ORA-01031: insufficient privileges (login as sysdba)

It's a been a while since my last post.  As you may know, I normally blog about solutions that are hard to find that haven't already been blogged about.  Here's my latest encounter...

I was receiving this error when trying to login via "sqlplus / as sysdba" after completing an Oracle 11gR2 binary install using the "database home clone" methodology.  I checked that the binary permissions were set correctly, which they were.  Then finally I stumbled across someone else that had had this problem where the $ORACLE_HOME/rdbms/lib/config.c file wasn't configured properly. 

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ERROR:
ORA-01031: insufficient privileges

So I did the following:

cd <ORACLE_HOME>/rdbms/lib

cp -p config.c config.c.bak

vi config.c (with below changes)

relink oracle

config.c before changes:

/*  SS_DBA_GRP defines the UNIX group ID for sqldba adminstrative access.  */

/*  Refer to the Installation and User's Guide for further information.  */

/* IMPORTANT: this file needs to be in sync with

              rdbms/src/server/osds/config.c, specifically regarding the

              number of elements in the ss_dba_grp array.

 */

#define SS_DBA_GRP ""

#define SS_OPER_GRP ""

#define SS_ASM_GRP ""

char *ss_dba_grp[] = {SS_DBA_GRP, SS_OPER_GRP, SS_ASM_GRP};

config.c after changes:

/*  SS_DBA_GRP defines the UNIX group ID for sqldba adminstrative access.  */

/*  Refer to the Installation and User's Guide for further information.  */

/* IMPORTANT: this file needs to be in sync with

              rdbms/src/server/osds/config.c, specifically regarding the

              number of elements in the ss_dba_grp array.

 */

#define SS_DBA_GRP "oinstall"

#define SS_OPER_GRP "oinstall"

#define SS_ASM_GRP ""

char *ss_dba_grp[] = {SS_DBA_GRP, SS_OPER_GRP, SS_ASM_GRP};