Add enable-monit-access command to bosh-agent#406
Draft
Conversation
Signed-off-by: Maria Shaldybin <maria.shaldybin@broadcom.com> Co-authored-by: Maria Shaldybin <maria.shaldybin@broadcom.com> Signed-off-by: Maria Shaldybin <maria.shaldybin@broadcom.com> Co-authored-by: Maria Shaldybin <maria.shaldybin@broadcom.com>
Add UID-based nftables firewall for NATS connections Implement a firewall mechanism that restricts NATS (mbus) connections to the bosh-agent process only, using UID-based filtering with nftables. Key changes: - Add platform/firewall package with Manager and NatsFirewallHook interfaces - Implement NftablesFirewall that creates UID-based egress rules - Add GetNatsFirewallHook() to Platform interface - Integrate BeforeConnect hook in nats_handler.go for connection/reconnection - Support DNS re-resolution on reconnect for HA failover scenarios - Add stub implementations for Windows and dummy platforms The firewall rules allow only the agent's UID to connect to NATS/director ports while blocking other processes, improving security posture. Co-authored-by: Maria Shaldybin <maria.shaldybin@broadcom.com>
Add unit tests for nftables firewall and NATS handler integration Add comprehensive unit tests for the new firewall functionality: platform/firewall tests (23 tests): - SetupMonitFirewall: table/chain/rule creation, error handling - SetupNATSFirewall: IPv4/IPv6, DNS resolution, https/empty URL handling - BeforeConnect: delegation to SetupNATSFirewall - Cleanup: table deletion and error handling mbus/nats_handler tests (4 new tests): - Firewall hook is called on Start - BeforeConnect receives correct mbus URL - Handler still starts when hook returns nil - Warning logged but no failure when BeforeConnect errors Also: - Add DNSResolver interface for testable DNS resolution - Inject resolver dependency via NewNftablesFirewallWithDeps - Configure test logging to use GinkgoWriter for visibility Co-authored-by: Aram Price <aram.price@broadcom.com>
Fix linter and cross-platform build issues - Fix ST1023 linter error: omit type from var declaration - Add linux_header.txt for counterfeiter to add build tags to Linux-only fakes - Regenerate fake_nftables_conn.go and fake_dnsresolver.go with //go:build linux tag - This fixes macOS/Windows build failures due to google/nftables being Linux-only Co-authored-by: Maria Shaldybin <maria.shaldybin@broadcom.com>
Address PR review feedback for nftables firewall - Fix nil pointer dereference in DisconnectErrHandler when err is nil - Remove iptables-based SetupNatsFirewall code (replaced by nftables) - Remove unused Cleanup() method from firewall interface - Move firewall initialization from lazy getter to explicit SetupFirewall() - Add comment explaining IPv6 loopback is intentionally not protected (monit only binds to 127.0.0.1:2822) Co-authored-by: Aram Price <aram.price@broadcom.com>
Remove unused error returns from internal firewall helper methods The nftables library batches operations until Flush() is called, so AddTable/AddChain/AddRule never return errors. Removing the misleading error return types from these internal helper methods. Co-authored-by: Maria Shaldybin <maria.shaldybin@broadcom.com>
Add two-chain architecture for monit firewall to preserve job rules Implement separate chains for agent-managed and job-managed monit access rules: - monit_access_jobs: Regular chain for job rules (never flushed by agent) - monit_access: Base chain that jumps to jobs chain first, then applies agent rules This allows BOSH jobs to add their own monit access rules via pre-start scripts that persist across agent restarts, while ensuring agent rules are always up-to-date by flushing and recreating them on each setup call. Co-authored-by: Aram Price <aram.price@broadcom.com>
Rename linux_header.txt to clarify its purpose Move to firewallfakes/linux_build_constraint.txt to make it clear this file contains a Go build constraint for counterfeiter-generated fakes, not a C header. Co-authored-by: Maria Shaldybin <maria.shaldybin@broadcom.com>
Co-authored-by: Aram Price <aram.price@broadcom.com>
Signed-off-by: Aram Price <aram.price@broadcom.com> Co-authored-by: Aram Price <aram.price@broadcom.com>
Signed-off-by: Aram Price <aram.price@broadcom.com> Co-authored-by: Aram Price <aram.price@broadcom.com>
cf-foundation-community-automation
bot
moved this to Inbox
in Foundational Infrastructure Working Group
Signed-off-by: Aram Price <aram.price@broadcom.com> Co-authored-by: Aram Price <aram.price@broadcom.com>
mariash
force-pushed
the
monit-access-uid-firewall
branch
from
4014e58 to
57b4a2a
Compare
rkoster
requested changes
Feb 20, 2026
| logger.UseTags([]boshlog.LogTag{{Name: "monit-access", LogLevel: boshlog.LevelDebug}}) | ||
|
|
||
| // Validate nftables mode: verify if nftables is available | ||
| if len(args) > 1 && args[0] == "--validate-nftables-present" { |
Contributor
There was a problem hiding this comment.
Shoudn't this flag parsing be something that sits somewhere closer to main. Like with the compile command: https://github.com/cloudfoundry/bosh-agent/blob/main/main/compile.go
Also nftables should always be there, its available on both jammy and noble so what is the use of this flag?
github-project-automation
bot
moved this from Inbox
to Waiting for Changes | Open for Contribution
in Foundational Infrastructure Working Group
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
3 participants
Add this suggestion to a batch that can be applied as a single commit.This suggestion is invalid because no changes were made to the code.Suggestions cannot be applied while the pull request is closed.Suggestions cannot be applied while viewing a subset of changes.Only one suggestion per line can be applied in a batch.Add this suggestion to a batch that can be applied as a single commit.Applying suggestions on deleted lines is not supported.You must change the existing code in this line in order to create a valid suggestion.Outdated suggestions cannot be applied.This suggestion has been applied or marked resolved.Suggestions cannot be applied from pending reviews.Suggestions cannot be applied on multi-line comments.Suggestions cannot be applied while the pull request is queued to merge.Suggestion cannot be applied right now. Please check back later.
This PR adds a new command to bosh-agent "enable-monit-access"
It will add an nftables rule for bosh monit job first based on cgroup and then fall back to UUID based rule.
This PR depends on #399
This pulls in cloudfoundry/pxc-release#97 bosh-monit-access package as a new bosh-agent "enable-monit-access" command.