Le lundi 12 mars 2007 20:28, James Carlson a écrit : > Julien Laganier writes: > > It's not the problem of the OS or its ABI compatibility > > if you insist on linking software compiled on the new > > OS with outdated libraries supporting the old OS. > > Actually, in thinking about it a bit more, I think the real problem > is with a strange usage case -- copying the addrinfo structure inside > a library will lead to a garbage result.
Or the other way, a rebuilt library against a non rebuilt software would yield to an out-of-bound memory read, as the library source code won't know to check for AI_EXTFLAGS bit and withdraw some bytes from sizeoz() if it's not set -- Currently, POSIX says this about the *hints* parameter: "If the argument hints is not null, it refers to a structure containing input values that may direct the operation by providing options and by limiting the returned information to a specific socket type, address family and/or protocol. In this hints structure every member other than ai_flags, ai_family, ai_socktype and ai_protocol must be zero or a null pointer." All of this four fields are integer and hence valid candidates for memory coypying, same (in general) for zeros/NULL. Maybe, instead of plain memory copy, one should memset, and copy any of the four allowed parameters. That makes no difference to my test case though, the AI_EXTFLAGS will be incorrectly passed through all the same, and the same error will occur afterward. So there is a known, if minor, problem, and a very low cost solution: Two new APIs and one struct (there are >1000 anyway). Also, generic/system-wide source address selection should and will be relied upon by most software. IMHO, better put the burden on those that use it, than on everything else. Regards, -- Rémi Denis-Courmont http://www.remlab.net/ -------------------------------------------------------------------- IETF IPv6 working group mailing list ipv6@ietf.org Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6 --------------------------------------------------------------------
