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From: Hyunchul Lee <hyc.lee@gmail.com>
To: Namjae Jeon <linkinjeon@kernel.org>
Cc: linux-cifs <linux-cifs@vger.kernel.org>,
	"Tom Talpey" <tom@talpey.com>,
	"Ronnie Sahlberg" <ronniesahlberg@gmail.com>,
	"Ralph Böhme" <slow@samba.org>,
	"Steve French" <smfrench@gmail.com>,
	"Sergey Senozhatsky" <senozhatsky@chromium.org>
Subject: Re: [PATCH 2/7] ksmbd: add request buffer validation in smb2_set_info
Date: Sat, 25 Sep 2021 17:13:56 +0900	[thread overview]
Message-ID: <CANFS6bYot0-tRYUdBctwmwLn3OUsYOWO_C3a3aZu74tXG2k=Mw@mail.gmail.com> (raw)
In-Reply-To: <20210924021254.27096-3-linkinjeon@kernel.org>

2021년 9월 24일 (금) 오전 11:13, Namjae Jeon <linkinjeon@kernel.org>님이 작성:

>
> Add buffer validation in smb2_set_info, and remove unused variable
> in set_file_basic_info. and smb2_set_info infolevel functions take
> structure pointer argument.
>
> Cc: Tom Talpey <tom@talpey.com>
> Cc: Ronnie Sahlberg <ronniesahlberg@gmail.com>
> Cc: Ralph Böhme <slow@samba.org>
> Cc: Steve French <smfrench@gmail.com>
> Cc: Hyunchul Lee <hyc.lee@gmail.com>
> Cc: Sergey Senozhatsky <senozhatsky@chromium.org>
> Signed-off-by: Namjae Jeon <linkinjeon@kernel.org>
> ---
>  fs/ksmbd/smb2pdu.c | 149 ++++++++++++++++++++++++++++++++-------------
>  fs/ksmbd/smb2pdu.h |   9 +++
>  2 files changed, 116 insertions(+), 42 deletions(-)
>
> diff --git a/fs/ksmbd/smb2pdu.c b/fs/ksmbd/smb2pdu.c
> index b22d4207c077..a930838fd6ac 100644
> --- a/fs/ksmbd/smb2pdu.c
> +++ b/fs/ksmbd/smb2pdu.c
> @@ -2107,16 +2107,22 @@ 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 = mnt_user_ns(path->mnt);
>         char *attr_name = NULL, *value;
>         int rc = 0;
> -       int next = 0;
> +       unsigned int next = 0;
> +
> +       if (buf_len < sizeof(struct smb2_ea_info) + eabuf->EaNameLength +
> +                       le16_to_cpu(eabuf->EaValueLength))
> +               return -EINVAL;
>
>         attr_name = kmalloc(XATTR_NAME_MAX + 1, GFP_KERNEL);
>         if (!attr_name)
> @@ -2181,7 +2187,13 @@ static int smb2_set_ea(struct smb2_ea_info *eabuf, struct path *path)
>
>  next:
>                 next = le32_to_cpu(eabuf->NextEntryOffset);
> +               if (next == 0 || buf_len < next)
> +                       break;
> +               buf_len -= next;
>                 eabuf = (struct smb2_ea_info *)((char *)eabuf + next);
> +               if (next < eabuf->EaNameLength + le16_to_cpu(eabuf->EaValueLength))
> +                       break;
> +
>         } while (next != 0);
>
>         kfree(attr_name);
> @@ -2771,7 +2783,15 @@ int smb2_open(struct ksmbd_work *work)
>                 created = true;
>                 user_ns = mnt_user_ns(path.mnt);
>                 if (ea_buf) {
> -                       rc = smb2_set_ea(&ea_buf->ea, &path);
> +                       if (le32_to_cpu(ea_buf->ccontext.DataLength) <
> +                           sizeof(struct smb2_ea_info)) {
> +                               rc = -EINVAL;
> +                               goto err_out;
> +                       }
> +
> +                       rc = smb2_set_ea(&ea_buf->ea,
> +                                        le32_to_cpu(ea_buf->ccontext.DataLength),
> +                                        &path);
>                         if (rc == -EOPNOTSUPP)
>                                 rc = 0;
>                         else if (rc)
> @@ -5354,7 +5374,7 @@ 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,
> +                           unsigned int buf_len, struct file *filp,
>                             struct nls_table *local_nls)
>  {
>         char *link_name = NULL, *target_name = NULL, *pathname = NULL;
> @@ -5362,6 +5382,10 @@ static int smb2_create_link(struct ksmbd_work *work,
>         bool file_present = true;
>         int rc;
>
> +       if (buf_len < sizeof(struct smb2_file_link_info) +
> +                       le32_to_cpu(file_info->FileNameLength))

Do we need to cast this to u64 or check FileNameLength to prevent
32-bit overflow?

