Merge pull request #223 from xen0n/issue219

Fix build on 32-bit platforms

Author: xen0n

.github/workflows/go.yml

@@ -17,10 +17,22 @@ on:
 jobs:
 
   build:
-    runs-on: ubuntu-latest
     strategy:
       matrix:
-        go: [ 'oldstable', 'stable' ]
+        include:
+          - go: 'oldstable'
+            goarch: amd64
+            runs-on: ubuntu-latest
+          - go: 'stable'
+            goarch: amd64
+            runs-on: ubuntu-latest
+          - go: 'stable'
+            goarch: '386'
+            runs-on: ubuntu-latest
+          - go: 'stable'
+            goarch: arm64
+            runs-on: ubuntu-24.04-arm
+    runs-on: ${{ matrix.runs-on }}
     steps:
     - uses: actions/checkout@v4
 
@@ -29,6 +41,9 @@ jobs:
       with:
         go-version: ${{ matrix.go }}
 
+    - name: Set up GOARCH
+      run: export GOARCH="${{ matrix.goarch }}"
+
     - name: Build
       run: go build -v ./...
 

internal/lowlevel/encryptor/mod.go

@@ -114,8 +114,8 @@ func (e *WorkwxEncryptor) prepareBufForEncryption(payload *WorkwxPayload) ([]byt
 	}
 
 	buf = buf[:cap(buf)] // grow to full capacity
-	msglen := len(payload.Msg)
-	if msglen < 0 || msglen > math.MaxUint32 {
+	msglen := uint64(len(payload.Msg))
+	if msglen > uint64(math.MaxUint32) {
 		return nil, errPayloadTooBig
 	}
 	binary.BigEndian.PutUint32(buf[16:], uint32(msglen))