go: fix CVE-2025-47906

If the PATH environment variable contains paths which are executables
(rather than just directories), passing certain strings to LookPath
("", ".", and ".."), can result in the binaries listed in the PATH
 being unexpectedly returned.

(From OE-Core rev: ed6df1883225ec08e637a0d7a15a6a5da4665d8d)

Signed-off-by: Archana Polampalli <archana.polampalli@windriver.com>
Signed-off-by: Steve Sakoman <steve@sakoman.com>

2 files changed, 184 insertions, 0 deletions

diff --git a/meta/recipes-devtools/go/go-1.22.12.inc b/meta/recipes-devtools/go/go-1.22.12.inc
index d0ce333117..a364e1aae8 100644
--- a/meta/recipes-devtools/go/go-1.22.12.inc
+++ b/meta/recipes-devtools/go/go-1.22.12.inc
@@ -20,6 +20,7 @@ SRC_URI += "\
     file://CVE-2025-4674.patch \
     file://CVE-2025-47907-pre.patch \
     file://CVE-2025-47907.patch \
+    file://CVE-2025-47906.patch \
 "
 SRC_URI[main.sha256sum] = "012a7e1f37f362c0918c1dfa3334458ac2da1628c4b9cf4d9ca02db986e17d71"
 
diff --git a/meta/recipes-devtools/go/go/CVE-2025-47906.patch b/meta/recipes-devtools/go/go/CVE-2025-47906.patch
new file mode 100644
index 0000000000..88895f496d
--- /dev/null
+++ b/meta/recipes-devtools/go/go/CVE-2025-47906.patch
@@ -0,0 +1,183 @@
+From 8fa31a2d7d9e60c50a3a94080c097b6e65773f4b Mon Sep 17 00:00:00 2001
+From: =?UTF-8?q?Olivier=20Mengu=C3=A9?= <olivier.mengue@gmail.com>
+Date: Mon, 30 Jun 2025 16:58:59 +0200
+Subject: [PATCH] [release-branch.go1.23] os/exec: fix incorrect expansion of
+ "", "." and ".." in LookPath Fix incorrect expansion of "" and "." when $PATH
+ contains an executable file or, on Windows, a parent directory of a %PATH%
+ element contains an file with the same name as the %PATH% element but with
+ one of the %PATHEXT% extension (ex: C:\utils\bin is in PATH, and
+ C:\utils\bin.exe exists).
+
+Fix incorrect expansion of ".." when $PATH contains an element which is
+an the concatenation of the path to an executable file (or on Windows
+a path that can be expanded to an executable by appending a %PATHEXT%
+extension), a path separator and a name.
+
+"", "." and ".." are now rejected early with ErrNotFound.
+
+Fixes CVE-2025-47906
+Fixes #74803
+
+Change-Id: Ie50cc0a660fce8fbdc952a7f2e05c36062dcb50e
+Reviewed-on: https://go-review.googlesource.com/c/go/+/685755
+LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
+Auto-Submit: Damien Neil <dneil@google.com>
+Reviewed-by: Roland Shoemaker <roland@golang.org>
+Reviewed-by: Damien Neil <dneil@google.com>
+(cherry picked from commit e0b07dc)
+Reviewed-on: https://go-review.googlesource.com/c/go/+/691855
+Reviewed-by: Michael Knyszek <mknyszek@google.com>
+
+CVE: CVE-2025-47906
+
+Upstream-Status: Backport [https://github.com/golang/go/commit/8fa31a2d7d9e60c50a3a94080c097b6e65773f4b]
+
+Signed-off-by: Archana Polampalli <archana.polampalli@windriver.com>
+---
+ src/os/exec/dot_test.go   | 56 +++++++++++++++++++++++++++++++++++++++
+ src/os/exec/exec.go       | 10 +++++++
+ src/os/exec/lp_plan9.go   |  4 +++
+ src/os/exec/lp_unix.go    |  4 +++
+ src/os/exec/lp_windows.go |  7 +++++
+ 5 files changed, 81 insertions(+)
+
+diff --git a/src/os/exec/dot_test.go b/src/os/exec/dot_test.go
+index ed4bad2..86e9cbb 100644
+--- a/src/os/exec/dot_test.go
++++ b/src/os/exec/dot_test.go
+@@ -178,4 +178,60 @@ func TestLookPath(t *testing.T) {
+                        }
+                }
+        })
++
++       checker := func(test string) func(t *testing.T) {
++               return func(t *testing.T) {
++                       t.Helper()
++                       t.Logf("PATH=%s", os.Getenv("PATH"))
++                       p, err := LookPath(test)
++                       if err == nil {
++                               t.Errorf("%q: error expected, got nil", test)
++                       }
++                       if p != "" {
++                               t.Errorf("%q: path returned should be \"\". Got %q", test, p)
++                       }
++               }
++       }
++
++       // Reference behavior for the next test
++       t.Run(pathVar+"=$OTHER2", func(t *testing.T) {
++               t.Run("empty", checker(""))
++               t.Run("dot", checker("."))
++               t.Run("dotdot1", checker("abc/.."))
++               t.Run("dotdot2", checker(".."))
++       })
++
++       // Test the behavior when PATH contains an executable file which is not a directory
