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fix(middleware-ssec): ssecMiddleware with strict base64 validation #5875

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merged 3 commits into from
Mar 18, 2024
Merged

fix(middleware-ssec): ssecMiddleware with strict base64 validation #5875

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fix(middleware-ssec): ssecMiddleware with strict base64 validation
RanVaknin Mar 8, 2024
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fix(middleware-ssec): ssecMiddleware with strict base64 validation, u…
RanVaknin Mar 12, 2024
ec42c41
fix(middleware-ssec): ssecMiddleware with strict base64 validation wi…
RanVaknin Mar 14, 2024
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19 changes: 17 additions & 2 deletions packages/middleware-ssec/src/index.ts
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Original file line number Diff line number Diff line change
Expand Up @@ -39,8 +39,7 @@ export function ssecMiddleware(options: PreviouslyResolved): InitializeMiddlewar
if (value) {
let valueForHash: Uint8Array;
if (typeof value === "string") {
const isBase64Encoded = /^(?:[A-Za-z0-9+/]{4})*([A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=)?$/.test(value);
if (isBase64Encoded) {
if (isValidBase64(value)) {
valueForHash = options.base64Decoder(value);
} else {
valueForHash = options.utf8Decoder(value);
Expand Down Expand Up @@ -78,3 +77,19 @@ export const getSsecPlugin = (config: PreviouslyResolved): Pluggable<any, any> =
clientStack.add(ssecMiddleware(config), ssecMiddlewareOptions);
},
});

function isValidBase64(str: string) {
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const base64Regex = /^(?:[A-Za-z0-9+/]{4})*([A-Za-z0-9+/]{2}==|[A-Za-z0-9+/]{3}=)?$/;

if (!base64Regex.test(str)) return false;

try {
const decodedBytes = Buffer.from(str, "base64");
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if (decodedBytes.length !== 32) return false;

const reEncoded = decodedBytes.toString("base64");
return str === reEncoded;
} catch {
return false;
}
}
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