diff options
Diffstat (limited to 'fs/xattr.c')
| -rw-r--r-- | fs/xattr.c | 1219 |
1 files changed, 906 insertions, 313 deletions
diff --git a/fs/xattr.c b/fs/xattr.c index 464c94bf65f9..32d445fb60aa 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -1,3 +1,4 @@ +// SPDX-License-Identifier: GPL-2.0-only /* File: fs/xattr.c @@ -8,13 +9,13 @@ Copyright (c) 2004 Red Hat, Inc., James Morris <jmorris@redhat.com> */ #include <linux/fs.h> +#include <linux/filelock.h> #include <linux/slab.h> #include <linux/file.h> #include <linux/xattr.h> #include <linux/mount.h> #include <linux/namei.h> #include <linux/security.h> -#include <linux/evm.h> #include <linux/syscalls.h> #include <linux/export.h> #include <linux/fsnotify.h> @@ -24,6 +25,8 @@ #include <linux/uaccess.h> +#include "internal.h" + static const char * strcmp_prefix(const char *a, const char *a_prefix) { @@ -52,7 +55,7 @@ strcmp_prefix(const char *a, const char *a_prefix) static const struct xattr_handler * xattr_resolve_name(struct inode *inode, const char **name) { - const struct xattr_handler **handlers = inode->i_sb->s_xattr; + const struct xattr_handler * const *handlers = inode->i_sb->s_xattr; const struct xattr_handler *handler; if (!(inode->i_opflags & IOP_XATTR)) { @@ -77,27 +80,45 @@ xattr_resolve_name(struct inode *inode, const char **name) return ERR_PTR(-EOPNOTSUPP); } +/** + * may_write_xattr - check whether inode allows writing xattr + * @idmap: idmap of the mount the inode was found from + * @inode: the inode on which to set an xattr + * + * Check whether the inode allows writing xattrs. Specifically, we can never + * set or remove an extended attribute on a read-only filesystem or on an + * immutable / append-only inode. + * + * We also need to ensure that the inode has a mapping in the mount to + * not risk writing back invalid i_{g,u}id values. + * + * Return: On success zero is returned. On error a negative errno is returned. + */ +int may_write_xattr(struct mnt_idmap *idmap, struct inode *inode) +{ + if (IS_IMMUTABLE(inode)) + return -EPERM; + if (IS_APPEND(inode)) + return -EPERM; + if (HAS_UNMAPPED_ID(idmap, inode)) + return -EPERM; + return 0; +} + /* * Check permissions for extended attribute access. This is a bit complicated * because different namespaces have very different rules. */ static int -xattr_permission(struct inode *inode, const char *name, int mask) +xattr_permission(struct mnt_idmap *idmap, struct inode *inode, + const char *name, int mask) { - /* - * We can never set or remove an extended attribute on a read-only - * filesystem or on an immutable / append-only inode. - */ if (mask & MAY_WRITE) { - if (IS_IMMUTABLE(inode) || IS_APPEND(inode)) - return -EPERM; - /* - * Updating an xattr will likely cause i_uid and i_gid - * to be writen back improperly if their true value is - * unknown to the vfs. - */ - if (HAS_UNMAPPED_ID(inode)) - return -EPERM; + int ret; + + ret = may_write_xattr(idmap, inode); + if (ret) + return ret; } /* @@ -126,19 +147,49 @@ xattr_permission(struct inode *inode, const char *name, int mask) if (!S_ISREG(inode->i_mode) && !S_ISDIR(inode->i_mode)) return (mask & MAY_WRITE) ? -EPERM : -ENODATA; if (S_ISDIR(inode->i_mode) && (inode->i_mode & S_ISVTX) && - (mask & MAY_WRITE) && !inode_owner_or_capable(inode)) + (mask & MAY_WRITE) && + !inode_owner_or_capable(idmap, inode)) return -EPERM; } - return inode_permission(inode, mask); + return inode_permission(idmap, inode, mask); } +/* + * Look for any handler that deals with the specified namespace. + */ int -__vfs_setxattr(struct dentry *dentry, struct inode *inode, const char *name, - const void *value, size_t size, int flags) +xattr_supports_user_prefix(struct inode *inode) { + const struct xattr_handler * const *handlers = inode->i_sb->s_xattr; const struct xattr_handler *handler; + if (!(inode->i_opflags & IOP_XATTR)) { + if (unlikely(is_bad_inode(inode))) + return -EIO; + return -EOPNOTSUPP; + } + + for_each_xattr_handler(handlers, handler) { + if (!strncmp(xattr_prefix(handler), XATTR_USER_PREFIX, + XATTR_USER_PREFIX_LEN)) + return 0; + } + + return -EOPNOTSUPP; +} +EXPORT_SYMBOL(xattr_supports_user_prefix); + +int +__vfs_setxattr(struct mnt_idmap *idmap, struct dentry *dentry, + struct inode *inode, const char *name, const void *value, + size_t size, int flags) +{ + const struct xattr_handler *handler; + + if (is_posix_acl_xattr(name)) + return -EOPNOTSUPP; + handler = xattr_resolve_name(inode, &name); if (IS_ERR(handler)) return PTR_ERR(handler); @@ -146,7 +197,8 @@ __vfs_setxattr(struct dentry *dentry, struct inode *inode, const char *name, return -EOPNOTSUPP; if (size == 0) value = ""; /* empty EA, do not remove */ - return handler->set(handler, dentry, inode, name, value, size, flags); + return handler->set(handler, idmap, dentry, inode, name, value, + size, flags); } EXPORT_SYMBOL(__vfs_setxattr); @@ -154,20 +206,22 @@ EXPORT_SYMBOL(__vfs_setxattr); * __vfs_setxattr_noperm - perform setxattr operation without performing * permission checks. * - * @dentry - object to perform setxattr on - * @name - xattr name to set - * @value - value to set @name to - * @size - size of @value - * @flags - flags to pass into filesystem operations + * @idmap: idmap of the mount the inode was found from + * @dentry: object to perform setxattr on + * @name: xattr name to set + * @value: value to set @name to + * @size: size of @value + * @flags: flags to pass into filesystem operations * * returns the result of the internal setxattr or setsecurity operations. * - * This function requires the caller to lock the inode's i_mutex before it + * This function requires the caller to lock the inode's i_rwsem before it * is executed. It also assumes that the caller will make the appropriate * permission checks. */ -int __vfs_setxattr_noperm(struct dentry *dentry, const char *name, - const void *value, size_t size, int flags) +int __vfs_setxattr_noperm(struct mnt_idmap *idmap, + struct dentry *dentry, const char *name, + const void *value, size_t size, int flags) { struct inode *inode = dentry->d_inode; int error = -EAGAIN; @@ -177,7 +231,8 @@ int __vfs_setxattr_noperm(struct dentry *dentry, const char *name, if (issec) inode->i_flags &= ~S_NOSEC; if (inode->i_opflags & IOP_XATTR) { - error = __vfs_setxattr(dentry, inode, name, value, size, flags); + error = __vfs_setxattr(idmap, dentry, inode, name, value, + size, flags); if (!error) { fsnotify_xattr(dentry); security_inode_post_setxattr(dentry, name, value, @@ -203,44 +258,97 @@ int __vfs_setxattr_noperm(struct dentry *dentry, const char *name, return error; } - +/** + * __vfs_setxattr_locked - set an extended attribute while holding the inode + * lock + * + * @idmap: idmap of the mount of the target inode + * @dentry: object to perform setxattr on + * @name: xattr name to set + * @value: value to set @name to + * @size: size of @value + * @flags: flags to pass into filesystem operations + * @delegated_inode: on return, will contain an inode pointer that + * a delegation was broken on, NULL if none. + */ int -vfs_setxattr(struct dentry *dentry, const char *name, const void *value, - size_t size, int flags) +__vfs_setxattr_locked(struct mnt_idmap *idmap, struct dentry *dentry, + const char *name, const void *value, size_t size, + int flags, struct delegated_inode *delegated_inode) { struct inode *inode = dentry->d_inode; int error; - error = xattr_permission(inode, name, MAY_WRITE); + error = xattr_permission(idmap, inode, name, MAY_WRITE); if (error) return error; - inode_lock(inode); - error = security_inode_setxattr(dentry, name, value, size, flags); + error = security_inode_setxattr(idmap, dentry, name, value, size, + flags); + if (error) + goto out; + + error = try_break_deleg(inode, delegated_inode); if (error) goto out; - error = __vfs_setxattr_noperm(dentry, name, value, size, flags); + error = __vfs_setxattr_noperm(idmap, dentry, name, value, + size, flags); out: + return error; +} +EXPORT_SYMBOL_GPL(__vfs_setxattr_locked); + +int +vfs_setxattr(struct mnt_idmap *idmap, struct dentry *dentry, + const char *name, const void *value, size_t size, int flags) +{ + struct inode *inode = dentry->d_inode; + struct delegated_inode delegated_inode = { }; + const void *orig_value = value; + int error; + + if (size && strcmp(name, XATTR_NAME_CAPS) == 0) { + error = cap_convert_nscap(idmap, dentry, &value, size); + if (error < 0) + return error; + size = error; + } + +retry_deleg: + inode_lock(inode); + error = __vfs_setxattr_locked(idmap, dentry, name, value, size, + flags, &delegated_inode); inode_unlock(inode); + + if (is_delegated(&delegated_inode)) { + error = break_deleg_wait(&delegated_inode); + if (!error) + goto retry_deleg; + } + if (value != orig_value) + kfree(value); + return error; } EXPORT_SYMBOL_GPL(vfs_setxattr); -ssize_t -xattr_getsecurity(struct inode *inode, const char *name, void *value, - size_t size) +static ssize_t +xattr_getsecurity(struct mnt_idmap *idmap, struct inode *inode, + const char *name, void *value, size_t size) { void *buffer = NULL; ssize_t len; if (!value || !size) { - len = security_inode_getsecurity(inode, name, &buffer, false); + len = security_inode_getsecurity(idmap, inode, name, + &buffer, false); goto out_noalloc; } - len = security_inode_getsecurity(inode, name, &buffer, true); + len = security_inode_getsecurity(idmap, inode, name, &buffer, + true); if (len < 0) return len; if (size < len) { @@ -249,30 +357,31 @@ xattr_getsecurity(struct inode *inode, const char *name, void *value, } memcpy(value, buffer, len); out: - security_release_secctx(buffer, len); + kfree(buffer); out_noalloc: return len; } -EXPORT_SYMBOL_GPL(xattr_getsecurity); /* * vfs_getxattr_alloc - allocate memory, if necessary, before calling getxattr * * Allocate memory, if not already allocated, or re-allocate correct size, - * before retrieving the extended attribute. + * before retrieving the extended attribute. The xattr value buffer should + * always be freed by the caller, even on error. * * Returns the result of alloc, if failed, or the getxattr operation. */ -ssize_t -vfs_getxattr_alloc(struct dentry *dentry, const char *name, char **xattr_value, - size_t xattr_size, gfp_t flags) +int +vfs_getxattr_alloc(struct mnt_idmap *idmap, struct dentry *dentry, + const char *name, char **xattr_value, size_t xattr_size, + gfp_t flags) { const struct xattr_handler *handler; struct inode *inode = dentry->d_inode; char *value = *xattr_value; int error; - error = xattr_permission(inode, name, MAY_READ); + error = xattr_permission(idmap, inode, name, MAY_READ); if (error) return error; @@ -303,6 +412,9 @@ __vfs_getxattr(struct dentry *dentry, struct inode *inode, const char *name, { const struct xattr_handler *handler; + if (is_posix_acl_xattr(name)) + return -EOPNOTSUPP; + handler = xattr_resolve_name(inode, &name); if (IS_ERR(handler)) return PTR_ERR(handler); @@ -313,12 +425,13 @@ __vfs_getxattr(struct dentry *dentry, struct inode *inode, const char *name, EXPORT_SYMBOL(__vfs_getxattr); ssize_t -vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size) +vfs_getxattr(struct mnt_idmap *idmap, struct dentry *dentry, + const char *name, void *value, size_t size) { struct inode *inode = dentry->d_inode; int error; - error = xattr_permission(inode, name, MAY_READ); + error = xattr_permission(idmap, inode, name, MAY_READ); if (error) return error; @@ -329,7 +442,8 @@ vfs_getxattr(struct dentry *dentry, const char *name, void *value, size_t size) if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN)) { const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; - int ret = xattr_getsecurity(inode, suffix, value, size); + int ret = xattr_getsecurity(idmap, inode, suffix, value, + size); /* * Only overwrite the return value if a security module * is actually active. @@ -343,6 +457,28 @@ nolsm: } EXPORT_SYMBOL_GPL(vfs_getxattr); +/** + * vfs_listxattr - retrieve \0 separated list of xattr names + * @dentry: the dentry from whose inode the xattr names are retrieved + * @list: buffer to store xattr names into + * @size: size of the buffer + * + * This function returns the names of all xattrs associated with the + * inode of @dentry. + * + * Note, for legacy reasons the vfs_listxattr() function