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//! A simple example showing how to manipulate capabilities.
//!
//! It clears Permitted set to show its interaction
//! with Effective set.
//!
//! This is an example ONLY: do NOT panic/unwrap/assert
//! in production code!
type ExResult<T> = Result<T, Box<dyn std::error::Error + 'static>>;
fn main() -> ExResult<()> {
use caps::{CapSet, Capability};
// Check if `CAP_CHOWN` was originally available.
let cur = caps::read(None, CapSet::Permitted)?;
println!("-> Current permitted caps: {:?}.", cur);
let cur = caps::read(None, CapSet::Effective)?;
println!("-> Current effective caps: {:?}.", cur);
let perm_chown = caps::has_cap(None, CapSet::Permitted, Capability::CAP_CHOWN);
assert!(perm_chown.is_ok());
if !perm_chown? {
return Err(
"Try running this again as root/sudo or with CAP_CHOWN file capability!".into(),
);
}
// Clear all effective caps.
let r = caps::clear(None, CapSet::Effective);
assert!(r.is_ok());
println!("Cleared effective caps.");
let cur = caps::read(None, CapSet::Effective)?;
println!("-> Current effective caps: {:?}.", cur);
// Since `CAP_CHOWN` is still in permitted, it can be raised again.
let r = caps::raise(None, CapSet::Effective, Capability::CAP_CHOWN);
assert!(r.is_ok());
println!("Raised CAP_CHOWN in effective set.");
let cur = caps::read(None, CapSet::Effective)?;
println!("-> Current effective caps: {:?}.", cur);
// Clearing Permitted also impacts effective.
let r = caps::clear(None, CapSet::Permitted);
assert!(r.is_ok());
println!("Cleared permitted caps.");
let cur = caps::read(None, CapSet::Permitted)?;
println!("-> Current permitted caps: {:?}.", cur);
let cur = caps::read(None, CapSet::Effective)?;
println!("-> Current effective caps: {:?}.", cur);
// Trying to raise `CAP_CHOWN` now fails.
let r = caps::raise(None, CapSet::Effective, Capability::CAP_CHOWN);
assert!(r.is_err());
println!("Tried to raise CAP_CHOWN but failed.");
let cur = caps::read(None, CapSet::Effective)?;
println!("-> Current effective caps: {:?}.", cur);
Ok(())
}
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