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test: assume priv ports start at 1024 if it can't be changed #46536

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merged 3 commits into from
Mar 2, 2023

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An update to test/parallel/test-cluster-bind-privileged-port.js checks the lowest privileged port to ensure 42 is privileged This only works on kernels > 4.1. On older kernels, this is locked at 1024 so the check is not needed.

Fixes: #45838

An update to test/parallel/test-cluster-bind-privileged-port.js
checks the lowest privileged port to ensure 42 is privileged
This only works on kernels > 4.1. On older kernels, this is
locked at 1024 so the check is not needed.

Fixes: nodejs#45838
@nodejs-github-bot nodejs-github-bot added needs-ci PRs that need a full CI run. test Issues and PRs related to the tests. labels Feb 7, 2023
Comment on lines 30 to 36
const procFileName = '/proc/sys/net/ipv4/ip_unprivileged_port_start';
// Does not exist for Kernel < 4.1 where answer is 1024. So only test limit if limit exists
if (statSync(procFileName, { throwIfNoEntry: false })) {
const unprivilegedPortStart = parseInt(readFileSync(procFileName));
if (unprivilegedPortStart <= 42) {
common.skip('Port 42 is unprivileged');
}
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This is a TOCTOU pattern. While mostly academic in this context, node users sometimes copy "best practices" from the test suite so I'd rather not merge this code as-is. Open the file and handle the error when it's not there.

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Agreed. While the TOCTOU race condition can never occur here, your reasoning is all sound. I'll replace it with a try block. Just dislike empty catch blocks but we'll throw a comment in there.
Done.

if (unprivilegedPortStart <= 42) {
common.skip('Port 42 is unprivileged');
try {
const sysctlOutput = execSync('sysctl net.ipv4.ip_unprivileged_port_start').toString();
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@lpinca lpinca Feb 8, 2023

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This basically reverts f69e84c. Can't you simply handle the error thrown by readFileSync('/proc/sys/net/ipv4/ip_unprivileged_port_start') when the file does not exist?

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Oh, that is so embarrassing. I am doing this in v19 and v18 (the one I'm actually trying to deploy). Went back to the old one. Ignore this. Will fix in next few hours. ARGGHHH

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OK, fixed. Needed more coffee. Working in 3 places (v19 source, v18 source, my build).

if (unprivilegedPortStart <= 42) {
common.skip('Port 42 is unprivileged');
try {
const unprivilegedPortStart = parseInt(readFileSync('/proc/sys/net/ipv4/ip_unprivileged_port_start'));
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Just a nit that you are free to ignore. I would put only readFileSync() in the try...catch.

let unprivilegedPortStart:

try {
  unprivilegedPortStart = readFileSync('/proc/sys/net/ipv4/ip_unprivileged_port_start');
} catch {
  // Do nothing.
}

if (parseInt(unprivilegedPortStart) <= 42) {
  common.skip('Port 42 is unprivileged');
}

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I considered that (and even wrote it). The above I dislike a bit because parseInt returns NaN and Nan <=42 which means it'll work but it's very obscure. First thing you think is "isn't this broken"? So you probably want a "unprivilegedPortStart = 1024;" in the catch which is what the scenario REALLY is when the readFileSync fails.

BUT The entire test of minimum ports, etc is irrelevant when that read fails. That indicates the ability to change the minimum doesn't exist hence even considering it is irrelevant.

So I went with "if the read fails, this entire block of code is irrelevant".

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We could be explicit and do

if (unprivilegedPortStart !== undefined && parseInt(unprivilegedPortStart) <= 42) {
  common.skip('Port 42 is unprivileged');
}

My reasoning is that only things that are expected to throws errors should be in the try block to avoid hiding unexpected exception.

Anyway, it is only a nit. It is ok as is.

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@aduh95 aduh95 added commit-queue Add this label to land a pull request using GitHub Actions. commit-queue-squash Add this label to instruct the Commit Queue to squash all the PR commits into the first one. labels Mar 2, 2023
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@nodejs-github-bot nodejs-github-bot merged commit 024e648 into nodejs:main Mar 2, 2023
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targos pushed a commit that referenced this pull request Mar 13, 2023
An update to test/parallel/test-cluster-bind-privileged-port.js
checks the lowest privileged port to ensure 42 is privileged
This only works on kernels > 4.1. On older kernels, this is
locked at 1024 so the check is not needed.

Fixes: #45838
PR-URL: #46536
Reviewed-By: Luigi Pinca <[email protected]>
targos pushed a commit that referenced this pull request Mar 14, 2023
An update to test/parallel/test-cluster-bind-privileged-port.js
checks the lowest privileged port to ensure 42 is privileged
This only works on kernels > 4.1. On older kernels, this is
locked at 1024 so the check is not needed.

Fixes: #45838
PR-URL: #46536
Reviewed-By: Luigi Pinca <[email protected]>
danielleadams pushed a commit that referenced this pull request Apr 11, 2023
An update to test/parallel/test-cluster-bind-privileged-port.js
checks the lowest privileged port to ensure 42 is privileged
This only works on kernels > 4.1. On older kernels, this is
locked at 1024 so the check is not needed.

Fixes: #45838
PR-URL: #46536
Reviewed-By: Luigi Pinca <[email protected]>
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test: check net.ipv4.ip_unprivileged_port_start in parallel/test-cluster-bind-privileged-port
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