Re: [PATCH 20/24] bpf: Restrict kernel image access functions when the kernel is locked down

2017-04-06 Thread Alexei Starovoitov
On Wed, Apr 05, 2017 at 09:17:25PM +0100, David Howells wrote: > From: Chun-Yi Lee > > There are some bpf functions can be used to read kernel memory: > bpf_probe_read, bpf_probe_write_user and bpf_trace_printk. These allow > private keys in kernel memory (e.g. the hibernation image signing key)

Re: [PATCH 18/27] bpf: Restrict kernel image access functions when the kernel is locked down

2017-10-19 Thread Alexei Starovoitov
On Thu, Oct 19, 2017 at 03:52:49PM +0100, David Howells wrote: > From: Chun-Yi Lee > > There are some bpf functions can be used to read kernel memory: > bpf_probe_read, bpf_probe_write_user and bpf_trace_printk. These allow > private keys in kernel memory (e.g. the hibernation image signing key)

Re: [PATCH 18/27] bpf: Restrict kernel image access functions when the kernel is locked down

2017-10-19 Thread Alexei Starovoitov
On Thu, Oct 19, 2017 at 11:48:34PM +0100, David Howells wrote: > Alexei Starovoitov wrote: > > > > @@ -65,6 +65,11 @@ BPF_CALL_3(bpf_probe_read, void *, dst, u32, size, > > > const void *, unsafe_ptr) > > > { > > > int ret; >

Re: [GIT PULL] Kernel lockdown for secure boot

2018-04-03 Thread Alexei Starovoitov
On Tue, Apr 03, 2018 at 08:11:07AM -0700, Andy Lutomirski wrote: > > > >> "bpf: Restrict kernel image access functions when the kernel is locked > >> down": > >> This patch just sucks in general. > > > > Yes - but that's what Alexei Star

Re: [GIT PULL] Kernel lockdown for secure boot

2018-04-03 Thread Alexei Starovoitov
On Tue, Apr 3, 2018 at 9:26 AM, Andy Lutomirski wrote: > On Tue, Apr 3, 2018 at 8:41 AM, Alexei Starovoitov > wrote: >> On Tue, Apr 03, 2018 at 08:11:07AM -0700, Andy Lutomirski wrote: >>> > >>> >> "bpf: Restrict kernel image access functions when the

Re: [GIT PULL] Kernel lockdown for secure boot

2018-04-08 Thread Alexei Starovoitov
On Sun, Apr 08, 2018 at 04:07:42PM +0800, joeyli wrote: > > > If the only thing that folks are paranoid about is reading > > arbitrary kernel memory with bpf_probe_read() helper > > then preferred patch would be to disable it during verification > > when in lockdown mode > > Sorry for I didn't fu