diff options
| -rw-r--r-- | src/lib.rs | 24 |
1 files changed, 20 insertions, 4 deletions
@@ -2,6 +2,7 @@ use cap_std::fs::{Dir, OpenOptions}; use pam::constants::{PamFlag, PamResultCode}; use pam::module::{PamHandle, PamHooks}; use std::ffi::CStr; +use std::fmt::{Display, Write as _}; use std::io::{ErrorKind, Write}; use std::path::Path; use std::process; @@ -31,15 +32,30 @@ impl From<std::io::Error> for SessionError { } } +trait MaxDisplayLength: Display { + const MAX_DISPLAY_LENGTH: usize; +} +impl MaxDisplayLength for u32 { + const MAX_DISPLAY_LENGTH: usize = u32::MAX.ilog10() as usize + 1; +} + +fn safe_to_string<T: MaxDisplayLength>(v: T) -> Result<String, SessionError> { + let mut buf = String::new(); + buf.try_reserve_exact(T::MAX_DISPLAY_LENGTH) + .or(Err(SessionError))?; + write!(buf, "{v}").unwrap(); + Ok(buf) +} + fn open_session(h: &mut PamHandle) -> Result<(), SessionError> { let user = h.get_user(None).or(Err(SessionError))?; let user = users::get_user_by_name(&user).ok_or(SessionError)?; - let aa = cap_std::ambient_authority(); - let d = Dir::open_ambient_dir(CG_MOUNT, aa)?; + let uid = safe_to_string(user.uid())?; + let d = Dir::open_ambient_dir(CG_MOUNT, cap_std::ambient_authority())?; let d = create_and_open_dir(&d, "user")?; - let d = create_and_open_dir(&d, &user.uid().to_string())?; + let d = create_and_open_dir(&d, &uid)?; let d = create_and_open_dir(&d, "leaf")?; - let pid = process::id().to_string(); + let pid = safe_to_string(process::id())?; let mut options = OpenOptions::new(); options.write(true); let mut procs = d.open_with("cgroup.procs", &options)?; |