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Groups > linux.kernel > #1607015
| From | Thomas Garnier <thgarnie@google.com> |
|---|---|
| Newsgroups | linux.kernel |
| Subject | Re: [PATCH v4 1/4] syscalls: Restore address limit after a syscall |
| Date | 2017-03-22 22:00 +0100 |
| Message-ID | <tnVwl-8pR-1@gated-at.bofh.it> (permalink) |
| References | <tnVcZ-8hP-5@gated-at.bofh.it> <tnVmG-8m4-15@gated-at.bofh.it> |
| Organization | linux.* mail to news gateway |
On Wed, Mar 22, 2017 at 1:44 PM, Andy Lutomirski <luto@amacapital.net> wrote: > On Wed, Mar 22, 2017 at 1:38 PM, Thomas Garnier <thgarnie@google.com> wrote: >> This patch ensures a syscall does not return to user-mode with a kernel >> address limit. If that happened, a process can corrupt kernel-mode >> memory and elevate privileges. >> >> For example, it would mitigation this bug: >> >> - https://bugs.chromium.org/p/project-zero/issues/detail?id=990 >> >> If the CONFIG_BUG_ON_DATA_CORRUPTION option is enabled, an incorrect >> state will result in a BUG_ON. > > I'm a bit confused about this choice of configurability. I can see > two sensible choices: > > 1. Enable this hardening feature: BUG if there's an exploitable bug. > > 2. Don't enable it at all. > > While it's possible that silently papering over the bug is slightly > faster than BUGging, it will allow bugs to continue to exist > undetected. We can default to BUGging. I think my approach was avoiding doing a BUG_ON just to avoid breaking people. > > --Andy -- Thomas
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[PATCH v4 1/4] syscalls: Restore address limit after a syscall Thomas Garnier <thgarnie@google.com> - 2017-03-22 21:40 +0100
[PATCH v4 4/4] arm64/syscalls: Specific usage of verify_pre_usermode_state Thomas Garnier <thgarnie@google.com> - 2017-03-22 21:40 +0100
Re: [PATCH v4 1/4] syscalls: Restore address limit after a syscall Andy Lutomirski <luto@amacapital.net> - 2017-03-22 21:50 +0100
Re: [PATCH v4 1/4] syscalls: Restore address limit after a syscall Thomas Garnier <thgarnie@google.com> - 2017-03-22 22:00 +0100
Re: [PATCH v4 1/4] syscalls: Restore address limit after a syscall "H. Peter Anvin" <hpa@zytor.com> - 2017-03-22 22:20 +0100
Re: [PATCH v4 1/4] syscalls: Restore address limit after a syscall Thomas Garnier <thgarnie@google.com> - 2017-03-23 16:20 +0100
Re: [PATCH v4 1/4] syscalls: Restore address limit after a syscall Borislav Petkov <bp@alien8.de> - 2017-03-23 16:40 +0100
Re: [PATCH v4 1/4] syscalls: Restore address limit after a syscall Thomas Garnier <thgarnie@google.com> - 2017-03-23 16:50 +0100
Re: [PATCH v4 1/4] syscalls: Restore address limit after a syscall "H. Peter Anvin" <hpa@zytor.com> - 2017-03-22 22:20 +0100
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