From patchwork Wed Mar 23 15:44:17 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Roesch X-Patchwork-Id: 12789851 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 691B2C433FE for ; Wed, 23 Mar 2022 15:44:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242681AbiCWPqB (ORCPT ); Wed, 23 Mar 2022 11:46:01 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37996 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S241180AbiCWPp7 (ORCPT ); Wed, 23 Mar 2022 11:45:59 -0400 Received: from mx0a-00082601.pphosted.com (mx0a-00082601.pphosted.com [67.231.145.42]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CAA393B01B for ; Wed, 23 Mar 2022 08:44:29 -0700 (PDT) Received: from pps.filterd (m0109334.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.1.2/8.16.1.2) with ESMTP id 22NBcsYL002373 for ; Wed, 23 Mar 2022 08:44:29 -0700 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=fb.com; h=from : to : cc : subject : date : message-id : in-reply-to : references : mime-version : content-transfer-encoding : content-type; s=facebook; bh=vOKmr/vrRfDGrDjMmzLYwzgJ+RL6bljKkS+ekZ0ooOk=; b=gbyKGICLJWHzXprGxN/3wk90qcvpa/vPYFtT1iXIvMoRTQazFaR4n6tcBEi52jv9nou7 LXHY/XgonnKIwwY1JSdx0dUPmZ/nhakNNQg7DacZQaRvjXzpR7OcjTjfuM/mHAZ1/xqI C3DXOVOQ4gcWur64uwG/DYCsA59RJLwGz/E= Received: from maileast.thefacebook.com ([163.114.130.16]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3f02uvsqx0-2 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Wed, 23 Mar 2022 08:44:29 -0700 Received: from twshared37304.07.ash9.facebook.com (2620:10d:c0a8:1b::d) by mail.thefacebook.com (2620:10d:c0a8:82::f) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.21; Wed, 23 Mar 2022 08:44:27 -0700 Received: by devvm225.atn0.facebook.com (Postfix, from userid 425415) id 7BC89CA024C5; Wed, 23 Mar 2022 08:44:22 -0700 (PDT) From: Stefan Roesch To: , , CC: , , Subject: [PATCH v13 1/4] fs: split off setxattr_copy and do_setxattr function from setxattr Date: Wed, 23 Mar 2022 08:44:17 -0700 Message-ID: <20220323154420.3301504-2-shr@fb.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20220323154420.3301504-1-shr@fb.com> References: <20220323154420.3301504-1-shr@fb.com> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-ORIG-GUID: apLOM8UDLAmQFj0zWQmv6ifF0idewj8l X-Proofpoint-GUID: apLOM8UDLAmQFj0zWQmv6ifF0idewj8l X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.850,Hydra:6.0.425,FMLib:17.11.64.514 definitions=2022-03-23_07,2022-03-23_01,2022-02-23_01 Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org This splits of the setup part of the function setxattr in its own dedicated function called setxattr_copy. In addition it also exposes a new function called do_setxattr for making the setxattr call. This makes it possible to call these two functions from io_uring in the processing of an xattr request. Signed-off-by: Stefan Roesch Acked-by: Christian Brauner --- fs/internal.h | 24 +++++++++++++++ fs/xattr.c | 82 ++++++++++++++++++++++++++++++++++++--------------- 2 files changed, 82 insertions(+), 24 deletions(-) diff --git a/fs/internal.h b/fs/internal.h index 56c0477f4215..96bbab6b58ba 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -196,3 +196,27 @@ long splice_file_to_pipe(struct file *in, struct pipe_inode_info *opipe, loff_t *offset, size_t len, unsigned int flags); + +/* + * fs/xattr.c: + */ +struct xattr_name { + char name[XATTR_NAME_MAX + 1]; +}; + +struct xattr_ctx { + /* Value of attribute */ + union { + const void __user *cvalue; + void __user *value; + }; + void *kvalue; + size_t size; + /* Attribute name */ + struct xattr_name *kname; + unsigned int flags; +}; + +int setxattr_copy(const char __user *name, struct xattr_ctx *ctx); +int do_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry, + struct xattr_ctx *ctx); diff --git a/fs/xattr.c b/fs/xattr.c index 5c8c5175b385..717b3904c2e5 100644 --- a/fs/xattr.c +++ b/fs/xattr.c @@ -25,6 +25,8 @@ #include +#include "internal.h" + static const char * strcmp_prefix(const char *a, const char *a_prefix) { @@ -539,43 +541,75 @@ EXPORT_SYMBOL_GPL(vfs_removexattr); /* * Extended attribute SET operations */ -static long -setxattr(struct user_namespace *mnt_userns, struct dentry *d, - const char __user *name, const void __user *value, size_t size, - int flags) + +int setxattr_copy(const char __user *name, struct 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; + 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) return error; - if (size) { - if (size > XATTR_SIZE_MAX) + error = 0; + 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(mnt_userns, kvalue, size); } - error = vfs_setxattr(mnt_userns, d, kname, kvalue, size, flags); -out: - kvfree(kvalue); + return error; +} + +static void setxattr_convert(struct user_namespace *mnt_userns, + struct xattr_ctx *ctx) +{ + if (ctx->size && + ((strcmp(ctx->kname->name, XATTR_NAME_POSIX_ACL_ACCESS) == 0) || + (strcmp(ctx->kname->name, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))) + posix_acl_fix_xattr_from_user(mnt_userns, ctx->kvalue, ctx->size); +} + +int do_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry, + struct xattr_ctx *ctx) +{ + setxattr_convert(mnt_userns, ctx); + return vfs_setxattr(mnt_userns, dentry, ctx->kname->name, + ctx->kvalue, ctx->size, ctx->flags); +} + +static long +setxattr(struct user_namespace *mnt_userns, struct dentry *d, + const char __user *name, const void __user *value, size_t size, + int flags) +{ + 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; + + error = do_setxattr(mnt_userns, d, &ctx); + kvfree(ctx.kvalue); return error; }