lists POSIX + * ACLs as well. Since POSIX ACLs are decoupled from IOP_XATTR the + * vfs_listxattr() function doesn't check for this flag since a + * filesystem could implement POSIX ACLs without implementing any other + * xattrs. + * + * However, since all codepaths that remove IOP_XATTR also assign of + * inode operations that either don't implement or implement a stub + * ->listxattr() operation. + * + * Return: On success, the size of the buffer that was used. On error a + * negative error code. + */ ssize_t vfs_listxattr(struct dentry *dentry, char *list, size_t size) { @@ -352,8 +488,8 @@ vfs_listxattr(struct dentry *dentry, char *list, size_t size) error = security_inode_listxattr(dentry); if (error) return error; - if (inode->i_op->listxattr && (inode->i_opflags & IOP_XATTR)) { - error = -EOPNOTSUPP; + + if (inode->i_op->listxattr) { error = inode->i_op->listxattr(dentry, list, size); } else { error = security_inode_listsecurity(inode, list, size); @@ -365,104 +501,168 @@ vfs_listxattr(struct dentry *dentry, char *list, size_t size) EXPORT_SYMBOL_GPL(vfs_listxattr); int -__vfs_removexattr(struct dentry *dentry, const char *name) +__vfs_removexattr(struct mnt_idmap *idmap, struct dentry *dentry, + const char *name) { struct inode *inode = d_inode(dentry); const struct xattr_handler *handler; + if (is_posix_acl_xattr(name)) + return -EOPNOTSUPP; + handler = xattr_resolve_name(inode, &name); if (IS_ERR(handler)) return PTR_ERR(handler); if (!handler->set) return -EOPNOTSUPP; - return handler->set(handler, dentry, inode, name, NULL, 0, XATTR_REPLACE); + return handler->set(handler, idmap, dentry, inode, name, NULL, 0, + XATTR_REPLACE); } EXPORT_SYMBOL(__vfs_removexattr); +/** + * __vfs_removexattr_locked - set an extended attribute while holding the inode + * lock + * + * @idmap: idmap of the mount of the target inode + * @dentry: object to perform setxattr on + * @name: name of xattr to remove + * @delegated_inode: on return, will contain an inode pointer that + * a delegation was broken on, NULL if none. + */ int -vfs_removexattr(struct dentry *dentry, const char *name) +__vfs_removexattr_locked(struct mnt_idmap *idmap, + struct dentry *dentry, const char *name, + struct delegated_inode *delegated_inode) { struct inode *inode = dentry->d_inode; int error; - error = xattr_permission(inode, name, MAY_WRITE); + error = xattr_permission(idmap, inode, name, MAY_WRITE); if (error) return error; - inode_lock(inode); - error = security_inode_removexattr(dentry, name); + error = security_inode_removexattr(idmap, dentry, name); + if (error) + goto out; + + error = try_break_deleg(inode, delegated_inode); if (error) goto out; - error = __vfs_removexattr(dentry, name); + error = __vfs_removexattr(idmap, dentry, name); + if (error) + return error; - if (!error) { - fsnotify_xattr(dentry); - evm_inode_post_removexattr(dentry, name); - } + fsnotify_xattr(dentry); + security_inode_post_removexattr(dentry, name); out: + return error; +} +EXPORT_SYMBOL_GPL(__vfs_removexattr_locked); + +int +vfs_removexattr(struct mnt_idmap *idmap, struct dentry *dentry, + const char *name) +{ + struct inode *inode = dentry->d_inode; + struct delegated_inode delegated_inode = { }; + int error; + +retry_deleg: + inode_lock(inode); + error = __vfs_removexattr_locked(idmap, dentry, + name, &delegated_inode); inode_unlock(inode); + + if (is_delegated(&delegated_inode)) { + error = break_deleg_wait(&delegated_inode); + if (!error) + goto retry_deleg; + } + return error; } EXPORT_SYMBOL_GPL(vfs_removexattr); +int import_xattr_name(struct xattr_name *kname, const char __user *name) +{ + int error = strncpy_from_user(kname->name, name, + sizeof(kname->name)); + if (error == 0 || error == sizeof(kname->name)) + return -ERANGE; + if (error < 0) + return error; + return 0; +} /* * Extended attribute SET operations */ -static long -setxattr(struct dentry *d, const char __user *name, const void __user *value, - size_t size, int flags) + +int setxattr_copy(const char __user *name, struct kernel_xattr_ctx *ctx) { int error; - void *kvalue = NULL; - char kname[XATTR_NAME_MAX + 1]; - if (flags & ~(XATTR_CREATE|XATTR_REPLACE)) + if (ctx->flags & ~(XATTR_CREATE|XATTR_REPLACE)) return -EINVAL; - error = strncpy_from_user(kname, name, sizeof(kname)); - if (error == 0 || error == sizeof(kname)) - error = -ERANGE; - if (error < 0) + error = import_xattr_name(ctx->kname, name); + if (error) return error; - if (size) { - if (size > XATTR_SIZE_MAX) + if (ctx->size) { + if (ctx->size > XATTR_SIZE_MAX) return -E2BIG; - kvalue = kvmalloc(size, GFP_KERNEL); - if (!kvalue) - return -ENOMEM; - if (copy_from_user(kvalue, value, size)) { - error = -EFAULT; - goto out; + + ctx->kvalue = vmemdup_user(ctx->cvalue, ctx->size); + if (IS_ERR(ctx->kvalue)) { + error = PTR_ERR(ctx->kvalue); + ctx->kvalue = NULL; } - if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) || - (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)) - posix_acl_fix_xattr_from_user(kvalue, size); } - error = vfs_setxattr(d, kname, kvalue, size, flags); -out: - kvfree(kvalue); + return error; +} + +static int do_setxattr(struct mnt_idmap *idmap, struct dentry *dentry, + struct kernel_xattr_ctx *ctx) +{ + if (is_posix_acl_xattr(ctx->kname->name)) + return do_set_acl(idmap, dentry, ctx->kname->name, + ctx->kvalue, ctx->size); + + return vfs_setxattr(idmap, dentry, ctx->kname->name, + ctx->kvalue, ctx->size, ctx->flags); +} + +int file_setxattr(struct file *f, struct kernel_xattr_ctx *ctx) +{ + int error = mnt_want_write_file(f); + if (!error) { + audit_file(f); + error = do_setxattr(file_mnt_idmap(f), f->f_path.dentry, ctx); + mnt_drop_write_file(f); + } return error; } -static int path_setxattr(const char __user *pathname, - const char __user *name, const void __user *value, - size_t size, int flags, unsigned int lookup_flags) +/* unconditionally consumes filename */ +int filename_setxattr(int dfd, struct filename *filename, + unsigned int lookup_flags, struct kernel_xattr_ctx *ctx) { struct path path; int error; + retry: - error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); + error = filename_lookup(dfd, filename, lookup_flags, &path, NULL); if (error) - return error; + goto out; error = mnt_want_write(path.mnt); if (!error) { - error = setxattr(path.dentry, name, value, size, flags); + error = do_setxattr(mnt_idmap(path.mnt), path.dentry, ctx); mnt_drop_write(path.mnt); } path_put(&path); @@ -470,127 +670,238 @@ retry: lookup_flags |= LOOKUP_REVAL; goto retry; } + +out: + putname(filename); + return error; +} + +static int path_setxattrat(int dfd, const char __user *pathname, + unsigned int at_flags, const char __user *name, + const void __user *value, size_t size, int flags) +{ + struct xattr_name kname; + struct kernel_xattr_ctx ctx = { + .cvalue = value, + .kvalue = NULL, + .size = size, + .kname = &kname, + .flags = flags, + }; + struct filename *filename; + unsigned int lookup_flags = 0; + int error; + + if ((at_flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0) + return -EINVAL; + + if (!(at_flags & AT_SYMLINK_NOFOLLOW)) + lookup_flags = LOOKUP_FOLLOW; + + error = setxattr_copy(name, &ctx); + if (error) + return error; + + filename = getname_maybe_null(pathname, at_flags); + if (!filename && dfd >= 0) { + CLASS(fd, f)(dfd); + if (fd_empty(f)) + error = -EBADF; + else + error = file_setxattr(fd_file(f), &ctx); + } else { + error = filename_setxattr(dfd, filename, lookup_flags, &ctx); + } + kvfree(ctx.kvalue); return error; } +SYSCALL_DEFINE6(setxattrat, int, dfd, const char __user *, pathname, unsigned int, at_flags, + const char __user *, name, const struct xattr_args __user *, uargs, + size_t, usize) +{ + struct xattr_args args = {}; + int error; + + BUILD_BUG_ON(sizeof(struct xattr_args) < XATTR_ARGS_SIZE_VER0); + BUILD_BUG_ON(sizeof(struct xattr_args) != XATTR_ARGS_SIZE_LATEST); + + if (unlikely(usize < XATTR_ARGS_SIZE_VER0)) + return -EINVAL; + if (usize > PAGE_SIZE) + return -E2BIG; + + error = copy_struct_from_user(&args, sizeof(args), uargs, usize); + if (error) + return error; + + return path_setxattrat(dfd, pathname, at_flags, name, + u64_to_user_ptr(args.value), args.size, + args.flags); +} + SYSCALL_DEFINE5(setxattr, const char __user *, pathname, const char __user *, name, const void __user *, value, size_t, size, int, flags) { - return path_setxattr(pathname, name, value, size, flags, LOOKUP_FOLLOW); + return path_setxattrat(AT_FDCWD, pathname, 0, name, value, size, flags); } SYSCALL_DEFINE5(lsetxattr, const char __user *, pathname, const char __user *, name, const void __user *, value, size_t, size, int, flags) { - return path_setxattr(pathname, name, value, size, flags, 0); + return path_setxattrat(AT_FDCWD, pathname, AT_SYMLINK_NOFOLLOW, name, + value, size, flags); } SYSCALL_DEFINE5(fsetxattr, int, fd, const char __user *, name, const void __user *,value, size_t, size, int, flags) { - struct fd f = fdget(fd); - int error = -EBADF; - - if (!f.file) - return error; - audit_file(f.file); - error = mnt_want_write_file(f.file); - if (!error) { - error = setxattr(f.file->f_path.dentry, name, value, size, flags); - mnt_drop_write_file(f.file); - } - fdput(f); - return error; + return path_setxattrat(fd, NULL, AT_EMPTY_PATH, name, + value, size, flags); } /* * Extended attribute GET operations */ static ssize_t -getxattr(struct dentry *d, const char __user *name, void __user *value, - size_t size) +do_getxattr(struct mnt_idmap *idmap, struct dentry *d, + struct kernel_xattr_ctx *ctx) { ssize_t error; + char *kname = ctx->kname->name; void *kvalue = NULL; - char kname[XATTR_NAME_MAX + 1]; - - error = strncpy_from_user(kname, name, sizeof(kname)); - if (error == 0 || error == sizeof(kname)) - error = -ERANGE; - if (error < 0) - return error; - if (size) { - if (size > XATTR_SIZE_MAX) - size = XATTR_SIZE_MAX; - kvalue = kvzalloc(size, GFP_KERNEL); + if (ctx->size) { + if (ctx->size > XATTR_SIZE_MAX) + ctx->size = XATTR_SIZE_MAX; + kvalue = kvzalloc(ctx->size, GFP_KERNEL); if (!kvalue) return -ENOMEM; } - error = vfs_getxattr(d, kname, kvalue, size); + if (is_posix_acl_xattr(kname)) + error = do_get_acl(idmap, d, kname, kvalue, ctx->size); + else + error = vfs_getxattr(idmap, d, kname, kvalue, ctx->size); if (error > 0) { - if ((strcmp(kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) || - (strcmp(kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0)) - posix_acl_fix_xattr_to_user(kvalue, size); - if (size && copy_to_user(value, kvalue, error)) + if (ctx->size && copy_to_user(ctx->value, kvalue, error)) error = -EFAULT; - } else if (error == -ERANGE && size >= XATTR_SIZE_MAX) { + } else if (error == -ERANGE && ctx->size >= XATTR_SIZE_MAX) { /* The file system tried to returned a value bigger than XATTR_SIZE_MAX bytes. Not possible. */ error = -E2BIG; } kvfree(kvalue); - return error; } -static ssize_t path_getxattr(const char __user *pathname, - const char __user *name, void __user *value, - size_t size, unsigned int lookup_flags) +ssize_t file_getxattr(struct file *f, struct kernel_xattr_ctx *ctx) +{ + audit_file(f); + return do_getxattr(file_mnt_idmap(f), f->f_path.dentry, ctx); +} + +/* unconditionally consumes filename */ +ssize_t filename_getxattr(int dfd, struct filename *filename, + unsigned int lookup_flags, struct kernel_xattr_ctx *ctx) { struct path path; ssize_t error; retry: - error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); + error = filename_lookup(dfd, filename, lookup_flags, &path, NULL); if (error) - return error; - error = getxattr(path.dentry, name, value, size); + goto out; + error = do_getxattr(mnt_idmap(path.mnt), path.dentry, ctx); path_put(&path); if (retry_estale(error, lookup_flags)) { lookup_flags |= LOOKUP_REVAL; goto retry; } +out: + putname(filename); return error; } +static ssize_t path_getxattrat(int dfd, const char __user *pathname, + unsigned int at_flags, const char __user *name, + void __user *value, size_t size) +{ + struct xattr_name kname; + struct kernel_xattr_ctx ctx = { + .value = value, + .size = size, + .kname = &kname, + .flags = 0, + }; + struct filename *filename; + ssize_t error; + + if ((at_flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0) + return -EINVAL; + + error = import_xattr_name(&kname, name); + if (error) + return error; + + filename = getname_maybe_null(pathname, at_flags); + if (!filename && dfd >= 0) { + CLASS(fd, f)(dfd); + if (fd_empty(f)) + return -EBADF; + return file_getxattr(fd_file(f), &ctx); + } else { + int lookup_flags = 0; + if (!