From 7ad0df963ce3e55f40f00048ef2fa5814fb55269 Mon Sep 17 00:00:00 2001
From: Charles Herlin <charles.herlin@corp.ovh.com>
Date: Wed, 13 Feb 2019 16:07:06 +0100
Subject: [PATCH] IMP: enhance scripts that check duplicate UID

Add exception handling in 13.14_check_duplicate_uid
Clarifies output message and explicitly displays found exceptions
Add tests
Apply shellcheck recommendation

modified:   bin/hardening/13.14_check_duplicate_uid.sh
modified:   bin/hardening/13.5_find_0_uid_non_root_account.sh
new file:   tests/hardening/13.14_check_duplicate_uid.sh
new file:   tests/hardening/13.5_find_0_uid_non_root_account.sh
---
 bin/hardening/13.14_check_duplicate_uid.sh    | 54 +++++++++++++------
 .../13.5_find_0_uid_non_root_account.sh       | 23 ++++----
 tests/hardening/13.14_check_duplicate_uid.sh  | 33 ++++++++++++
 .../13.5_find_0_uid_non_root_account.sh       | 31 +++++++++++
 4 files changed, 116 insertions(+), 25 deletions(-)
 create mode 100644 tests/hardening/13.14_check_duplicate_uid.sh
 create mode 100644 tests/hardening/13.5_find_0_uid_non_root_account.sh

diff --git a/bin/hardening/13.14_check_duplicate_uid.sh b/bin/hardening/13.14_check_duplicate_uid.sh
index 945aa36..592409d 100755
--- a/bin/hardening/13.14_check_duplicate_uid.sh
+++ b/bin/hardening/13.14_check_duplicate_uid.sh
@@ -1,5 +1,5 @@
 #!/bin/bash
-
+# run-shellcheck
 #
 # CIS Debian Hardening
 #
@@ -11,28 +11,38 @@
 set -e # One error, it's over
 set -u # One variable unset, it's over
 
+# shellcheck disable=2034
 HARDENING_LEVEL=2
-DESCRIPTION="There is no duplicate UIDs."
+# shellcheck disable=2034
+DESCRIPTION="Checking for duplicate UIDs."
+EXCEPTIONS=""
 
 ERRORS=0
 
 # This function will be called if the script status is on enabled / audit mode
 audit () {
-    RESULT=$(cat /etc/passwd | cut -f3 -d":" | sort -n | uniq -c | awk {'print $1":"$2'} )
-    for LINE in $RESULT; do 
+    RESULT=$(cut -f3 -d":" < /etc/passwd | sort -n | uniq -c | awk '{print $1":"$2}' )
+    FOUND_EXCEPTIONS=""
+    for LINE in $RESULT; do
         debug "Working on line $LINE"
-        OCC_NUMBER=$(awk -F: {'print $1'} <<< $LINE)
-        USERID=$(awk -F: {'print $2'} <<< $LINE) 
-        if [ $OCC_NUMBER -gt 1 ]; then
-            USERS=$(awk -F: '($3 == n) { print $1 }' n=$USERID /etc/passwd | xargs)
-            ERRORS=$((ERRORS+1))
-            crit "Duplicate UID ($USERID): ${USERS}"
+        OCC_NUMBER=$(awk -F: '{print $1}' <<< "$LINE")
+        USERID=$(awk -F: '{print $2}' <<< "$LINE")
+        if [ "$OCC_NUMBER" -gt 1 ]; then
+            USERS=$(awk -F: '($3 == n) { print $1 }' n="$USERID" /etc/passwd | xargs)
+            ID_NAMES="($USERID): ${USERS}"
+            if echo "$EXCEPTIONS" | grep -qw "$USERID"; then
+                debug "$USERID is confirmed as an exception"
+                FOUND_EXCEPTIONS="$FOUND_EXCEPTIONS $ID_NAMES"
+            else
+                ERRORS=$((ERRORS+1))
+                crit "Duplicate UID $ID_NAMES"
+            fi
         fi
-    done 
+    done
 
     if [ $ERRORS = 0 ]; then
-        ok "No duplicate UIDs"
-    fi 
+        ok "No duplicate UIDs${FOUND_EXCEPTIONS:+ apart from configured exceptions:}${FOUND_EXCEPTIONS}"
+    fi
 }
 
