From: Igor Stoppa <igor.stoppa@gmail.com> To: Peter Zijlstra <peterz@infradead.org> Cc: Mimi Zohar <zohar@linux.vnet.ibm.com>, Kees Cook <keescook@chromium.org>, Matthew Wilcox <willy@infradead.org>, Dave Chinner <david@fromorbit.com>, James Morris <jmorris@namei.org>, Michal Hocko <mhocko@kernel.org>, kernel-hardening@lists.openwall.com, linux-integrity@vger.kernel.org, linux-security-module@vger.kernel.org, igor.stoppa@huawei.com, Dave Hansen <dave.hansen@linux.intel.com>, Jonathan Corbet <corbet@lwn.net>, Laura Abbott <labbott@redhat.com>, Vlastimil Babka <vbabka@suse.cz>, "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>, Andrew Morton <akpm@linux-foundation.org>, Pavel Tatashin <pasha.tatashin@oracle.com>, linux-mm@kvack.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH 02/17] prmem: write rare for static allocation Date: Mon, 29 Oct 2018 22:01:22 +0200 Message-ID: <e3ef00ef-3d28-2336-7bae-2e4f738a6e44@gmail.com> (raw) In-Reply-To: <20181026094105.GE3159@worktop.c.hoisthospitality.com> On 26/10/2018 10:41, Peter Zijlstra wrote: > On Wed, Oct 24, 2018 at 12:34:49AM +0300, Igor Stoppa wrote: >> +static __always_inline > > That's far too large for inline. The reason for it is that it's supposed to minimize the presence of gadgets that might be used in JOP attacks. I am ready to stand corrected, if I'm wrong, but this is the reason why I did it. Regarding the function being too large, yes, I would not normally choose it for inlining. Actually, I would not normally use "__always_inline" and instead I would limit myself to plain "inline", at most. > >> +bool wr_memset(const void *dst, const int c, size_t n_bytes) >> +{ >> + size_t size; >> + unsigned long flags; >> + uintptr_t d = (uintptr_t)dst; >> + >> + if (WARN(!__is_wr_after_init(dst, n_bytes), WR_ERR_RANGE_MSG)) >> + return false; >> + while (n_bytes) { >> + struct page *page; >> + uintptr_t base; >> + uintptr_t offset; >> + uintptr_t offset_complement; >> + >> + local_irq_save(flags); >> + page = virt_to_page(d); >> + offset = d & ~PAGE_MASK; >> + offset_complement = PAGE_SIZE - offset; >> + size = min(n_bytes, offset_complement); >> + base = (uintptr_t)vmap(&page, 1, VM_MAP, PAGE_KERNEL); >> + if (WARN(!base, WR_ERR_PAGE_MSG)) { >> + local_irq_restore(flags); >> + return false; >> + } >> + memset((void *)(base + offset), c, size); >> + vunmap((void *)base); > > BUG yes, somehow I managed to drop this debug configuration from the debug builds I made. [...] > Also, I see an amount of duplication here that shows you're not nearly > lazy enough. I did notice a certain amount of duplication, but I didn't know how to exploit it. -- igor
