From 5b1c2c1b1ca462ec4699f2311091c4dd5628237d Mon Sep 17 00:00:00 2001
From: Guillem Jover <gjover@sipwise.com>
Date: Mon, 15 Nov 2021 20:53:14 +0100
Subject: [PATCH] Limit bytes read by Uvariant to <= 10
Forwarded: https://github.com/dennwc/varint/pull/1

This matches the change done in the upstream Go 1.17 compiler in
commit aafad20b617ee63d58fcd4f6e0d98fe27760678c.

Bump the go required version to 1.17 so that the test cases match what
is implemented there.
---
 .travis.yml    |  4 ++--
 go.mod         |  2 +-
 varint.go      | 18 ++++++++++--------
 varint_test.go |  8 ++++----
 4 files changed, 17 insertions(+), 15 deletions(-)

diff --git a/.travis.yml b/.travis.yml
index b3da258..b7d85f5 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -1,7 +1,7 @@
 language: go
 
 go:
-  - 1.12.x
+  - 1.17.x
 
 env:
-  - GO111MODULE=on
\ No newline at end of file
+  - GO111MODULE=on
diff --git a/go.mod b/go.mod
index f7883d4..0df49b1 100644
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,3 @@
 module github.com/dennwc/varint
 
-go 1.12
+go 1.17
diff --git a/varint.go b/varint.go
index 83278c2..486d30b 100644
--- a/varint.go
+++ b/varint.go
@@ -153,10 +153,11 @@ func Uvarint(buf []byte) (uint64, int) {
 		} else if sz == 10 {
 			return 0, 0
 		}
-		for j, b := range buf[10:] {
-			if b < bit {
-				return 0, -(11 + j)
-			}
+
+		if sz > MaxLen64 {
+			// Catch byte reads past MaxLen64.
+			// See issue https://golang.org/issues/41185
+			return 0, -(MaxLen64 + 1) // overflow
 		}
 		return 0, 0
 	}
@@ -261,10 +262,11 @@ func Uvarint(buf []byte) (uint64, int) {
 	} else if sz == 10 {
 		return 0, 0
 	}
-	for j, b := range buf[10:] {
-		if b < bit {
-			return 0, -(11 + j)
-		}
+
+	if sz > MaxLen64 {
+		// Catch byte reads past MaxLen64.
+		// See issue https://golang.org/issues/41185
+		return 0, -(MaxLen64 + 1) // overflow
 	}
 	return 0, 0
 }
diff --git a/varint_test.go b/varint_test.go
index 810dcc2..65b9e8e 100644
--- a/varint_test.go
+++ b/varint_test.go
@@ -90,10 +90,10 @@ func TestUvarint(t *testing.T) {
 		b[1] = 0xff
 		n := binary.PutUvarint(b[2:], maxUint64)
 		p := b[:n+2]
-		if _, n2 := binary.Uvarint(p); n2 != -12 {
+		if _, n2 := binary.Uvarint(p); n2 != -11 {
 			t.Fatalf("unexpected error: %d", n2)
 		}
-		if _, n2 := Uvarint(p); n2 != -12 {
+		if _, n2 := Uvarint(p); n2 != -11 {
 			t.Fatalf("unexpected error: %d", n2)
 		}
 	})
@@ -104,10 +104,10 @@ func TestUvarint(t *testing.T) {
 		n := binary.PutUvarint(b[2:], maxUint64)
 		p := b[:n+2]
 		p[len(p)-1] = 0xff
-		if _, n2 := binary.Uvarint(p); n2 != 0 {
+		if _, n2 := binary.Uvarint(p); n2 != -11 {
 			t.Fatalf("unexpected error: %d", n2)
 		}
-		if _, n2 := Uvarint(p); n2 != 0 {
+		if _, n2 := Uvarint(p); n2 != -11 {
 			t.Fatalf("unexpected error: %d", n2)
 		}
 	})
-- 
2.33.1