diff options
Diffstat (limited to 'fs/xattr.c')
| -rw-r--r-- | fs/xattr.c | 773 |
1 files changed, 480 insertions, 293 deletions
diff --git a/fs/xattr.c b/fs/xattr.c index adab9a70b536..32d445fb60aa 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -9,13 +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> @@ -55,7 +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)) { @@ -82,7 +82,7 @@ xattr_resolve_name(struct inode *inode, const char **name) /** * may_write_xattr - check whether inode allows writing xattr - * @mnt_userns: User namespace of the mount the inode was found from + * @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 @@ -94,13 +94,13 @@ xattr_resolve_name(struct inode *inode, const char **name) * * Return: On success zero is returned. On error a negative errno is returned. */ -int may_write_xattr(struct user_namespace *mnt_userns, struct inode *inode) +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(mnt_userns, inode)) + if (HAS_UNMAPPED_ID(idmap, inode)) return -EPERM; return 0; } @@ -110,13 +110,13 @@ int may_write_xattr(struct user_namespace *mnt_userns, struct inode *inode) * because different namespaces have very different rules. */ static int -xattr_permission(struct user_namespace *mnt_userns, struct inode *inode, +xattr_permission(struct mnt_idmap *idmap, struct inode *inode, const char *name, int mask) { if (mask & MAY_WRITE) { int ret; - ret = may_write_xattr(mnt_userns, inode); + ret = may_write_xattr(idmap, inode); if (ret) return ret; } @@ -148,22 +148,21 @@ xattr_permission(struct user_namespace *mnt_userns, struct inode *inode, return (mask & MAY_WRITE) ? -EPERM : -ENODATA; if (S_ISDIR(inode->i_mode) && (inode->i_mode & S_ISVTX) && (mask & MAY_WRITE) && - !inode_owner_or_capable(mnt_userns, inode)) + !inode_owner_or_capable(idmap, inode)) return -EPERM; } - return inode_permission(mnt_userns, inode, mask); + return inode_permission(idmap, inode, mask); } /* * Look for any handler that deals with the specified namespace. */ int -xattr_supported_namespace(struct inode *inode, const char *prefix) +xattr_supports_user_prefix(struct inode *inode) { - 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; - size_t preflen; if (!(inode->i_opflags & IOP_XATTR)) { if (unlikely(is_bad_inode(inode))) @@ -171,19 +170,18 @@ xattr_supported_namespace(struct inode *inode, const char *prefix) return -EOPNOTSUPP; } - preflen = strlen(prefix); - for_each_xattr_handler(handlers, handler) { - if (!strncmp(xattr_prefix(handler), prefix, preflen)) + if (!strncmp(xattr_prefix(handler), XATTR_USER_PREFIX, + XATTR_USER_PREFIX_LEN)) return 0; } return -EOPNOTSUPP; } -EXPORT_SYMBOL(xattr_supported_namespace); +EXPORT_SYMBOL(xattr_supports_user_prefix); int -__vfs_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry, +__vfs_setxattr(struct mnt_idmap *idmap, struct dentry *dentry, struct inode *inode, const char *name, const void *value, size_t size, int flags) { @@ -199,7 +197,7 @@ __vfs_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry, return -EOPNOTSUPP; if (size == 0) value = ""; /* empty EA, do not remove */ - return handler->set(handler, mnt_userns, dentry, inode, name, value, + return handler->set(handler, idmap, dentry, inode, name, value, size, flags); } EXPORT_SYMBOL(__vfs_setxattr); @@ -208,7 +206,7 @@ EXPORT_SYMBOL(__vfs_setxattr); * __vfs_setxattr_noperm - perform setxattr operation without performing * permission checks. * - * @mnt_userns: user namespace of the mount the inode was found from + * @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 @@ -217,11 +215,11 @@ EXPORT_SYMBOL(__vfs_setxattr); * * 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 user_namespace *mnt_userns, +int __vfs_setxattr_noperm(struct mnt_idmap *idmap, struct dentry *dentry, const char *name, const void *value, size_t size, int flags) { @@ -233,7 +231,7 @@ int __vfs_setxattr_noperm(struct user_namespace *mnt_userns, if (issec) inode->i_flags &= ~S_NOSEC; if (inode->i_opflags & IOP_XATTR) { - error = __vfs_setxattr(mnt_userns, dentry, inode, name, value, + error = __vfs_setxattr(idmap, dentry, inode, name, value, size, flags); if (!error) { fsnotify_xattr(dentry); @@ -264,7 +262,7 @@ int __vfs_setxattr_noperm(struct user_namespace *mnt_userns, * __vfs_setxattr_locked - set an extended attribute while holding the inode * lock * - * @mnt_userns: user namespace of the mount of the target inode + * @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 @@ -274,18 +272,18 @@ int __vfs_setxattr_noperm(struct user_namespace *mnt_userns, * a delegation was broken on, NULL if none. */ int -__vfs_setxattr_locked(struct user_namespace *mnt_userns, struct dentry *dentry, +__vfs_setxattr_locked(struct mnt_idmap *idmap, struct dentry *dentry, const char *name, const void *value, size_t size, - int flags, struct inode **delegated_inode) + int flags, struct delegated_inode *delegated_inode) { struct inode *inode = dentry->d_inode; int error; - error = xattr_permission(mnt_userns, inode, name, MAY_WRITE); + error = xattr_permission(idmap, inode, name, MAY_WRITE); if (error) return error; - error = security_inode_setxattr(mnt_userns, dentry, name, value, size, + error = security_inode_setxattr(idmap, dentry, name, value, size, flags); if (error) goto out; @@ -294,7 +292,7 @@ __vfs_setxattr_locked(struct user_namespace *mnt_userns, struct dentry *dentry, if (error) goto out; - error = __vfs_setxattr_noperm(mnt_userns, dentry, name, value, + error = __vfs_setxattr_noperm(idmap, dentry, name, value, size, flags); out: @@ -303,16 +301,16 @@ out: EXPORT_SYMBOL_GPL(__vfs_setxattr_locked); int -vfs_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry, +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 inode *delegated_inode = NULL; + struct delegated_inode delegated_inode = { }; const void *orig_value = value; int error; if (size && strcmp(name, XATTR_NAME_CAPS) == 0) { - error = cap_convert_nscap(mnt_userns, dentry, &value, size); + error = cap_convert_nscap(idmap, dentry, &value, size); if (error < 0) return error; size = error; @@ -320,11 +318,11 @@ vfs_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry, retry_deleg: inode_lock(inode); - error = __vfs_setxattr_locked(mnt_userns, dentry, name, value, size, + error = __vfs_setxattr_locked(idmap, dentry, name, value, size, flags, &delegated_inode); inode_unlock(inode); - if (delegated_inode) { + if (is_delegated(&delegated_inode)) { error = break_deleg_wait(&delegated_inode); if (!error) goto retry_deleg; @@ -337,19 +335,19 @@ retry_deleg: EXPORT_SYMBOL_GPL(vfs_setxattr); static ssize_t -xattr_getsecurity(struct user_namespace *mnt_userns, struct inode *inode, +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(mnt_userns, inode, name, + len = security_inode_getsecurity(idmap, inode, name, &buffer, false); goto out_noalloc; } - len = security_inode_getsecurity(mnt_userns, inode, name, &buffer, + len = security_inode_getsecurity(idmap, inode, name, &buffer, true); if (len < 0) return len; @@ -374,7 +372,7 @@ out_noalloc: * Returns the result of alloc, if failed, or the getxattr operation. */ int -vfs_getxattr_alloc(struct user_namespace *mnt_userns, struct dentry *dentry, +vfs_getxattr_alloc(struct mnt_idmap *idmap, struct dentry *dentry, const char *name, char **xattr_value, size_t xattr_size, gfp_t flags) { @@ -383,7 +381,7 @@ vfs_getxattr_alloc(struct user_namespace *mnt_userns, struct dentry *dentry, char *value = *xattr_value; int error; - error = xattr_permission(mnt_userns, inode, name, MAY_READ); + error = xattr_permission(idmap, inode, name, MAY_READ); if (error) return error; @@ -427,13 +425,13 @@ __vfs_getxattr(struct dentry *dentry, struct inode *inode, const char *name, EXPORT_SYMBOL(__vfs_getxattr); ssize_t -vfs_getxattr(struct user_namespace *mnt_userns, struct dentry *dentry, +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(mnt_userns, inode, name, MAY_READ); + error = xattr_permission(idmap, inode, name, MAY_READ); if (error) return error; @@ -444,7 +442,7 @@ vfs_getxattr(struct user_namespace *mnt_userns, struct dentry *dentry, if (!strncmp(name, XATTR_SECURITY_PREFIX, XATTR_SECURITY_PREFIX_LEN)) { const char *suffix = name + XATTR_SECURITY_PREFIX_LEN; - int ret = xattr_getsecurity(mnt_userns, inode, suffix, value, + int ret = xattr_getsecurity(idmap, inode, suffix, value, size); /* * Only overwrite the return value if a security module @@ -459,6 +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) { @@ -468,7 +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)) { + + if (inode->i_op->listxattr) { error = inode->i_op->listxattr(dentry, list, size); } else { error = security_inode_listsecurity(inode, list, size); @@ -480,7 +501,7 @@ vfs_listxattr(struct dentry *dentry, char *list, size_t size) EXPORT_SYMBOL_GPL(vfs_listxattr); int -__vfs_removexattr(struct user_namespace *mnt_userns, struct dentry *dentry, +__vfs_removexattr(struct mnt_idmap *idmap, struct dentry *dentry, const char *name) { struct inode *inode = d_inode(dentry); @@ -494,7 +515,7 @@ __vfs_removexattr(struct user_namespace *mnt_userns, struct dentry *dentry, return PTR_ERR(handler); if (!handler->set) return -EOPNOTSUPP; - return handler->set(handler, mnt_userns, dentry, inode, name, NULL, 0, + return handler->set(handler, idmap, dentry, inode, name, NULL, 0, XATTR_REPLACE); } EXPORT_SYMBOL(__vfs_removexattr); @@ -503,25 +524,25 @@ EXPORT_SYMBOL(__vfs_removexattr); * __vfs_removexattr_locked - set an extended attribute while holding the inode * lock * - * @mnt_userns: user namespace of the mount of the target inode + * @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_locked(struct user_namespace *mnt_userns, +__vfs_removexattr_locked(struct mnt_idmap *idmap, struct dentry *dentry, const char *name, - struct inode **delegated_inode) + struct delegated_inode *delegated_inode) { struct inode *inode = dentry->d_inode; int error; - error = xattr_permission(mnt_userns, inode, name, MAY_WRITE); + error = xattr_permission(idmap, inode, name, MAY_WRITE); if (error) return error; - error = security_inode_removexattr(mnt_userns, dentry, name); + error = security_inode_removexattr(idmap, dentry, name); if (error) goto out; @@ -529,12 +550,12 @@ __vfs_removexattr_locked(struct user_namespace *mnt_userns, if (error) goto out; - error = __vfs_removexattr(mnt_userns, 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; @@ -542,20 +563,20 @@ out: EXPORT_SYMBOL_GPL(__vfs_removexattr_locked); int -vfs_removexattr(struct user_namespace *mnt_userns, struct dentry *dentry, +vfs_removexattr(struct mnt_idmap *idmap, struct dentry *dentry, const char *name) { struct inode *inode = dentry->d_inode; - struct