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DOST: Ceph in a security critical OpenStack cloud
The document discusses implementing Ceph within a secure OpenStack cloud environment, particularly focusing on Deutsche Telekom's NFV cloud design and security measures. It outlines proactive and reactive countermeasures against various attack surfaces and emphasizes the importance of separation of security zones and robust key management. The document also highlights ongoing efforts to enhance security practices, including encryption and vulnerability assessment processes.
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DOST: Ceph in a security critical OpenStack cloud
- 1. Ceph in asecurity critical OpenStack cloud Danny Al-Gaaf (Deutsche Telekom) Deutsche OpenStack Tage 2015 - Frankfurt
- 2. ● Ceph andOpenStack ● Secure NFV cloud at DT ● Attack surface ● Proactive countermeasures ○ Setup ○ Vulnerability prevention ○ Breach mitigation ● Reactive countermeasures ○ 0-days, CVEs ○ Security support SLA and lifecycle ● Conclusions Overview 2
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- 6. Secure NFV Cloud@ DT
- 7. NFV Cloud @Deutsche Telekom ● Datacenter design ○ BDCs ■ few but classic DCs ■ high SLAs for infrastructure and services ■ for private/customer data and services ○ FDCs ■ small but many ■ near to the customer ■ lower SLAs, can fail at any time ■ NFVs: ● spread over many FDCs ● failures are handled by services and not the infrastructure ● Run telco core services @ OpenStack/KVM/Ceph 7
- 8. Fundamentals - TheCIA Triad 8 CONFIDENTIALITY INTEGRITY AVAILABILITY Preventing sensitive data against unauthorized access Maintaining consistency, accuracy, and trustworthiness of data Protecting systems against disrupting services and availability of information
- 9. High Security Requirements ●Multiple security placement zones (PZ) ○ e.g. EHD, DMZ, MZ, SEC, Management ○ TelcoWG “Security Segregation” use case ● Separation between PZs required for: ○ compute ○ networks ○ storage ● Protect against many attack vectors ● Enforced and reviewed by security department 9
- 10. Solutions for storageseparation ● Physical separation ○ Large number of clusters (>100) ○ Large hardware demand (compute and storage) ○ High maintenance effort ○ Less flexibility ● RADOS pool separation ○ Much more flexible ○ Efficient use of hardware ● Question: ○ Can we get the same security as physical separation? 10
- 11. Separation through PlacementZones ● One RADOS pool for each security zone ○ Limit access using Ceph capabilities ● OpenStack AZs as PZs ○ Cinder ■ Configure one backend/volume type per pool (with own key) ■ Need to map between AZs and volume types via policy ○ Glance ■ Lacks separation between control and compute/storage layer ■ Separate read-only vs management endpoints ○ Manila ■ Currently not planned to use in production with CephFS ■ May use RBD via NFS 11
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- 13. RadosGW attack surface ●S3/Swift ○ Network access to gateway only ○ No direct access for consumer to other Ceph daemons ● Single API attack surface 13
- 14. RBD librbd attacksurface ● Protection from hypervisor block layer ○ transparent for the guest ○ No network access or CephX keys needed at guest level ● Issue: ○ hypervisor is software and therefore not 100% secure… ■ breakouts are no mythical creature ■ e.g., Virtunoid, SYSENTER, Venom!14
- 15. RBD.ko attack surface ●RBD kernel module ○ e.g. used with XEN or on bare metal ○ Requires direct access to Ceph public network ○ Requires CephX keys/secret at guest level ● Issue: ○ no separation between cluster and guest 15
