Make sure the prefixlength of subnets is sane.

Thanks to Sven-Haegar Koch for spotting the bug and providing a fix.

diff --git a/src/subnet.c b/src/subnet.c
index a4ec2b3..52ed443 100644 (file)
--- a/src/subnet.c
+++ b/src/subnet.c
@@ -188,11 +188,17 @@ bool str2net(subnet_t *subnet, const char *subnetstr)
 
        if(sscanf(subnetstr, "%hu.%hu.%hu.%hu/%d",
                          &x[0], &x[1], &x[2], &x[3], &l) == 5) {
+               if(l < 0 || l > 32)
+                       return false;
+
                subnet->type = SUBNET_IPV4;
                subnet->net.ipv4.prefixlength = l;
 
-               for(i = 0; i < 4; i++)
+               for(i = 0; i < 4; i++) {
+                       if(x[i] > 255)
+                               return false;
                        subnet->net.ipv4.address.x[i] = x[i];
+               }
 
                return true;
        }
@@ -200,6 +206,9 @@ bool str2net(subnet_t *subnet, const char *subnetstr)
        if(sscanf(subnetstr, "%hx:%hx:%hx:%hx:%hx:%hx:%hx:%hx/%d",
                          &x[0], &x[1], &x[2], &x[3], &x[4], &x[5], &x[6], &x[7],
                          &l) == 9) {
+               if(l < 0 || l > 128)
+                       return false;
+
                subnet->type = SUBNET_IPV6;
                subnet->net.ipv6.prefixlength = l;
 
@@ -213,8 +222,11 @@ bool str2net(subnet_t *subnet, const char *subnetstr)
                subnet->type = SUBNET_IPV4;
                subnet->net.ipv4.prefixlength = 32;
 
-               for(i = 0; i < 4; i++)
+               for(i = 0; i < 4; i++) {
+                       if(x[i] > 255)
+                               return false;
                        subnet->net.ipv4.address.x[i] = x[i];
+               }
 
                return true;
        }
@@ -348,6 +360,8 @@ subnet_t *lookup_subnet_ipv4(const ipv4_t *address)
                                /* Otherwise, see if there is a bigger enclosing subnet */
 
                                subnet.net.ipv4.prefixlength = p->net.ipv4.prefixlength - 1;
+                               if(subnet.net.ipv4.prefixlength < 0 || subnet.net.ipv4.prefixlength > 32)
+                                       return NULL;
                                maskcpy(&subnet.net.ipv4.address, &p->net.ipv4.address, subnet.net.ipv4.prefixlength, sizeof(ipv4_t));
                        }
                }
@@ -384,6 +398,8 @@ subnet_t *lookup_subnet_ipv6(const ipv6_t *address)
                                /* Otherwise, see if there is a bigger enclosing subnet */
 
                                subnet.net.ipv6.prefixlength = p->net.ipv6.prefixlength - 1;
+                               if(subnet.net.ipv6.prefixlength < 0 || subnet.net.ipv6.prefixlength > 128)
+                                       return NULL;
                                maskcpy(&subnet.net.ipv6.address, &p->net.ipv6.address, subnet.net.ipv6.prefixlength, sizeof(ipv6_t));
                        }
                }