Bug#321462: exim4-config: Issue a warning if CFILEMODE allows world-read and config file has any hide options

[Marc Haber]

On Wed, Aug 10, 2005 at 02:09:16PM -0600, Dave wrote:
> This is a quicky that I've barely tested (and used constant directory 
> paths/names in), but this should be along those lines (except for the 
> case of no configuration files, which I presume is an illegal state)
> 
> #in bash:
> cd /etc/exim4
> let MODE=`find .. -printf '0%m&'|sed 's/&$//'`\&0$CFILEMODE
> chmod `printf %o`$MODE /var/lib/exim4/config.autogenerated

Yuck!

I would like to propose the following patch to ue4.conf to add the
requested warnings. Please comment.

Greetings
Marc

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Marc Haber         | "I don't trust Computers. They | Mailadresse im Header
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-------------- next part --------------
--- /usr/sbin/update-exim4.conf	2005-08-21 11:48:27.000000000 +0200
+++ update-exim4.conf	2005-10-01 21:43:20.000000000 +0200
@@ -99,6 +99,13 @@
 [ "x${dc_localdelivery}" = "x" ] && dc_localdelivery='mail_spool'
 [ "x${UPEX4C_comments}" = "x" ] && UPEX4C_comments="${ue4c_keepcomments:-no}"
 
+# this file has its mode narrowed to the narrowest mode of any input file
+# read, so that we can later complain about a too wide CFILEMODE. This
+# detour is necessary because cat_parts runs in a subshell
+touch ${UPEX4C_outputfile}.mode
+chmod 0777 ${UPEX4C_outputfile}.mode
+READFILEMODE=0777
+
 mailname=`cat /etc/mailname | head -n 1`
 
 # add localhost, get rid of spaces and trailing colons
@@ -191,16 +198,19 @@
        if [ ! -d "$1" ]; then
                errormessage "$0: internal cat_parts called, but $1 does not exist or is not a directory."
        fi
+       CP_READFILEMODE=511 # 0777
        for file in `run_parts $1`; do
                echo "#####################################################"
                echo "### $file"
                echo "#####################################################"
                cat $file
+	       CP_READFILEMODE="$(( $READFILEMODE & 0$(find $file -printf %m) ))"
 	       echo
                echo "#####################################################"
                echo "### end $file"
                echo "#####################################################"
        done
+       chmod 0$( printf %o $(( $CP_READFILEMODE & 0$(find ${UPEX4C_outputfile}.mode -printf %m) )) ) ${UPEX4C_outputfile}.mode
 }
 
 # check whether the file given as argument was modified by the user
@@ -307,8 +317,10 @@
                 else
 			LOCALMACROS=""
 			if [ -e "/etc/exim4/exim4.conf.localmacros" ]; then
-			  LOCALMACROS="/etc/exim4/exim4.conf.localmacros"
+				LOCALMACROS="/etc/exim4/exim4.conf.localmacros"
+	 			READFILEMODE="$(( $READFILEMODE & 0$(find $LOCALMACROS -printf %m) ))"
 			fi
+			READFILEMODE="$(( $READFILEMODE & 0$(find /etc/exim4/exim4.conf.template -printf %m) ))"
                         cat $LOCALMACROS /etc/exim4/exim4.conf.template | \
                         removecomments | \
                         sed -e "s/DEBCONF[^D][^E][^B].*DEBCONF//g" \
@@ -372,7 +384,9 @@
 	LOCALMACROS=""
 	if [ -e "/etc/exim4/exim4.conf.localmacros" ]; then
 		LOCALMACROS="/etc/exim4/exim4.conf.localmacros"
+		READFILEMODE="$(( $READFILEMODE & 0$(find $LOCALMACROS -printf %m) ))"
 	fi
+	READFILEMODE="$(( $READFILEMODE & 0$(find /etc/exim4/exim4.conf.template -printf %m) ))"
 	cat $LOCALMACROS /etc/exim4/exim4.conf.template \
 	| sed -e "s?DEBCONFlocal_domainsDEBCONF?@:${local_domains}?g" \
 		-e "s?DEBCONFrelay_domainsDEBCONF?${dc_relay_domains}?g" \
@@ -409,4 +423,13 @@
 fi
 
 mv -f ${UPEX4C_outputfile}.tmp ${UPEX4C_outputfile}
+if grep -q '^[[:space:]]\+hide' ${UPEX4C_outputfile}; then
+	if [ "$(( 0$CFILEMODE & 044 ))" -ne 0 ]; then
+  		errormessage "${UPEX4C_outputfile} contains hide directives, but is readable for group and/or world"
+	fi
+fi
+READFILEMODE="0$(( $READFILEMODE & 0$(find ${UPEX4C_outputfile}.mode -printf %m) ))"
+if [ "$(( 0$CFILEMODE ))" -gt "$READFILEMODE" ]; then
+	errormessage "${UPEX4C_outputfile} contains input from files which have a narrower mode than $CFILEMODE"
+fi
 chmod ${CFILEMODE} ${UPEX4C_outputfile}