next prev parent reply index Thread overview: 140+ messages / expand[flat|nested] mbox.gz Atom feed top 2018-10-23 21:34 [RFC v1 PATCH 00/17] prmem: protected memory Igor Stoppa 2018-10-23 21:34 ` [PATCH 01/17] prmem: linker section for static write rare Igor Stoppa 2018-10-23 21:34 ` [PATCH 02/17] prmem: write rare for static allocation Igor Stoppa 2018-10-25 0:24 ` Dave Hansen 2018-10-29 18:03 ` Igor Stoppa 2018-10-26 9:41 ` Peter Zijlstra 2018-10-29 20:01 ` Igor Stoppa [this message] 2018-10-23 21:34 ` [PATCH 03/17] prmem: vmalloc support for dynamic allocation Igor Stoppa 2018-10-25 0:26 ` Dave Hansen 2018-10-29 18:07 ` Igor Stoppa 2018-10-23 21:34 ` [PATCH 04/17] prmem: " Igor Stoppa 2018-10-23 21:34 ` [PATCH 05/17] prmem: shorthands for write rare on common types Igor Stoppa 2018-10-25 0:28 ` Dave Hansen 2018-10-29 18:12 ` Igor Stoppa 2018-10-23 21:34 ` [PATCH 06/17] prmem: test cases for memory protection Igor Stoppa 2018-10-24 3:27 ` Randy Dunlap 2018-10-24 14:24 ` Igor Stoppa 2018-10-25 16:43 ` Dave Hansen 2018-10-29 18:16 ` Igor Stoppa 2018-10-23 21:34 ` [PATCH 07/17] prmem: lkdtm tests " Igor Stoppa 2018-10-23 21:34 ` [PATCH 08/17] prmem: struct page: track vmap_area Igor Stoppa 2018-10-24 3:12 ` Matthew Wilcox 2018-10-24 23:01 ` Igor Stoppa 2018-10-25 2:13 ` Matthew Wilcox 2018-10-29 18:21 ` Igor Stoppa 2018-10-23 21:34 ` [PATCH 09/17] prmem: hardened usercopy Igor Stoppa 2018-10-29 11:45 ` Chris von Recklinghausen 2018-10-29 18:24 ` Igor Stoppa 2018-10-23 21:34 ` [PATCH 10/17] prmem: documentation Igor Stoppa 2018-10-24 3:48 ` Randy Dunlap 2018-10-24 14:30 ` Igor Stoppa 2018-10-24 23:04 ` Mike Rapoport 2018-10-29 19:05 ` Igor Stoppa 2018-10-26 9:26 ` Peter Zijlstra 2018-10-26 10:20 ` Matthew Wilcox 2018-10-29 19:28 ` Igor Stoppa 2018-10-26 10:46 ` Kees Cook 2018-10-28 18:31 ` Peter Zijlstra 2018-10-29 21:04 ` Igor Stoppa 2018-10-30 15:26 ` Peter Zijlstra 2018-10-30 16:37 ` Kees Cook 2018-10-30 17:06 ` Andy Lutomirski 2018-10-30 17:58 ` Matthew Wilcox 2018-10-30 18:03 ` Dave Hansen 2018-10-31 9:18 ` Peter Zijlstra 2018-10-30 18:28 ` Tycho Andersen 2018-10-30 19:20 ` Matthew Wilcox 2018-10-30 20:43 ` Igor Stoppa 2018-10-30 21:02 ` Andy Lutomirski 2018-10-30 21:07 ` Kees Cook 2018-10-30 21:25 ` Igor Stoppa 2018-10-30 22:15 ` Igor Stoppa 2018-10-31 10:11 ` Peter Zijlstra 2018-10-31 20:38 ` Andy Lutomirski 2018-10-31 20:53 ` Andy Lutomirski 2018-10-31 9:45 ` Peter Zijlstra 2018-10-30 21:35 ` Matthew Wilcox 2018-10-30 21:49 ` Igor Stoppa 2018-10-31 4:41 ` Andy Lutomirski 2018-10-31 9:08 ` Igor Stoppa 2018-10-31 19:38 ` Igor Stoppa 2018-10-31 10:02 ` Peter Zijlstra 2018-10-31 20:36 ` Andy Lutomirski 2018-10-31 21:00 ` Peter Zijlstra 2018-10-31 22:57 ` Andy Lutomirski 2018-10-31 23:10 ` Igor Stoppa 2018-10-31 23:19 ` Andy Lutomirski 2018-10-31 23:26 ` Igor Stoppa 2018-11-01 8:21 ` Thomas Gleixner 