char *acl_name) +{ + struct inode *inode = d_inode(dentry); + struct posix_acl *acl; + int acl_type, error; + + acl_type = posix_acl_type(acl_name); + if (acl_type < 0) + return ERR_PTR(-EINVAL); + + /* + * The VFS has no restrictions on reading POSIX ACLs so calling + * something like xattr_permission() isn't needed. Only LSMs get a say. + */ + error = security_inode_get_acl(mnt_userns, dentry, acl_name); + if (error) + return ERR_PTR(error); + + if (!IS_POSIXACL(inode)) + return ERR_PTR(-EOPNOTSUPP); + if (S_ISLNK(inode->i_mode)) + return ERR_PTR(-EOPNOTSUPP); + + acl = __get_acl(mnt_userns, dentry, inode, acl_type); + if (IS_ERR(acl)) + return acl; + if (!acl) + return ERR_PTR(-ENODATA); + + return acl; +} +EXPORT_SYMBOL_GPL(vfs_get_acl); diff --git a/include/linux/posix_acl.h b/include/linux/posix_acl.h index 316b05c1dc97..86aec1efc80e 100644 --- a/include/linux/posix_acl.h +++ b/include/linux/posix_acl.h @@ -102,6 +102,8 @@ static inline void cache_no_acl(struct inode *inode) int vfs_set_acl(struct user_namespace *mnt_userns, struct dentry *dentry, const char *acl_name, struct posix_acl *kacl); +struct posix_acl *vfs_get_acl(struct user_namespace *mnt_userns, + struct dentry *dentry, const char *acl_name); #else static inline int posix_acl_chmod(struct user_namespace *mnt_userns, struct dentry *dentry, umode_t mode) @@ -136,6 +138,13 @@ static inline int vfs_set_acl(struct user_namespace *mnt_userns, { return -EOPNOTSUPP; } + +static inline struct posix_acl *vfs_get_acl(struct user_namespace *mnt_userns, + struct dentry *dentry, + const char *acl_name) +{ + return ERR_PTR(-EOPNOTSUPP); +} #endif /* CONFIG_FS_POSIX_ACL */ struct posix_acl *get_inode_acl(struct inode *inode, int type); diff --git a/include/linux/posix_acl_xattr.h b/include/linux/posix_acl_xattr.h index b86b7f170d43..bf30296389d7 100644 --- a/include/linux/posix_acl_xattr.h +++ b/include/linux/posix_acl_xattr.h @@ -38,6 +38,9 @@ void posix_acl_fix_xattr_to_user(void *value, size_t size); void posix_acl_getxattr_idmapped_mnt(struct user_namespace *mnt_userns, const struct inode *inode, void *value, size_t size); +ssize_t vfs_posix_acl_to_xattr(struct user_namespace *mnt_userns, + struct inode *inode, const struct posix_acl *acl, + void *buffer, size_t size); #else static inline void posix_acl_fix_xattr_from_user(void *value, size_t size) { @@ -51,6 +54,13 @@ posix_acl_getxattr_idmapped_mnt(struct user_namespace *mnt_userns, size_t size) { } +static inline ssize_t vfs_posix_acl_to_xattr(struct user_namespace *mnt_userns, + struct inode *inode, + const struct posix_acl *acl, + void *buffer, size_t size) +{ + return 0; +} #endif struct posix_acl *posix_acl_from_xattr(struct user_namespace *user_ns, |