Prevent remote proxies from impersonating users from different clusters#33536
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Prevent remote proxies from impersonating users from different clusters#33536
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This PR prevents root proxies from impersonating users from different clusters when accessing a leaf cluster.
During authentication, the proxy presents its certificate and sends the impersonation header.
A malicious attacker in possession of the root cluster proxy cert-key pair could bypass the root-leaf cluster permissions boundary by impersonating local users. This PR prevents that and remote proxies can only impersonate users belonging to their cluster.
KubeCSR Flow:
```mermaid
sequenceDiagram
ROOT PROXY->>+LEAF PROXY: Forward the request identity cert
LEAF PROXY ->> LEAF AUTH SRV: Sign identity via KubeCSR
LEAF AUTH SRV -->> LEAF PROXY: Identity cert
LEAF PROXY ->> LEAF KUBE SERVICE: Forward the request using cert
LEAF KUBE SERVICE -->> LEAF PROXY: Return response
LEAF PROXY -->> ROOT PROXY: Return response
```
Impersonation Flow:
```mermaid
sequenceDiagram
ROOT PROXY->>+LEAF PROXY: Forward the request identity by Impersonating
LEAF PROXY ->> LEAF KUBE SERVICE: Forward the request identity by Impersonating
LEAF KUBE SERVICE -->> LEAF PROXY: Return response
LEAF PROXY -->> ROOT PROXY: Return response
```
Fixes gravitational/teleport-private#968
Signed-off-by: Tiago Silva <tiago.silva@goteleport.com>
r0mant
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Oct 16, 2023
rosstimothy
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Oct 16, 2023
| if proxyClusterName != "" && | ||
| proxyClusterName != clusterName.GetClusterName() && | ||
| proxyClusterName != identityClusterName { | ||
| log.Warnf("received Kube CSR for %v", identityClusterName) |
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…rs (#33536) * Prevent remote proxies from impersonating users from different clusters This PR prevents root proxies from impersonating users from different clusters when accessing a leaf cluster. During authentication, the proxy presents its certificate and sends the impersonation header. A malicious attacker in possession of the root cluster proxy cert-key pair could bypass the root-leaf cluster permissions boundary by impersonating local users. This PR prevents that and remote proxies can only impersonate users belonging to their cluster. KubeCSR Flow: ```mermaid sequenceDiagram ROOT PROXY->>+LEAF PROXY: Forward the request identity cert LEAF PROXY ->> LEAF AUTH SRV: Sign identity via KubeCSR LEAF AUTH SRV -->> LEAF PROXY: Identity cert LEAF PROXY ->> LEAF KUBE SERVICE: Forward the request using cert LEAF KUBE SERVICE -->> LEAF PROXY: Return response LEAF PROXY -->> ROOT PROXY: Return response ``` Impersonation Flow: ```mermaid sequenceDiagram ROOT PROXY->>+LEAF PROXY: Forward the request identity by Impersonating LEAF PROXY ->> LEAF KUBE SERVICE: Forward the request identity by Impersonating LEAF KUBE SERVICE -->> LEAF PROXY: Return response LEAF PROXY -->> ROOT PROXY: Return response ``` Fixes gravitational/teleport-private#968 Signed-off-by: Tiago Silva <tiago.silva@goteleport.com> * fix message
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…rs (#33536) (#33542) * Prevent remote proxies from impersonating users from different clusters This PR prevents root proxies from impersonating users from different clusters when accessing a leaf cluster. During authentication, the proxy presents its certificate and sends the impersonation header. A malicious attacker in possession of the root cluster proxy cert-key pair could bypass the root-leaf cluster permissions boundary by impersonating local users. This PR prevents that and remote proxies can only impersonate users belonging to their cluster. KubeCSR Flow: ```mermaid sequenceDiagram ROOT PROXY->>+LEAF PROXY: Forward the request identity cert LEAF PROXY ->> LEAF AUTH SRV: Sign identity via KubeCSR LEAF AUTH SRV -->> LEAF PROXY: Identity cert LEAF PROXY ->> LEAF KUBE SERVICE: Forward the request using cert LEAF KUBE SERVICE -->> LEAF PROXY: Return response LEAF PROXY -->> ROOT PROXY: Return response ``` Impersonation Flow: ```mermaid sequenceDiagram ROOT PROXY->>+LEAF PROXY: Forward the request identity by Impersonating LEAF PROXY ->> LEAF KUBE SERVICE: Forward the request identity by Impersonating LEAF KUBE SERVICE -->> LEAF PROXY: Return response LEAF PROXY -->> ROOT PROXY: Return response ``` Fixes gravitational/teleport-private#968 Signed-off-by: Tiago Silva <tiago.silva@goteleport.com> * fix message
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This PR prevents root proxies from impersonating users from different clusters when accessing a leaf cluster.
During authentication, the proxy presents its certificate and sends the impersonation header.
A malicious attacker in possession of the root cluster proxy cert-key pair could bypass the root-leaf cluster permissions boundary by impersonating local users. This PR prevents that and remote proxies can only impersonate users belonging to their cluster.
KubeCSR Flow:
sequenceDiagram ROOT PROXY->>+LEAF PROXY: Forward the request identity cert LEAF PROXY ->> LEAF AUTH SRV: Sign identity via KubeCSR LEAF AUTH SRV -->> LEAF PROXY: Identity cert LEAF PROXY ->> LEAF KUBE SERVICE: Forward the request using cert LEAF KUBE SERVICE -->> LEAF PROXY: Return response LEAF PROXY -->> ROOT PROXY: Return responseImpersonation Flow:
sequenceDiagram ROOT PROXY->>+LEAF PROXY: Forward the request identity by Impersonating LEAF PROXY ->> LEAF KUBE SERVICE: Forward the request identity by Impersonating LEAF KUBE SERVICE -->> LEAF PROXY: Return response LEAF PROXY -->> ROOT PROXY: Return responseContributes to gravitational/teleport-private#968
Signed-off-by: Tiago Silva tiago.silva@goteleport.com