From mboxrd@z Thu Jan 1 00:00:00 1970 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=-17.5 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 2CE42C433EF for ; Wed, 22 Sep 2021 02:31:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0640F60FE6 for ; Wed, 22 Sep 2021 02:31:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229505AbhIVCd0 (ORCPT ); Tue, 21 Sep 2021 22:33:26 -0400 Received: from mail.kernel.org ([198.145.29.99]:54084 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229466AbhIVCd0 (ORCPT ); Tue, 21 Sep 2021 22:33:26 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id CAAB860527 for ; Wed, 22 Sep 2021 02:31:56 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1632277916; bh=LnnDlRjwdWe1I+MH0M0+H+LC2McFc4MRbd6k5MgJAmY=; h=In-Reply-To:References:From:Date:Subject:To:Cc:From; b=DehmMEO3z+YZNahFqoyOu5mim7CtlB1jkyqZVofi/RgQzVd0ZkRaDZ/TNwwUkB/9d 19CWmFxgaPCHBETTYgxfAeeJYogWgKlQlCgWIQ3SzxFXi0UTJuLAOLavuWuoFwYt1U flAj9YwqBV0CpF4WRASJ85+PSblhLYQzROV9rGYuy8FIa4EEVb8te/S9IT2JmThor6 LluQSn574l3NIVTUXTIq0Yu3TI8luacOQmsT4LUQ0OsPvOqp6ncst7Pf8nsbKi5vxU QVTH9oa8aidTwsVBo//Nhtyl2E0aHuKdFe5TwYdZXMKFhW6tQPh1C4QAkJXy+df4NW CahkbuGZsLuvQ== Received: by mail-oi1-f172.google.com with SMTP id w206so2241702oiw.4 for ; Tue, 21 Sep 2021 19:31:56 -0700 (PDT) X-Gm-Message-State: AOAM530BlMOtMF1u8K3Ro6/DMBiHIk3241KvX3Uj92CMDfiBbQClyTCy wKUElUiZZJ20MeOK2MtBI+5WxsqwotmxowNFtGM= X-Google-Smtp-Source: ABdhPJw8DrhEFezFW/dmwpu7qWOaficQ/9+7lHUSX8mv7PUKqW5EKRjfsEJ/EUwKOEDREsLpA6AxPGy5wXLL7o+1W+Q= X-Received: by 2002:a05:6808:21a7:: with SMTP id be39mr717556oib.138.1632277916212; Tue, 21 Sep 2021 19:31:56 -0700 (PDT) MIME-Version: 1.0 Received: by 2002:a8a:1342:0:0:0:0:0 with HTTP; Tue, 21 Sep 2021 19:31:55 -0700 (PDT) In-Reply-To: <890f7c14-b0b9-12e1-8d2e-e1ca5fb9c2d5@talpey.com> References: <20210919021315.642856-1-linkinjeon@kernel.org> <890f7c14-b0b9-12e1-8d2e-e1ca5fb9c2d5@talpey.com> From: Namjae Jeon Date: Wed, 22 Sep 2021 11:31:55 +0900 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH v2 1/4] ksmbd: add request buffer validation in smb2_set_info To: Tom Talpey Cc: linux-cifs@vger.kernel.org, Ronnie Sahlberg , =?UTF-8?B?UmFscGggQsO2aG1l?= , Steve French Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-cifs@vger.kernel.org 2021-09-21 23:23 GMT+09:00, Tom Talpey : > On 9/18/2021 10:13 PM, Namjae Jeon wrote: >> Add buffer validation in smb2_set_info. >> >> Cc: Ronnie Sahlberg >> Cc: Ralph B=C3=B6hme >> Cc: Steve French >> Signed-off-by: Namjae Jeon >> --- >> fs/ksmbd/smb2pdu.c | 113 +++++++++++++++++++++++++++++++++++---------- >> fs/ksmbd/smb2pdu.h | 9 ++++ >> 2 files changed, 97 insertions(+), 25 deletions(-) >> >> diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c >> index 46e0275a77a8..7763f69e1ae8 100644 >> --- a/fs/ksmbd/smb2pdu.c >> +++ b/fs/ksmbd/smb2pdu.c >> @@ -2107,17 +2107,23 @@ static noinline int create_smb2_pipe(struct >> ksmbd_work *work) >> * smb2_set_ea() - handler for setting extended attributes using set >> * info command >> * @eabuf: set info command buffer >> + * @buf_len: set info command buffer length >> * @path: dentry path for get ea >> * >> * Return: 0 on success, otherwise error >> */ >> -static int smb2_set_ea(struct smb2_ea_info *eabuf, struct path *path) >> +static int smb2_set_ea(struct smb2_ea_info *eabuf, unsigned int buf_len= , >> + struct path *path) >> { >> struct user_namespace *user_ns =3D mnt_user_ns(path->mnt); >> char *attr_name =3D NULL, *value; >> int rc =3D 0; >> int next =3D 0; >> >> + if (buf_len < sizeof(struct smb2_ea_info) + eabuf->EaNameLength + >> + le16_to_cpu(eabuf->EaValueLength)) >> + return -EINVAL; > > How certain is it that EaNameLength and EaValueLength are sane? One > might imagine a forged packet with various combinations of invalid > values, which arithmetically satisfy the above check... Sorry, I didn't fully understand what you pointed out. Could you please elaborate more ? > >> + >> attr_name =3D kmalloc(XATTR_NAME_MAX + 1, GFP_KERNEL); >> if (!attr_name) >> return -ENOMEM; >> @@ -2181,7 +2187,13 @@ static int smb2_set_ea(struct smb2_ea_info *eabuf= , >> struct path *path) >> >> next: >> next =3D le32_to_cpu(eabuf->NextEntryOffset); >> + if (next =3D=3D 0 || buf_len < next) >> + break; >> + buf_len -=3D next; > > Because buf_len is unsigned int and next is signed int, these compares > are risky. I think "next" should also be unsigned, but if not, testing > it for negative values before these checks is important. > > In the many changes below, buf_len is passed in as signed. Those should > be consistent with the same criteria. It pays to be paranoid everywhere! Okay, I will update it on next version. > > Tom. > >> eabuf =3D (struct smb2_ea_info *)((char *)eabuf + next); >> + if (next < eabuf->EaNameLength + le16_to_cpu(eabuf->EaValueLength)) >> + break; >> + >> } while (next !=3D 0); >> >> kfree(attr_name); >> @@ -2790,7 +2802,9 @@ int smb2_open(struct ksmbd_work *work) >> created =3D true; >> user_ns =3D mnt_user_ns(path.mnt); >> if (ea_buf) { >> - rc =3D smb2_set_ea(&ea_buf->ea, &path); >> + rc =3D smb2_set_ea(&ea_buf->ea, >> + le32_to_cpu(ea_buf->ccontext.DataLength), >> + &path); > > Again, is DataLength verified? This field is checked by create context validation patch. See: https://marc.info/?l=3Dlinux-cifs&m=3D163227401430586&w=3D2 > >> if (rc =3D=3D -EOPNOTSUPP) >> rc =3D 0; >> else if (rc) >> @@ -5375,7 +5389,7 @@ static int smb2_rename(struct ksmbd_work *work, >> static int smb2_create_link(struct ksmbd_work *work, >> struct ksmbd_share_config *share, >> struct smb2_file_link_info *file_info, >> - struct file *filp, >> + int buf_len, struct file *filp, >> struct nls_table *local_nls) >> { >> char *link_name =3D NULL, *target_name =3D NULL, *pathname =3D NULL; >> @@ -5383,6 +5397,10 @@ static int smb2_create_link(struct ksmbd_work >> *work, >> bool file_present =3D true; >> int rc; >> >> + if (buf_len < sizeof(struct smb2_file_link_info) + >> + le32_to_cpu(file_info->FileNameLength)) >> + return -EINVAL; >> + >> ksmbd_debug(SMB, "setting FILE_LINK_INFORMATION\n"); >> pathname =3D kmalloc(PATH_MAX, GFP_KERNEL); >> if (!pathname) >> @@ -5442,7 +5460,7 @@ static int smb2_create_link(struct ksmbd_work >> *work, >> static int set_file_basic_info(struct ksmbd_file *fp, char *buf, >> struct ksmbd_share_config *share) >> { >> - struct smb2_file_all_info *file_info; >> + struct smb2_file_basic_info *file_info; >> struct iattr attrs; >> struct timespec64 ctime; >> struct file *filp; >> @@ -5453,7 +5471,7 @@ static int set_file_basic_info(struct ksmbd_file >> *fp, char *buf, >> if (!