search for: uncreach

...system facility which provides IP packet filtering, accounting, and redirection. Among the many features, while discarding packets it can perform actions defined by the user, such as sending back TCP reset or ICMP unreachable packets. These operations can be performed by using the reset, reject or uncreach actions. II. Problem Description The firewall maintains a pointer to layer 4 header information in the event that it needs to send a TCP reset or ICMP error message to discard packets. Due to incorrect handling of IP fragments, this pointer fails to get initialized. III. Impact An attacker ca...

...system facility which provides IP packet filtering, accounting, and redirection. Among the many features, while discarding packets it can perform actions defined by the user, such as sending back TCP reset or ICMP unreachable packets. These operations can be performed by using the reset, reject or uncreach actions. II. Problem Description The firewall maintains a pointer to layer 4 header information in the event that it needs to send a TCP reset or ICMP error message to discard packets. Due to incorrect handling of IP fragments, this pointer fails to get initialized. III. Impact An attacker ca...

Now that x86-64 has directly accessible percpu variables, it can also implement the direct versions of these operations, which operate on a vcpu_info structure directly embedded in the percpu area. In fact, the 64-bit versions are more or less identical, and so can be shared. The only two differences are: 1. xen_restore_fl_direct takes its argument in eax on 32-bit, and rdi on 64-bit.