We should be allowing these to be larger than ~16000 bytes
Should be XATTR_SIZE_MAX 65536
but that can be done with different patch
On Wed, Feb 12, 2020 at 8:15 PM Ronnie Sahlberg <lsahlber@xxxxxxxxxx> wrote:
>
> RHBZ: 1752437
>
> Before we add a new EA we should check that this will not overflow
> the maximum buffer we have available to read the EAs back.
> Otherwise we can get into a situation where the EAs are so big that
> we can not read them back to the client and thus we can not list EAs
> anymore or delete them.
>
> Signed-off-by: Ronnie Sahlberg <lsahlber@xxxxxxxxxx>
> ---
> fs/cifs/smb2ops.c | 35 ++++++++++++++++++++++++++++++++++-
> 1 file changed, 34 insertions(+), 1 deletion(-)
>
> diff --git a/fs/cifs/smb2ops.c b/fs/cifs/smb2ops.c
> index baa825f4cec0..3c76f69f4ca7 100644
> --- a/fs/cifs/smb2ops.c
> +++ b/fs/cifs/smb2ops.c
> @@ -1116,7 +1116,8 @@ smb2_set_ea(const unsigned int xid, struct cifs_tcon *tcon,
> void *data[1];
> struct smb2_file_full_ea_info *ea = NULL;
> struct kvec close_iov[1];
> - int rc;
> + struct smb2_query_info_rsp *rsp;
> + int rc, used_len = 0;
>
> if (smb3_encryption_required(tcon))
> flags |= CIFS_TRANSFORM_REQ;
> @@ -1139,6 +1140,38 @@ smb2_set_ea(const unsigned int xid, struct cifs_tcon *tcon,
> cifs_sb);
> if (rc == -ENODATA)
> goto sea_exit;
> + } else {
> + /* If we are adding a attribute we should first check
> + * if there will be enough space available to store
> + * the new EA. If not we should not add it since we
> + * would not be able to even read the EAs back.
> + */
> + rc = smb2_query_info_compound(xid, tcon, utf16_path,
> + FILE_READ_EA,
> + FILE_FULL_EA_INFORMATION,
> + SMB2_O_INFO_FILE,
> + CIFSMaxBufSize -
> + MAX_SMB2_CREATE_RESPONSE_SIZE -
> + MAX_SMB2_CLOSE_RESPONSE_SIZE,
> + &rsp_iov[1], &resp_buftype[1], cifs_sb);
> + if (rc == 0) {
> + rsp = (struct smb2_query_info_rsp *)rsp_iov[1].iov_base;
> + used_len = rsp->OutputBufferLength;
> + }
> + free_rsp_buf(resp_buftype[1], rsp_iov[1].iov_base);
> + resp_buftype[1] = CIFS_NO_BUFFER;
> + memset(&rsp_iov[1], 0, sizeof(rsp_iov[1]));
> + rc = 0;
> +
> + /* Use a fudge factor of 256 bytes in case we collide
> + * with a different set_EAs command.
> + */
> + if(CIFSMaxBufSize - MAX_SMB2_CREATE_RESPONSE_SIZE -
> + MAX_SMB2_CLOSE_RESPONSE_SIZE - 256 <
> + used_len + ea_name_len + ea_value_len + 1) {
> + rc = -ENOSPC;
> + goto sea_exit;
> + }
> }
> }
>
> --
> 2.13.6
>
--
Thanks,
Steve
