From ac68c6c683409f98250d34ad282b9e1b0c9095ef Mon Sep 17 00:00:00 2001 From: Julie Qiu Date: Thu, 23 Jun 2022 23:18:56 +0000 Subject: [PATCH] path/filepath: fix stack exhaustion in Glob A limit is added to the number of path separators allowed by an input to Glob, to prevent stack exhaustion issues. Thanks to Juho Nurminen of Mattermost who reported the issue. Fixes CVE-2022-30632 Fixes #53416 Change-Id: I1b9fd4faa85411a05dbc91dceae1c0c8eb021f07 Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/1498176 Reviewed-by: Roland Shoemaker Reviewed-on: https://go-review.googlesource.com/c/go/+/417066 Reviewed-by: Heschi Kreinick TryBot-Result: Gopher Robot Run-TryBot: Michael Knyszek --- src/path/filepath/match.go | 12 +++++++++++- src/path/filepath/match_test.go | 10 ++++++++++ 2 files changed, 21 insertions(+), 1 deletion(-) diff --git a/src/path/filepath/match.go b/src/path/filepath/match.go index 847a78133d..b5cc4b8cf3 100644 --- a/src/path/filepath/match.go +++ b/src/path/filepath/match.go @@ -240,6 +240,16 @@ func getEsc(chunk string) (r rune, nchunk string, err error) { // The only possible returned error is ErrBadPattern, when pattern // is malformed. func Glob(pattern string) (matches []string, err error) { + return globWithLimit(pattern, 0) +} + +func globWithLimit(pattern string, depth int) (matches []string, err error) { + // This limit is used prevent stack exhaustion issues. See CVE-2022-30632. + const pathSeparatorsLimit = 10000 + if depth == pathSeparatorsLimit { + return nil, ErrBadPattern + } + // Check pattern is well-formed. if _, err := Match(pattern, ""); err != nil { return nil, err @@ -269,7 +279,7 @@ func Glob(pattern string) (matches []string, err error) { } var m []string - m, err = Glob(dir) + m, err = globWithLimit(dir, depth+1) if err != nil { return } diff --git a/src/path/filepath/match_test.go b/src/path/filepath/match_test.go index 375c41a7e9..d6282596fe 100644 --- a/src/path/filepath/match_test.go +++ b/src/path/filepath/match_test.go @@ -155,6 +155,16 @@ func TestGlob(t *testing.T) { } } +func TestCVE202230632(t *testing.T) { + // Prior to CVE-2022-30632, this would cause a stack exhaustion given a + // large number of separators (more than 4,000,000). There is now a limit + // of 10,000. + _, err := Glob("/*" + strings.Repeat("/", 10001)) + if err != ErrBadPattern { + t.Fatalf("Glob returned err=%v, want ErrBadPattern", err) + } +} + func TestGlobError(t *testing.T) { bad := []string{`[]`, `nonexist/[]`} for _, pattern := range bad { -- 2.50.0