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Bug#1006768: bullseye-pu: package golang-1.15/1.15.15-1~deb11u4



Package: release.debian.org
Severity: normal
Tags: bullseye
User: release.debian.org@packages.debian.org
Usertags: pu
X-Debbugs-Cc: zhsj@debian.org, team@security.debian.org

[ Reason ]

Backport patch for CVE-2022-24921.

[ Impact ]

CVE-2022-24921:
regexp: stack exhaustion compiling deeply nested expressions

This is bug in standard library.

[ Tests ]

The backported patch has new regression tests in it.

[ Risks ]

Low, change is small. Backport from 1.16 release without modification.

[ Checklist ]
  [x] *all* changes are documented in the d/changelog
  [x] I reviewed all changes and I approve them
  [x] attach debdiff against the package in (old)stable
  [ ] the issue is verified as fixed in unstable
      golang-1.15 has been removed from unstable.

[ Changes ]

See attachment.

[ Other info ]

I don't think the severity needs to rebuild other Go packages.
diff -Nru golang-1.15-1.15.15/debian/changelog golang-1.15-1.15.15/debian/changelog
--- golang-1.15-1.15.15/debian/changelog	2022-02-11 23:45:44.000000000 +0800
+++ golang-1.15-1.15.15/debian/changelog	2022-03-04 21:48:18.000000000 +0800
@@ -1,3 +1,10 @@
+golang-1.15 (1.15.15-1~deb11u4) bullseye; urgency=medium
+
+  * Backport patch for CVE-2022-24921:
+    regexp: stack exhaustion compiling deeply nested expressions
+
+ -- Shengjing Zhu <zhsj@debian.org>  Fri, 04 Mar 2022 21:48:18 +0800
+
 golang-1.15 (1.15.15-1~deb11u3) bullseye; urgency=medium
 
