Files
redox-kernel/src/syscall/validate.rs
jD91mZM2 fe705d9b63 Switch to 2018 edition
Most of this was generated by the absolutely extraordinary `cargo fix`
subcommand. There were still 2 errors and a few warnings to patch up,
but compared to the normal 600+ errors, I'd say the fixer did a damn
good job! I'm also amazed that I could still start the VM after this,
I half expected some kinds of runtime failure...
2019-06-21 12:12:01 +02:00

49 lines
1.8 KiB
Rust

use core::{mem, slice};
use crate::paging::{ActivePageTable, Page, VirtualAddress};
use crate::paging::entry::EntryFlags;
use crate::syscall::error::*;
fn validate(address: usize, size: usize, flags: EntryFlags) -> Result<()> {
let end_offset = size.checked_sub(1).ok_or(Error::new(EFAULT))?;
let end_address = address.checked_add(end_offset).ok_or(Error::new(EFAULT))?;
let active_table = unsafe { ActivePageTable::new() };
let start_page = Page::containing_address(VirtualAddress::new(address));
let end_page = Page::containing_address(VirtualAddress::new(end_address));
for page in Page::range_inclusive(start_page, end_page) {
if let Some(page_flags) = active_table.translate_page_flags(page) {
if ! page_flags.contains(flags) {
//println!("{:X}: Not {:?}", page.start_address().get(), flags);
return Err(Error::new(EFAULT));
}
} else {
//println!("{:X}: Not found", page.start_address().get());
return Err(Error::new(EFAULT));
}
}
Ok(())
}
/// Convert a pointer and length to slice, if valid
pub fn validate_slice<T>(ptr: *const T, len: usize) -> Result<&'static [T]> {
if len == 0 {
Ok(&[])
} else {
validate(ptr as usize, len * mem::size_of::<T>(), EntryFlags::PRESENT | EntryFlags::USER_ACCESSIBLE)?;
Ok(unsafe { slice::from_raw_parts(ptr, len) })
}
}
/// Convert a pointer and length to slice, if valid
pub fn validate_slice_mut<T>(ptr: *mut T, len: usize) -> Result<&'static mut [T]> {
if len == 0 {
Ok(&mut [])
} else {
validate(ptr as usize, len * mem::size_of::<T>(), EntryFlags::PRESENT | EntryFlags::WRITABLE | EntryFlags::USER_ACCESSIBLE)?;
Ok(unsafe { slice::from_raw_parts_mut(ptr, len) })
}
}