> +               return -EINVAL;
> +
>         ksmbd_debug(SMB, "setting FILE_LINK_INFORMATION\n");
>         pathname = kmalloc(PATH_MAX, GFP_KERNEL);
>         if (!pathname)
> @@ -5418,10 +5442,10 @@ static int smb2_create_link(struct ksmbd_work *work,
>         return rc;
>  }
>
> -static int set_file_basic_info(struct ksmbd_file *fp, char *buf,
> +static int set_file_basic_info(struct ksmbd_file *fp,
> +                              struct smb2_file_basic_info *file_info,
>                                struct ksmbd_share_config *share)
>  {
> -       struct smb2_file_all_info *file_info;
>         struct iattr attrs;
>         struct timespec64 ctime;
>         struct file *filp;
> @@ -5432,7 +5456,6 @@ static int set_file_basic_info(struct ksmbd_file *fp, char *buf,
>         if (!(fp->daccess & FILE_WRITE_ATTRIBUTES_LE))
>                 return -EACCES;
>
> -       file_info = (struct smb2_file_all_info *)buf;
>         attrs.ia_valid = 0;
>         filp = fp->filp;
>         inode = file_inode(filp);
> @@ -5509,7 +5532,8 @@ static int set_file_basic_info(struct ksmbd_file *fp, char *buf,
>  }
>
>  static int set_file_allocation_info(struct ksmbd_work *work,
> -                                   struct ksmbd_file *fp, char *buf)
> +                                   struct ksmbd_file *fp,
> +                                   struct smb2_file_alloc_info *file_alloc_info)
>  {
>         /*
>          * TODO : It's working fine only when store dos attributes
> @@ -5517,7 +5541,6 @@ static int set_file_allocation_info(struct ksmbd_work *work,
>          * properly with any smb.conf option
>          */
>
> -       struct smb2_file_alloc_info *file_alloc_info;
>         loff_t alloc_blks;
>         struct inode *inode;
>         int rc;
> @@ -5525,7 +5548,6 @@ static int set_file_allocation_info(struct ksmbd_work *work,
>         if (!(fp->daccess & FILE_WRITE_DATA_LE))
>                 return -EACCES;
>
> -       file_alloc_info = (struct smb2_file_alloc_info *)buf;
>         alloc_blks = (le64_to_cpu(file_alloc_info->AllocationSize) + 511) >> 9;
>         inode = file_inode(fp->filp);
>
> @@ -5561,9 +5583,8 @@ static int set_file_allocation_info(struct ksmbd_work *work,
>  }
>
>  static int set_end_of_file_info(struct ksmbd_work *work, struct ksmbd_file *fp,
> -                               char *buf)
> +                               struct smb2_file_eof_info *file_eof_info)
>  {
> -       struct smb2_file_eof_info *file_eof_info;
>         loff_t newsize;
>         struct inode *inode;
>         int rc;
> @@ -5571,7 +5592,6 @@ static int set_end_of_file_info(struct ksmbd_work *work, struct ksmbd_file *fp,
>         if (!(fp->daccess & FILE_WRITE_DATA_LE))
>                 return -EACCES;
>
> -       file_eof_info = (struct smb2_file_eof_info *)buf;
>         newsize = le64_to_cpu(file_eof_info->EndOfFile);
>         inode = file_inode(fp->filp);
>
> @@ -5598,7 +5618,8 @@ 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,
> +                          unsigned int buf_len)
>  {
>         struct user_namespace *user_ns;
>         struct ksmbd_file *parent_fp;
> @@ -5611,6 +5632,10 @@ static int set_rename_info(struct ksmbd_work *work, struct ksmbd_file *fp,
>                 return -EACCES;
>         }
>
> +       if (buf_len < sizeof(struct smb2_file_rename_info) +
> +                       le32_to_cpu(rename_info->FileNameLength))

Also we need to cast or check FileNameLength?
Looks good to me except these.