++       t.Run(pathVar+"=exe", func(t *testing.T) {
++               // Inject an executable file (not a directory) in PATH.
++               // Use our own binary os.Args[0].
++               testenv.MustHaveExec(t)
++               exe, err := os.Executable()
++               if err != nil {
++                       t.Fatal(err)
++               }
++
++               t.Setenv(pathVar, exe)
++               t.Run("empty", checker(""))
++               t.Run("dot", checker("."))
++               t.Run("dotdot1", checker("abc/.."))
++               t.Run("dotdot2", checker(".."))
++       })
++
++       // Test the behavior when PATH contains an executable file which is not a directory
++       t.Run(pathVar+"=exe/xx", func(t *testing.T) {
++               // Inject an executable file (not a directory) in PATH.
++               // Use our own binary os.Args[0].
++               testenv.MustHaveExec(t)
++               exe, err := os.Executable()
++               if err != nil {
++                       t.Fatal(err)
++               }
++
++               t.Setenv(pathVar, filepath.Join(exe, "xx"))
++               t.Run("empty", checker(""))
++               t.Run("dot", checker("."))
++               t.Run("dotdot1", checker("abc/.."))
++               t.Run("dotdot2", checker(".."))
++       })
+ }
+diff --git a/src/os/exec/exec.go b/src/os/exec/exec.go
+index b8ef5a0..2c7f510 100644
+--- a/src/os/exec/exec.go
++++ b/src/os/exec/exec.go
+@@ -1310,3 +1310,13 @@ func addCriticalEnv(env []string) []string {
+ // Code should use errors.Is(err, ErrDot), not err == ErrDot,
+ // to test whether a returned error err is due to this condition.
+ var ErrDot = errors.New("cannot run executable found relative to current directory")
++
++// validateLookPath excludes paths that can't be valid
++// executable names. See issue #74466 and CVE-2025-47906.
++func validateLookPath(s string) error {
++       switch s {
++       case "", ".", "..":
++               return ErrNotFound
++       }
++       return nil
++}
+diff --git a/src/os/exec/lp_plan9.go b/src/os/exec/lp_plan9.go
+index dffdbac..39f3d33 100644
+--- a/src/os/exec/lp_plan9.go
++++ b/src/os/exec/lp_plan9.go
+@@ -36,6 +36,10 @@ func findExecutable(file string) error {
+ // As of Go 1.19, LookPath will instead return that path along with an error satisfying
+ // errors.Is(err, ErrDot). See the package documentation for more details.
+ func LookPath(file string) (string, error) {
++       if err := validateLookPath(file); err != nil {
++               return "", &Error{file, err}
++       }
++
+        // skip the path lookup for these prefixes
+        skip := []string{"/", "#", "./", "../"}
+
+diff --git a/src/os/exec/lp_unix.go b/src/os/exec/lp_unix.go
+index 3787132..2543525 100644
+--- a/src/os/exec/lp_unix.go
++++ b/src/os/exec/lp_unix.go
+@@ -54,6 +54,10 @@ func LookPath(file string) (string, error) {
+        // (only bypass the path if file begins with / or ./ or ../)
+        // but that would not match all the Unix shells.
+
++       if err := validateLookPath(file); err != nil {
++               return "", &Error{file, err}
++       }
++
+        if strings.Contains(file, "/") {
+                err := findExecutable(file)
+                if err == nil {
+diff --git a/src/os/exec/lp_windows.go b/src/os/exec/lp_windows.go
+index 698a97c..e0b74e3 100644
+--- a/src/os/exec/lp_windows.go
++++ b/src/os/exec/lp_windows.go
+@@ -68,6 +68,9 @@ func findExecutable(file string, exts []string) (string, error) {
+ // As of Go 1.19, LookPath will instead return that path along with an error satisfying
+ // errors.Is(err, ErrDot). See the package documentation for more details.
+ func LookPath(file string) (string, error) {
++       if err := validateLookPath(file); err != nil {
++               return "", &Error{file, err}
++       }
+        return lookPath(file, pathExt())
+ }
+
+@@ -81,6 +84,10 @@ func LookPath(file string) (string, error) {
+ // "C:\foo\example.com" would be returned as-is even if the
+ // program is actually "C:\foo\example.com.exe".
+ func lookExtensions(path, dir string) (string, error) {
++       if err := validateLookPath(path); err != nil {
++               return "", &Error{path, err}
++       }
++
+        if filepath.Base(path) == path {
+                path = "." + string(filepath.Separator) + path
+        }
+--
+2.40.0