Improper Null Termination on Software Bus Message handling

[chillfig]

Checklist (Please check before submitting)

• I reviewed the Contributing Guide.
• I performed a cursory search to see if the bug report is relevant, not redundant, nor in conflict with other tickets.

Describe the bug
It is not guarenteed that the source or destination arguments of strncpy for software bus message uses in ds/apps/fsw/src assure Null termination. Many standard functions such as strcpy, strlen, strcmp among others rely on arrays of characters to be Null terminated.

To Reproduce
From local ds repo, command grep -r strncpy and view uses where argument is a software bus message.

Expected behavior
No expected behavior changes. Replace strncpy with CFE_SB_MessageStringGet

Code snips
The below code snips are DS strncpy uses that do not guarentee null-termination

DS/fsw/src/ds_cmds.c

Line 742 in 04c0154

strncpy(pDest->Pathname, DS_DestPathCmd->Pathname, sizeof(pDest->Pathname));

DS/fsw/src/ds_cmds.c

Line 809 in 04c0154

strncpy(pDest->Basename, DS_DestBaseCmd->Basename, sizeof(pDest->Basename));

DS/fsw/src/ds_cmds.c

Line 876 in 04c0154

strncpy(pDest->Extension, DS_DestExtCmd->Extension, sizeof(pDest->Extension));

This strncpy example in FM may help with null-terminated destination but does not guarentee null-terminated source:
FM strncpy example

System observed on:
imported from JSC static analysis audit

Additional context
The FM example above proves to assure Null termination for the destination, however, it may be best approach to replace strncpy with CFE_SB_MessageStringGet to consolidate handling of strings.

Reporter Info
Justin Figueroa, Vantage Systems