Technology
Provenance
Pointer provenance describes the legitimate origin and derivation of authority to access memory.
Why it matters
This blocks a class of behaviour in which software turns arbitrary data into a usable pointer and makes authority flow more explicit.
In brief
Pointer provenance describes the legitimate origin and derivation of authority to access memory. In CHERI, a valid capability must derive from existing valid authority; converting or inventing an integer address does not create the corresponding capability.
Key considerations
1. Origin
Capabilities ultimately derive from authority established by the system and delegated through software.
2. Derivation
Arithmetic can adjust an address within the rules, while bounds and permissions cannot be freely increased.
3. Language
Compiler and ABI rules determine how C/C++ casts, integers and pointers preserve or lose provenance.
Evidence and caveats
Provenance is technically subtle and architecture- and language-model-specific. Use the matching programming guide and specification for normative behaviour.
Use the exact architecture and software specification implemented by the target. Separate architectural guarantees from system-level outcomes.