Why not keep the current behavious as default, and have ann /etc/ftpd.conf
file in which the CMASK value can be specified?

On Fri, 28 Mar 1997, Curt Sampson wrote:

> 
> The following is a set of diffs I'm proposing to apply to our FTP
> daemon in order to make anonymous uploads more secure (i.e., less
> open to abuse).
> 
> It does the following:
> 
> * Sets the default umask for anonymous users to 707, thus clearing
>   out all but group read/write/execute access on uploaded files.
> 
> * Disables the umask, chmod, delete and rmdir commands for anonymous
>   users.
> 
> The idea is this:
> 
> Directories in which files may be uploaded are owned by ftp, and
> have owner permissions of wx or rwx. This allows anonymous users
> to change to that directory, upload files to it, and optionally
> see the contents of that directory. 
> 
> Uploaded files will be owned by ftp and that directory's group.
> The ftp user will not be able to read the contents of or overwrite
> uploaded files. Nor will they be able to remove files or directories,
> or change the permissions on files or directories.
> 
> Users who are members of the group that owns the directory will be
> able to do all the standard file management stuff in that directory.
> Users who are not members of the group will not be able to read
> the files uploaded, and may have fewer permissions, depending on
> the permission bits the sysadmin sets on the directory.
> 
> If the site prefers a more `open' policy, it can recompile ftpd
> with GUEST_CMASK set to something else. This would be pretty foolish
> if the machine were on the Internet, however, since this would open
> it to being an exchange site for pirated software.
> 
> I would also add a section to the ftpd manual page explaining all
> of this.
> 
> Does anyone see any problem with this?
> 
> cjs
> 
> Curt Sampson    cjs@portal.ca		Info at http://www.portal.ca/
> Internet Portal Services, Inc.	
> Vancouver, BC   (604) 257-9400		De gustibus, aut bene aut nihil.
> 
> ---------- Forwarded message ----------
> Date: Thu, 27 Mar 1997 23:58:18 -0800 (PST)
> From: Curt Sampson <cjs@gnostic.cynic.net>
> To: cjs@portal.ca
> Subject: ftp diffs
> 
> Index: ftpd.c
> ===================================================================
> RCS file: /usr2/CVSRoot/netbsd/src/libexec/ftpd/ftpd.c,v
> retrieving revision 1.1.1.3
> diff -u -r1.1.1.3 ftpd.c
> --- ftpd.c	1997/02/09 06:34:09	1.1.1.3
> +++ ftpd.c	1997/03/28 07:58:04
> @@ -126,6 +126,9 @@
>  #undef CMASK
>  #define CMASK 027
>  #endif
> +#if !defined(GUEST_CMASK)
> +#define GUEST_CMASK 0707
> +#endif
>  int	defumask = CMASK;		/* default umask value */
>  char	tmpline[7];
>  char	hostname[MAXHOSTNAMELEN];
> @@ -665,7 +668,10 @@
>  			syslog(LOG_INFO, "FTP LOGIN FROM %s as %s",
>  			    remotehost, pw->pw_name);
>  	}
> -	(void) umask(defumask);
> +	if (guest) 
> +	    (void) umask(GUEST_CMASK);
> +	else
> +	    (void) umask(defumask);
>  	return;
>  bad:
>  	/* Forget all about it... */
> Index: ftpcmd.y
> ===================================================================
> RCS file: /usr2/CVSRoot/netbsd/src/libexec/ftpd/ftpcmd.y,v
> retrieving revision 1.1.1.3
> diff -u -r1.1.1.3 ftpcmd.y
> --- ftpcmd.y	1996/04/10 11:27:25	1.1.1.3
> +++ ftpcmd.y	1997/03/28 07:58:13
> @@ -292,10 +292,15 @@
>  		}
>  	| DELE check_login SP pathname CRLF
>  		{
> -			if ($2 && $4 != NULL)
> -				delete($4);
> -			if ($4 != NULL)
> -				free($4);
> +			if (guest)  {
> +			    reply(502,
> +			        "Anonymous users may not use this command.");
> +			} else {
> +			    if ($2 && $4 != NULL)
> +				    delete($4);
> +			    if ($4 != NULL)
> +				    free($4);
> +			}
>  		}
>  	| RNTO SP pathname CRLF
>  		{
> @@ -356,10 +361,15 @@
>  		}
>  	| RMD check_login SP pathname CRLF
>  		{
> -			if ($2 && $4 != NULL)
> -				removedir($4);
> -			if ($4 != NULL)
> -				free($4);
> +			if (guest)  {
> +			    reply(502,
> +			        "Anonymous users may not use this command.");
> +			} else {
> +			    if ($2 && $4 != NULL)
> +				    removedir($4);
> +			    if ($4 != NULL)
> +				    free($4);
> +			}
>  		}
>  	| PWD check_login CRLF
>  		{
> @@ -394,7 +404,10 @@
>  			int oldmask;
>  
>  			if ($4) {
> -				if (($6 == -1) || ($6 > 0777)) {
> +				if (guest)
> +				    reply(502,
> +				"Anonymous users may not use this command.");
> +				else if (($6 == -1) || ($6 > 0777)) {
>  					reply(501, "Bad UMASK value");
>  				} else {
>  					oldmask = umask($6);
> @@ -407,7 +420,10 @@
>  	| SITE SP CHMOD check_login SP octal_number SP pathname CRLF
>  		{
>  			if ($4 && ($8 != NULL)) {
> -				if ($6 > 0777)
> +				if (guest)
> +				    reply(502,
> +				"Anonymous users may not use this command.");
> +				else if ($6 > 0777)
>  					reply(501,
>  				"CHMOD: Mode value must be between 0 and 0777");
>  				else if (chmod($8, $6) < 0)
> 
> 

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