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Don't panic on mprotect for unmapped pages

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This commit is contained in:
bjorn3
2020-07-09 10:55:29 +02:00
parent 92cad589d9
commit 7b76ab3356
1 changed files with 30 additions and 21 deletions
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51
src/syscall/process.rs
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@@ -1316,30 +1316,39 @@ pub fn mprotect(address: usize, size: usize, flags: MapFlags) -> Result<usize> {
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(mut page_flags) = active_table.translate_page_flags(page) {
if flags.contains(PROT_EXEC) {
page_flags.remove(EntryFlags::NO_EXECUTE);
} else {
page_flags.insert(EntryFlags::NO_EXECUTE);
}
if flags.contains(PROT_WRITE) {
//TODO: Not allowing gain of write privileges
} else {
page_flags.remove(EntryFlags::WRITABLE);
}
if flags.contains(PROT_READ) {
//TODO: No flags for readable pages
} else {
//TODO: No flags for readable pages
}
let flush = active_table.remap(page, page_flags);
flush_all.consume(flush);
// Check if the page is actually mapped before trying to change the flags.
// FIXME can other processes change if a page is mapped beneath our feet?
let mut page_flags = if let Some(page_flags) = active_table.translate_page_flags(page) {
page_flags
} else {
flush_all.flush(&mut active_table);
return Err(Error::new(EFAULT));
};
if !page_flags.contains(EntryFlags::PRESENT) {
flush_all.flush(&mut active_table);
return Err(Error::new(EFAULT));
}
if flags.contains(PROT_EXEC) {
page_flags.remove(EntryFlags::NO_EXECUTE);
} else {
page_flags.insert(EntryFlags::NO_EXECUTE);
}
if flags.contains(PROT_WRITE) {
//TODO: Not allowing gain of write privileges
} else {
page_flags.remove(EntryFlags::WRITABLE);
}
if flags.contains(PROT_READ) {
//TODO: No flags for readable pages
} else {
//TODO: No flags for readable pages
}
let flush = active_table.remap(page, page_flags);
flush_all.consume(flush);
}
flush_all.flush(&mut active_table);