(fp->daccess & FILE_WRITE_ATTRIBUTES_LE)) >> return -EACCES; >> >> - file_info =3D (struct smb2_file_all_info *)buf; >> + file_info =3D (struct smb2_file_basic_info *)buf; >> attrs.ia_valid =3D 0; >> filp =3D fp->filp; >> inode =3D file_inode(filp); >> @@ -5619,7 +5637,8 @@ static int set_end_of_file_info(struct ksmbd_work >> *work, struct ksmbd_file *fp, >> } >> >> static int set_rename_info(struct ksmbd_work *work, struct ksmbd_file >> *fp, >> - char *buf) >> + struct smb2_file_rename_info *rename_info, >> + int buf_len) >> { >> struct user_namespace *user_ns; >> struct ksmbd_file *parent_fp; >> @@ -5632,6 +5651,10 @@ static int set_rename_info(struct ksmbd_work *wor= k, >> struct ksmbd_file *fp, >> return -EACCES; >> } >> >> + if (buf_len < sizeof(struct smb2_file_rename_info) + >> + le32_to_cpu(rename_info->FileNameLength)) >> + return -EINVAL; >> + >> user_ns =3D file_mnt_user_ns(fp->filp); >> if (ksmbd_stream_fd(fp)) >> goto next; >> @@ -5654,8 +5677,7 @@ static int set_rename_info(struct ksmbd_work *work= , >> struct ksmbd_file *fp, >> } >> } >> next: >> - return smb2_rename(work, fp, user_ns, >> - (struct smb2_file_rename_info *)buf, >> + return smb2_rename(work, fp, user_ns, rename_info, >> work->sess->conn->local_nls); >> } >> >> @@ -5741,40 +5763,71 @@ static int set_file_mode_info(struct ksmbd_file >> *fp, char *buf) >> * TODO: need to implement an error handling for >> STATUS_INFO_LENGTH_MISMATCH >> */ >> static int smb2_set_info_file(struct ksmbd_work *work, struct ksmbd_fi= le >> *fp, >> - int info_class, char *buf, >> + struct smb2_set_info_req *req, >> struct ksmbd_share_config *share) >> { >> - switch (info_class) { >> + int buf_len =3D le32_to_cpu(req->BufferLength); >> + >> + switch (req->FileInfoClass) { >> case FILE_BASIC_INFORMATION: >> - return set_file_basic_info(fp, buf, share); >> + { >> + if (buf_len < sizeof(struct smb2_file_basic_info)) >> + return -EINVAL; >> >> + return set_file_basic_info(fp, req->Buffer, share); >> + } >> case FILE_ALLOCATION_INFORMATION: >> - return set_file_allocation_info(work, fp, buf); >> + { >> + if (buf_len < sizeof(struct smb2_file_alloc_info)) >> + return -EINVAL; >> >> + return set_file_allocation_info(work, fp, req->Buffer); >> + } >> case FILE_END_OF_FILE_INFORMATION: >> - return set_end_of_file_info(work, fp, buf); >> + { >> + if (buf_len < sizeof(struct smb2_file_eof_info)) >> + return -EINVAL; >> >> + return set_end_of_file_info(work, fp, req->Buffer); >> + } >> case FILE_RENAME_INFORMATION: >> + { >> if (!test_tree_conn_flag(work->tcon, KSMBD_TREE_CONN_FLAG_WRITABLE)) >> { >> ksmbd_debug(SMB, >> "User does not have write permission\n"); >> return -EACCES; >> } >> - return set_rename_info(work, fp, buf); >> >> + if (buf_len < sizeof(struct smb2_file_rename_info)) >> + return -EINVAL; >> + >> + return