There are 2 umasks, - the SAP profile parameter install/umask. Use RZ11 to check this value. - the unix umask setting.
You should use install/umask to influence the permissions of files created from within R/3. This can also be used in conjunction with directory and os umask settings.
note #24869 Files are created with incorrect permissions
All files created from an R/3 system should be created by the <SID>adm account. The permissions of these files are controlled by the profile parameter install/umask (see attached note #68718).
Within R/3, the UNIX level umask for <SID>adm is not used, instead the install/umask value is applied.
When touching a file outside of R/3, the install/unmask is not used, so the <SID>adm umask is used with the Unix global system umask to deliver permissions.
68718 Problems with file authorizations and umask