crates/nonstick: src/module.rs comparison

comparison src/module.rs @ 51:9d1160b02d2c

Safety and doc fixes: - Don't panic when given a string with a null character; instead return `PAM_CONV_ERR`. - Improve pattern matching and use ?s where appropriate. - Format etc.

author	Paul Fisher <paul@pfish.zone>
date	Sat, 03 May 2025 18:41:25 -0400
parents	a921b72743e4
children

comparison

equal deleted inserted replaced

-:171fb1171053
+:9d1160b02d2c
 //! Functions for use in pam modules.
+use crate::constants::{PamFlag, PamResultCode};
+use crate::items::{Item, ItemType};
 use libc::c_char;
 use std::ffi::{CStr, CString};
-use crate::constants::{PamFlag, PamResultCode};
-use crate::items::ItemType;
 /// Opaque type, used as a pointer when making pam API calls.
 ///
 /// A module is invoked via an external function such as `pam_sm_authenticate`.
 /// Such a call provides a pam handle pointer.  The same pointer should be given
 ///
 /// # Safety
 ///
 /// The data stored under the provided key must be of type `T` otherwise the
 /// behaviour of this function is undefined.
-pub unsafe fn get_data<T>(&self, key: &str) -> PamResult<&T> {
+///
-let c_key = CString::new(key).unwrap();
+/// The data, if present, is owned by the current PAM conversation.
+pub unsafe fn get_data<T>(&self, key: &str) -> PamResult<Option<&T>> {
+let c_key = CString::new(key).map_err(|_| PamResultCode::PAM_CONV_ERR)?;
 let mut ptr: *const libc::c_void = std::ptr::null();
-let res = pam_get_data(self, c_key.as_ptr(), &mut ptr);
+to_result(pam_get_data(self, c_key.as_ptr(), &mut ptr))?;
-if PamResultCode::PAM_SUCCESS == res && !ptr.is_null() {
+match ptr.is_null() {
-let typed_ptr = ptr.cast::<T>();
+true => Ok(None),
-let data: &T = &*typed_ptr;
+false => {
-Ok(data)
+let typed_ptr = ptr.cast::<T>();
-} else {
+Ok(Some(&*typed_ptr))
-Err(res)
+}
 }
 }
-/// Stores a value that can be retrieved later with `get_data`.  The value lives
+/// Stores a value that can be retrieved later with `get_data`.
-/// as long as the current pam cycle.
+/// The conversation takes ownership of the data.
 ///
 /// See the [`pam_set_data` manual page](
 /// https://www.man7.org/linux/man-pages/man3/pam_set_data.3.html).
 ///
 /// # Errors
 ///
 /// Returns an error if the underlying PAM function call fails.
-pub fn set_data<T>(&self, key: &str, data: Box<T>) -> PamResult<()> {
+pub fn set_data<T>(&mut self, key: &str, data: Box<T>) -> PamResult<()> {
-let c_key = CString::new(key).unwrap();
+let c_key = CString::new(key).map_err(|_| PamResultCode::PAM_CONV_ERR)?;
 let res = unsafe {
 pam_set_data(
 self,
 c_key.as_ptr(),
 Box::into_raw(data).cast::<libc::c_void>(),
 )
 };
 to_result(res)
 }
-/// Retrieves a value that has been set, possibly by the pam client.  This is
+/// Retrieves a value that has been set, possibly by the pam client.
-/// particularly useful for getting a `PamConv` reference.
+/// This is particularly useful for getting a `PamConv` reference.
+///
+/// These items are *references to PAM memory*
+/// which are *owned by the conversation*.
 ///
 /// See the [`pam_get_item` manual page](
 /// https://www.man7.org/linux/man-pages/man3/pam_get_item.3.html).
 ///
 /// # Errors
 ///
 /// Returns an error if the underlying PAM function call fails.
 pub fn get_item<T: crate::items::Item>(&self) -> PamResult<Option<T>> {
 let mut ptr: *const libc::c_void = std::ptr::null();
-let (res, item) = unsafe {
+let out = unsafe {
 let r = pam_get_item(self, T::type_id(), &mut ptr);
+to_result(r)?;
 let typed_ptr = ptr.cast::<T::Raw>();
-let t = if typed_ptr.is_null() {
+match typed_ptr.is_null() {
-None
+true => None,
-} else {
+false => Some(T::from_raw(typed_ptr)),
-Some(T::from_raw(typed_ptr))
+}
-};
-(r, t)
 };
-match res {
+Ok(out)
-PamResultCode::PAM_SUCCESS => Ok(item),
+}
-other => Err(other),
-}
