[LTP] ujson: Fix 4-byte UTF-8 sequence decoding

[linuxtestproject.agent@gmail.com]

Hi Andrea,

On 13 October 2026, Andrea Cervesato wrote:
> ujson: Fix 4-byte UTF-8 sequence decoding

--- [PATCH 7/15] ---

> ujson: reader: Check for signed integer overflow
> diff --git a/libs/ujson/ujson_reader.c b/libs/ujson/ujson_reader.c
> +	if (sign < 0)
> +		res->val_int = -(long)val;

Medium severity: the bound allows LONG_MAX + 1 for negative input, but
-(long)val then negates LONG_MIN, causing signed overflow on both LP64 and
ILP32. Parsing [-9223372036854775808] on LP64 triggers UBSan here. Assign
LONG_MIN directly for that magnitude, or accumulate negative values without
negating LONG_MIN.

Verdict - Needs revision

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LTP AI Reviewer