(at_flags & AT_SYMLINK_NOFOLLOW)) + lookup_flags = LOOKUP_FOLLOW; + return filename_getxattr(dfd, filename, lookup_flags, &ctx); + } +} + +SYSCALL_DEFINE6(getxattrat, int, dfd, const char __user *, pathname, unsigned int, at_flags, + const char __user *, name, struct xattr_args __user *, uargs, size_t, usize) +{ + struct xattr_args args = {}; + int error; + + BUILD_BUG_ON(sizeof(struct xattr_args) < XATTR_ARGS_SIZE_VER0); + BUILD_BUG_ON(sizeof(struct xattr_args) != XATTR_ARGS_SIZE_LATEST); + + if (unlikely(usize < XATTR_ARGS_SIZE_VER0)) + return -EINVAL; + if (usize > PAGE_SIZE) + return -E2BIG; + + error = copy_struct_from_user(&args, sizeof(args), uargs, usize); + if (error) + return error; + + if (args.flags != 0) + return -EINVAL; + + return path_getxattrat(dfd, pathname, at_flags, name, + u64_to_user_ptr(args.value), args.size); +} + SYSCALL_DEFINE4(getxattr, const char __user *, pathname, const char __user *, name, void __user *, value, size_t, size) { - return path_getxattr(pathname, name, value, size, LOOKUP_FOLLOW); + return path_getxattrat(AT_FDCWD, pathname, 0, name, value, size); } SYSCALL_DEFINE4(lgetxattr, const char __user *, pathname, const char __user *, name, void __user *, value, size_t, size) { - return path_getxattr(pathname, name, value, size, 0); + return path_getxattrat(AT_FDCWD, pathname, AT_SYMLINK_NOFOLLOW, name, + value, size); } SYSCALL_DEFINE4(fgetxattr, int, fd, const char __user *, name, void __user *, value, size_t, size) { - struct fd f = fdget(fd); - ssize_t error = -EBADF; - - if (!f.file) - return error; - audit_file(f.file); - error = getxattr(f.file->f_path.dentry, name, value, size); - fdput(f); - return error; + return path_getxattrat(fd, NULL, AT_EMPTY_PATH, name, value, size); } /* @@ -625,79 +936,120 @@ listxattr(struct dentry *d, char __user *list, size_t size) return error; } -static ssize_t path_listxattr(const char __user *pathname, char __user *list, - size_t size, unsigned int lookup_flags) +static +ssize_t file_listxattr(struct file *f, char __user *list, size_t size) +{ + audit_file(f); + return listxattr(f->f_path.dentry, list, size); +} + +/* unconditionally consumes filename */ +static +ssize_t filename_listxattr(int dfd, struct filename *filename, + unsigned int lookup_flags, + char __user *list, size_t size) { struct path path; ssize_t error; retry: - error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); + error = filename_lookup(dfd, filename, lookup_flags, &path, NULL); if (error) - return error; + goto out; error = listxattr(path.dentry, list, size); path_put(&path); if (retry_estale(error, lookup_flags)) { lookup_flags |= LOOKUP_REVAL; goto retry; } +out: + putname(filename); return error; } +static ssize_t path_listxattrat(int dfd, const char __user *pathname, + unsigned int at_flags, char __user *list, + size_t size) +{ + struct filename *filename; + int lookup_flags; + + if ((at_flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0) + return -EINVAL; + + filename = getname_maybe_null(pathname, at_flags); + if (!filename) { + CLASS(fd, f)(dfd); + if (fd_empty(f)) + return -EBADF; + return file_listxattr(fd_file(f), list, size); + } + + lookup_flags = (at_flags & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW; + return filename_listxattr(dfd, filename, lookup_flags, list, size); +} + +SYSCALL_DEFINE5(listxattrat, int, dfd, const char __user *, pathname, + unsigned int, at_flags, + char __user *, list, size_t, size) +{ + return path_listxattrat(dfd, pathname, at_flags, list, size); +} + SYSCALL_DEFINE3(listxattr, const char __user *, pathname, char __user *, list, size_t, size) { - return path_listxattr(pathname, list, size, LOOKUP_FOLLOW); + return path_listxattrat(AT_FDCWD, pathname, 0, list, size); } SYSCALL_DEFINE3(llistxattr, const char __user *, pathname, char __user *, list, size_t, size) { - return path_listxattr(pathname, list, size, 0); + return path_listxattrat(AT_FDCWD, pathname, AT_SYMLINK_NOFOLLOW, list, size); } SYSCALL_DEFINE3(flistxattr, int, fd, char __user *, list, size_t, size) { - struct fd f = fdget(fd); - ssize_t error = -EBADF; - - if (!f.file) - return error; - audit_file(f.file); - error = listxattr(f.file->f_path.dentry, list, size); - fdput(f); - return error; + return path_listxattrat(fd, NULL, AT_EMPTY_PATH, list, size); } /* * Extended attribute REMOVE operations */ static long -removexattr(struct dentry *d, const char __user *name) +removexattr(struct mnt_idmap *idmap, struct dentry *d, const char *name) { - int error; - char kname[XATTR_NAME_MAX + 1]; + if (is_posix_acl_xattr(name)) + return vfs_remove_acl(idmap, d, name); + return vfs_removexattr(idmap, d, name); +} - error = strncpy_from_user(kname, name, sizeof(kname)); - if (error == 0 || error == sizeof(kname)) - error = -ERANGE; - if (error < 0) - return error; +static int file_removexattr(struct file *f, struct xattr_name *kname) +{ + int error = mnt_want_write_file(f); - return vfs_removexattr(d, kname); + if (!error) { + audit_file(f); + error = removexattr(file_mnt_idmap(f), + f->f_path.dentry, kname->name); + mnt_drop_write_file(f); + } + return error; } -static int path_removexattr(const char __user *pathname, - const char __user *name, unsigned int lookup_flags) +/* unconditionally consumes filename */ +static int filename_removexattr(int dfd, struct filename *filename, + unsigned int lookup_flags, struct xattr_name *kname) { struct path path; int error; + retry: - error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); + error = filename_lookup(dfd, filename, lookup_flags, &path, NULL); if (error) - return error; + goto out; error = mnt_want_write(path.mnt); if (!error) { - error = removexattr(path.dentry, name); + error = removexattr(mnt_idmap(path.mnt), path.dentry, kname->name); mnt_drop_write(path.mnt); } path_put(&path); @@ -705,73 +1057,103 @@ retry: lookup_flags |= LOOKUP_REVAL; goto retry; } +out: + putname(filename); return error; } +static int path_removexattrat(int dfd, const char __user *pathname, + unsigned int at_flags, const char __user *name) +{ + struct xattr_name kname; + struct filename *filename; + unsigned int lookup_flags; + int error; + + if ((at_flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0) + return -EINVAL; + + error = import_xattr_name(&kname, name); + if (error) + return error; + + filename = getname_maybe_null(pathname, at_flags); + if (!filename) { + CLASS(fd, f)(dfd); + if (fd_empty(f)) + return -EBADF; + return file_removexattr(fd_file(f), &kname); + } + lookup_flags = (at_flags & AT_SYMLINK_NOFOLLOW) ? 