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Make code safer by disallowing NULL argv, empty argv and NULL values for pointer arguments to functions

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This commit is contained in:
R Aadarsh
2026-06-03 20:09:31 +05:30
parent 8c65ed481a
commit fefea0f0a9
5 changed files with 101 additions and 53 deletions
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src/header/spawn/file_actions.rs
+34 -19
View File
@@ -1,4 +1,4 @@
use core::{mem::ManuallyDrop, ptr::null_mut};
use core::{mem::ManuallyDrop, slice};
use alloc::{ffi::CString, vec::Vec};
@@ -13,7 +13,6 @@ const CHDIR: c_char = 3;
const FCHDIR: c_char = 4;
const DUP2: c_char = 5;
#[repr(C)]
#[derive(Debug, Clone)]
pub enum Action {
Open {
@@ -31,15 +30,19 @@ pub enum Action {
#[repr(C)]
#[derive(Debug, Clone, Copy)]
pub struct posix_spawn_file_actions_t {
file_actions: *mut Action,
file_actions: usize,
length: usize,
capacity: usize,
}
impl posix_spawn_file_actions_t {
pub fn add_action(&mut self, action: Action) {
let v = unsafe { &mut Vec::from_raw_parts(self.file_actions, self.length, self.capacity) };
let mut v = unsafe {
Vec::from_raw_parts(self.file_actions as *mut Action, self.length, self.capacity)
};
v.push(action);
let raw = v.into_raw_parts();
(self.file_actions, self.length, self.capacity) = (raw.0.addr(), raw.1, raw.2);
}
}
@@ -53,10 +56,9 @@ impl Iterator for FileActionsIter {
fn next(&mut self) -> Option<Self::Item> {
let actions = unsafe {
&Vec::from_raw_parts(
self.actions.file_actions,
slice::from_raw_parts(
self.actions.file_actions as *const Action,
self.actions.length,
self.actions.capacity,
)
};
let e = actions.get(self.curr)?;
@@ -80,10 +82,11 @@ impl<'a> IntoIterator for &'a posix_spawn_file_actions_t {
#[unsafe(no_mangle)]
pub unsafe extern "C" fn posix_spawn_file_actions_init(
file_actions: &mut posix_spawn_file_actions_t,
file_actions: *mut posix_spawn_file_actions_t,
) -> c_int {
let mut v = ManuallyDrop::new(Vec::new());
file_actions.file_actions = v.as_mut_ptr();
let file_actions = unsafe { file_actions.as_mut().expect("file_actions cannot be NULL") };
let mut v = ManuallyDrop::new(Vec::<Action>::new());
file_actions.file_actions = v.as_mut_ptr().addr();
file_actions.capacity = v.capacity();
file_actions.length = 0;
0
@@ -91,30 +94,35 @@ pub unsafe extern "C" fn posix_spawn_file_actions_init(
#[unsafe(no_mangle)]
pub unsafe extern "C" fn posix_spawn_file_actions_destroy(
file_actions: &mut posix_spawn_file_actions_t,
file_actions: *mut posix_spawn_file_actions_t,
) -> c_int {
let file_actions = unsafe { file_actions.as_mut().expect("file_actions cannot be NULL") };
let v = unsafe {
&Vec::from_raw_parts(
file_actions.file_actions,
Vec::from_raw_parts(
file_actions.file_actions as *mut Action,
file_actions.length,
file_actions.capacity,
)
};
file_actions.capacity = 0;
file_actions.length = 0;
file_actions.file_actions = null_mut();
file_actions.file_actions = 0;
0
}
#[unsafe(no_mangle)]
pub unsafe extern "C" fn posix_spawn_file_actions_addopen(
file_actions: &mut posix_spawn_file_actions_t,
file_actions: *mut posix_spawn_file_actions_t,
fd: c_int,
path: *const c_char,
oflag: c_int,
mode: mode_t,
) -> c_int {
let file_actions = unsafe { file_actions.as_mut().expect("file_actions cannot be NULL") };
if path.is_null() {
panic!("path cannot be NULL");
}
if fd < 0 {
return EBADF;
}
@@ -133,9 +141,10 @@ pub unsafe extern "C" fn posix_spawn_file_actions_addopen(
#[unsafe(no_mangle)]
pub unsafe extern "C" fn posix_spawn_file_actions_addclose(
file_actions: &mut posix_spawn_file_actions_t,
file_actions: *mut posix_spawn_file_actions_t,
fd: c_int,
) -> c_int {
let file_actions = unsafe { file_actions.as_mut().expect("file_actions cannot be NULL") };
