From: Tracey Emery <tracey@traceyemery.net>
Subject: Re: fix tog segfault during search
To: gameoftrees@openbsd.org
Date: Thu, 16 Jun 2022 14:45:42 -0600

On Thu, Jun 16, 2022 at 10:43:06PM +0200, Stefan Sperling wrote:
> When searching in diff or blame views, and pressing n or N repeatedly,
> tog can segfault in expand_tab. Patch below seems to fix this for me.
> 
> Reported by Omar on IRC.
> 
> ok?

ok

> 
> diff 87411fa9fa02ed103ef9b39edb8f2751155567c7 /home/stsp/src/got
> blob - bdff5844ccda157277e95325887def00e1f69e73
> file + tog/tog.c
> --- tog/tog.c
> +++ tog/tog.c
> @@ -3671,7 +3671,7 @@ search_next_diff_view(struct tog_view *view)
>  	struct tog_diff_view_state *s = &view->state.diff;
>  	const struct got_error *err = NULL;
>  	int lineno;
> -	char *exstr = NULL, *line = NULL;
> +	char *line = NULL;
>  	size_t linesize = 0;
>  	ssize_t linelen;
>  
> @@ -3709,24 +3709,26 @@ search_next_diff_view(struct tog_view *view)
>  			return got_error_from_errno("fseeko");
>  		}
>  		linelen = getline(&line, &linesize, s->f);
> -		err = expand_tab(&exstr, line);
> -		if (err)
> -			break;
> -		if (linelen != -1 &&
> -		    match_line(exstr, &view->regex, 1, &view->regmatch)) {
> -			view->search_next_done = TOG_SEARCH_HAVE_MORE;
> -			s->matched_line = lineno;
> -			break;
> +		if (linelen != -1) {
> +			char *exstr;
> +			err = expand_tab(&exstr, line);
> +			if (err)
> +				break;
> +			if (match_line(exstr, &view->regex, 1,
> +			    &view->regmatch)) {
> +				view->search_next_done = TOG_SEARCH_HAVE_MORE;
> +				s->matched_line = lineno;
> +				free(exstr);
> +				break;
> +			}
> +			free(exstr);
>  		}
> -		free(exstr);
> -		exstr = NULL;
>  		if (view->searching == TOG_SEARCH_FORWARD)
>  			lineno++;
>  		else
>  			lineno--;
>  	}
>  	free(line);
> -	free(exstr);
>  
>  	if (s->matched_line) {
>  		s->first_displayed_line = s->matched_line;
> @@ -4810,7 +4812,7 @@ search_next_blame_view(struct tog_view *view)
>  	struct tog_blame_view_state *s = &view->state.blame;
>  	const struct got_error *err = NULL;
>  	int lineno;
> -	char *exstr = NULL, *line = NULL;
> +	char *line = NULL;
>  	size_t linesize = 0;
>  	ssize_t linelen;
>  
> @@ -4848,24 +4850,26 @@ search_next_blame_view(struct tog_view *view)
>  			return got_error_from_errno("fseeko");
>  		}
>  		linelen = getline(&line, &linesize, s->blame.f);
> -		err = expand_tab(&exstr, line);
> -		if (err)
> -			break;
> -		if (linelen != -1 &&
> -		    match_line(exstr, &view->regex, 1, &view->regmatch)) {
> -			view->search_next_done = TOG_SEARCH_HAVE_MORE;
> -			s->matched_line = lineno;
> -			break;
> +		if (linelen != -1) {
> +			char *exstr;
> +			err = expand_tab(&exstr, line);
> +			if (err)
> +				break;
> +			if (match_line(exstr, &view->regex, 1,
> +			    &view->regmatch)) {
> +				view->search_next_done = TOG_SEARCH_HAVE_MORE;
> +				s->matched_line = lineno;
> +				free(exstr);
> +				break;
> +			}
> +			free(exstr);
>  		}
> -		free(exstr);
> -		exstr = NULL;
>  		if (view->searching == TOG_SEARCH_FORWARD)
>  			lineno++;
>  		else
>  			lineno--;
>  	}
>  	free(line);
> -	free(exstr);
>  
>  	if (s->matched_line) {
>  		s->first_displayed_line = s->matched_line;
> 

-- 

Tracey Emery