From: Borislav Petkov <bp@alien8.de> To: Andy Lutomirski <luto@kernel.org> Cc: x86@kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, Nadav Amit <nadav.amit@gmail.com>, Kees Cook <keescook@chromium.org>, Brian Gerst <brgerst@gmail.com>, "kernel-hardening@lists.openwall.com" <kernel-hardening@lists.openwall.com>, Linus Torvalds <torvalds@linux-foundation.org>, Josh Poimboeuf <jpoimboe@redhat.com>, Jann Horn <jann@thejh.net>, Heiko Carstens <heiko.carstens@de.ibm.com> Subject: Re: [PATCH v2 03/13] x86/cpa: Warn if kernel_unmap_pages_in_pgd is used inappropriately Date: Fri, 17 Jun 2016 22:30:45 +0200 [thread overview] Message-ID: <20160617203045.GB3842@pd.tnic> (raw) In-Reply-To: <3336bb02792d56c49d18e2f7a435fd194a4a22e4.1466192946.git.luto@kernel.org> On Fri, Jun 17, 2016 at 01:00:39PM -0700, Andy Lutomirski wrote: > It's currently only used in the EFI code, which is safe AFAICT. "It is basically useful for a pagetable hierarchy which is not init_mm." > Warn if anyone tries to use it on the normal kernel pgd. > > Signed-off-by: Andy Lutomirski <luto@kernel.org> > --- > arch/x86/mm/pageattr.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c > index 6a8026918bf6..e9b9c5cedbb8 100644 > --- a/arch/x86/mm/pageattr.c > +++ b/arch/x86/mm/pageattr.c > @@ -1996,6 +1996,9 @@ out: > void kernel_unmap_pages_in_pgd(pgd_t *root, unsigned long address, > unsigned numpages) > { > + /* Unmapping kernel entries from init_mm's pgd is not allowed. */ > + WARN_ON(root == init_mm.pgd); We can also return and not do the unmapping: if (WARN_ON(root == init_mm.pgd)) return; -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply.
WARNING: multiple messages have this Message-ID (diff)
From: Borislav Petkov <bp@alien8.de> To: Andy Lutomirski <luto@kernel.org> Cc: x86@kernel.org, linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org, Nadav Amit <nadav.amit@gmail.com>, Kees Cook <keescook@chromium.org>, Brian Gerst <brgerst@gmail.com>, "kernel-hardening@lists.openwall.com" <kernel-hardening@lists.openwall.com>, Linus Torvalds <torvalds@linux-foundation.org>, Josh Poimboeuf <jpoimboe@redhat.com>, Jann Horn <jann@thejh.net>, Heiko Carstens <heiko.carstens@de.ibm.com> Subject: [kernel-hardening] Re: [PATCH v2 03/13] x86/cpa: Warn if kernel_unmap_pages_in_pgd is used inappropriately Date: Fri, 17 Jun 2016 22:30:45 +0200 [thread overview] Message-ID: <20160617203045.GB3842@pd.tnic> (raw) In-Reply-To: <3336bb02792d56c49d18e2f7a435fd194a4a22e4.1466192946.git.luto@kernel.org> On Fri, Jun 17, 2016 at 01:00:39PM -0700, Andy Lutomirski wrote: > It's currently only used in the EFI code, which is safe AFAICT. "It is basically useful for a pagetable hierarchy which is not init_mm." > Warn if anyone tries to use it on the normal kernel pgd. > > Signed-off-by: Andy Lutomirski <luto@kernel.org> > --- > arch/x86/mm/pageattr.c | 3 +++ > 1 file changed, 3 insertions(+) > > diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c > index 6a8026918bf6..e9b9c5cedbb8 100644 > --- a/arch/x86/mm/pageattr.c > +++ b/arch/x86/mm/pageattr.c > @@ -1996,6 +1996,9 @@ out: > void kernel_unmap_pages_in_pgd(pgd_t *root, unsigned long address, > unsigned numpages) > { > + /* Unmapping kernel entries from init_mm's pgd is not allowed. */ > + WARN_ON(root == init_mm.pgd); We can also return and not do the unmapping: if (WARN_ON(root == init_mm.pgd)) return; -- Regards/Gruss, Boris. ECO tip #101: Trim your mails when you reply.
