ss: avoid passing negative numbers to malloc

Example:

$ ss state established \( sport = :4060  or sport = :4061 or sport = :4062  or sport = :4063 or sport = :4064  or sport = :4065 or sport = :4066  or sport = :4067 \)  > /dev/null
Aborted

In the example above ssfilter_bytecompile(...) will return (int)136.
char l1 = 136; means -120 which will result in a negative number
being passed to malloc at misc/ss.c:913.

Simply declare l1 and l2 as integers to avoid the char overflow.

This is one of the issues originally reported in http://bugs.debian.org/511720

Fix the same problem in other code paths as well (thanks to Eric Dumazet).
Reported-by: Andreas Schuldei <andreas@debian.org>
Signed-off-by: Andreas Henriksson <andreas@fatal.se>
Reviewed-by: Eric Dumazet <edumazet@google.com>

misc/ss.c

@@ -894,7 +894,8 @@ static int ssfilter_bytecompile(struct ssfilter *f, char **bytecode)
 
 		case SSF_AND:
 	{
-		char *a1, *a2, *a, l1, l2;
+		char *a1, *a2, *a;
+		int l1, l2;
 		l1 = ssfilter_bytecompile(f->pred, &a1);
 		l2 = ssfilter_bytecompile(f->post, &a2);
 		if (!(a = malloc(l1+l2))) abort();
@@ -907,7 +908,8 @@ static int ssfilter_bytecompile(struct ssfilter *f, char **bytecode)
 	}
 		case SSF_OR:
 	{
-		char *a1, *a2, *a, l1, l2;
+		char *a1, *a2, *a;
+		int l1, l2;
 		l1 = ssfilter_bytecompile(f->pred, &a1);
 		l2 = ssfilter_bytecompile(f->post, &a2);
 		if (!(a = malloc(l1+l2+4))) abort();
@@ -920,7 +922,8 @@ static int ssfilter_bytecompile(struct ssfilter *f, char **bytecode)
 	}
 		case SSF_NOT:
 	{
-		char *a1, *a, l1;
+		char *a1, *a;
+		int l1;
 		l1 = ssfilter_bytecompile(f->pred, &a1);
 		if (!(a = malloc(l1+4))) abort();
 		memcpy(a, a1, l1);