+/// Sets an item in the pam context. It can be retrieved using `get_item`.
-}
-/// Sets a value in the pam context. The value can be retrieved using
-/// `get_item`.
-///
-/// Note that all items are strings, except `PAM_CONV` and `PAM_FAIL_DELAY`.
 ///
 /// See the [`pam_set_item` manual page](
 /// https://www.man7.org/linux/man-pages/man3/pam_set_item.3.html).
 ///
 /// # Errors
 ///
 /// Returns an error if the underlying PAM function call fails.
-///
+pub fn set_item<T: Item>(&mut self, item: T) -> PamResult<()> {
-/// # Panics
-///
-/// Panics if the provided item key contains a nul byte.
-pub fn set_item_str<T: crate::items::Item>(&mut self, item: T) -> PamResult<()> {
 let res =
 unsafe { pam_set_item(self, T::type_id(), item.into_raw().cast::<libc::c_void>()) };
 to_result(res)
 }
 /// https://www.man7.org/linux/man-pages/man3/pam_get_user.3.html).
 ///
 /// # Errors
 ///
 /// Returns an error if the underlying PAM function call fails.
-///
-/// # Panics
-///
-/// Panics if the provided prompt string contains a nul byte.
 pub fn get_user(&self, prompt: Option<&str>) -> PamResult<String> {
-let prompt_string;
+let prompt = option_cstr(prompt)?;
-let c_prompt = match prompt {
-Some(p) => {
-prompt_string = CString::new(p).unwrap();
-prompt_string.as_ptr()
-}
-None => std::ptr::null(),
-};
 let output: *mut c_char = std::ptr::null_mut();
-let res = unsafe { pam_get_user(self, &output, c_prompt) };
+let res = unsafe { pam_get_user(self, &output, prompt_ptr(prompt.as_ref())) };
 match res {
 PamResultCode::PAM_SUCCESS => copy_pam_string(output),
 otherwise => Err(otherwise),
 }
 }
 /// https://www.man7.org/linux/man-pages/man3/pam_get_authtok.3.html).
 ///
 /// # Errors
 ///
 /// Returns an error if the underlying PAM function call fails.
-///
-/// # Panics
-///
-/// Panics if the provided prompt string contains a nul byte.
 pub fn get_authtok(&self, prompt: Option<&str>) -> PamResult<String> {
-let prompt_string;
+let prompt = option_cstr(prompt)?;
-let c_prompt = match prompt {
+let output: *mut c_char = std::ptr::null_mut();
-Some(p) => {
+let res = unsafe {
-prompt_string = CString::new(p).unwrap();
+pam_get_authtok(
-prompt_string.as_ptr()
+self,
-}
+ItemType::AuthTok,
-None => std::ptr::null(),
+&output,
+prompt_ptr(prompt.as_ref()),
+)
 };
-let output: *mut c_char = std::ptr::null_mut();
+to_result(res)?;
-let res = unsafe { pam_get_authtok(self, ItemType::AuthTok, &output, c_prompt) };
+copy_pam_string(output)
-match res {
+}
-PamResultCode::PAM_SUCCESS => copy_pam_string(output),
+}
-otherwise => Err(otherwise),
-}
+/// Safely converts a `&str` option to a `CString` option.
+fn option_cstr(prompt: Option<&str>) -> PamResult<Option<CString>> {
+prompt
+.map(CString::new)
+.transpose()
+.map_err(|_| PamResultCode::PAM_CONV_ERR)
+}
+/// The pointer to the prompt CString, or null if absent.
+fn prompt_ptr(prompt: Option<&CString>) -> *const c_char {
+match prompt {
+Some(c_str) => c_str.as_ptr(),
+None => std::ptr::null(),
 }
 }
 /// Creates an owned copy of a string that is returned from a
 /// <code>pam_get_<var>whatever</var></code> function.
 fn copy_pam_string(result_ptr: *const c_char) -> PamResult<String> {
 // We really shouldn't get a null pointer back here, but if we do, return nothing.
 if result_ptr.is_null() {
-return Ok(String::from(""));
+return Ok(String::new());
 }
-let bytes = unsafe { CStr::from_ptr(result_ptr).to_bytes() };
+let bytes = unsafe { CStr::from_ptr(result_ptr) };
-String::from_utf8(bytes.to_vec()).map_err(|_| PamResultCode::PAM_CONV_ERR)
+Ok(bytes
+.to_str()
+.map_err(|_| PamResultCode::PAM_CONV_ERR)?
+.into())
 }
 /// Convenience to transform a `PamResultCode` into a unit `PamResult`.
 fn to_result(result: PamResultCode) -> PamResult<()> {
 match result {

Mercurial > crates > nonstick

comparison src/module.rs @ 51:9d1160b02d2c