- 16. CephFS attack surface ●pure CephFS tears a big hole in hypervisor separation ○ Requires direct access to Ceph public network ○ Requires CephX keys/secret at guest level ○ Complete file system visible to guest ■ Separation currently only via POSIX user/group 16
- 17. Host attack surface ●If KVM is compromised, the attacker ... ○ has access to neighbor VMs ○ has access to local Ceph keys ○ has access to Ceph public network and Ceph daemons ● Firewalls, deep packet inspection (DPI), ... ○ partly impractical due to used protocols ○ implications to performance and cost ● Bottom line: Ceph daemons must resist attack ○ C/C++ is harder to secure than e.g. Python ○ Homogenous: if one daemon is vulnerable, all in the cluster are! 17
- 18. Network attack surface ●Sessions are authenticated ○ Attacker cannot impersonate clients or servers ○ Attacker cannot mount man-in-the-middle attacks ● Client/cluster sessions are not encrypted ○ Sniffer can recover any data read or written 18
- 19. Denial of Service ●Attack against: ○ Ceph Cluster: ■ Submit many / large / expensive IOs ■ Open many connections ■ Use flaws to crash Ceph daemons ■ Identify non-obvious but expensive features of client/OSD interface ○ Ceph Cluster hosts: ■ Crash complete cluster hosts e.g. through flaws in kernel network layer ○ VMs on same host: ■ Saturate the network bandwidth of the host 19
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- 21. Deployment and Setup ●Network ○ Always use separated cluster and public networks ○ Always separate your control nodes from other networks ○ Don’t expose cluster to the open internet ○ Encrypt inter-datacenter traffic ● Avoid hyper-converged infrastructure ○ Don’t mix ■ compute and storage resources, isolate them! ■ OpenStack and Ceph control nodes ○ Scale resources independently ○ Risk mitigation if daemons are compromised or DoS’d 21
- 22. Deploying RadosGW ● Bigand easy target through HTTP(S) protocol ● Small appliance per tenant with ○ Separate network ○ SSL terminated proxy forwarding requests to radosgw ○ WAF (mod_security) to filter ○ Placed in secure/managed zone ○ different type of webserver than RadosGW ● Don’t share buckets/users between tenants22
- 23. Ceph security: CephX ●Monitors are trusted key servers ○ Store copies of all entity keys ○ Each key has an associated “capability” ■ Plaintext description of what the key user is allowed to do ● What you get ○ Mutual authentication of client + server ○ Extensible authorization w/ “capabilities” ○ Protection from man-in-the-middle, TCP session hijacking ● What you don’t get ○ Secrecy (encryption over the wire) 23
- 24. Ceph security: CephXtake-aways ● Monitors must be secured ○ Protect the key database ● Key management is important ○ Separate key for each Cinder backend/AZ ○ Restrict capabilities associated with each key ○ Limit administrators’ power ■ use ‘allow profile admin’ and ‘allow profile readonly’ ■ restrict role-definer or ‘allow *’ keys ○ Careful key distribution (Ceph and OpenStack nodes) ● To do: ○ Thorough CephX code review by security experts ○ Audit OpenStack deployment tools’ key distribution ○ Improve security documentation24
- 25. ● Static CodeAnalysis (SCA) ○ Buffer overflows and other code flaws ○ Regular Coverity scans ■ 996 fixed, 284 dismissed; 420 outstanding ■ defect density 0.97 ○ cppcheck ○ LLVM: clang/scan-build ● Runtime analysis ○ valgrind memcheck ● Plan ○ Reduce backlog of low-priority issues (e.g., issues in test code) ○ Automated reporting of new SCA issues on pull requests ○ Improve code reviewer awareness of security defects Preventing Breaches - Defects 25
- 26. ● Pen-testing ○ humanattempt to subvert security, generally guided by code review ● Fuzz testing ○ computer attempt to subvert or crash, by feeding garbage input ● Harden build ○ -fpie -fpic ○ -stack-protector=strong ○ -Wl,-z,relro,-z,now ○ -D_FORTIFY_SOURCE=2 -O2 (?) ○ Check for performance regression! Preventing Breaches - Hardening 26