inode *delegated_inode = NULL; + struct delegated_inode delegated_inode = { }; int error; retry_deleg: inode_lock(inode); - error = __vfs_removexattr_locked(mnt_userns, dentry, + error = __vfs_removexattr_locked(idmap, dentry, name, &delegated_inode); inode_unlock(inode); - if (delegated_inode) { + if (is_delegated(&delegated_inode)) { error = break_deleg_wait(&delegated_inode); if (!error) goto retry_deleg; @@ -565,25 +586,32 @@ retry_deleg: } 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 */ -int setxattr_copy(const char __user *name, struct xattr_ctx *ctx) +int setxattr_copy(const char __user *name, struct kernel_xattr_ctx *ctx) { int error; if (ctx->flags & ~(XATTR_CREATE|XATTR_REPLACE)) return -EINVAL; - error = strncpy_from_user(ctx->kname->name, name, - sizeof(ctx->kname->name)); - if (error == 0 || error == sizeof(ctx->kname->name)) - return -ERANGE; - if (error < 0) + error = import_xattr_name(ctx->kname, name); + if (error) return error; - error = 0; if (ctx->size) { if (ctx->size > XATTR_SIZE_MAX) return -E2BIG; @@ -598,57 +626,43 @@ int setxattr_copy(const char __user *name, struct xattr_ctx *ctx) return error; } -int do_setxattr(struct mnt_idmap *idmap, struct dentry *dentry, - struct xattr_ctx *ctx) +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(mnt_idmap_owner(idmap), dentry, ctx->kname->name, + return vfs_setxattr(idmap, dentry, ctx->kname->name, ctx->kvalue, ctx->size, ctx->flags); } -static long -setxattr(struct mnt_idmap *idmap, struct dentry *d, - const char __user *name, const void __user *value, size_t size, - int flags) +int file_setxattr(struct file *f, struct kernel_xattr_ctx *ctx) { - struct xattr_name kname; - struct xattr_ctx ctx = { - .cvalue = value, - .kvalue = NULL, - .size = size, - .kname = &kname, - .flags = flags, - }; - int error; - - error = setxattr_copy(name, &ctx); - if (error) - return error; + int error = mnt_want_write_file(f); - error = do_setxattr(idmap, d, &ctx); - - kvfree(ctx.kvalue); + 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(mnt_idmap(path.mnt), path.dentry, name, - value, size, flags); + error = do_setxattr(mnt_idmap(path.mnt), path.dentry, ctx); mnt_drop_write(path.mnt); } path_put(&path); @@ -656,68 +670,123 @@ 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(file_mnt_idmap(f.file), - 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 */ -ssize_t +static ssize_t do_getxattr(struct mnt_idmap *idmap, struct dentry *d, - struct xattr_ctx *ctx) + struct kernel_xattr_ctx *ctx) { ssize_t error; char *kname = ctx->kname->name; + void *kvalue = NULL; if (ctx->size) { if (ctx->size > XATTR_SIZE_MAX) ctx->size = XATTR_SIZE_MAX; - ctx->kvalue = kvzalloc(ctx->size, GFP_KERNEL); - if (!ctx->kvalue) + kvalue = kvzalloc(ctx->size, GFP_KERNEL); + if (!kvalue) return -ENOMEM; } - if (is_posix_acl_xattr(ctx->kname->name)) - error = do_get_acl(idmap, d, kname, ctx->kvalue, ctx->size); + if (is_posix_acl_xattr(kname)) + error = do_get_acl(idmap, d, kname, kvalue, ctx->size); else - error = vfs_getxattr(mnt_idmap_owner(idmap), d, kname, - ctx->kvalue, ctx->size); + error = vfs_getxattr(idmap, d, kname, kvalue, ctx->size); if (error > 0) { - if (ctx->size && copy_to_user(ctx->value, ctx->kvalue, error)) + if (ctx->size && copy_to_user(ctx->value, kvalue, error)) error = -EFAULT; } else if (error == -ERANGE && ctx->size >= XATTR_SIZE_MAX) { /* The file system tried to returned a value bigger @@ -725,79 +794,114 @@ do_getxattr(struct mnt_idmap *idmap, struct dentry *d, error = -E2BIG; } + kvfree(kvalue); return