From 99975c0e42e1ee8f2172cd94c408296b42d5f85d Mon Sep 17 00:00:00 2001
From: 4lDO2 <4lDO2@protonmail.com>
Date: Thu, 29 Jun 2023 11:47:52 +0200
Subject: [PATCH] WIP: Ensure that Grant::borrow does not borrow nonpresent
grants.
---
src/context/memory.rs | 26 +++++++++++++++++++++-----
src/lib.rs | 1 +
2 files changed, 22 insertions(+), 5 deletions(-)
diff --git a/src/context/memory.rs b/src/context/memory.rs
index ffc61415..2c649285 100644
--- a/src/context/memory.rs
+++ b/src/context/memory.rs
@@ -644,7 +644,7 @@ impl Grant {
dst_mapper: &mut PageMapper,
dst_flusher: impl Flusher<RmmA>,
eager: bool,
- ) -> Result<Vec<Grant>, Enomem> {
+ ) -> Result<Vec<Grant>> {
/*
if eager {
for page in PageSpan::new(src_base, page_count) {
@@ -653,16 +653,22 @@ impl Grant {
}
*/
- // TODO: If grants are missing for certain ranges specified, fill with Provider::External
- // grants anyway, which will in turn fill the host address space will zeroed grants. This
- // is required before schemes can be safe.
-
let mut dst_grants = Vec::with_capacity(1);
let src_span = PageSpan::new(src_base, page_count);
+ let mut prev_span = None;
for (src_grant_base, src_grant) in src_address_space.grants.conflicts(src_span) {
let grant_span = PageSpan::new(src_grant_base, src_grant.page_count);
+ let prev_span = prev_span.replace(grant_span);
+
+ if prev_span.is_none() && src_grant_base > src_base {
+ log::warn!("Grant too far away, prev_span {:?} src_base {:?} grant base {:?} grant {:#?}", prev_span, src_base, src_grant_base, src_grant);
+ return Err(Error::new(EINVAL));
+ } else if let Some(prev) = prev_span && prev.end() != src_grant_base {
+ log::warn!("Hole between grants, prev_span {:?} src_base {:?} grant base {:?} grant {:#?}", prev_span, src_base, src_grant_base, src_grant);
+ return Err(Error::new(EINVAL));
+ }
let common_span = src_span.intersection(grant_span);
let offset_from_src_base = common_span.base.offset_from(src_base);
@@ -690,6 +696,16 @@ impl Grant {
});
}
+ let Some(last_span) = prev_span else {
+ log::warn!("Called Grant::borrow, but no grants were there!");
+ return Err(Error::new(EINVAL));
+ };
+
+ if last_span.end() < src_span.end() {
+ log::warn!("Requested end page too far away from last grant");
+ return Err(Error::new(EINVAL));
+ }
+
Ok(dst_grants)
}
// TODO: This is limited to one grant. Should it be (if some magic new proc: API is introduced)?
diff --git a/src/lib.rs b/src/lib.rs
index 94be6424..b6312060 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -50,6 +50,7 @@
#![feature(const_option)]
#![feature(arbitrary_self_types)]
#![feature(int_roundings)]
+#![feature(let_chains)]
#![feature(naked_functions)]
#![feature(slice_ptr_get, slice_ptr_len)]
#![feature(sync_unsafe_cell)]
--
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