From a0c3a1b6769c9849577eb6426fdac39d40372307 Mon Sep 17 00:00:00 2001 From: "Bryan C. Mills" Date: Thu, 17 Aug 2023 17:12:44 -0400 Subject: [PATCH] cmd/go: reject toolchain directives containing path separators If GOTOOLCHAIN="path" or "auto", the go command uses exec.LookPath to search for it in order to allow toolchains to refer to local-only toolchain variants (such as toolchains built from enterprise- or distro-patched source). However, those toolchains should only be resolved from $PATH, not relative to the working directory of the command. Thanks to Juho Nurminen of Mattermost for reporting this issue. Fixes #62198. Fixes CVE-2023-39320. Change-Id: I247c7acea95d737362dd0475e9fc8515430d0fcc Reviewed-on: https://team-review.git.corp.google.com/c/golang/go-private/+/1996318 Run-TryBot: Roland Shoemaker Reviewed-by: Damien Neil Reviewed-by: Roland Shoemaker Reviewed-on: https://go-review.googlesource.com/c/go/+/526158 Reviewed-by: Bryan Mills LUCI-TryBot-Result: Go LUCI --- src/cmd/go/internal/gover/toolchain.go | 7 ++++ .../testdata/script/mod_toolchain_slash.txt | 32 +++++++++++++++++++ 2 files changed, 39 insertions(+) create mode 100644 src/cmd/go/testdata/script/mod_toolchain_slash.txt diff --git a/src/cmd/go/internal/gover/toolchain.go b/src/cmd/go/internal/gover/toolchain.go index b520277618549..a24df98168056 100644 --- a/src/cmd/go/internal/gover/toolchain.go +++ b/src/cmd/go/internal/gover/toolchain.go @@ -22,6 +22,13 @@ import ( // FromToolchain("go1.2.3-bigcorp") == "1.2.3" // FromToolchain("invalid") == "" func FromToolchain(name string) string { + if strings.ContainsAny(name, "\\/") { + // The suffix must not include a path separator, since that would cause + // exec.LookPath to resolve it from a relative directory instead of from + // $PATH. + return "" + } + var v string if strings.HasPrefix(name, "go") { v = name[2:] diff --git a/src/cmd/go/testdata/script/mod_toolchain_slash.txt b/src/cmd/go/testdata/script/mod_toolchain_slash.txt new file mode 100644 index 0000000000000..bb1f770a6a625 --- /dev/null +++ b/src/cmd/go/testdata/script/mod_toolchain_slash.txt @@ -0,0 +1,32 @@ +[!exec:/bin/sh] skip + +chmod 0777 go1.999999-/run.sh +chmod 0777 run.sh + +! go list all +! stdout 'RAN SCRIPT' + +cd subdir +! go list all +! stdout 'RAN SCRIPT' + +-- go.mod -- +module exploit + +go 1.21 +toolchain go1.999999-/run.sh +-- go1.999999-/run.sh -- +#!/bin/sh +printf 'RAN SCRIPT\n' +exit 1 +-- run.sh -- +#!/bin/sh +printf 'RAN SCRIPT\n' +exit 1 +-- subdir/go.mod -- +module exploit + +go 1.21 +toolchain go1.999999-/../../run.sh +-- subdir/go1.999999-/README.txt -- +heh heh heh