> Store with Caller's PSW Key There are the various "move with specified key" instructions.
Best practice for writing a PC routine requires that you make use of those or equivalent services. > But would such a facility be useful to an intruder I don't think it would provide any information that would not be provided by ordinary access with an ESPIE routine. Charles -----Original Message----- From: IBM Mainframe Assembler List [mailto:ASSEMBLER-LIST@LISTSERV.UGA.EDU] On Behalf Of Paul Gilmartin Sent: Saturday, March 5, 2022 2:52 PM To: ASSEMBLER-LIST@LISTSERV.UGA.EDU Subject: Re: Testing address validity On Mar 5, 2022, at 15:11:41, Tony Thigpen wrote: > > Since I support software that is called by any number of users, I would like to validate that they provided valid parms. As a called subsystem, I can't be messing with the callers error handling routines that may already be handling SOC4s. I don't want to know if it's 'in storage', just that it is accessible even if a page-fault is needed. > Interesting problem. How do Supervisor services, which might operate in a privileged state deal with wild reply buffer addresses? Might that provide a model? I could wish for a "Store with Caller's PSW Key" instruction. (Does cross-memory services provide something similar?) Let the callers handle the damage; it's their fault. But how to provide meaningful diagnostics? > I wish there was a simple: > TEST MEMORY AND BRANCH INVALID > operands R1 is a register pair with R1=address and R1+1=length to validate. (Like an MVCL.) > > Instead of a SOC4, just branch to the address provided as the second operand where I have placed an error handler. > But would such a facility be useful to an intruder probing for a weakness to exploit?