0 : LOOKUP_FOLLOW; + return filename_removexattr(dfd, filename, lookup_flags, &kname); +} + +SYSCALL_DEFINE4(removexattrat, int, dfd, const char __user *, pathname, + unsigned int, at_flags, const char __user *, name) +{ + return path_removexattrat(dfd, pathname, at_flags, name); +} + SYSCALL_DEFINE2(removexattr, const char __user *, pathname, const char __user *, name) { - return path_removexattr(pathname, name, LOOKUP_FOLLOW); + return path_removexattrat(AT_FDCWD, pathname, 0, name); } SYSCALL_DEFINE2(lremovexattr, const char __user *, pathname, const char __user *, name) { - return path_removexattr(pathname, name, 0); + return path_removexattrat(AT_FDCWD, pathname, AT_SYMLINK_NOFOLLOW, name); } SYSCALL_DEFINE2(fremovexattr, int, fd, const char __user *, name) { - struct fd f = fdget(fd); - int error = -EBADF; + return path_removexattrat(fd, NULL, AT_EMPTY_PATH, name); +} - if (!f.file) - return error; - audit_file(f.file); - error = mnt_want_write_file(f.file); - if (!error) { - error = removexattr(f.file->f_path.dentry, name); - mnt_drop_write_file(f.file); +int xattr_list_one(char **buffer, ssize_t *remaining_size, const char *name) +{ + size_t len; + + len = strlen(name) + 1; + if (*buffer) { + if (*remaining_size < len) + return -ERANGE; + memcpy(*buffer, name, len); + *buffer += len; } - fdput(f); - return error; + *remaining_size -= len; + return 0; } -/* +/** + * generic_listxattr - run through a dentry's xattr list() operations + * @dentry: dentry to list the xattrs + * @buffer: result buffer + * @buffer_size: size of @buffer + * * Combine the results of the list() operation from every xattr_handler in the - * list. + * xattr_handler stack. + * + * Note that this will not include the entries for POSIX ACLs. */ ssize_t generic_listxattr(struct dentry *dentry, char *buffer, size_t buffer_size) { - const struct xattr_handler *handler, **handlers = dentry->d_sb->s_xattr; - unsigned int size = 0; + const struct xattr_handler *handler, * const *handlers = dentry->d_sb->s_xattr; + ssize_t remaining_size = buffer_size; - if (!buffer) { - for_each_xattr_handler(handlers, handler) { - if (!handler->name || - (handler->list && !handler->list(dentry))) - continue; - size += strlen(handler->name) + 1; - } - } else { - char *buf = buffer; - size_t len; - - for_each_xattr_handler(handlers, handler) { - if (!handler->name || - (handler->list && !handler->list(dentry))) - continue; - len = strlen(handler->name); - if (len + 1 > buffer_size) - return -ERANGE; - memcpy(buf, handler->name, len + 1); - buf += len + 1; - buffer_size -= len + 1; - } - size = buf - buffer; + for_each_xattr_handler(handlers, handler) { + int err; + + if (!handler->name || (handler->list && !handler->list(dentry))) + continue; + err = xattr_list_one(&buffer, &remaining_size, handler->name); + if (err) + return err; } - return size; + + return buffer_size - remaining_size; } EXPORT_SYMBOL(generic_listxattr); @@ -799,8 +1181,49 @@ const char *xattr_full_name(const struct xattr_handler *handler, } EXPORT_SYMBOL(xattr_full_name); -/* - * Allocate new xattr and copy in the value; but leave the name to callers. +/** + * simple_xattr_space - estimate the memory used by a simple xattr + * @name: the full name of the xattr + * @size: the size of its value + * + * This takes no account of how much larger the two slab objects actually are: + * that would depend on the slab implementation, when what is required is a + * deterministic number, which grows with name length and size and quantity. + * + * Return: The approximate number of bytes of memory used by such an xattr. + */ +size_t simple_xattr_space(const char *name, size_t size) +{ + /* + * Use "40" instead of sizeof(struct simple_xattr), to return the + * same result on 32-bit and 64-bit, and even if simple_xattr grows. + */ + return 40 + size + strlen(name); +} + +/** + * simple_xattr_free - free an xattr object + * @xattr: the xattr object + * + * Free the xattr object. Can handle @xattr being NULL. + */ +void simple_xattr_free(struct simple_xattr *xattr) +{ + if (xattr) + kfree(xattr->name); + kvfree(xattr); +} + +/** + * simple_xattr_alloc - allocate new xattr object + * @value: value of the xattr object + * @size: size of @value + * + * Allocate a new xattr object and initialize respective members. The caller is + * responsible for handling the name of the xattr. + * + * Return: On success a new xattr object is returned. On failure NULL is + * returned. */ struct simple_xattr *simple_xattr_alloc(const void *value, size_t size) { @@ -812,7 +1235,7 @@ struct simple_xattr *simple_xattr_alloc(const void *value, size_t size) if (len < sizeof(*new_xattr)) return NULL; - new_xattr = kmalloc(len, GFP_KERNEL); + new_xattr = kvmalloc(len, GFP_KERNEL_ACCOUNT); if (!new_xattr) return NULL; @@ -821,20 +1244,69 @@ struct simple_xattr *simple_xattr_alloc(const void *value, size_t size) return new_xattr; } -/* - * xattr GET operation for in-memory/pseudo filesystems +/** + * rbtree_simple_xattr_cmp - compare xattr name with current rbtree xattr entry + * @key: xattr name + * @node: current node + * + * Compare the xattr name with the xattr name attached to @node in the rbtree. + * + * Return: Negative value if continuing left, positive if continuing right, 0 + * if the xattr attached to @node matches @key. + */ +static int rbtree_simple_xattr_cmp(const void *key, const struct rb_node *node) +{ + const char *xattr_name = key; + const struct simple_xattr *xattr; + + xattr = rb_entry(node, struct simple_xattr, rb_node); + return strcmp(xattr->name, xattr_name); +} + +/** + * rbtree_simple_xattr_node_cmp - compare two xattr rbtree nodes + * @new_node: new node + * @node: current node + * + * Compare the xattr attached to @new_node with the xattr attached to @node. + * + * Return: Negative value if continuing left, positive if continuing right, 0 + * if the xattr attached to @new_node matches the xattr attached to @node. + */ +static int rbtree_simple_xattr_node_cmp(struct rb_node *new_node, + const struct rb_node *node) +{ + struct simple_xattr *xattr; + xattr = rb_entry(new_node, struct simple_xattr, rb_node); + return rbtree_simple_xattr_cmp(xattr->name, node); +} + +/** + * simple_xattr_get - get an xattr object + * @xattrs: the header of the xattr object + * @name: the name of the xattr to retrieve + * @buffer: the buffer to store the value into + * @size: the size of @buffer + * + * Try to find and retrieve the xattr object associated with @name. + * If @buffer is provided store the value of @xattr in @buffer + * otherwise just return the length. The size of @buffer is limited + * to XATTR_SIZE_MAX which currently is 65536. + * + * Return: On success the length of the xattr value is returned. On error a + * negative error code is returned. */ int simple_xattr_get(struct simple_xattrs *xattrs, const char *name, void *buffer, size_t size) { - struct simple_xattr *xattr; + struct simple_xattr *xattr = NULL; + struct rb_node *rbp; int ret = -ENODATA; - spin_lock(&xattrs->lock); - list_for_each_entry(xattr, &xattrs->head, list) { - if (strcmp(name, xattr->name)) - continue; - + read_lock(&xattrs->lock); + rbp = rb_find(name, &xattrs->rb_root, rbtree_simple_xattr_cmp); + if (rbp) { + xattr = rb_entry(rbp, struct simple_xattr, rb_node); ret = xattr->size; if (buffer) { if (size < xattr->size) @@ -842,75 +1314,113 @@ int simple_xattr_get(struct simple_xattrs *xattrs, const char *name, else memcpy(buffer, xattr->value, xattr->size); } - break; } - spin_unlock(&xattrs->lock); + read_unlock(&xattrs->lock); return ret; } /** - * simple_xattr_set - xattr SET operation for in-memory/pseudo filesystems - * @xattrs: target simple_xattr list - * @name: name of the extended attribute - * @value: value of the xattr. If %NULL, will remove the attribute. - * @size: size of the new xattr - * @flags: %XATTR_{CREATE|REPLACE} - * - * %XATTR_CREATE is set, the xattr shouldn't exist already; otherwise fails - * with -EEXIST. If %XATTR_REPLACE is set, the xattr should exist; - * otherwise, fails with -ENODATA. - * - * Returns 0 on success, -errno on failure. + * simple_xattr_set - set an xattr object + * @xattrs: the header of the xattr object + * @name: the name of the xattr to retrieve + * @value: the value to store along the xattr + * @size: the size of @value + * @flags: the flags determining how to set the xattr + * + * Set a new xattr object. + * If @value is passed a new xattr object will be allocated. If XATTR_REPLACE + * is specified in @flags a matching xattr object for @name must already exist. + * If it does it will be replaced with the new xattr object. If it doesn't we + * fail. If XATTR_CREATE is specified and a matching xattr does already exist + * we fail. If it doesn't we create a new xattr. If @flags is zero we simply + * insert the new xattr replacing any existing one. + * + * If @value is empty and a matching xattr object is found we delete it if + * XATTR_REPLACE is specified in @flags or @flags is zero. + * + * If @value is empty and no matching xattr object for @name is found we do + * nothing if XATTR_CREATE is specified in @flags or @flags is zero. For + * XATTR_REPLACE we fail as mentioned above. + * + * Return: On success, the removed or replaced xattr is returned, to be freed + * by the caller; or NULL if none. On failure a negative error code is returned. */ -int simple_xattr_set(struct simple_xattrs *xattrs, const char *name, - const void *value, size_t size, int flags) +struct simple_xattr *simple_xattr_set(struct simple_xattrs *xattrs, + const char *name, const void *value, + size_t size, int flags) { - struct simple_xattr *xattr; - struct simple_xattr *new_xattr = NULL; - int err = 0; + struct simple_xattr *old_xattr = NULL, *new_xattr = NULL; + struct rb_node *parent = NULL, **rbp; + int err = 0, ret; /* value == NULL means remove */ if (value) { new_xattr = simple_xattr_alloc(value, size); if (!new_xattr) - return -ENOMEM; + return ERR_PTR(-ENOMEM); - new_xattr->name = kstrdup(name, GFP_KERNEL); + new_xattr->name = kstrdup(name, GFP_KERNEL_ACCOUNT); if (!new_xattr->name) { - kfree(new_xattr); - return -ENOMEM; + simple_xattr_free(new_xattr); + return ERR_PTR(-ENOMEM); } } - spin_lock(&xattrs->lock); - list_for_each_entry(xattr, &xattrs->head, list) { - if (!strcmp(name, xattr->name)) { - if (flags & XATTR_CREATE) { - xattr = new_xattr; - err = -EEXIST; - } else if (new_xattr) { - list_replace(&xattr->list, &new_xattr->list); - } else { - list_del(&xattr->list); - } - goto out; - } + write_lock(&xattrs->lock); + rbp = &xattrs->rb_root.rb_node; + while (*rbp) { + parent = *rbp; + ret = rbtree_simple_xattr_cmp(name, *rbp); + if (ret < 0) + rbp = &(*rbp)->rb_left; + else if (ret > 0) + rbp = &(*rbp)->rb_right; + else + old_xattr = rb_entry(*rbp, struct simple_xattr, rb_node); + if (old_xattr) + break; } - if (flags & XATTR_REPLACE) { - xattr = new_xattr; - err = -ENODATA; + + if (old_xattr) { + /* Fail if XATTR_CREATE is requested and the xattr exists. */ + if (flags & XATTR_CREATE) { + err = -EEXIST; + goto out_unlock; + } + + if (new_xattr) + rb_replace_node(&old_xattr->rb_node, + &new_xattr->rb_node, &xattrs->rb_root); + else + rb_erase(&old_xattr->rb_node, &xattrs->rb_root); } else { - list_add(&new_xattr->list, &xattrs->head); - xattr = NULL; - } -out: - spin_unlock(&xattrs->lock); - if (xattr) { - kfree(xattr->name); - kfree(xattr); + /* Fail if XATTR_REPLACE is requested but no xattr is found. */ + if (flags & XATTR_REPLACE) { + err = -ENODATA; + goto out_unlock; + } + + /* + * If XATTR_CREATE or no flags are specified together with a + * new value simply insert it. + */ + if (new_xattr) { + rb_link_node(&new_xattr->rb_node, parent, rbp); + rb_insert_color(&new_xattr->rb_node, &xattrs->rb_root); + } + + /* + * If XATTR_CREATE or no flags are specified and neither an + * old or new xattr exist then we don't need to do anything. + */ } - return err; +out_unlock: + write_unlock(&xattrs->lock); + if (!err) + return old_xattr; + simple_xattr_free(new_xattr); + return ERR_PTR(err); } static bool xattr_is_trusted(const char *name) @@ -918,68 +1428,151 @@ static bool xattr_is_trusted(const char *name) return !strncmp(name, XATTR_TRUSTED_PREFIX, XATTR_TRUSTED_PREFIX_LEN); } -static int xattr_list_one(char **buffer, ssize_t *remaining_size, - const char *name) +static bool xattr_is_maclabel(const char *name) { - size_t len = strlen(name) + 1; - if (*buffer) { - if (*remaining_size < len) - return -ERANGE; - memcpy(*buffer, name, len); - *buffer += len; - } - *remaining_size -= len; - return 0; + const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; + + return !strncmp(name, XATTR_SECURITY_PREFIX, + XATTR_SECURITY_PREFIX_LEN) && + security_ismaclabel(suffix); } -/* - * xattr LIST operation for in-memory/pseudo filesystems +/** + * simple_xattr_list - list all xattr objects + * @inode: inode from which to get the xattrs + * @xattrs: the header of the xattr object + * @buffer: the buffer to store all xattrs into + * @size: the size of @buffer + * + * List all xattrs associated with @inode. If @buffer is NULL we returned + * the required size of the buffer. If @buffer is provided we store the + * xattrs value into it provided it is big enough. + * + * Note, the number of xattr names that can be listed with listxattr(2) is + * limited to XATTR_LIST_MAX aka 65536 bytes. If a larger buffer is passed + * then vfs_listxattr() caps it to XATTR_LIST_MAX and if more xattr names + * are found it will return -E2BIG. + * + * Return: On success the required size or the size of the copied xattrs is + * returned. On error a negative error code is returned. */ ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs, char *buffer, size_t size) { - bool trusted = capable(CAP_SYS_ADMIN); + bool trusted = ns_capable_noaudit(&init_user_ns, CAP_SYS_ADMIN); struct simple_xattr *xattr; + struct rb_node *rbp; ssize_t remaining_size = size; int err = 0; -#ifdef CONFIG_FS_POSIX_ACL - if (inode->i_acl) { - err = xattr_list_one(&buffer, &remaining_size, - XATTR_NAME_POSIX_ACL_ACCESS); - if (err) - return err; - } - if (inode->i_default_acl) { - err = xattr_list_one(&buffer, &remaining_size, - XATTR_NAME_POSIX_ACL_DEFAULT); - if (err) - return err; + err = posix_acl_listxattr(inode, &buffer, &remaining_size); + if (err) + return err; + + err = security_inode_listsecurity(inode, buffer, remaining_size); + if (err < 0) + return err; + + if (buffer) { + if (remaining_size < err) + return -ERANGE; + buffer += err; } -#endif + remaining_size -= err; + err = 0; + + read_lock(&xattrs->lock); + for (rbp = rb_first(&xattrs->rb_root); rbp; rbp = rb_next(rbp)) { + xattr = rb_entry(rbp, struct simple_xattr, rb_node); - spin_lock(&xattrs->lock); - list_for_each_entry(xattr, &xattrs->head, list) { /* skip "trusted." attributes for unprivileged callers */ if (!trusted && xattr_is_trusted(xattr->name)) continue; + /* skip MAC labels; these are provided by LSM above */ + if (xattr_is_maclabel(xattr->name)) + continue; + err = xattr_list_one(&buffer, &remaining_size, xattr->name); if (err) break; } - spin_unlock(&xattrs->lock); + read_unlock(&xattrs->lock); return err ? err : size - remaining_size; } -/* - * Adds an extended attribute to the list +/** + * rbtree_simple_xattr_less - compare two xattr rbtree nodes + * @new_node: new node + * @node: current node + * + * Compare the xattr attached to @new_node with the xattr attached to @node. + * Note that this function technically tolerates duplicate entries. + * + * Return: True if insertion point in the rbtree is found. + */ +static bool rbtree_simple_xattr_less(struct rb_node *new_node, + const struct rb_node *node) +{ + return rbtree_simple_xattr_node_cmp(new_node, node) < 0; +} + +/** + * simple_xattr_add - add xattr objects + * @xattrs: the header of the xattr object + * @new_xattr: the xattr object to add + * + * Add an xattr object to @xattrs. This assumes no replacement or removal + * of matching xattrs is wanted. Should only be called during inode + * initialization when a few distinct initial xattrs are supposed to be set. + */ +void simple_xattr_add(struct simple_xattrs *xattrs, + struct simple_xattr *new_xattr) +{ + write_lock(&xattrs->lock); + rb_add(&new_xattr->rb_node, &xattrs->rb_root, rbtree_simple_xattr_less); + write_unlock(&xattrs->lock); +} + +/** + * simple_xattrs_init - initialize new xattr header + * @xattrs: header to initialize + * + * Initialize relevant fields of a an xattr header. + */ +void simple_xattrs_init(struct simple_xattrs *xattrs) +{ + xattrs->rb_root = RB_ROOT; + rwlock_init(&xattrs->lock); +} + +/** + * simple_xattrs_free - free xattrs + * @xattrs: xattr header whose xattrs to destroy + * @freed_space: approximate number of bytes of memory freed from @xattrs + * + * Destroy all xattrs in @xattr. When this is called no one can hold a + * reference to any of the xattrs anymore. */ -void simple_xattr_list_add(struct simple_xattrs *xattrs, - struct simple_xattr *new_xattr) +void simple_xattrs_free(struct simple_xattrs *xattrs, size_t *freed_space) { - spin_lock(&xattrs->lock); - list_add(&new_xattr->list, &xattrs->head); - spin_unlock(&xattrs->lock); + struct rb_node *rbp; + + if (freed_space) + *freed_space = 0; + rbp = rb_first(&xattrs->rb_root); + while (rbp) { + struct simple_xattr *xattr; + struct rb_node *rbp_next; + + rbp_next = rb_next(rbp); + xattr = rb_entry(rbp, struct simple_xattr, rb_node); + rb_erase(&xattr->rb_node, &xattrs->rb_root); + if (freed_space) + *freed_space += simple_xattr_space(xattr->name, + xattr->size); + simple_xattr_free(xattr); + rbp = rbp_next; + } } |