From patchwork Thu Dec 23 19:56:55 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Stefan Roesch X-Patchwork-Id: 12698621 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 01867C4332F for ; Thu, 23 Dec 2021 19:57:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1350181AbhLWT5Z (ORCPT ); Thu, 23 Dec 2021 14:57:25 -0500 Received: from mx0a-00082601.pphosted.com ([67.231.145.42]:30926 "EHLO mx0a-00082601.pphosted.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1350134AbhLWT5Y (ORCPT ); Thu, 23 Dec 2021 14:57:24 -0500 Received: from pps.filterd (m0148461.ppops.net [127.0.0.1]) by mx0a-00082601.pphosted.com (8.16.1.2/8.16.1.2) with ESMTP id 1BN6toF1032203 for ; Thu, 23 Dec 2021 11:57:24 -0800 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=7/A1DepU/fBrUyy/BRZEvS2npa+SOw9kN2ynssO49yc=; b=Q/x7jk3g0JRosLVgG4TEM0VamlV3WBiDQvhKkwQH1oDMC+rmbpNlDK84ykIGRjHXYxao YNFQhntLymrtjNTK3+wOytxkPZuAV6D76aofWJOUHBSQx9hlc0lyrLdjaD2HOo2Ek9rC FbKGih+ZI5fIX8b95qOPrUscbaatEG9As5g= Received: from mail.thefacebook.com ([163.114.132.120]) by mx0a-00082601.pphosted.com (PPS) with ESMTPS id 3d4m96vhsv-19 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT) for ; Thu, 23 Dec 2021 11:57:24 -0800 Received: from twshared3115.02.ash8.facebook.com (2620:10d:c085:208::f) by mail.thefacebook.com (2620:10d:c085:11d::4) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2308.20; Thu, 23 Dec 2021 11:57:20 -0800 Received: by devvm225.atn0.facebook.com (Postfix, from userid 425415) id C2E5B87A074B; Thu, 23 Dec 2021 11:57:08 -0800 (PST) From: Stefan Roesch To: , , CC: , , Subject: [PATCH v7 2/5] fs: split off setxattr_copy and do_setxattr function from setxattr Date: Thu, 23 Dec 2021 11:56:55 -0800 Message-ID: <20211223195658.2805049-3-shr@fb.com> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20211223195658.2805049-1-shr@fb.com> References: <20211223195658.2805049-1-shr@fb.com> MIME-Version: 1.0 X-FB-Internal: Safe X-Proofpoint-ORIG-GUID: qp5S-x1_sbAnFvb--hlnLHkobFfDQZ5L X-Proofpoint-GUID: qp5S-x1_sbAnFvb--hlnLHkobFfDQZ5L X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.205,Aquarius:18.0.790,Hydra:6.0.425,FMLib:17.11.62.513 definitions=2021-12-23_04,2021-12-22_01,2021-12-02_01 X-Proofpoint-Spam-Details: rule=fb_outbound_notspam policy=fb_outbound score=0 suspectscore=0 adultscore=0 impostorscore=0 priorityscore=1501 mlxlogscore=999 clxscore=1015 spamscore=0 bulkscore=0 malwarescore=0 lowpriorityscore=0 mlxscore=0 phishscore=0 classifier=spam adjust=0 reason=mlx scancount=1 engine=8.12.0-2110150000 definitions=main-2112230102 X-FB-Internal: deliver 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 --- fs/internal.h | 19 +++++++++++ fs/xattr.c | 87 ++++++++++++++++++++++++++++++++++++++------------- 2 files changed, 84 insertions(+), 22 deletions(-) diff --git a/fs/internal.h b/fs/internal.h index 432ea3ce76ec..28b9f947f26e 100644 --- a/fs/internal.h +++ b/fs/internal.h @@ -202,3 +202,22 @@ struct linux_dirent64; int vfs_getdents(struct file *file, struct linux_dirent64 __user *dirent, unsigned int count, loff_t *pos); + + /* + * fs/xattr.c: + */ +struct xattr_ctx { + /* Value of attribute */ + const void __user *value; + size_t size; + /* Attribute name */ + char *kname; + int kname_sz; + unsigned int flags; +}; + + +int setxattr_copy(const char __user *name, struct xattr_ctx *ctx, + void **xattr_val); +int do_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry, + struct xattr_ctx *ctx, void *xattr_val); diff --git a/fs/xattr.c b/fs/xattr.c index 5c8c5175b385..fbe6c2b7ec47 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 +541,84 @@ 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, + void **xattr_val) { - int error; void *kvalue = NULL; - char kname[XATTR_NAME_MAX + 1]; + int error; - 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, ctx->kname_sz); + if (error == 0 || error == ctx->kname_sz) + return -ERANGE; if (error < 0) 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); + + kvalue = kvmalloc(ctx->size, GFP_KERNEL); if (!kvalue) return -ENOMEM; - if (copy_from_user(kvalue, value, size)) { - error = -EFAULT; - goto out; + + if (copy_from_user(kvalue, ctx->value, ctx->size)) { + kvfree(kvalue); + return -EFAULT; } - 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); + *xattr_val = kvalue; + return 0; +} + +static void setxattr_convert(struct user_namespace *mnt_userns, + struct xattr_ctx *ctx, void *xattr_value) +{ + if (ctx->size && + ((strcmp(ctx->kname, XATTR_NAME_POSIX_ACL_ACCESS) == 0) || + (strcmp(ctx->kname, XATTR_NAME_POSIX_ACL_DEFAULT) == 0))) + posix_acl_fix_xattr_from_user(mnt_userns, xattr_value, ctx->size); +} + +int do_setxattr(struct user_namespace *mnt_userns, struct dentry *dentry, + struct xattr_ctx *ctx, void *xattr_value) +{ + int error; + + setxattr_convert(mnt_userns, ctx, xattr_value); + error = vfs_setxattr(mnt_userns, dentry, ctx->kname, + xattr_value, ctx->size, ctx->flags); + + return error; +} + +static long +setxattr(struct user_namespace *mnt_userns, struct dentry *d, + const char __user *name, const void __user *value, size_t size, + int flags) +{ + char kname[XATTR_NAME_MAX + 1]; + struct xattr_ctx ctx = { + .value = value, + .size = size, + .kname = kname, + .kname_sz = sizeof(kname), + .flags = flags, + }; + void *xattr_value = NULL; + int error; + + error = setxattr_copy(name, &ctx, &xattr_value); + if (error) + return error; + + error = do_setxattr(mnt_userns, d, &ctx, xattr_value); + kvfree(xattr_value); return error; }