opentelemetry-go: BSD kenv command not using absolute path enables PATH hijacking

Summary

The fix for GHSA-9h8m-3fm2-qjrq (CVE-2026-24051) changed the Darwin ioreg command to use an absolute path but left the BSD kenv command using a bare name, allowing the same PATH hijacking attack on BSD and Solaris platforms.

Root Cause

sdk/resource/host_id.go line 42:

if result, err := r.execCommand("kenv", "-q", "smbios.system.uuid"); err == nil {

Compare with the fixed Darwin path at line 58:

result, err := r.execCommand("/usr/sbin/ioreg", "-rd1", "-c", "IOPlatformExpertDevice")

The execCommand helper at sdk/resource/host_id_exec.go uses exec.Command(name, arg...) which searches $PATH when the command name contains no path separator.

Affected platforms (per build tag in host_id_bsd.go:4): DragonFly BSD, FreeBSD, NetBSD, OpenBSD, Solaris.

The kenv path is reached when /etc/hostid does not exist (line 38-40), which is common on FreeBSD systems.

Attack

1. Attacker has local access to a system running a Go application that imports go.opentelemetry.io/otel/sdk
2. Attacker places a malicious kenv binary earlier in $PATH
3. Application initializes OpenTelemetry resource detection at startup
4. hostIDReaderBSD.read() calls exec.Command("kenv", ...) which resolves to the malicious binary
5. Arbitrary code executes in the context of the application

Same attack vector and impact as CVE-2026-24051.

Suggested Fix

Use the absolute path:

if result, err := r.execCommand("/bin/kenv", "-q", "smbios.system.uuid"); err == nil {

On FreeBSD, kenv is located at /bin/kenv.