Headline
CVE-2023-41332: proxy: Ignore visibility annotation if proxy is disabled by sayboras · Pull Request #27597 · cilium/cilium
Cilium is a networking, observability, and security solution with an eBPF-based dataplane. In Cilium clusters where Cilium’s Layer 7 proxy has been disabled, creating workloads with policy.cilium.io/proxy-visibility annotations (in Cilium >= v1.13) or io.cilium.proxy-visibility annotations (in Cilium <= v1.12) causes the Cilium agent to segfault on the node to which the workload is assigned. Existing traffic on the affected node will continue to flow, but the Cilium agent on the node will not able to process changes to workloads running on the node. This will also prevent workloads from being able to start on the affected node. The denial of service will be limited to the node on which the workload is scheduled, however an attacker may be able to schedule workloads on the node of their choosing, which could lead to targeted attacks. This issue has been resolved in Cilium versions 1.14.2, 1.13.7, and 1.12.14. Users unable to upgrade can avoid this denial of service attack by enabling the Layer 7 proxy.
This is to avoid the below error if proxy is disabled as part of
installation, but the visibility annotation is added to pods later.
2023-08-11T12:42:41.390575371Z goroutine 1522 [running]: 2023-08-11T12:42:41.390581994Z github.com/cilium/cilium/pkg/proxy.(*Proxy).CreateOrUpdateRedirect(0x0, {0x3ae74b8, 0xc000650280}, {0x3aeb440?, 0xc0016e4560?}, {0xc0010ba1b0, 0x12}, {0x3afd260, 0xc000982000}, 0xc001c9c980) 2023-08-11T12:42:41.390589198Z github.com/cilium/cilium/pkg/proxy/proxy.go:459 +0xb7 2023-08-11T12:42:41.390596081Z github.com/cilium/cilium/pkg/endpoint.(*Endpoint).addVisibilityRedirects(0xc000982000, 0x1, 0xc001874ba0?, 0xc001c9c980?) 2023-08-11T12:42:41.390602613Z github.com/cilium/cilium/pkg/endpoint/bpf.go:343 +0x443 2023-08-11T12:42:41.390614345Z github.com/cilium/cilium/pkg/endpoint.(*Endpoint).addNewRedirects(0xc000982000, 0xc001874870?) 2023-08-11T12:42:41.390651325Z github.com/cilium/cilium/pkg/endpoint/bpf.go:424 +0x3c5 2023-08-11T12:42:41.390658068Z github.com/cilium/cilium/pkg/endpoint.(*Endpoint).runPreCompilationSteps(0xc000982000, 0xc000e31800, 0x0) 2023-08-11T12:42:41.390663999Z github.com/cilium/cilium/pkg/endpoint/bpf.go:802 +0x4fe 2023-08-11T12:42:41.390669690Z github.com/cilium/cilium/pkg/endpoint.(*Endpoint).regenerateBPF(0xc000982000, 0xc000e31800) 2023-08-11T12:42:41.390675451Z github.com/cilium/cilium/pkg/endpoint/bpf.go:542 +0x1a5 2023-08-11T12:42:41.390681112Z github.com/cilium/cilium/pkg/endpoint.(*Endpoint).regenerate(0xc000982000, 0xc000e31800) 2023-08-11T12:42:41.390686893Z github.com/cilium/cilium/pkg/endpoint/policy.go:467 +0x9c6 2023-08-11T12:42:41.390692564Z github.com/cilium/cilium/pkg/endpoint.(*EndpointRegenerationEvent).Handle(0xc000131b50, 0x0?) 2023-08-11T12:42:41.390698385Z github.com/cilium/cilium/pkg/endpoint/events.go:53 +0x325 2023-08-11T12:42:41.390704045Z github.com/cilium/cilium/pkg/eventqueue.(*EventQueue).run.func1() 2023-08-11T12:42:41.390709716Z github.com/cilium/cilium/pkg/eventqueue/eventqueue.go:245 +0x142
Testing was done locally with l7Proxy=false, and then annotate a pod with visibility annotation
$ k annotate pod client-77bf9989dc-984xp policy.cilium.io/proxy-visibility="<Egress/80/TCP/HTTP>" --overwrite pod/client-77bf9989dc-984xp annotate $ ksyslo ds/cilium --timestamps | zgrep “ignoring L7 proxy visibility policy as L7 proxy is disabled” 2023-08-20T13:02:08.241508927Z level=warning msg="ignoring L7 proxy visibility policy as L7 proxy is disabled" ciliumEndpointName=default/client-77bf9989dc-984xp containerID=1ea0a77f5d containerInterface=eth0 datapathPolicyRevision=0 desiredPolicyRevision=0 endpointID=759 identity=831 ipv4=10.244.0.19 ipv6= k8sPodName=default/client-77bf9989dc-984xp subsys=endpoint
Related news
### Impact In Cilium clusters where Cilium's Layer 7 proxy has been disabled, creating workloads with - `policy.cilium.io/proxy-visibility` annotations (in Cilium >= v1.13) - `io.cilium.proxy-visibility` annotations (in Cilium <= v1.12) causes the Cilium agent to segfault on the node to which the workload is assigned. Existing traffic on the affected node will continue to flow, but the Cilium agent on the node will not able to process changes to workloads running on the node. This will also prevent workloads from being able to start on the affected node. The denial of service will be limited to the node on which the workload is scheduled, however an attacker may be able to schedule workloads on the node of their choosing, which could lead to targeted attacks. ### Patches [Pull request with fix](https://github.com/cilium/cilium/pull/27597) This issue affects: Cilium <= v1.14.1 Cilium <= v1.13.6 Cilium <= v1.12.13 This issue has been resolved in: Cilium v1.14.2 Cilium v1.13.7 C...