fix: do not proxy traffic to sockets #60
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This commit implements a proxy-exception for traffic targeting local sockets instead of a "host:port" combination. If such traffic would be forwarded through the proxy, the socket destination info would be lost, while a "localhost:80" destination would be added. This means that the proxy cannot handle such requests correctly either way, which makes sending traffic to the proxy pointless. Because of that, if the agent receives traffic destined for a socket, it will simply use the fallback agent to handle that traffic.
tommyknows
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Oct 19, 2022
For CLIv2, all traffic is proxied through a local server that the CLIv2 spawns. This is achieved by updating the `http.globalAgent` and `http.request` and `http.get` functions through the `global-agent` library. However, this causes issues with HTTP traffic that is supposed to go to local sockets. For example, `snyk container` talks to the `/var/run/docker.sock` socket for doing some image operations (if the socket exists). When the http agent and functions are replaced, this causes traffic to the socket to be routed to / through the proxy, and because at that point it is "proper" HTTP traffic, the destination is not the socket anymore but `localhost:80` (the fallback). The proxy has no way of handling this correctly, as all the information of the socket is lost. To fix this, there would have been two possibilities: - Make it possible to use custom agents. Currently, even if a user creates a custom agent and passes it to `http.request` or `http.get`, this custom agent will not be used. This is because the `global-agent` library *enforces* the usage of the proxy-agent. There is a flag to change this behaviour (`forceGLobalAgent`), but we do not want to use this as traffic should *always* go through the proxy. - Fix the `global-agent` library to not use the proxy-agent if traffic is supposed to go to sockets. A [PR](gajus/global-agent#60) has been raised on the library, but the repository seems to be unmaintaned. Because we need this fix to continue with the app vulnerability enablement, this commit adds a `postinstall` hook that patches the library in the `node-modules` folder through a `git apply` command. With the applied patch, traffic to the Docker socket (and all other sockets) will not be rerouted through the proxy anymore.
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This commit implements a proxy-exception for traffic targeting local sockets instead of a "host:port" combination. If such traffic would be forwarded through the proxy, the socket destination info would be lost, while a "localhost:80" destination would be added. This means that the proxy cannot handle such requests correctly either way, which makes sending traffic to the proxy pointless.
Because of that, if the agent receives traffic destined for a socket, it will simply use the fallback agent to handle that traffic.
Fixes #59.