2018-11-01 15:58 ` Igor Stoppa 2018-11-01 17:08 ` Peter Zijlstra 2018-10-30 18:51 ` Andy Lutomirski 2018-10-30 19:14 ` Kees Cook 2018-10-30 21:25 ` Matthew Wilcox 2018-10-30 21:55 ` Igor Stoppa 2018-10-30 22:08 ` Matthew Wilcox 2018-10-31 9:29 ` Peter Zijlstra 2018-10-30 23:18 ` Nadav Amit 2018-10-31 9:08 ` Peter Zijlstra 2018-11-01 16:31 ` Nadav Amit 2018-11-02 21:11 ` Nadav Amit 2018-10-31 9:36 ` Peter Zijlstra 2018-10-31 11:33 ` Matthew Wilcox 2018-11-13 14:25 ` Igor Stoppa 2018-11-13 17:16 ` Andy Lutomirski 2018-11-13 17:43 ` Nadav Amit 2018-11-13 17:47 ` Andy Lutomirski 2018-11-13 18:06 ` Nadav Amit 2018-11-13 18:31 ` Igor Stoppa 2018-11-13 18:33 ` Igor Stoppa 2018-11-13 18:36 ` Andy Lutomirski 2018-11-13 19:03 ` Igor Stoppa 2018-11-21 16:34 ` Igor Stoppa 2018-11-21 17:36 ` Nadav Amit 2018-11-21 18:01 ` Igor Stoppa 2018-11-21 18:15 ` Andy Lutomirski 2018-11-22 19:27 ` Igor Stoppa 2018-11-22 20:04 ` Matthew Wilcox 2018-11-22 20:53 ` Andy Lutomirski 2018-12-04 12:34 ` Igor Stoppa 2018-11-13 18:48 ` Andy Lutomirski 2018-11-13 19:35 ` Igor Stoppa 2018-11-13 18:26 ` Igor Stoppa 2018-11-13 18:35 ` Andy Lutomirski 2018-11-13 19:01 ` Igor Stoppa 2018-10-31 9:27 ` Igor Stoppa 2018-10-26 11:09 ` Markus Heiser 2018-10-29 19:35 ` Igor Stoppa 2018-10-26 15:05 ` Jonathan Corbet 2018-10-29 19:38 ` Igor Stoppa 2018-10-29 20:35 ` Igor Stoppa 2018-10-23 21:34 ` [PATCH 11/17] prmem: llist: use designated initializer Igor Stoppa 2018-10-23 21:34 ` [PATCH 12/17] prmem: linked list: set alignment Igor Stoppa 2018-10-26 9:31 ` Peter Zijlstra 2018-10-23 21:35 ` [PATCH 13/17] prmem: linked list: disable layout randomization Igor Stoppa 2018-10-24 13:43 ` Alexey Dobriyan 2018-10-29 19:40 ` Igor Stoppa 2018-10-26 9:32 ` Peter Zijlstra 2018-10-26 10:17 ` Matthew Wilcox 2018-10-30 15:39 ` Peter Zijlstra 2018-10-23 21:35 ` [PATCH 14/17] prmem: llist, hlist, both plain and rcu Igor Stoppa 2018-10-24 11:37 ` Mathieu Desnoyers 2018-10-24 14:03 ` Igor Stoppa 2018-10-24 14:56 ` Tycho Andersen 2018-10-24 22:52 ` Igor Stoppa 2018-10-25 8:11 ` Tycho Andersen 2018-10-28 9:52 ` Steven Rostedt 2018-10-29 19:43 ` Igor Stoppa 2018-10-26 9:38 ` Peter Zijlstra 2018-10-23 21:35 ` [PATCH 15/17] prmem: test cases for prlist and prhlist Igor Stoppa 2018-10-23 21:35 ` [PATCH 16/17] prmem: pratomic-long Igor Stoppa 2018-10-25 0:13 ` Peter Zijlstra 2018-10-29 21:17 ` Igor Stoppa 2018-10-30 15:58 ` Peter Zijlstra 2018-10-30 16:28 ` Will Deacon 2018-10-31 9:10 ` Peter Zijlstra 2018-11-01 3:28 ` Kees Cook 2018-10-23 21:35 ` [PATCH 17/17] prmem: ima: turn the measurements list write rare Igor Stoppa 2018-10-24 23:03 ` [RFC v1 PATCH 00/17] prmem: protected memory Dave Chinner 2018-10-29 19:47 ` Igor Stoppa
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