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Fix unbounded recursion (DoS) in UefiParser.parse_firmware_volume via zero-length FV header - #115
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sys-xmlcli wants to merge 1 commit into
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prakashb72
approved these changes
Sep 28, 2026
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Copilot review overview
🟡 Changes recommended
The security fix lacks a focused regression test covering a zero-length firmware-volume header.
Review effort: Balanced
Findings: 1
Open (1)
What changed in this PR
Prevents infinite recursion when parsing malformed zero-length UEFI firmware volumes.
Changes:
- Rejects firmware-volume headers whose
FvLengthis zero. - Ensures recursive parsing advances through the buffer.
| File | Description |
|---|---|
src/xmlcli/common/bios_fw_parser.py |
Validates firmware-volume length before parsing. |
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| has_valid_zero_vector = utils.get_integer_value(firmware_volume_header.get_value("ZeroVector")) == 0 | ||
| if has_valid_signature and has_valid_zero_vector: | ||
| # FvLength must be non-zero to guarantee forward progress on the recursive parse walk | ||
| has_valid_length = utils.get_integer_value(firmware_volume_header.get_value("FvLength")) > 0 |
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