On Sunday 20 August 2006 18:16, Solar Designer wrote: > On Sun, Aug 20, 2006 at 10:34:43AM +0200, Andi Kleen wrote: > > In general I don't think it makes sense to submit stuff for 2.4 > > that isn't in 2.6. > > In general I agree, however right now I had the choice between > submitting these changes for 2.4 first and not submitting them at all > (at least for some months more). I chose the former.
If there is really a length checking bug it shouldn't be that hard to fix it in both. > We're on UP. sys_getsockopt() does get_user() (due to the patch) and > makes sure that the passed *optlen is sane. Even if this get_user() > sleeps, the value it returns in "len" is what's currently in memory at > the time of the get_user() return (correct?) Then an underlying > *getsockopt() function does another get_user() on optlen (same address), > without doing any other user-space data accesses or anything else that > could sleep first. Is it possible that this second get_user() > invocation would sleep? I think not since it's the same address that > we've just read a value from, we did not leave kernel space, and we're > on UP (so no other processor could have changed the mapping). So the > patch appears to be sufficient for this special case (which is not > unlikely). > > Of course, it is possible that I am wrong about some of the above; > please correct me if so. Nah you're right (except on a preemptible kernel which 2.4 isn't unpatched) However if there is any other user access before the second get_user the race could happen again even on UP. -Andi - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
