From patchwork Tue Sep 21 04:40:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Namjae Jeon X-Patchwork-Id: 12507229 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-17.0 required=3.0 tests=BAYES_00,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id DFBABC433EF for ; Tue, 21 Sep 2021 04:41:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B460761038 for ; Tue, 21 Sep 2021 04:41:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229547AbhIUEmf (ORCPT ); Tue, 21 Sep 2021 00:42:35 -0400 Received: from mail-pf1-f175.google.com ([209.85.210.175]:38481 "EHLO mail-pf1-f175.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229528AbhIUEmf (ORCPT ); Tue, 21 Sep 2021 00:42:35 -0400 Received: by mail-pf1-f175.google.com with SMTP id y4so16766133pfe.5 for ; Mon, 20 Sep 2021 21:41:07 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:from:to:cc:subject:date:message-id:mime-version :content-transfer-encoding; bh=vypsXh7GqcRDYOWJpLw6MHf+/r/txHRBTkQAHR1/Y1g=; b=PCaycE34c4ajbmUFzWhZc3t5WQlkqR1iY7RkOiJv8QJkSquK6OOrJDyZttoIs+BYa/ rrq64vtJx3iQDhFrnWIFstpKTTWCKR5G9OdikOMGqAJdAuppm4G2RtSL/+jWrveC7ozU 1IVPnaePO85aJslNMUiBFBPRVqite/GCMLvOWflOeqWD0MBhNM2pK5roVa/NUu86rMCz WPOOL9dttU7VQKmD9CmOArxAiBVK1r1ww7tn90vZafKIOCUGYGHvgJLlZCOYQv6irrRu QCM3ObN5qGwUZfCHu+monzF9zSDQXWPpmYS0WgqZb+u/D6+TXokTG84XuLunu+QgWICf wFyw== X-Gm-Message-State: AOAM531SGpjfDJz81bQjMRhsPD/Oz2dk/83OystkNATS7h7/0SUctEfK JXgZCNWPtWYcJIa9R2vxWen00uPmJoF2Jw== X-Google-Smtp-Source: ABdhPJyATBBM+5lhsTRPw241FXB33qnd8Jx1i+V2DmSP3OFwbSbKZy7PI4as/m1u6exgamWeYNluRQ== X-Received: by 2002:a63:551a:: with SMTP id j26mr26989018pgb.142.1632199267005; Mon, 20 Sep 2021 21:41:07 -0700 (PDT) Received: from localhost.localdomain ([61.74.27.164]) by smtp.gmail.com with ESMTPSA id u24sm16863257pfm.81.2021.09.20.21.41.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 20 Sep 2021 21:41:06 -0700 (PDT) From: Namjae Jeon To: linux-cifs@vger.kernel.org Cc: Namjae Jeon , Ronnie Sahlberg , =?utf-8?q?Ralph_B=C3=B6hme?= , Steve French Subject: [PATCH v2] ksmbd: remove follow symlinks support Date: Tue, 21 Sep 2021 13:40:39 +0900 Message-Id: <20210921044040.624769-1-linkinjeon@kernel.org> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org This patch remove symlink support that can be vulnerable and access out of share, and we re-implement it as reparse point later. Cc: Ronnie Sahlberg Cc: Ralph Böhme Cc: Steve French Signed-off-by: Namjae Jeon Acked-by: Ronnie Sahlberg --- v2: - reorganize path lookup in smb2_open to call only one ksmbd_vfs_kern_path(). fs/ksmbd/smb2pdu.c | 60 ++++++++++------------------------------------ fs/ksmbd/vfs.c | 50 ++++++++------------------------------ 2 files changed, 22 insertions(+), 88 deletions(-) diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c index e08c6b26b6f0..de044802fc5b 100644 --- a/fs/ksmbd/smb2pdu.c +++ b/fs/ksmbd/smb2pdu.c @@ -2648,19 +2648,9 @@ int smb2_open(struct ksmbd_work *work) goto err_out1; } - if (req->CreateOptions & FILE_DELETE_ON_CLOSE_LE) { - if (test_share_config_flag(work->tcon->share_conf, - KSMBD_SHARE_FLAG_FOLLOW_SYMLINKS)) { - /* - * On delete request, instead of following up, need to - * look the current entity - */ - rc = ksmbd_vfs_kern_path(name, 0, &path, 1); - } else { - rc = ksmbd_vfs_kern_path(name, LOOKUP_NO_SYMLINKS, &path, 1); - } - - if (!rc) { + rc = ksmbd_vfs_kern_path(name, LOOKUP_NO_SYMLINKS, &path, 1); + if (!rc) { + if (req->CreateOptions & FILE_DELETE_ON_CLOSE_LE) { /* * If file exists with under flags, return access * denied error. @@ -2679,26 +2669,10 @@ int smb2_open(struct ksmbd_work *work) path_put(&path); goto err_out; } - } - } else { - if (test_share_config_flag(work->tcon->share_conf, - KSMBD_SHARE_FLAG_FOLLOW_SYMLINKS)) { - /* - * Use LOOKUP_FOLLOW to follow the path of - * symlink in path buildup - */ - rc = ksmbd_vfs_kern_path(name, LOOKUP_FOLLOW, &path, 1); - if (rc) { /* Case for broken link ?*/ - rc = ksmbd_vfs_kern_path(name, 0, &path, 1); - } - } else { - rc = ksmbd_vfs_kern_path(name, LOOKUP_NO_SYMLINKS, - &path, 1); - if (!rc && d_is_symlink(path.dentry)) { - rc = -EACCES; - path_put(&path); - goto err_out; - } + } else if (d_is_symlink(path.dentry)) { + rc = -EACCES; + path_put(&path); + goto err_out; } } @@ -4781,12 +4755,8 @@ static int smb2_get_info_filesystem(struct ksmbd_work *work, struct path path; int rc = 0, len; int fs_infoclass_size = 0; - int lookup_flags = LOOKUP_NO_SYMLINKS; - - if (test_share_config_flag(share, KSMBD_SHARE_FLAG_FOLLOW_SYMLINKS)) - lookup_flags = LOOKUP_FOLLOW; - rc = ksmbd_vfs_kern_path(share->path, lookup_flags, &path, 0); + rc = ksmbd_vfs_kern_path(share->path, LOOKUP_NO_SYMLINKS, &path, 0); if (rc) { pr_err("cannot create vfs path\n"); return -EIO; @@ -5293,7 +5263,7 @@ static int smb2_rename(struct ksmbd_work *work, char *pathname = NULL; struct path path; bool file_present = true; - int rc, lookup_flags = LOOKUP_NO_SYMLINKS; + int rc; ksmbd_debug(SMB, "setting FILE_RENAME_INFO\n"); pathname = kmalloc(PATH_MAX, GFP_KERNEL); @@ -5362,11 +5332,8 @@ static int smb2_rename(struct ksmbd_work *work, goto out; } - if (test_share_config_flag(share, KSMBD_SHARE_FLAG_FOLLOW_SYMLINKS)) - lookup_flags = LOOKUP_FOLLOW; - ksmbd_debug(SMB, "new name %s\n", new_name); - rc = ksmbd_vfs_kern_path(new_name, lookup_flags, &path, 1); + rc = ksmbd_vfs_kern_path(new_name, LOOKUP_NO_SYMLINKS, &path, 1); if (rc) file_present = false; else @@ -5416,7 +5383,7 @@ static int smb2_create_link(struct ksmbd_work *work, char *link_name = NULL, *target_name = NULL, *pathname = NULL; struct path path; bool file_present = true; - int rc, lookup_flags = LOOKUP_NO_SYMLINKS; + int rc; ksmbd_debug(SMB, "setting FILE_LINK_INFORMATION\n"); pathname = kmalloc(PATH_MAX, GFP_KERNEL); @@ -5439,11 +5406,8 @@ static int smb2_create_link(struct ksmbd_work *work, goto out; } - if (test_share_config_flag(share, KSMBD_SHARE_FLAG_FOLLOW_SYMLINKS)) - lookup_flags = LOOKUP_FOLLOW; - ksmbd_debug(SMB, "target name is %s\n", target_name); - rc = ksmbd_vfs_kern_path(link_name, lookup_flags, &path, 0); + rc = ksmbd_vfs_kern_path(link_name, LOOKUP_NO_SYMLINKS, &path, 0); if (rc) file_present = false; else diff --git a/fs/ksmbd/vfs.c b/fs/ksmbd/vfs.c index 53047f013371..3733e4944c1d 100644 --- a/fs/ksmbd/vfs.c +++ b/fs/ksmbd/vfs.c @@ -164,13 +164,9 @@ int ksmbd_vfs_create(struct ksmbd_work *work, const char *name, umode_t mode) { struct path path; struct dentry *dentry; - int err, lookup_flags = LOOKUP_NO_SYMLINKS; - - if (test_share_config_flag(work->tcon->share_conf, - KSMBD_SHARE_FLAG_FOLLOW_SYMLINKS)) - lookup_flags = LOOKUP_FOLLOW; + int err; - dentry = kern_path_create(AT_FDCWD, name, &path, lookup_flags); + dentry = kern_path_create(AT_FDCWD, name, &path, LOOKUP_NO_SYMLINKS); if (IS_ERR(dentry)) { err = PTR_ERR(dentry); if (err != -ENOENT) @@ -205,14 +201,10 @@ int ksmbd_vfs_mkdir(struct ksmbd_work *work, const char *name, umode_t mode) struct user_namespace *user_ns; struct path path; struct dentry *dentry; - int err, lookup_flags = LOOKUP_NO_SYMLINKS; - - if (test_share_config_flag(work->tcon->share_conf, - KSMBD_SHARE_FLAG_FOLLOW_SYMLINKS)) - lookup_flags = LOOKUP_FOLLOW; + int err; dentry = kern_path_create(AT_FDCWD, name, &path, - lookup_flags | LOOKUP_DIRECTORY); + LOOKUP_NO_SYMLINKS | LOOKUP_DIRECTORY); if (IS_ERR(dentry)) { err = PTR_ERR(dentry); if (err != -EEXIST) @@ -597,16 +589,11 @@ int ksmbd_vfs_remove_file(struct ksmbd_work *work, char *name) struct path path; struct dentry *parent; int err; - int flags = LOOKUP_NO_SYMLINKS; if (ksmbd_override_fsids(work)) return -ENOMEM; - if (test_share_config_flag(work->tcon->share_conf, - KSMBD_SHARE_FLAG_FOLLOW_SYMLINKS)) - flags = LOOKUP_FOLLOW; - - err = kern_path(name, flags, &path); + err = kern_path(name, LOOKUP_NO_SYMLINKS, &path); if (err) { ksmbd_debug(VFS, "can't get %s, err %d\n", name, err); ksmbd_revert_fsids(work); @@ -661,16 +648,11 @@ int ksmbd_vfs_link(struct ksmbd_work *work, const char *oldname, struct path oldpath, newpath; struct dentry *dentry; int err; - int flags = LOOKUP_NO_SYMLINKS; if (ksmbd_override_fsids(work)) return -ENOMEM; - if (test_share_config_flag(work->tcon->share_conf, - KSMBD_SHARE_FLAG_FOLLOW_SYMLINKS)) - flags = LOOKUP_FOLLOW; - - err = kern_path(oldname, flags, &oldpath); + err = kern_path(oldname, LOOKUP_NO_SYMLINKS, &oldpath); if (err) { pr_err("cannot get linux path for %s, err = %d\n", oldname, err); @@ -678,7 +660,7 @@ int ksmbd_vfs_link(struct ksmbd_work *work, const char *oldname, } dentry = kern_path_create(AT_FDCWD, newname, &newpath, - flags | LOOKUP_REVAL); + LOOKUP_NO_SYMLINKS | LOOKUP_REVAL); if (IS_ERR(dentry)) { err = PTR_ERR(dentry); pr_err("path create err for %s, err %d\n", newname, err); @@ -797,7 +779,6 @@ int ksmbd_vfs_fp_rename(struct ksmbd_work *work, struct ksmbd_file *fp, struct dentry *src_dent, *trap_dent, *src_child; char *dst_name; int err; - int flags = LOOKUP_NO_SYMLINKS; dst_name = extract_last_component(newname); if (!dst_name) @@ -806,13 +787,8 @@ int ksmbd_vfs_fp_rename(struct ksmbd_work *work, struct ksmbd_file *fp, src_dent_parent = dget_parent(fp->filp->f_path.dentry); src_dent = fp->filp->f_path.dentry; - flags = LOOKUP_DIRECTORY; - if (test_share_config_flag(work->tcon->share_conf, - KSMBD_SHARE_FLAG_FOLLOW_SYMLINKS)) - flags = LOOKUP_FOLLOW; - flags |= LOOKUP_DIRECTORY; - - err = kern_path(newname, flags, &dst_path); + err = kern_path(newname, LOOKUP_NO_SYMLINKS | LOOKUP_DIRECTORY, + &dst_path); if (err) { ksmbd_debug(VFS, "Cannot get path for %s [%d]\n", newname, err); goto out; @@ -871,13 +847,7 @@ int ksmbd_vfs_truncate(struct ksmbd_work *work, const char *name, int err = 0; if (name) { - int flags = LOOKUP_NO_SYMLINKS; - - if (test_share_config_flag(work->tcon->share_conf, - KSMBD_SHARE_FLAG_FOLLOW_SYMLINKS)) - flags = LOOKUP_FOLLOW; - - err = kern_path(name, flags, &path); + err = kern_path(name, LOOKUP_NO_SYMLINKS, &path); if (err) { pr_err("cannot get linux path for %s, err %d\n", name, err);