next prev parent reply other threads:[~2016-06-17 20:30 UTC|newest] Thread overview: 93+ messages / expand[flat|nested] mbox.gz Atom feed top 2016-06-17 20:00 [PATCH v2 00/13] Virtually mapped stacks with guard pages (x86, core) Andy Lutomirski 2016-06-17 20:00 ` [kernel-hardening] " Andy Lutomirski 2016-06-17 20:00 ` Andy Lutomirski 2016-06-17 20:00 ` [PATCH v2 01/13] x86/mm/hotplug: Don't remove PGD entries in remove_pagetable() Andy Lutomirski 2016-06-17 20:00 ` [kernel-hardening] " Andy Lutomirski 2016-06-17 20:00 ` Andy Lutomirski 2016-06-17 20:00 ` Andy Lutomirski 2016-06-17 20:00 ` [PATCH v2 02/13] x86/cpa: In populate_pgd, don't set the pgd entry until it's populated Andy Lutomirski 2016-06-17 20:00 ` [kernel-hardening] " Andy Lutomirski 2016-06-17 20:00 ` Andy Lutomirski 2016-06-17 20:00 ` [PATCH v2 03/13] x86/cpa: Warn if kernel_unmap_pages_in_pgd is used inappropriately Andy Lutomirski 2016-06-17 20:00 ` [kernel-hardening] " Andy Lutomirski 2016-06-17 20:00 ` Andy Lutomirski 2016-06-17 20:30 ` Borislav Petkov [this message] 2016-06-17 20:30 ` [kernel-hardening] " Borislav Petkov 2016-06-17 20:30 ` Borislav Petkov 2016-06-18 10:29 ` Andy Lutomirski 2016-06-18 10:29 ` [kernel-hardening] " Andy Lutomirski 2016-06-18 10:29 ` Andy Lutomirski 2016-06-18 10:37 ` Borislav Petkov 2016-06-18 10:37 ` [kernel-hardening] " Borislav Petkov 2016-06-18 10:37 ` Borislav Petkov 2016-06-17 20:00 ` [PATCH v2 04/13] mm: Track NR_KERNEL_STACK in KiB instead of number of stacks Andy Lutomirski 2016-06-17 20:00 ` [kernel-hardening] " Andy Lutomirski 2016-06-17 20:00 ` Andy Lutomirski 2016-06-17 20:00 ` Andy Lutomirski 2016-06-20 13:16 ` Michal Hocko 2016-06-20 13:16 ` [kernel-hardening] " Michal Hocko 2016-06-20 13:16 ` Michal Hocko 2016-06-20 13:16 ` Michal Hocko 2016-06-17 20:00 ` [PATCH v2 05/13] mm: Move memcg stack accounting to account_kernel_stack Andy Lutomirski 2016-06-17 20:00 ` [kernel-hardening] " Andy Lutomirski 2016-06-17 20:00 ` Andy Lutomirski 2016-06-17 20:00 ` Andy Lutomirski 2016-06-17 20:55 ` Josh Poimboeuf 2016-06-17 20:55 ` [kernel-hardening] " Josh Poimboeuf 2016-06-17 20:55 ` Josh Poimboeuf 2016-06-17 20:55 ` Josh Poimboeuf 2016-06-17 22:18 ` Andy Lutomirski 2016-06-17 22:18 ` [kernel-hardening] " Andy Lutomirski 2016-06-17 22:18 ` Andy Lutomirski 2016-06-17 22:18 ` Andy Lutomirski 2016-06-20 13:02 ` Michal Hocko 2016-06-20 13:02 ` [kernel-hardening] " Michal Hocko 2016-06-20 13:02 ` Michal Hocko 2016-06-20 13:02 ` Michal Hocko 2016-06-20 16:05 ` Andy Lutomirski 2016-06-20 16:05 ` [kernel-hardening] " Andy Lutomirski 2016-06-20 16:05 ` Andy Lutomirski 2016-06-20 16:05 ` Andy Lutomirski 2016-06-17 20:00 ` [PATCH v2 06/13] fork: Add generic vmalloced stack support Andy Lutomirski 2016-06-17 20:00 ` [kernel-hardening] " Andy Lutomirski 2016-06-17 20:00 ` Andy Lutomirski 2016-06-17 20:57 ` Josh Poimboeuf 2016-06-17 20:57 ` [kernel-hardening] " Josh Poimboeuf 2016-06-17 20:57 ` Josh Poimboeuf 2016-06-17 22:18 ` Andy Lutomirski 2016-06-17 22:18 ` [kernel-hardening] " Andy Lutomirski 2016-06-17 22:18 ` Andy Lutomirski 2016-06-20 13:36 ` Michal Hocko 2016-06-20 13:36 ` [kernel-hardening] " Michal Hocko 2016-06-20 13:36 ` Michal Hocko 2016-06-20 13:36 ` Michal Hocko 2016-06-20 16:13 ` Andy Lutomirski 2016-06-20 16:13 ` [kernel-hardening] " Andy Lutomirski 2016-06-20 16:13 ` Andy Lutomirski 2016-06-21 8:46 ` Michal Hocko 2016-06-21 8:46 ` [kernel-hardening] " Michal Hocko 2016-06-21 8:46 ` Michal Hocko 2016-06-21 17:01 ` Andy Lutomirski 2016-06-21 17:01 ` [kernel-hardening] " Andy Lutomirski 2016-06-21 17:01 ` Andy Lutomirski 2016-06-17 20:00 ` [PATCH v2 07/13] x86/die: Don't try to recover from an OOPS on a non-default stack Andy Lutomirski 2016-06-17 20:00 ` [kernel-hardening] " Andy Lutomirski 2016-06-17 20:00 ` Andy Lutomirski 2016-06-17 20:00 ` [PATCH v2 08/13] x86/dumpstack: When OOPSing, rewind the stack before do_exit Andy Lutomirski 2016-06-17 20:00 ` [kernel-hardening] " Andy Lutomirski 2016-06-17 20:00 ` Andy Lutomirski 2016-06-17 20:00 ` [PATCH v2 09/13] x86/dumpstack: When dumping stack bytes due to OOPS, start with regs->sp Andy Lutomirski 2016-06-17 20:00 ` [kernel-hardening] " Andy Lutomirski 2016-06-17 20:00 ` Andy Lutomirski 2016-06-17 20:00 ` [PATCH v2 10/13] x86/dumpstack: Try harder to get a call trace on stack overflow Andy Lutomirski 2016-06-17 20:00 ` [kernel-hardening] " Andy Lutomirski 2016-06-17 20:00 ` Andy Lutomirski 2016-06-17 20:00 ` [PATCH v2 11/13] x86/dumpstack/64: Handle faults when printing the "Stack:" part of an OOPS Andy Lutomirski 2016-06-17 20:00 ` [kernel-hardening] " Andy Lutomirski 2016-06-17 20:00 ` Andy Lutomirski 2016-06-17 20:00 ` [PATCH v2 12/13] x86/mm/64: Enable vmapped stacks Andy Lutomirski 2016-06-17 20:00 ` [kernel-hardening] " Andy Lutomirski 2016-06-17 20:00 ` Andy Lutomirski 2016-06-17 20:00 ` [PATCH v2 13/13] x86/mm: Improve stack-overflow #PF handling Andy Lutomirski 2016-06-17 20:00 ` [kernel-hardening] " Andy Lutomirski 2016-06-17 20:00 ` Andy Lutomirski
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=20160617203045.GB3842@pd.tnic \ --to=bp@alien8.de \ --cc=brgerst@gmail.com \ --cc=heiko.carstens@de.ibm.com \ --cc=jann@thejh.net \ --cc=jpoimboe@redhat.com \ --cc=keescook@chromium.org \ --cc=kernel-hardening@lists.openwall.com \ --cc=linux-arch@vger.kernel.org \ --cc=linux-kernel@vger.kernel.org \ --cc=luto@kernel.org \ --cc=nadav.amit@gmail.com \ --cc=torvalds@linux-foundation.org \ --cc=x86@kernel.org \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.