if fd < 0 {
return EBADF;
}
@@ -145,9 +154,13 @@ pub unsafe extern "C" fn posix_spawn_file_actions_addclose(
#[unsafe(no_mangle)]
pub unsafe extern "C" fn posix_spawn_file_actions_addchdir(
file_actions: &mut posix_spawn_file_actions_t,
file_actions: *mut posix_spawn_file_actions_t,
path: *const c_char,
) -> c_int {
let file_actions = unsafe { file_actions.as_mut().expect("file_actions cannot be NULL") };
if path.is_null() {
panic!("path cannot be NULL");
}
file_actions.add_action(Action::Chdir(unsafe {
if path.is_null() {
CString::new("").unwrap()
@@ -160,9 +173,10 @@ pub unsafe extern "C" fn posix_spawn_file_actions_addchdir(
#[unsafe(no_mangle)]
pub unsafe extern "C" fn posix_spawn_file_actions_addfchdir(
file_actions: &mut posix_spawn_file_actions_t,
file_actions: *mut posix_spawn_file_actions_t,
fd: c_int,
) -> c_int {
let file_actions = unsafe { file_actions.as_mut().expect("file_actions cannot be NULL") };
if fd < 0 {
return EBADF;
}
@@ -172,10 +186,11 @@ pub unsafe extern "C" fn posix_spawn_file_actions_addfchdir(
#[unsafe(no_mangle)]
pub unsafe extern "C" fn posix_spawn_file_actions_adddup2(
file_actions: &mut posix_spawn_file_actions_t,
file_actions: *mut posix_spawn_file_actions_t,
fd: c_int,
new: c_int,
) -> c_int {
let file_actions = unsafe { file_actions.as_mut().expect("file_actions cannot be NULL") };
if fd < 0 || new < 0 {
return EBADF;
}
src/header/spawn/mod.rs
+39 -6
View File
@@ -17,6 +17,7 @@ use crate::{
errno::ENOENT,
stdlib::getenv,
},
iter::NulTerminated,
platform::{
self, Pal,
sys::path,
@@ -29,8 +30,8 @@ unsafe fn spawn(
mut program: String,
file_actions: Option<&posix_spawn_file_actions_t>,
spawn_attr: Option<&posix_spawnattr_t>,
argv: *const *mut c_char,
envp: Option<*const *mut c_char>,
argv: NulTerminated<*mut c_char>,
envp: Option<NulTerminated<*mut c_char>>,
use_path: bool,
) -> Result<()> {
let original_cwd = path::clone_cwd().unwrap().to_string();
@@ -101,7 +102,23 @@ pub unsafe extern "C" fn posix_spawn(
argv: *const *mut c_char,
envp: *const *mut c_char,
) -> c_int {
let program = unsafe { CStr::from_ptr(path).to_str().unwrap().to_string() };
let argv = {
if argv.is_null() {
panic!("argv cannot be NULL")
} else {
if unsafe { (*argv).is_null() } {
panic!("argv must contain the program name");
}
unsafe { NulTerminated::new(argv).unwrap() }
}
};
let envp = unsafe { NulTerminated::new(envp) };
let program = unsafe {
CStr::from_ptr(path)
.to_str()
.expect("path cannot be NULL")
.to_string()
};
if let Err(e) = unsafe {
spawn(
@@ -110,7 +127,7 @@ pub unsafe extern "C" fn posix_spawn(
file_actions.as_ref(),
attrp.as_ref(),
argv,
if envp.is_null() { None } else { Some(envp) },
envp,
false,
)
} {
@@ -128,7 +145,23 @@ pub unsafe extern "C" fn posix_spawnp(
argv: *const *mut c_char,
envp: *const *mut c_char,
) -> c_int {
let program = unsafe { CStr::from_ptr(path).to_str().unwrap().to_string() };
let argv = {
if argv.is_null() {
panic!("argv cannot be NULL")
} else {
if unsafe { (*argv).is_null() } {
panic!("argv must contain the program name");
}
unsafe { NulTerminated::new(argv).unwrap() }
}
};
let envp = unsafe { NulTerminated::new(envp) };
let program = unsafe {
CStr::from_ptr(path)
.to_str()
.expect("path cannot be NULL")
.to_string()
};
if let Err(e) = unsafe {
spawn(
@@ -137,7 +170,7 @@ pub unsafe extern "C" fn posix_spawnp(
file_actions.as_ref(),
attrp.as_ref(),
argv,
if envp.is_null() { None } else { Some(envp) },
envp,
if program.contains('/') { false } else { true },
)
} {
src/iter.rs
+6
View File
@@ -30,6 +30,12 @@ unsafe impl Zero for wchar_t {
}
}
unsafe impl Zero for *mut c_char {
fn is_zero(&self) -> bool {
self.is_null()
}
}
/// An iterator over a nul-terminated buffer.
