From 2d2d708500a670eb07b414c3b6fcd0fc55edecdd Mon Sep 17 00:00:00 2001
From: Mackenzie Clark <mackenzie.a.z.c@gmail.com>
Date: Fri, 15 Feb 2019 13:14:42 -0800
Subject: [PATCH] Validate descriptor max on creating new table or memory
 (#186)

---
 lib/runtime-core/src/error.rs      | 6 ++++++
 lib/runtime-core/src/memory/mod.rs | 9 +++++++++
 lib/runtime-core/src/table/mod.rs  | 8 ++++++++
 3 files changed, 23 insertions(+)

diff --git a/lib/runtime-core/src/error.rs b/lib/runtime-core/src/error.rs
index 98f0198f4..e88a5692c 100644
--- a/lib/runtime-core/src/error.rs
+++ b/lib/runtime-core/src/error.rs
@@ -266,6 +266,7 @@ impl std::fmt::Display for CallError {
 pub enum CreationError {
     UnableToCreateMemory,
     UnableToCreateTable,
+    InvalidDescriptor(String),
 }
 
 impl PartialEq for CreationError {
@@ -279,6 +280,11 @@ impl std::fmt::Display for CreationError {
         match self {
             CreationError::UnableToCreateMemory => write!(f, "Unable to Create Memory"),
             CreationError::UnableToCreateTable => write!(f, "Unable to Create Table"),
+            CreationError::InvalidDescriptor(msg) => write!(
+                f,
+                "Unable to create because the supplied descriptor is invalid: \"{}\"",
+                msg
+            ),
         }
     }
 }
diff --git a/lib/runtime-core/src/memory/mod.rs b/lib/runtime-core/src/memory/mod.rs
index 30fab393e..56d4c643b 100644
--- a/lib/runtime-core/src/memory/mod.rs
+++ b/lib/runtime-core/src/memory/mod.rs
@@ -63,6 +63,15 @@ impl Memory {
     /// # }
     /// ```
     pub fn new(desc: MemoryDescriptor) -> Result<Self, CreationError> {
+        if let Some(max) = desc.maximum {
+            if max < desc.minimum {
+                return Err(CreationError::InvalidDescriptor(
+                    "Max number of memory pages is less than the minimum number of pages"
+                        .to_string(),
+                ));
+            }
+        }
+
         let variant = if !desc.shared {
             MemoryVariant::Unshared(UnsharedMemory::new(desc)?)
         } else {
diff --git a/lib/runtime-core/src/table/mod.rs b/lib/runtime-core/src/table/mod.rs
index db4b943c8..1bad9a3c4 100644
--- a/lib/runtime-core/src/table/mod.rs
+++ b/lib/runtime-core/src/table/mod.rs
@@ -50,6 +50,14 @@ impl Table {
     /// # }
     /// ```
     pub fn new(desc: TableDescriptor) -> Result<Self, CreationError> {
+        if let Some(max) = desc.maximum {
+            if max < desc.minimum {
+                return Err(CreationError::InvalidDescriptor(
+                    "Max table size is less than the minimum size".to_string(),
+                ));
+            }
+        }
+
         let mut local = vm::LocalTable {
             base: ptr::null_mut(),
             count: 0,