Messages in this thread | | | From | kuznet@ms2 ... | Subject | Re: Don't allow mapped address after binding to ipv4. | Date | Sat, 5 Aug 2000 22:26:43 +0400 (MSK DST) |
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Hello!
> > > linux-2.2.16 and linux-2.4.0-test5 allow to let an application bind an > > > inet6 socket sd6 to an address / a port that is already bound to inet > > > socket sd4. > > > > Yeah... Ugly. 8) But we have no choice. Thank you. > > Does this not leave us open to 'binding closer' type attacks like NFS packet > theft ?
Seems, with this patch theft is impossible. Without this patch IPv6 can steal sockets used by IP, indeed.
Test !sk2->rcv_saddr prevents binding to place used both by IPv6 and IP wildcard. The problem is that native IP sockets do not initialize IPv6 rcv_saddr and it is always ::, so that we cannot check for net_pinfo.af_inet6.rcv_saddr==:: instead of !sk2->rcv_saddr (and it is OK), but unfortunately we also forgot to check for coincidence of real IPv4 identities. The patch fixes this and problems disappear. Seems. 8)
Though, I am not 100% sure. You frightened me. 8) This place need to be analyzed more carefully yet.
Alexey
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