fix: add decompression size limit to prevent decompression bomb DoS#1780
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eddieran wants to merge 1 commit intoHopding:masterfrom
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fix: add decompression size limit to prevent decompression bomb DoS#1780eddieran wants to merge 1 commit intoHopding:masterfrom
eddieran wants to merge 1 commit intoHopding:masterfrom
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Add a configurable maximum decompressed size limit (default 100 MB) to DecodeStream. When the accumulated decompressed output exceeds this threshold, an error is thrown instead of continuing to allocate memory. This prevents denial-of-service attacks where a small, crafted compressed PDF stream expands into gigabytes of data, exhausting the host's available memory. The limit is enforced in ensureBuffer() and defaults to 100 MB, which is sufficient for legitimate PDF content while blocking pathological expansion ratios. Fixes Hopding#1777
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Summary
Adds a configurable maximum decompressed size limit to
DecodeStreamto prevent decompression bomb denial-of-service attacks.Problem: A crafted PDF can contain a small compressed stream that expands into gigabytes of data when decompressed, exhausting the host's available memory (decompression bomb / zip bomb). The
DecodeStreambase class had no upper bound on buffer growth —ensureBuffer()would keep doubling the internal buffer indefinitely.Fix: Enforce a maximum decompressed size (default 100 MB) in
ensureBuffer(). When the accumulated output exceeds this threshold, an error is thrown instead of continuing to allocate memory. The limit is configurable via themaxDecompressedSizeconstructor parameter for users who need to process legitimately large streams.Changes
DEFAULT_MAX_DECOMPRESSED_SIZEconstant (100 MB)maxDecompressedSizeparameter toDecodeStreamconstructor (with default)ensureBuffer()that throws before allocating beyond the limitBackward Compatibility
The new parameter has a default value, so all existing subclasses (
FlateStream,LZWStream,AsciiHexStream,Ascii85Stream,RunLengthStream) work without modification. The 100 MB default is large enough for any legitimate PDF content.Fixes #1777. Replaces #1779 (which was auto-closed when the source fork was deleted).