Date: Wed, 05 Aug 2009 10:05:55 +0800 From: Eugene Teo <eugene@...hat.com> To: oss-security@...ts.openwall.com CC: "Steven M. Christey" <coley@...us.mitre.org>, jon@...rheide.org Subject: Re: CVE request - kernel: information leak in sigaltstack Eugene Teo wrote: > do_sigaltstack: avoid copying 'stack_t' as a structure to user space > > Ulrich Drepper correctly points out that there is generally padding in > the structure on 64-bit hosts, and that copying the structure from > kernel to user space can leak information from the kernel stack in those > padding bytes. > > Avoid the whole issue by just copying the three members one by one > instead, which also means that the function also can avoid the need for > a stack frame. This also happens to match how we copy the new structure > from user space, so it all even makes sense. > > Upstream commit: > http://git.kernel.org/linus/0083fc2c50e6c5127c2802ad323adf8143ab7856 > > Reference: > https://bugzilla.redhat.com/show_bug.cgi?id=515392 Reproducer: http://milw0rm.com/exploits/9352 Thanks, Eugene
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