 # This function will be called if the script status is on enabled mode
@@ -40,9 +50,20 @@ apply () {
     info "Editing automatically uids may seriously harm your system, report only here"
 }
 
+# This function will create the config file for this check with default values
+create_config() {
+    cat <<EOF
+status=disabled
+# Put here valid UIDs for which multiple usernames are accepted
+EXCEPTIONS=""
+EOF
+}
+
 # This function will check config parameters required
 check_config() {
-    :
+    if [ -z "$EXCEPTIONS" ]; then
+        EXCEPTIONS="@"
+    fi
 }
 
 # Source Root Dir Parameter
@@ -56,8 +77,9 @@ if [ -z "$CIS_ROOT_DIR" ]; then
 fi
 
 # Main function, will call the proper functions given the configuration (audit, enabled, disabled)
-if [ -r $CIS_ROOT_DIR/lib/main.sh ]; then
-    . $CIS_ROOT_DIR/lib/main.sh
+if [ -r "$CIS_ROOT_DIR"/lib/main.sh ]; then
+    # shellcheck source=/opt/debian-cis/lib/main.sh
+    . "$CIS_ROOT_DIR"/lib/main.sh
 else
     echo "Cannot find main.sh, have you correctly defined your root directory? Current value is $CIS_ROOT_DIR in /etc/default/cis-hardening"
     exit 128
diff --git a/bin/hardening/13.5_find_0_uid_non_root_account.sh b/bin/hardening/13.5_find_0_uid_non_root_account.sh
index 9e77406..68e91c9 100755
--- a/bin/hardening/13.5_find_0_uid_non_root_account.sh
+++ b/bin/hardening/13.5_find_0_uid_non_root_account.sh
@@ -1,5 +1,5 @@
 #!/bin/bash
-
+# run-shellcheck
 #
 # CIS Debian Hardening
 #
@@ -11,8 +11,11 @@
 set -e # One error, it's over
 set -u # One variable unset, it's over
 
+# shellcheck disable=2034
 HARDENING_LEVEL=2
+# shellcheck disable=2034
 DESCRIPTION="Verify root is the only UID 0 account."
+EXCEPTIONS=""
 
 FILE='/etc/passwd'
 RESULT=''
@@ -20,23 +23,24 @@ RESULT=''
 # This function will be called if the script status is on enabled / audit mode
 audit () {
     info "Checking if accounts have uid 0"
-    RESULT=$(cat $FILE | awk -F: '($3 == 0 && $1!="root" ) { print $1 }')
+    RESULT=$(awk -F: '($3 == 0 && $1!="root" ) { print $1 }' "$FILE" )
+    FOUND_EXCEPTIONS=""
     for ACCOUNT in $RESULT; do
         debug "Account : $ACCOUNT"
         debug "Exceptions : $EXCEPTIONS"
-        debug "echo \"$EXCEPTIONS\" | grep -q $ACCOUNT"
-        if echo "$EXCEPTIONS" | grep -q $ACCOUNT; then
+        debug "echo \"$EXCEPTIONS\" | grep -qw $ACCOUNT"
+        if echo "$EXCEPTIONS" | grep -qw "$ACCOUNT"; then
             debug "$ACCOUNT is confirmed as an exception"
             RESULT=$(sed "s!$ACCOUNT!!" <<< "$RESULT")
+            FOUND_EXCEPTIONS="$FOUND_EXCEPTIONS $ACCOUNT"
         else
             debug "$ACCOUNT not found in exceptions"
         fi
     done
     if [ ! -z "$RESULT" ]; then
-        crit "Some accounts have uid 0"
-        crit $RESULT
+        crit "Some accounts have uid 0: $(tr '\n' ' ' <<< "$RESULT")"
     else
-        ok "No account with uid 0 appart from root and potential configured exceptions"
+        ok "No account with uid 0 appart from root ${FOUND_EXCEPTIONS:+and configured exceptions:}$FOUND_EXCEPTIONS"
     fi
 }
 
