fix: two memcpy calls in kquant_helpers in kquant_helpers.h

[orbisai0security]

Summary

Fix critical severity security issue in include/kquant_helpers.h.

Vulnerability

Field	Value
ID	V-001
Severity	CRITICAL
Scanner	multi_agent_ai
Rule	V-001
File	include/kquant_helpers.h:20
CWE	CWE-120

Description: Two memcpy calls in kquant_helpers.h use hardcoded byte counts (12 and 16) without verifying that the destination buffers 'aux' and 'out' are at least that large. If the destination buffers are declared smaller than the hardcoded sizes due to a type mismatch or caller error, or if the source 'scales' buffer is smaller than 12 bytes, a heap or stack buffer overflow or out-of-bounds read occurs. These helpers are invoked during quantized model weight processing, meaning a crafted model file can reliably trigger this code path.

Changes

• include/kquant_helpers.h

Verification

• Build passes
• Scanner re-scan confirms fix
• LLM code review passed

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Automated security fix by OrbisAI Security

[k0zi]

aux[4] is size of 4. I understand that 3 is derived from 12 but isn't it better use 4*sizeof?

[orbisai0security]

I think 3 * sizeof(uint32_t) is intentional rather than 4 * sizeof(uint32_t): the function copies the 12-byte packed scale representation into aux[0..2], then computes aux[3] from the packed bits before writing the 16-byte unpacked result to out. Changing the first copy to 4 * sizeof(uint32_t) would read 16 bytes from scales, which may be incorrect if the caller provides the expected 12-byte packed buffer.