> +               return -EINVAL;
> +
>         user_ns = file_mnt_user_ns(fp->filp);
>         if (ksmbd_stream_fd(fp))
>                 goto next;
> @@ -5633,14 +5658,13 @@ 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);
>  }
>
> -static int set_file_disposition_info(struct ksmbd_file *fp, char *buf)
> +static int set_file_disposition_info(struct ksmbd_file *fp,
> +                                    struct smb2_file_disposition_info *file_info)
>  {
> -       struct smb2_file_disposition_info *file_info;
>         struct inode *inode;
>
>         if (!(fp->daccess & FILE_DELETE_LE)) {
> @@ -5649,7 +5673,6 @@ static int set_file_disposition_info(struct ksmbd_file *fp, char *buf)
>         }
>
>         inode = file_inode(fp->filp);
> -       file_info = (struct smb2_file_disposition_info *)buf;
>         if (file_info->DeletePending) {
>                 if (S_ISDIR(inode->i_mode) &&
>                     ksmbd_vfs_empty_dir(fp) == -ENOTEMPTY)
> @@ -5661,15 +5684,14 @@ static int set_file_disposition_info(struct ksmbd_file *fp, char *buf)
>         return 0;
>  }
>
> -static int set_file_position_info(struct ksmbd_file *fp, char *buf)
> +static int set_file_position_info(struct ksmbd_file *fp,
> +                                 struct smb2_file_pos_info *file_info)
>  {
> -       struct smb2_file_pos_info *file_info;
>         loff_t current_byte_offset;
>         unsigned long sector_size;
>         struct inode *inode;
>
>         inode = file_inode(fp->filp);
> -       file_info = (struct smb2_file_pos_info *)buf;
>         current_byte_offset = le64_to_cpu(file_info->CurrentByteOffset);
>         sector_size = inode->i_sb->s_blocksize;
>
> @@ -5685,12 +5707,11 @@ static int set_file_position_info(struct ksmbd_file *fp, char *buf)
>         return 0;
>  }
>
> -static int set_file_mode_info(struct ksmbd_file *fp, char *buf)
> +static int set_file_mode_info(struct ksmbd_file *fp,
> +                             struct smb2_file_mode_info *file_info)
>  {
> -       struct smb2_file_mode_info *file_info;
>         __le32 mode;
>
> -       file_info = (struct smb2_file_mode_info *)buf;
>         mode = file_info->Mode;
>
>         if ((mode & ~FILE_MODE_INFO_MASK) ||
> @@ -5720,40 +5741,74 @@ 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_file *fp,
> -                             int info_class, char *buf,
> +                             struct smb2_set_info_req *req,
>                               struct ksmbd_share_config *share)
>  {
> -       switch (info_class) {
> +       unsigned int buf_len = 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, (struct smb2_file_basic_info *)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,
> +                                               (struct smb2_file_alloc_info *)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,
> +                                           (struct smb2_file_eof_info *)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,
> +                                                (struct smb2_file_disposition_info *)req->Buffer);
> +       }
>         case FILE_FULL_EA_INFORMATION:
>         {
>                 if (!(fp->daccess & FILE_WRITE_EA_LE)) {
> @@ -5762,18 +5817,29 @@ 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, (struct smb2_file_pos_info *)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, (struct smb2_file_mode_info *)req->Buffer);
> +       }
>         }
>
> -       pr_err("Unimplemented Fileinfoclass :%d\n", info_class);
> +       pr_err("Unimplemented Fileinfoclass :%d\n", req->FileInfoClass);
>         return -EOPNOTSUPP;
>  }
>
> @@ -5834,8 +5900,7 @@ 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 = smb2_set_info_file(work, fp, req->FileInfoClass,
> -                                       req->Buffer, work->tcon->share_conf);
> +               rc = 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 encoding of response to level 18 */
>         char   FileName[1];
>  } __packed; /* level 18 Query */
>
> +struct smb2_file_basic_info { /* data block encoding of response to level 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];
> --
> 2.25.1
>


--
Thanks,
Hyunchul

  reply	other threads:[~2021-09-25  8:22 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-09-24  2:12 [PATCH 0/7] a bunch of patches that have not yet been reviewed Namjae Jeon
2021-09-24  2:12 ` [PATCH 1/7] ksmbd: add validation in smb2_ioctl Namjae Jeon
2021-09-25 10:16   ` Hyunchul Lee
2021-09-25 10:44     ` Namjae Jeon
2021-09-24  2:12 ` [PATCH 2/7] ksmbd: add request buffer validation in smb2_set_info Namjae Jeon
2021-09-25  8:13   ` Hyunchul Lee [this message]
2021-09-25  9:19     ` Namjae Jeon
2021-09-24  2:12 ` [PATCH 3/7] ksmbd: remove RFC1002 check in smb2 request Namjae Jeon
2021-09-25  8:18   ` Hyunchul Lee
2021-09-24  2:12 ` [PATCH 4/7] ksmbd: check strictly data area in ksmbd_smb2_check_message() Namjae Jeon
2021-09-25 10:27   ` Hyunchul Lee
2021-09-25 10:46     ` Namjae Jeon
2021-09-24  2:12 ` [PATCH 5/7] ksmbd: add the check to vaildate if stream protocol length exceeds maximum value Namjae Jeon
2021-09-25  8:41   ` Hyunchul Lee
2021-09-25  9:24     ` Namjae Jeon
2021-09-24  2:12 ` [PATCH 6/7] ksmbd: fix invalid request buffer access in compound Namjae Jeon
2021-09-25  9:41   ` Hyunchul Lee
2021-09-24  2:12 ` [PATCH 7/7] ksmbd: add validation in smb2 negotiate Namjae Jeon
2021-09-24  4:58   ` Namjae Jeon

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