error; } -static ssize_t -getxattr(struct mnt_idmap *idmap, struct dentry *d, - const char __user *name, void __user *value, size_t size) +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 = filename_lookup(dfd, filename, lookup_flags, &path, NULL); + if (error) + 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 xattr_ctx ctx = { + struct kernel_xattr_ctx ctx = { .value = value, - .kvalue = NULL, .size = size, .kname = &kname, .flags = 0, }; + struct filename *filename; + ssize_t error; - error = strncpy_from_user(kname.name, name, sizeof(kname.name)); - if (error == 0 || error == sizeof(kname.name)) - error = -ERANGE; - if (error < 0) - return error; + if ((at_flags & ~(AT_SYMLINK_NOFOLLOW | AT_EMPTY_PATH)) != 0) + return -EINVAL; - error = do_getxattr(idmap, d, &ctx); + error = import_xattr_name(&kname, name); + if (error) + return error; - kvfree(ctx.kvalue); - 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); + } } -static ssize_t path_getxattr(const char __user *pathname, - const char __user *name, void __user *value, - size_t size, unsigned int lookup_flags) +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 path path; - ssize_t error; -retry: - error = user_path_at(AT_FDCWD, pathname, lookup_flags, &path); + 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; - error = getxattr(mnt_idmap(path.mnt), path.dentry, name, value, size); - path_put(&path); - if (retry_estale(error, lookup_flags)) { - lookup_flags |= LOOKUP_REVAL; - goto retry; - } - 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(file_mnt_idmap(f.file), f.file->f_path.dentry, - name, value, size); - fdput(f); - return error; + return path_getxattrat(fd, NULL, AT_EMPTY_PATH, name, value, size); } /* @@ -832,83 +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 mnt_idmap *idmap, 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]; - - error = strncpy_from_user(kname, name, sizeof(kname)); - if (error == 0 || error == sizeof(kname)) - error = -ERANGE; - if (error < 0) - return error; + if (is_posix_acl_xattr(name)) + return vfs_remove_acl(idmap, d, name); + return vfs_removexattr(idmap, d, name); +} - if (is_posix_acl_xattr(kname)) - return vfs_remove_acl(mnt_idmap_owner(idmap), d, kname); +static int file_removexattr(struct file *f, struct xattr_name *kname) +{ + int error = mnt_want_write_file(f); - return vfs_removexattr(mnt_idmap_owner(idmap), 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(mnt_idmap(path.mnt), path.dentry, name); + error = removexattr(mnt_idmap(path.mnt), path.dentry, kname->name); mnt_drop_write(path.mnt); } path_put(&path); @@ -916,74 +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(file_mnt_idmap(f.file), - 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); @@ -1012,12 +1182,32 @@ const char *xattr_full_name(const struct xattr_handler *handler, EXPORT_SYMBOL(xattr_full_name); /** - * free_simple_xattr - free an xattr object + * 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. */ -static inline void free_simple_xattr(struct simple_xattr *xattr) +void simple_xattr_free(struct simple_xattr *xattr) { if (xattr) kfree(xattr->name); @@ -1045,7 +1235,7 @@ struct simple_xattr *simple_xattr_alloc(const void *value, size_t size) if (len < sizeof(*new_xattr)) return NULL; - new_xattr = kvmalloc(len, GFP_KERNEL); + new_xattr = kvmalloc(len, GFP_KERNEL_ACCOUNT); if (!new_xattr) return NULL; @@ -1136,7 +1326,6 @@ int simple_xattr_get(struct simple_xattrs *xattrs, const char *name, * @value: the value to store along the xattr * @size: the size of @value * @flags: the flags determining how to set the xattr - * @removed_size: the size of the removed xattr * * Set a new xattr object. * If @value is passed a new xattr object will be allocated. If XATTR_REPLACE @@ -1153,29 +1342,27 @@ int simple_xattr_get(struct simple_xattrs *xattrs, const char *name, * nothing if XATTR_CREATE is specified in @flags or @flags is zero. For * XATTR_REPLACE we fail as mentioned above. * - * Return: On success zero and on error a negative error code is returned. + * 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, - ssize_t *removed_size) +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 = NULL, *new_xattr = NULL; + struct simple_xattr *old_xattr = NULL, *new_xattr = NULL; struct rb_node *parent = NULL, **rbp; int err = 0, ret; - if (removed_size) - *removed_size = -1; - /* 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) { - free_simple_xattr(new_xattr); - return -ENOMEM; + simple_xattr_free(new_xattr); + return ERR_PTR(-ENOMEM); } } @@ -1189,12 +1376,12 @@ int simple_xattr_set(struct simple_xattrs *xattrs, const char *name, else if (ret > 0) rbp = &(*rbp)->rb_right; else - xattr = rb_entry(*rbp, struct simple_xattr, rb_node); - if (xattr) + old_xattr = rb_entry(*rbp, struct simple_xattr, rb_node); + if (old_xattr) break; } - if (xattr) { + if (old_xattr) { /* Fail if XATTR_CREATE is requested and the xattr exists. */ if (flags & XATTR_CREATE) { err = -EEXIST; @@ -1202,12 +1389,10 @@ int simple_xattr_set(struct simple_xattrs *xattrs, const char *name, } if (new_xattr) - rb_replace_node(&xattr->rb_node, &new_xattr->rb_node, - &xattrs->rb_root); + rb_replace_node(&old_xattr->rb_node, + &new_xattr->rb_node, &xattrs->rb_root); else - rb_erase(&xattr->rb_node, &xattrs->rb_root); - if (!err && removed_size) - *removed_size = xattr->size; + rb_erase(&old_xattr->rb_node, &xattrs->rb_root); } else { /* Fail if XATTR_REPLACE is requested but no xattr is found. */ if (flags & XATTR_REPLACE) { @@ -1232,12 +1417,10 @@ int simple_xattr_set(struct simple_xattrs *xattrs, const char *name, out_unlock: write_unlock(&xattrs->lock); - if (err) - free_simple_xattr(new_xattr); - else - free_simple_xattr(xattr); - return err; - + if (!err) + return old_xattr; + simple_xattr_free(new_xattr); + return ERR_PTR(err); } static bool xattr_is_trusted(const char *name) @@ -1245,18 +1428,13 @@ 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); } /** @@ -1287,22 +1465,21 @@ ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs, ssize_t remaining_size = size; int err = 0; -#ifdef CONFIG_FS_POSIX_ACL - if (IS_POSIXACL(inode)) { - 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)) { @@ -1312,6 +1489,10 @@ ssize_t simple_xattr_list(struct inode *inode, struct simple_xattrs *xattrs, 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; @@ -1369,14 +1550,17 @@ void simple_xattrs_init(struct simple_xattrs *xattrs) /** * 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_xattrs_free(struct simple_xattrs *xattrs) +void simple_xattrs_free(struct simple_xattrs *xattrs, size_t *freed_space) { struct rb_node *rbp; + if (freed_space) + *freed_space = 0; rbp = rb_first(&xattrs->rb_root); while (rbp) { struct simple_xattr *xattr; @@ -1385,7 +1569,10 @@ void simple_xattrs_free(struct simple_xattrs *xattrs) rbp_next = rb_next(rbp); xattr = rb_entry(rbp, struct simple_xattr, rb_node); rb_erase(&xattr->rb_node, &xattrs->rb_root); - free_simple_xattr(xattr); + if (freed_space) + *freed_space += simple_xattr_space(xattr->name, + xattr->size); + simple_xattr_free(xattr); rbp = rbp_next; } } |