avoid signed overflow in cache memory limit

Read the cache values as unsigned integers and keep the megabyte to byte conversion in size_t, so the memory limit no longer wraps at 2048MB and above. Reject non-integer and negative values in the JavaScript layer.

Author: metsw24-max

lib/utility.mjs

@@ -114,6 +114,12 @@ function cache (options) {
       return sharp.cache(0, 0, 0);
     }
   } else if (is.object(options)) {
+    for (const property of ['memory', 'files', 'items']) {
+      const value = options[property];
+      if (is.defined(value) && !(is.integer(value) && value >= 0)) {
+        throw is.invalidParameterError(property, 'a positive integer', value);
+      }
+    }
     return sharp.cache(options.memory, options.files, options.items);
   } else {
     return sharp.cache();

src/utilities.cc

@@ -23,15 +23,15 @@ Napi::Value cache(const Napi::CallbackInfo& info) {
 
   // Set memory limit
   if (info[size_t(0)].IsNumber()) {
-    vips_cache_set_max_mem(info[size_t(0)].As<Napi::Number>().Int32Value() * 1048576);
+    vips_cache_set_max_mem(static_cast<size_t>(info[size_t(0)].As<Napi::Number>().Uint32Value()) * 1048576);
   }
   // Set file limit
   if (info[size_t(1)].IsNumber()) {
-    vips_cache_set_max_files(info[size_t(1)].As<Napi::Number>().Int32Value());
+    vips_cache_set_max_files(info[size_t(1)].As<Napi::Number>().Uint32Value());
   }
   // Set items limit
   if (info[size_t(2)].IsNumber()) {
-    vips_cache_set_max(info[size_t(2)].As<Napi::Number>().Int32Value());
+    vips_cache_set_max(info[size_t(2)].As<Napi::Number>().Uint32Value());
   }
 
   // Get memory stats

test/unit/util.js

@@ -57,6 +57,11 @@ suite('Utilities', () => {
       t.assert.strictEqual(cache.files.max, 100);
       t.assert.strictEqual(cache.items.max, 1000);
     });
+    test('Can be set to a memory maximum of 4096MB', (t) => {
+      t.plan(1);
+      const cache = sharp.cache({ memory: 4096, files: 0, items: 0 });
+      t.assert.strictEqual(cache.memory.max, 4096);
+    });
     test('Ignores invalid values', (t) => {
       t.plan(3);
       sharp.cache(true);
@@ -65,6 +70,12 @@ suite('Utilities', () => {
       t.assert.strictEqual(cache.files.max, 20);
       t.assert.strictEqual(cache.items.max, 100);
     });
+    test('Rejects negative values', (t) => {
+      t.plan(3);
+      t.assert.throws(() => sharp.cache({ memory: -1 }), /Expected a positive integer for memory but received -1 of type number/);
+      t.assert.throws(() => sharp.cache({ files: -1 }), /Expected a positive integer for files but received -1 of type number/);
+      t.assert.throws(() => sharp.cache({ items: 1.5 }), /Expected a positive integer for items but received 1.5 of type number/);
+    });
   });
 
   suite('Concurrency', () => {