Re: [PATCH 06/17] x86/alternative: use temporary mm for text poking

2019-01-17 Thread hpa
On January 17, 2019 1:43:54 PM PST, Nadav Amit wrote: >> On Jan 17, 2019, at 12:47 PM, Andy Lutomirski >wrote: >> >> On Thu, Jan 17, 2019 at 12:27 PM Andy Lutomirski >wrote: >>> On Wed, Jan 16, 2019 at 4:33 PM Rick Edgecombe >>> wrote: From: Nadav Amit text_poke() can potentia

Re: [PATCH 06/17] x86/alternative: use temporary mm for text poking

2019-01-17 Thread Nadav Amit
> On Jan 17, 2019, at 1:43 PM, Nadav Amit wrote: > >> On Jan 17, 2019, at 12:47 PM, Andy Lutomirski wrote: >> >> On Thu, Jan 17, 2019 at 12:27 PM Andy Lutomirski wrote: >>> On Wed, Jan 16, 2019 at 4:33 PM Rick Edgecombe >>> wrote: From: Nadav Amit text_poke() can potentially

Re: [PATCH 06/17] x86/alternative: use temporary mm for text poking

2019-01-17 Thread Nadav Amit
> On Jan 17, 2019, at 12:47 PM, Andy Lutomirski wrote: > > On Thu, Jan 17, 2019 at 12:27 PM Andy Lutomirski wrote: >> On Wed, Jan 16, 2019 at 4:33 PM Rick Edgecombe >> wrote: >>> From: Nadav Amit >>> >>> text_poke() can potentially compromise the security as it sets temporary >>> PTEs in the

Re: [PATCH 06/17] x86/alternative: use temporary mm for text poking

2019-01-17 Thread Andy Lutomirski
On Thu, Jan 17, 2019 at 12:27 PM Andy Lutomirski wrote: > > On Wed, Jan 16, 2019 at 4:33 PM Rick Edgecombe > wrote: > > > > From: Nadav Amit > > > > text_poke() can potentially compromise the security as it sets temporary > > PTEs in the fixmap. These PTEs might be used to rewrite the kernel cod

Re: [PATCH 06/17] x86/alternative: use temporary mm for text poking

2019-01-17 Thread Andy Lutomirski
On Wed, Jan 16, 2019 at 4:33 PM Rick Edgecombe wrote: > > From: Nadav Amit > > text_poke() can potentially compromise the security as it sets temporary > PTEs in the fixmap. These PTEs might be used to rewrite the kernel code > from other cores accidentally or maliciously, if an attacker gains th