Re: [PATCH] fuzz: add new oss-fuzz fuzzer for date.c / date.h

From: Junio C Hamano <gitster@pobox.com>
Date: Nov 12, 2023, 12:39 UTC
Message-ID: <xmqq7cmnno1n.fsf@gitster.g>
In-Reply-To: <xmqqfs1bo6l4.fsf@gitster.g>

Junio C Hamano <gitster@pobox.com> writes:

Show 8 quoted lines

> As I used the first byte to fuzz dmtype and .local, let's use the
> next three bytes to allow feeding overly wild timezone values to the
> machinery and see what breaks, perhaps like so:
>
> 	tz = *data++; /* int tz; */
> 	tz = (tz << 8) | *data++;
> 	tz = (tz << 8) | *data++;
> 	size -= 3;

Just this part. As data points at unsigned char, the above would not give us any negative number. We'd need to sign-extend the 24-bit resulting value if we are going to adopt the above approach.