x/vuln: reports could exclude calls with unaffected arguments

[prattmic]

What version of Go are you using (go version)?

$ go version
go version go1.19-pre4 cl/455575533 +12f49fe0ed linux/amd64

Does this issue reproduce at the latest version of golang.org/x/vuln?

Yes, using v0.0.0-20220902211423-27dd78d2ca39

What operating system and processor architecture are you using (go env)?

go env Output

$ go env
GO111MODULE=""
GOARCH="amd64"
GOBIN=""
GOCACHE="/usr/local/google/home/mpratt/.cache/go-build"
GOENV="/usr/local/google/home/mpratt/.config/go/env"
GOEXE=""
GOEXPERIMENT=""
GOFLAGS=""
GOHOSTARCH="amd64"
GOHOSTOS="linux"
GOINSECURE=""
GOMODCACHE="/usr/local/google/home/mpratt/go/pkg/mod"
GONOPROXY=""
GONOSUMDB=""
GOOS="linux"
GOPATH="/usr/local/google/home/mpratt/go"
GOPRIVATE=""
GOPROXY="https://proxy.golang.org,direct"
GOROOT="/usr/lib/google-golang"
GOSUMDB="sum.golang.org"
GOTMPDIR=""
GOTOOLDIR="/usr/lib/google-golang/pkg/tool/linux_amd64"
GOVCS=""
GOVERSION="go1.19-pre4 cl/455575533 +12f49fe0ed"
GCCGO="gccgo"
GOAMD64="v1"
AR="ar"
CC="clang"
CXX="clang++"
CGO_ENABLED="1"
GOMOD="/dev/null"
GOWORK=""
CGO_CFLAGS="-g -O2"
CGO_CPPFLAGS=""
CGO_CXXFLAGS="-g -O2"
CGO_FFLAGS="-g -O2"
CGO_LDFLAGS="-g -O2"
PKG_CONFIG="pkg-config"
GOGCCFLAGS="-fPIC -m64 -pthread -fno-caret-diagnostics -Qunused-arguments -Wl,--no-gc-sections -fmessage-length=0 -fdebug-prefix-map=/tmp/go-build4085128731=/tmp/go-build -gno-record-gcc-switches"

What did you do?

$ git clone https://github.com/google/gvisor
$ cd gvisor
$ git checkout go
$ govulncheck ./...

What did you expect to see?

Vulnerabilities affecting these packages.

What did you see instead?

Vulnerability #1: GO-2022-0493
  When called with a non-zero flags parameter, the Faccessat         
  function can incorrectly report that a file is accessible.

  Call stacks in your code:
      runsc/cmd/do.go:228:23: gvisor.dev/gvisor/runsc/cmd.resolvePath calls golang.org/x/sys/unix.Access

  Found in: golang.org/x/sys/unix@v0.0.0-20211019181941-9d821ace8654
  Fixed in: golang.org/x/sys/unix@v1.18.2 
  More info: https://pkg.go.dev/vuln/GO-2022-0493

This vulnerability affects Faccessat when called with flags != 0. This report flags a call via unix.Access, which always passes flags == 0.

In theory vulncheck could encode that this vulnerability depends on a certain argument value and then statically find calls that don't match that value.

[zpavlinovic]

Thank you for reporting this issue!

It is currently out of scope for vulncheck to automatically do analysis of call arguments to vulnerable symbols. However, unix.Access should not be considered a vulnerable symbol for the reasons you outlined. We'll investigate a potential remedy.