- 27. Mitigating Breaches ● Runnon-root daemons (WIP: PR #4456) ○ Prevent escalating privileges to get root ○ Run as ‘ceph’ user and group ○ Pending for Infernalis ● MAC ○ SELinux / AppArmor ○ Profiles for daemons and tools planned for Infernalis ● Run (some) daemons in VMs or containers ○ Monitor and RGW - less resource intensive ○ MDS - maybe ○ OSD - prefers direct access to hardware ● Separate MON admin network 27
- 28. Encryption: Data atRest ● Encryption at application vs cluster level ● Some deployment tools support dm-crypt ○ Encrypt raw block device (OSD and journal) ○ Allow disks to be safely discarded if key remains secret ● Key management is still very simple ○ Encryption key stored on disk via LUKS ○ LUKS key stored in /etc/ceph/keys ● Plan ○ Petera, a new key escrow project from Red Hat ■ https://github.com/npmccallum/petera ○ Alternative: simple key management via monitor (CDS blueprint) 28
- 29. ● Goal ○ Protectdata from someone listening in on network ○ Protect administrator sessions configuring client keys ● Plan ○ Generate per-session keys based on existing tickets ○ Selectively encrypt monitor administrator sessions ○ alternative: make use of IPSec (performance and management implications) Encryption: On Wire 29
- 30. ● Limit loadfrom client ○ Use qemu IO throttling features - set safe upper bound ● To do: ○ Limit max open sockets per OSD ○ Limit max open sockets per source IP ■ handle on Ceph or in the network layer? ○ Throttle operations per-session or per-client (vs just globally)? Denial of Service attacks 30
- 31. CephFS ● No standardvirtualization layer (unlike block) ○ Filesystem passthrough (9p/virtfs) to host ○ Proxy through gateway (NFS?) ○ Allow direct access from tenant VM (most unsecure) ● Granularity of access control is harder ○ No simple mapping to RADOS objects ● Work in progress ○ root_squash (Infernalis blueprint) ○ Restrict mount to subtree ○ Restrict mount to user 31
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- 33. ● Community ○ Singlepoint of contact: security@ceph.com ■ Core development team ■ Red Hat, SUSE, Canonical security teams ○ Security related fixes are prioritized and backported ○ Releases may be accelerated on ad hoc basis ○ Security advisories to ceph-announce@ceph.com ● Red Hat Ceph ○ Strict SLA on issues raised with Red Hat security team ○ Escalation process to Ceph developers ○ Red Hat security team drives CVE process ○ Hot fixes distributed via Red Hat’s CDN Reactive Security Process 33
- 34. Detecting and PreventingBreaches ● Brute force attacks ○ Good logging of any failed authentication ○ Monitoring easy via existing tools like e.g. Nagios ● To do: ○ Automatic blacklisting IPs/clients after n-failed attempts on Ceph level (Jewel blueprint) ● Unauthorized injection of keys ○ Monitor the audit log ■ trigger alerts for auth events -> monitoring ○ Periodic comparison with signed backup of auth database? 34
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- 36. Summary ● Reactive processesare in place ○ security@ceph.com, CVEs, downstream product updates, etc. ● Proactive measures in progress ○ Code quality improves (SCA, etc.) ○ Unprivileged daemons ○ MAC (SELinux, AppArmor) ○ Encryption ● Progress defining security best-practices ○ Document best practices for security ● Ongoing process 36
- 37. Get involved ! ●Ceph ○ https://ceph.com/community/contribute/ ○ ceph-devel@vger.kernel.org ○ IRC: OFTC ■ #ceph, ■ #ceph-devel ○ Ceph Developer Summit ● OpenStack ○ Telco Working Group ■ #openstack-nfv ○ Cinder, Glance, Manila, ... 37
- 38. danny.al-gaaf@telekom.de dalgaaf linkedin.com/in/dalgaaf Danny Al-Gaaf Senior CloudTechnologist IRC THANK YOU!