   * Backport patches for CVE-2022-23806 CVE-2022-23772 CVE-2022-23773
diff -Nru golang-1.15-1.15.15/debian/patches/0015-CVE-2022-24921.patch golang-1.15-1.15.15/debian/patches/0015-CVE-2022-24921.patch
--- golang-1.15-1.15.15/debian/patches/0015-CVE-2022-24921.patch	1970-01-01 08:00:00.000000000 +0800
+++ golang-1.15-1.15.15/debian/patches/0015-CVE-2022-24921.patch	2022-03-04 21:48:18.000000000 +0800
@@ -0,0 +1,169 @@
+From: Russ Cox <rsc@golang.org>
+Date: Wed, 2 Feb 2022 16:41:32 -0500
+Subject: CVE-2022-24921
+
+Origin: backport, https://github.com/golang/go/commit/2b65cde5
+---
+ src/regexp/syntax/parse.go      | 72 +++++++++++++++++++++++++++++++++++++++--
+ src/regexp/syntax/parse_test.go |  7 ++++
+ 2 files changed, 77 insertions(+), 2 deletions(-)
+
+diff --git a/src/regexp/syntax/parse.go b/src/regexp/syntax/parse.go
+index 7b40309..d7cf2af 100644
+--- a/src/regexp/syntax/parse.go
++++ b/src/regexp/syntax/parse.go
+@@ -76,13 +76,29 @@ const (
+ 	opVerticalBar
+ )
+ 
++// maxHeight is the maximum height of a regexp parse tree.
++// It is somewhat arbitrarily chosen, but the idea is to be large enough
++// that no one will actually hit in real use but at the same time small enough
++// that recursion on the Regexp tree will not hit the 1GB Go stack limit.
++// The maximum amount of stack for a single recursive frame is probably
++// closer to 1kB, so this could potentially be raised, but it seems unlikely
++// that people have regexps nested even this deeply.
++// We ran a test on Google's C++ code base and turned up only
++// a single use case with depth > 100; it had depth 128.
++// Using depth 1000 should be plenty of margin.
++// As an optimization, we don't even bother calculating heights
++// until we've allocated at least maxHeight Regexp structures.
++const maxHeight = 1000
++
+ type parser struct {
+ 	flags       Flags     // parse mode flags
+ 	stack       []*Regexp // stack of parsed expressions
+ 	free        *Regexp
+ 	numCap      int // number of capturing groups seen
+ 	wholeRegexp string
+-	tmpClass    []rune // temporary char class work space
++	tmpClass    []rune          // temporary char class work space
++	numRegexp   int             // number of regexps allocated
++	height      map[*Regexp]int // regexp height for height limit check
+ }
+ 
+ func (p *parser) newRegexp(op Op) *Regexp {
+@@ -92,16 +108,52 @@ func (p *parser) newRegexp(op Op) *Regexp {
+ 		*re = Regexp{}
+ 	} else {
+ 		re = new(Regexp)
++		p.numRegexp++
+ 	}
+ 	re.Op = op
+ 	return re
+ }
+ 
+ func (p *parser) reuse(re *Regexp) {
++	if p.height != nil {
++		delete(p.height, re)
++	}
+ 	re.Sub0[0] = p.free
+ 	p.free = re
+ }
+ 
++func (p *parser) checkHeight(re *Regexp) {
++	if p.numRegexp < maxHeight {
++		return
++	}
++	if p.height == nil {
++		p.height = make(map[*Regexp]int)
++		for _, re := range p.stack {
++			p.checkHeight(re)
++		}
++	}
++	if p.calcHeight(re, true) > maxHeight {
++		panic(ErrInternalError)
++	}
++}
++
++func (p *parser) calcHeight(re *Regexp, force bool) int {
++	if !force {
++		if h, ok := p.height[re]; ok {
++			return h
++		}
++	}
++	h := 1
++	for _, sub := range re.Sub {
++		hsub := p.calcHeight(sub, false)
++		if h < 1+hsub {
++			h = 1 + hsub
++		}
++	}
++	p.height[re] = h
++	return h
++}
++
+ // Parse stack manipulation.
+ 
+ // push pushes the regexp re onto the parse stack and returns the regexp.
+@@ -137,6 +189,7 @@ func (p *parser) push(re *Regexp) *Regexp {
+ 	}
+ 
+ 	p.stack = append(p.stack, re)
++	p.checkHeight(re)
+ 	return re
+ }
+ 
+@@ -246,6 +299,7 @@ func (p *parser) repeat(op Op, min, max int, before, after, lastRepeat string) (
+ 	re.Sub = re.Sub0[:1]
+ 	re.Sub[0] = sub
+ 	p.stack[n-1] = re
++	p.checkHeight(re)
+ 
+ 	if op == OpRepeat && (min >= 2 || max >= 2) && !repeatIsValid(re, 1000) {
+ 		return "", &Error{ErrInvalidRepeatSize, before[:len(before)-len(after)]}
+@@ -693,6 +747,21 @@ func literalRegexp(s string, flags Flags) *Regexp {
+ // Flags, and returns a regular expression parse tree. The syntax is
+ // described in the top-level comment.
+ func Parse(s string, flags Flags) (*Regexp, error) {
++	return parse(s, flags)
++}
++
++func parse(s string, flags Flags) (_ *Regexp, err error) {
++	defer func() {
++		switch r := recover(); r {
++		default:
++			panic(r)
++		case nil:
++			// ok
++		case ErrInternalError:
++			err = &Error{Code: ErrInternalError, Expr: s}
++		}
++	}()
++
+ 	if flags&Literal != 0 {
+ 		// Trivial parser for literal string.
+ 		if err := checkUTF8(s); err != nil {
+@@ -704,7 +773,6 @@ func Parse(s string, flags Flags) (*Regexp, error) {
+ 	// Otherwise, must do real work.
+ 	var (
+ 		p          parser
+-		err        error
+ 		c          rune
+ 		op         Op
+ 		lastRepeat string
+diff --git a/src/regexp/syntax/parse_test.go b/src/regexp/syntax/parse_test.go
+index 5581ba1..1ef6d8a 100644
+--- a/src/regexp/syntax/parse_test.go
++++ b/src/regexp/syntax/parse_test.go
+@@ -207,6 +207,11 @@ var parseTests = []parseTest{
+ 	// Valid repetitions.
+ 	{`((((((((((x{2}){2}){2}){2}){2}){2}){2}){2}){2}))`, ``},
+ 	{`((((((((((x{1}){2}){2}){2}){2}){2}){2}){2}){2}){2})`, ``},
++
++	// Valid nesting.
++	{strings.Repeat("(", 999) + strings.Repeat(")", 999), ``},
++	{strings.Repeat("(?:", 999) + strings.Repeat(")*", 999), ``},
++	{"(" + strings.Repeat("|", 12345) + ")", ``}, // not nested at all
+ }
+ 
+ const testFlags = MatchNL | PerlX | UnicodeGroups
+@@ -482,6 +487,8 @@ var invalidRegexps = []string{
+ 	`a{100000}`,
+ 	`a{100000,}`,
+ 	"((((((((((x{2}){2}){2}){2}){2}){2}){2}){2}){2}){2})",
++	strings.Repeat("(", 1000) + strings.Repeat(")", 1000),
++	strings.Repeat("(?:", 1000) + strings.Repeat(")*", 1000),
+ 	`\Q\E*`,
+ }
+ 
diff -Nru golang-1.15-1.15.15/debian/patches/series golang-1.15-1.15.15/debian/patches/series
--- golang-1.15-1.15.15/debian/patches/series	2022-02-11 23:45:44.000000000 +0800
+++ golang-1.15-1.15.15/debian/patches/series	2022-03-04 21:48:18.000000000 +0800
@@ -12,3 +12,4 @@
 0012-CVE-2022-23806.patch
 0013-CVE-2022-23772.patch
 0014-CVE-2022-23773.patch
+0015-CVE-2022-24921.patch

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