escape crlf and quotes in streaming multipart part headers#3418
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yvasyliev
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velo
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Thanks for tightening the streaming multipart header generation. The escaping is covered for both field name and filename, it fixes a real header-injection risk, and I do not see a compatibility issue with the percent-encoded quoted parameter values.
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Backport of #3417 to the streaming
MultipartFormEncoderadded in #3414, as requested there.Repro: send a streamed multipart request whose part
nameorFormDatafilenamecontains"or a CRLF, e.g.evil"\r\nX-Injected: 1.Cause:
AbstractPartEncoder.createHeadersappends the field name and file name straight into the quotedContent-Dispositionparameters, so the value can close the quote and start a new header line or part. Same issue as the legacy writers fixed in #3417, on the new streaming path.Fix: percent-encode
\r,\nand"in those parameters (escapeHeaderParameter), matching the WHATWGmultipart/form-dataencoding rules. AddedAbstractPartEncoderTestcovering an injected name and file name.