set_rename_info(work, fp, >> + (struct smb2_file_rename_info *)req->Buffer, >> + buf_len); >> + } >> case FILE_LINK_INFORMATION: >> + { >> + if (buf_len < sizeof(struct smb2_file_link_info)) >> + return -EINVAL; >> + >> return smb2_create_link(work, work->tcon->share_conf, >> - (struct smb2_file_link_info *)buf, fp->filp, >> + (struct smb2_file_link_info *)req->Buffer, >> + buf_len, fp->filp, >> work->sess->conn->local_nls); >> - >> + } >> case FILE_DISPOSITION_INFORMATION: >> + { >> if (!test_tree_conn_flag(work->tcon, KSMBD_TREE_CONN_FLAG_WRITABLE)) >> { >> ksmbd_debug(SMB, >> "User does not have write permission\n"); >> return -EACCES; >> } >> - return set_file_disposition_info(fp, buf); >> >> + if (buf_len < sizeof(struct smb2_file_disposition_info)) >> + return -EINVAL; >> + >> + return set_file_disposition_info(fp, req->Buffer); >> + } >> case FILE_FULL_EA_INFORMATION: >> { >> if (!(fp->daccess & FILE_WRITE_EA_LE)) { >> @@ -5783,18 +5836,29 @@ static int smb2_set_info_file(struct ksmbd_work >> *work, struct ksmbd_file *fp, >> return -EACCES; >> } >> >> - return smb2_set_ea((struct smb2_ea_info *)buf, >> - &fp->filp->f_path); >> - } >> + if (buf_len < sizeof(struct smb2_ea_info)) >> + return -EINVAL; >> >> + return smb2_set_ea((struct smb2_ea_info *)req->Buffer, >> + buf_len, &fp->filp->f_path); >> + } >> case FILE_POSITION_INFORMATION: >> - return set_file_position_info(fp, buf); >> + { >> + if (buf_len < sizeof(struct smb2_file_pos_info)) >> + return -EINVAL; >> >> + return set_file_position_info(fp, req->Buffer); >> + } >> case FILE_MODE_INFORMATION: >> - return set_file_mode_info(fp, buf); >> + { >> + if (buf_len < sizeof(struct smb2_file_mode_info)) >> + return -EINVAL; >> + >> + return set_file_mode_info(fp, req->Buffer); >> + } >> } >> >> - pr_err("Unimplemented Fileinfoclass :%d\n", info_class); >> + pr_err("Unimplemented Fileinfoclass :%d\n", req->FileInfoClass); >> return -EOPNOTSUPP; >> } >> >> @@ -5855,8 +5919,7 @@ int smb2_set_info(struct ksmbd_work *work) >> switch (req->InfoType) { >> case SMB2_O_INFO_FILE: >> ksmbd_debug(SMB, "GOT SMB2_O_INFO_FILE\n"); >> - rc =3D smb2_set_info_file(work, fp, req->FileInfoClass, >> - req->Buffer, work->tcon->share_conf); >> + rc =3D smb2_set_info_file(work, fp, req, work->tcon->share_conf); >> break; >> case SMB2_O_INFO_SECURITY: >> ksmbd_debug(SMB, "GOT SMB2_O_INFO_SECURITY\n"); >> diff --git a/fs/ksmbd/smb2pdu.h b/fs/ksmbd/smb2pdu.h >> index bcec845b03f3..261825d06391 100644 >> --- a/fs/ksmbd/smb2pdu.h >> +++ b/fs/ksmbd/smb2pdu.h >> @@ -1464,6 +1464,15 @@ struct smb2_file_all_info { /* data block encodin= g >> of response to level 18 */ >> char FileName[1]; >> } __packed; /* level 18 Query */ >> >> +struct smb2_file_basic_info { /* data block encoding of response to lev= el >> 18 */ >> + __le64 CreationTime; /* Beginning of FILE_BASIC_INFO equivalent */ >> + __le64 LastAccessTime; >> + __le64 LastWriteTime; >> + __le64 ChangeTime; >> + __le32 Attributes; >> + __u32 Pad1; /* End of FILE_BASIC_INFO_INFO equivalent */ >> +} __packed; >> + >> struct smb2_file_alt_name_info { >> __le32 FileNameLength; >> char FileName[0]; >> >