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Revert "Zeroize memory in munmap"

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This reverts commit 1e456f025d6b4e34a726180e7a27a04424fe79d1.
This commit results in segmentation fault when the application munmaps
its own stack. Should be committed back after removing the dependency of
sysret on the user space stack.
This commit is contained in:
He Sun 2020-07-14 10:32:12 +08:00
parent 518ff76228
commit b4750c0fcd
2 changed files with 13 additions and 15 deletions
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1
src/libos/src/lib.rs
View File

@ -11,7 +11,6 @@
#![feature(alloc_layout_extra)]
#![feature(concat_idents)]
#![feature(trace_macros)]
#![feature(slice_fill)]
#[macro_use]
extern crate alloc;

27
src/libos/src/vm/vm_manager.rs
View File

@ -24,18 +24,26 @@ impl VMInitializer {
// Do nothing
}
VMInitializer::FillZeros() => {
// Filling zero is done in munmap
for b in buf {
*b = 0;
}
}
VMInitializer::CopyFrom { range } => {
let src_slice = unsafe { range.as_slice() };
let copy_len = min(buf.len(), src_slice.len());
buf[..copy_len].copy_from_slice(&src_slice[..copy_len]);
for b in &mut buf[copy_len..] {
*b = 0;
}
}
VMInitializer::LoadFromFile { file, offset } => {
// TODO: make sure that read_at does not move file cursor
let len = file
.read_at(*offset, buf)
.cause_err(|_| errno!(EIO, "failed to init memory from file"))?;
for b in &mut buf[len..] {
*b = 0;
}
}
}
Ok(())
@ -333,9 +341,6 @@ impl VMManager {
// Reset memory permissions
Self::apply_perms(&intersection_range, VMPerms::default());
unsafe {
intersection_range.as_slice_mut().fill(0);
}
vma.subtract(&intersection_range)
})
@ -728,18 +733,12 @@ impl VMManager {
impl Drop for VMManager {
fn drop(&mut self) {
// Ensure that all allocated memories are restored to the default permissions and zeroed
// Ensure that memory permissions are recovered
for vma in &self.vmas {
if vma.size() != 0 {
warn!("There are unmapped memories");
if vma.perms() != VMPerms::default() {
Self::apply_perms(vma, VMPerms::default());
}
unsafe {
vma.as_slice_mut().fill(0);
}
if vma.size() == 0 || vma.perms() == VMPerms::default() {
continue;
}
Self::apply_perms(vma, VMPerms::default());
}
}
}