Re: [Fwd: Bug#488430: iproute: lnstat causes segmentation fault]

[Andreas Henriksson <andreas@fatal.se>]

On mån, 2008-06-30 at 10:36 -0700, Stephen Hemminger wrote:
> The problem is that MAX_FIELDS is 64, but lnstat is finding 71 fields.
> This causes a array out of range problem.
> 
> Just bump MAX_FIELDS to 128

Oh, stupid me to not catch that when I was thinking it used un-allocated
memory and all...
Here's a patch that prevents the overflow and throws a warning instead.


diff --git a/misc/lnstat.c b/misc/lnstat.c
index b56598a..5a0c349 100644
--- a/misc/lnstat.c
+++ b/misc/lnstat.c
@@ -121,6 +121,10 @@ static int map_field_params(struct lnstat_file *lnstat_files,
 				if (!fps->params[j].print.width)
 					fps->params[j].print.width =
 							FIELD_WIDTH_DEFAULT;
+				if (j >= MAX_FIELDS) {
+					fprintf(stderr, "WARN: MAX_FIELDS (%d) reached, truncating input data.\n", MAX_FIELDS);
+					break;
+				}
 				j++;
 			}
 		}
@@ -269,8 +273,10 @@ int main(int argc, char **argv)
 				for (tok = strtok(tmp, ",");
 				     tok;
 				     tok = strtok(NULL, ",")) {
-					if (fp.num >= MAX_FIELDS)
+					if (fp.num >= MAX_FIELDS) {
+						fprintf(stderr, "WARN: MAX_FIELDS (%d) reached, truncating given keys.\n", MAX_FIELDS);
 						break;
+					}
 					fp.params[fp.num++].name = tok;
 				}
 				break;

-- 
Regards,
Andreas Henriksson