go: fix CVE-2022-23772

math/big: prevent large memory consumption in Rat.SetString

An attacker can cause unbounded memory growth in a program using (*Rat).SetString
due to an unhandled overflow.

Upstream-Status: Backport [https://go.dev/issue/50699]
CVE: CVE-2022-23772
(From OE-Core rev: e4d15040f62744265b9236ad7276f3371a9172da)

Signed-off-by:Minjae Kim <flowergom@gmail.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

meta/recipes-devtools/go/go-1.14.inc

@@ -20,6 +20,7 @@ SRC_URI += "\
     file://CVE-2021-33196.patch \
     file://CVE-2021-33197.patch \
     file://CVE-2022-23806.patch \
+    file://CVE-2022-23772.patch \
 "
 SRC_URI_append_libc-musl = " file://0009-ld-replace-glibc-dynamic-linker-with-musl.patch"
 SRC_URI[main.sha256sum] = "7ed13b2209e54a451835997f78035530b331c5b6943cdcd68a3d815fdc009149"

meta/recipes-devtools/go/go-1.14/CVE-2022-23772.patch

@@ -0,0 +1,50 @@
+From 70882eedccac803ddcf1c3215e0ae8fd59847e39 Mon Sep 17 00:00:00 2001
+From: Katie Hockman <katie@golang.org>
+Date: Sat, 26 Feb 2022 20:03:38 +0000
+Subject: [PATCH] [release-branch.go1.16] math/big: prevent overflow in
+ (*Rat).SetString
+
+Credit to rsc@ for the original patch.
+
+Thanks to the OSS-Fuzz project for discovering this
+issue and to Emmanuel Odeke (@odeke_et) for reporting it.
+
+Updates #50699
+Fixes #50700
+Fixes CVE-2022-23772
+---
+ src/math/big/ratconv.go      | 5 +++++
+ src/math/big/ratconv_test.go | 1 +
+ 2 files changed, 6 insertions(+)
+
+diff --git a/src/math/big/ratconv.go b/src/math/big/ratconv.go
+index 941139e..e8cbdbe 100644
+--- a/src/math/big/ratconv.go
++++ b/src/math/big/ratconv.go
+@@ -168,6 +168,11 @@ func (z *Rat) SetString(s string) (*Rat, bool) {
+ 		n := exp5
+ 		if n < 0 {
+ 			n = -n
++			if n < 0 {
++				// This can occur if -n overflows. -(-1 << 63) would become
++				// -1 << 63, which is still negative.
++				return nil, false
++			}
+ 		}
+ 		pow5 := z.b.abs.expNN(natFive, nat(nil).setWord(Word(n)), nil) // use underlying array of z.b.abs
+ 		if exp5 > 0 {
+diff --git a/src/math/big/ratconv_test.go b/src/math/big/ratconv_test.go
+index ba0d1ba..b820df4 100644
+--- a/src/math/big/ratconv_test.go
++++ b/src/math/big/ratconv_test.go
+@@ -104,6 +104,7 @@ var setStringTests = []StringTest{
+ 	{in: "4/3/"},
+ 	{in: "4/3."},
+ 	{in: "4/"},
++	{in: "13e-9223372036854775808"}, // CVE-2022-23772
+ 
+ 	// valid
+ 	{"0", "0", true},
+-- 
+2.17.1
+