@@ -72,8 +76,9 @@ if [ -z "$CIS_ROOT_DIR" ]; then
 fi
 
 # Main function, will call the proper functions given the configuration (audit, enabled, disabled)
-if [ -r $CIS_ROOT_DIR/lib/main.sh ]; then
-    . $CIS_ROOT_DIR/lib/main.sh
+if [ -r "$CIS_ROOT_DIR"/lib/main.sh ]; then
+    # shellcheck source=/opt/debian-cis/lib/main.sh
+    . "$CIS_ROOT_DIR"/lib/main.sh
 else
     echo "Cannot find main.sh, have you correctly defined your root directory? Current value is $CIS_ROOT_DIR in /etc/default/cis-hardening"
     exit 128
diff --git a/tests/hardening/13.14_check_duplicate_uid.sh b/tests/hardening/13.14_check_duplicate_uid.sh
new file mode 100644
index 0000000..6c6c662
--- /dev/null
+++ b/tests/hardening/13.14_check_duplicate_uid.sh
@@ -0,0 +1,33 @@
+# run-shellcheck
+test_audit() {
+    describe Running on blank host
+    register_test retvalshouldbe 0
+    register_test contain "[ OK ] No duplicate UIDs"
+    # shellcheck disable=2154
+    run blank /opt/debian-cis/bin/hardening/"${script}".sh --audit-all
+
+    useradd usertest1
+    useradd usertest2
+    sed -i 's/1001/1000/g' /etc/passwd
+
+    # Proceed to operation that will end up to a non compliant system
+    describe Tests purposely failing
+    register_test retvalshouldbe 1
+    register_test contain "[ KO ] Duplicate UID (1000): usertest1 usertest2"
+    run noncompliant /opt/debian-cis/bin/hardening/"${script}".sh --audit-all
+
+    # shellcheck disable=2016
+    echo 'EXCEPTIONS="$EXCEPTIONS 1000"' >> /opt/debian-cis/etc/conf.d/"${script}".cfg
+
+    describe Adding exceptions
+    register_test retvalshouldbe 0
+    register_test contain "[ OK ] No duplicate UIDs apart from configured exceptions: (1000): usertest1 usertest2"
+    run exception /opt/debian-cis/bin/hardening/"${script}".sh --audit-all
+
+    # Cleanup
+    userdel usertest1
+    userdel usertest2
+    sed -i '/usertest1/d' /etc/group
+    sed -i '/usertest2/d' /etc/group
+}
+
diff --git a/tests/hardening/13.5_find_0_uid_non_root_account.sh b/tests/hardening/13.5_find_0_uid_non_root_account.sh
new file mode 100644
index 0000000..fe6635d
--- /dev/null
+++ b/tests/hardening/13.5_find_0_uid_non_root_account.sh
@@ -0,0 +1,31 @@
+# run-shellcheck
+test_audit() {
+    describe Running on blank host
+    register_test retvalshouldbe 0
+    register_test contain "[ OK ] No account with uid 0 appart from root"
+    # shellcheck disable=2154
+    run blank /opt/debian-cis/bin/hardening/"${script}".sh --audit-all
+
+    useradd usertest1
+    sed -i 's/1000/0/g' /etc/passwd
+
+    # Proceed to operation that will end up to a non compliant system
+    describe Tests purposely failing
+    register_test retvalshouldbe 1
+    register_test contain "[ KO ] Some accounts have uid 0: usertest1"
+    run noncompliant /opt/debian-cis/bin/hardening/"${script}".sh --audit-all
+
+    # shellcheck disable=2016
+    echo 'EXCEPTIONS="$EXCEPTIONS usertest1"' >> /opt/debian-cis/etc/conf.d/"${script}".cfg
+
+    describe Adding exceptions
+    register_test retvalshouldbe 0
+    register_test contain "[ OK ] No account with uid 0 appart from root and configured exceptions: usertest1"
+    run exception /opt/debian-cis/bin/hardening/"${script}".sh --audit-all
+
+    # Cleanup
+    sed -i '/usertest1/d' /etc/passwd
+    sed -i '/usertest1/d' /etc/shadow
+    sed -i '/usertest1/d' /etc/group
+}
+