From: Johan Abildskov <randomsort@gmail.com>
Date: Wed, 22 Mar 2023 06:31:25 +0000 (+0000)
Subject: encoding/gob: extend partially allocated string slices
X-Git-Tag: go1.21rc1~1174
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=3d5391ed87d813110e10b954c62bf7ed578b591f;p=gostls13.git

encoding/gob: extend partially allocated string slices

Fixes #59172

Change-Id: I54d5e724f10117a40ec5dd58c810f6bbb2475933
GitHub-Last-Rev: d1a986698c820415b2e0be12141091a3cbf6fde3
GitHub-Pull-Request: golang/go#59173
Reviewed-on: https://go-review.googlesource.com/c/go/+/478215
Run-TryBot: Ian Lance Taylor <iant@golang.org>
Reviewed-by: Rob Pike <r@golang.org>
Run-TryBot: Ian Lance Taylor <iant@google.com>
Reviewed-by: Ian Lance Taylor <iant@google.com>
TryBot-Result: Gopher Robot <gobot@golang.org>
Auto-Submit: Ian Lance Taylor <iant@google.com>
Reviewed-by: Heschi Kreinick <heschi@google.com>
---

diff --git a/src/encoding/gob/codec_test.go b/src/encoding/gob/codec_test.go
index 54c356c464..28cd6088af 100644
--- a/src/encoding/gob/codec_test.go
+++ b/src/encoding/gob/codec_test.go
@@ -1544,6 +1544,10 @@ type LargeSliceStruct struct {
 	S []StringPair
 }
 
+type LargeSliceString struct {
+	S []string
+}
+
 func testEncodeDecode(t *testing.T, in, out any) {
 	t.Helper()
 	var b bytes.Buffer
@@ -1592,4 +1596,14 @@ func TestLargeSlice(t *testing.T) {
 		rt := &LargeSliceStruct{}
 		testEncodeDecode(t, st, rt)
 	})
+	t.Run("string", func(t *testing.T) {
+		t.Parallel()
+		s := make([]string, 1<<21)
+		for i := range s {
+			s[i] = string(rune(i))
+		}
+		st := &LargeSliceString{S: s}
+		rt := &LargeSliceString{}
+		testEncodeDecode(t, st, rt)
+	})
 }
diff --git a/src/encoding/gob/dec_helpers.go b/src/encoding/gob/dec_helpers.go
index a09ac8fc1a..098ba7254a 100644
--- a/src/encoding/gob/dec_helpers.go
+++ b/src/encoding/gob/dec_helpers.go
@@ -358,6 +358,9 @@ func decStringSlice(state *decoderState, v reflect.Value, length int, ovfl error
 		if state.b.Len() == 0 {
 			errorf("decoding string array or slice: length exceeds input size (%d elements)", length)
 		}
+		if i >= len(slice) {
+			growSlice(v, &slice, length)
+		}
 		u := state.decodeUint()
 		n := int(u)
 		if n < 0 || uint64(n) != u || n > state.b.Len() {