From 9a518853aaea13e0a60411b7be7d3ff1f05962de Mon Sep 17 00:00:00 2001 From: Alexander Potapenko Date: Wed, 30 Jul 2025 10:44:47 +0200 Subject: pkg/flatrpc, pkg/vminfo, executor: introduce readonly coverage Add a new vminfo feature, FeatureKcovResetIoctl, that is true if the kernel supports ioctl(KCOV_RESET_TRACE) making it possible to reset the coverage buffer on the kernel side. This, in turn, allows us to map the coverage buffer read-only, which will prevent all sorts of userspace-generated corruptions at a cost of an extra syscall per program execution. The corresponding exec env flag, ExecEnv::ReadOnlyCoverage, turns on read-only coverage in the executor. It is enabled by default if FeatureKcovResetIoctl is on. --- pkg/vminfo/features.go | 2 ++ 1 file changed, 2 insertions(+) (limited to 'pkg/vminfo') diff --git a/pkg/vminfo/features.go b/pkg/vminfo/features.go index 2be067d32..6c4d6ae6d 100644 --- a/pkg/vminfo/features.go +++ b/pkg/vminfo/features.go @@ -138,6 +138,8 @@ func (ctx *checkContext) featureToFlags(feat flatrpc.Feature) (flatrpc.ExecEnv, case flatrpc.FeatureDelayKcovMmap: envFlags |= flatrpc.ExecEnvSignal | flatrpc.ExecEnvDelayKcovMmap execFlags |= flatrpc.ExecFlagCollectSignal | flatrpc.ExecFlagCollectCover + case flatrpc.FeatureKcovResetIoctl: + envFlags |= flatrpc.ExecEnvReadOnlyCoverage case flatrpc.FeatureSandboxNone: envFlags &= ^ctx.cfg.Sandbox envFlags |= flatrpc.ExecEnvSandboxNone -- cgit mrf-deployment