///
/// This is intended to allow safe, ergonomic iteration over C-style byte and
src/platform/pal/mod.rs
+3 -2
View File
@@ -15,6 +15,7 @@ use crate::{
sys_utsname::utsname,
time::{itimerspec, timespec},
},
iter::NulTerminated,
ld_so::tcb::OsSpecific,
out::Out,
pthread,
@@ -437,8 +438,8 @@ pub trait Pal {
program: CStr,
fac: Option<&crate::header::spawn::posix_spawn_file_actions_t>,
fat: Option<&crate::header::spawn::posix_spawnattr_t>,
argv: *const *mut c_char,
envp: Option<*const *mut c_char>,
argv: NulTerminated<*mut c_char>,
envp: Option<NulTerminated<*mut c_char>>,
use_path: bool,
) -> Result<pid_t>;
src/platform/redox/mod.rs
+19 -26
View File
@@ -41,7 +41,6 @@ use crate::{
signal::{NSIG, SIGEV_NONE, SIGEV_SIGNAL, SIGEV_THREAD, SIGRTMIN, sigevent},
stdio::RENAME_NOREPLACE,
stdlib::posix_memalign,
string::strlen,
sys_file,
sys_mman::{MAP_ANONYMOUS, PROT_READ, PROT_WRITE},
sys_random,
@@ -57,6 +56,7 @@ use crate::{
unistd::{F_OK, R_OK, SEEK_CUR, SEEK_SET, W_OK, X_OK},
},
io::{self, BufReader, prelude::*},
iter::NulTerminated,
ld_so::tcb::OsSpecific,
out::Out,
platform::{
@@ -1205,8 +1205,8 @@ impl Pal for Sys {
program: CStr,
fac: Option<&crate::header::spawn::posix_spawn_file_actions_t>,
fat: Option<&crate::header::spawn::posix_spawnattr_t>,
mut argv: *const *mut c_char,
envp: Option<*const *mut c_char>,
argv: NulTerminated<*mut c_char>,
envp: Option<NulTerminated<*mut c_char>>,
use_path: bool,
) -> Result<pid_t> {
use crate::header::spawn::Flags;
@@ -1230,31 +1230,25 @@ impl Pal for Sys {
let mut args = Vec::new();
let mut envs = Vec::new();
let len = unsafe { strlen(*argv) };
let program_name =
str::from_utf8(unsafe { slice::from_raw_parts(*argv as *const u8, len) }).unwrap();
let program_name: String =
redox_path::canonicalize_using_cwd(Some(original_cwd.as_str()), program_name)
.ok_or(Errno(ENOENT))?;
argv = unsafe { argv.add(1) };
args.push(program_name.as_bytes());
while unsafe { !(*argv).is_null() } {
let arg = unsafe { *argv };
let len = unsafe { strlen(arg) };
args.push(unsafe { slice::from_raw_parts(arg as *const u8, len) });
argv = unsafe { argv.add(1) };
for arg in argv {
args.push(unsafe { CStr::from_ptr(*arg).to_chars() });
}
if let Some(mut envp) = envp {
while unsafe { !(*envp).is_null() } {
let env = unsafe { *envp };
let len = unsafe { strlen(env) };
envs.push(unsafe { slice::from_raw_parts(env as *const u8, len) });
envp = unsafe { envp.add(1) };
if let Some(envp) = envp {
for env in envp {
envs.push(unsafe { CStr::from_ptr(*env).to_chars() });
}
}
let mut program_name = String::new();
program_name = redox_path::canonicalize_using_cwd(
Some(original_cwd.as_str()),
str::from_utf8(args[0]).unwrap(),
)
.ok_or(Errno(ENOENT))?;
args[0] = program_name.as_bytes();
let new_file_table = child.thr_fd.dup(b"filetable")?;
if let Some(fac) = fac {
@@ -1286,10 +1280,9 @@ impl Pal for Sys {
)?;
}
crate::header::spawn::Action::Chdir(path) => {
let path = path.to_str().unwrap();
cwd = path.to_string();
cwd = path.to_str().unwrap().to_string();
path::chdir(path)?;
path::chdir(path.to_str().unwrap())?;
}
crate::header::spawn::Action::FChdir(fd) => {
path::fchdir(fd)?;