static int commit_match(struct commit *commit, struct rev_info *opt)
{
	int retval;
	const char *encoding;
	const char *message;
	struct strbuf buf = STRBUF_INIT;

	if (!opt->grep_filter.pattern_list && !opt->grep_filter.header_list)
		return 1;

	/* Prepend "fake" headers as needed */
	if (opt->grep_filter.use_reflog_filter) {
		strbuf_addstr(&buf, "reflog ");
		get_reflog_message(&buf, opt->reflog_info);
		strbuf_addch(&buf, '\n');
	}

	/*
	 * We grep in the user's output encoding, under the assumption that it
	 * is the encoding they are most likely to write their grep pattern
	 * for. In addition, it means we will match the "notes" encoding below,
	 * so we will not end up with a buffer that has two different encodings
	 * in it.
	 */
	encoding = get_log_output_encoding();
	message = logmsg_reencode(commit, NULL, encoding);

	/* Copy the commit to temporary if we are using "fake" headers */
	if (buf.len)
		strbuf_addstr(&buf, message);

	if (opt->grep_filter.header_list && opt->mailmap) {
		if (!buf.len)
			strbuf_addstr(&buf, message);

		commit_rewrite_person(&buf, "\nauthor ", opt->mailmap);
		commit_rewrite_person(&buf, "\ncommitter ", opt->mailmap);
	}

	/* Append "fake" message parts as needed */
	if (opt->show_notes) {
		if (!buf.len)
			strbuf_addstr(&buf, message);
		format_display_notes(commit->object.sha1, &buf, encoding, 1);
	}

	/*
	 * Find either in the original commit message, or in the temporary.
	 * Note that we cast away the constness of "message" here. It is
	 * const because it may come from the cached commit buffer. That's OK,
	 * because we know that it is modifiable heap memory, and that while
	 * grep_buffer may modify it for speed, it will restore any
	 * changes before returning.
	 */
	if (buf.len)
		retval = grep_buffer(&opt->grep_filter, buf.buf, buf.len);
	else
		retval = grep_buffer(&opt->grep_filter,
				     (char *)message, strlen(message));
	strbuf_release(&buf);
	unuse_commit_buffer(commit, message);
	return opt->invert_grep ? !retval : retval;
}

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary. This may result in read or write operations on unexpected memory locations that could be linked to other variables, data structures, or internal program data.