From: Andy Lutomirski <luto@kernel.org>
To: Thomas Gleixner <tglx@linutronix.de>
Cc: Andy Lutomirski <luto@kernel.org>, X86 ML <x86@kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Borislav Petkov <bp@alien8.de>, Brian Gerst <brgerst@gmail.com>,
David Laight <David.Laight@aculab.com>,
Kees Cook <keescook@chromium.org>,
Peter Zijlstra <peterz@infradead.org>,
"Kirill A. Shutemov" <kirill@shutemov.name>,
Dave Hansen <dave.hansen@intel.com>
Subject: Re: [PATCH PTI v3 10/10] x86/pti: Put the LDT in its own PGD if PTI is on
Date: Fri, 15 Dec 2017 22:41:23 -0800 [thread overview]
Message-ID: <CALCETrWxC8VHwzE_FB9BFGAJhizUuXJ5oMjxGOxzPiRQAMsqQg@mail.gmail.com> (raw)
In-Reply-To: <alpine.DEB.2.20.1712160136460.2099@nanos>
On Fri, Dec 15, 2017 at 2:54 PM, Thomas Gleixner <tglx@linutronix.de> wrote:
> On Tue, 12 Dec 2017, Andy Lutomirski wrote:
>> +/* This is a multiple of PAGE_SIZE. */
>> +#define LDT_SLOT_STRIDE (LDT_ENTRIES * LDT_ENTRY_SIZE)
>> +
>> +static void *ldt_slot_va(int slot)
>
> How is that supposed to compile w/o warnings? Want's to be inline ....
Good question. But it does compile for me and apparently for the 0day
bot without warnings. Fixed in my tree.
On Fri, Dec 15, 2017 at 4:39 PM, Thomas Gleixner <tglx@linutronix.de> wrote:
> On Tue, 12 Dec 2017, Andy Lutomirski wrote:
>> +
>> + return 0;
>> +#else
>> + return -EINVAL;
>
> Errm. What's the point of that? Breaking non PTI?
That's embarrassing.
>
>> new_ldt = alloc_ldt_struct(old_mm->context.ldt->nr_entries);
>> if (!new_ldt) {
>> @@ -155,8 +266,17 @@ int init_new_context_ldt(struct task_struct *tsk, struct mm_struct *mm)
>> memcpy(new_ldt->entries, old_mm->context.ldt->entries,
>> new_ldt->nr_entries * LDT_ENTRY_SIZE);
>> finalize_ldt_struct(new_ldt);
>> + retval = map_ldt_struct(mm, new_ldt, 0);
>> + if (retval)
>> + goto out_free;
>>
>> mm->context.ldt = new_ldt;
>> + goto out_unlock;
>> +
>> +out_free:
>> + free_ldt_pgtables(mm);
>> + free_ldt_struct(new_ldt);
>> + return retval;
>
> Leaks old_mm->context_lock;
>
Indeed.
I'm going to go test the failure paths better tomorrow. Meanwhile,
all three issues should be fixed in my tree.
prev parent reply other threads:[~2017-12-16 6:41 UTC|newest]
Thread overview: 27+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-11 23:40 [PATCH PTI v3 00/10] Clean up pgd handling and fix VSYSCALL and LDT Andy Lutomirski
2017-12-12 10:09 ` Ingo Molnar
2017-12-12 15:58 ` Andy Lutomirski
2017-12-12 16:13 ` Borislav Petkov
2017-12-12 16:14 ` Juergen Gross
2017-12-12 16:20 ` Borislav Petkov
2017-12-12 15:56 ` [PATCH PTI v3 01/10] x86/espfix/64: Fix espfix double-fault handling on 5-level systems Andy Lutomirski
2017-12-12 17:18 ` Kirill A. Shutemov
2017-12-15 18:34 ` [tip:x86/urgent] " tip-bot for Andy Lutomirski
2017-12-12 15:56 ` [PATCH PTI v3 02/10] x86/pti: Vastly simplify pgd synchronization Andy Lutomirski
2017-12-12 15:56 ` [PATCH PTI v3 03/10] x86/pti/64: Fix ESPFIX64 user mapping Andy Lutomirski
2017-12-13 13:12 ` Kirill A. Shutemov
2017-12-13 17:01 ` Andy Lutomirski
2017-12-14 14:10 ` Kirill A. Shutemov
2017-12-14 16:18 ` Andy Lutomirski
2017-12-12 15:56 ` [PATCH PTI v3 04/10] Revert "x86/mm/pti: Disable native VSYSCALL" Andy Lutomirski
2017-12-12 15:56 ` [PATCH PTI v3 05/10] x86/vsyscall/64: Explicitly set _PAGE_USER in the pagetable hierarchy Andy Lutomirski
2017-12-12 15:56 ` [PATCH PTI v3 06/10] x86/vsyscall/64: Warn and fail vsyscall emulation in NATIVE mode Andy Lutomirski
2017-12-12 15:56 ` [PATCH PTI v3 07/10] x86/pti: Map the vsyscall page if needed Andy Lutomirski
2017-12-12 15:56 ` [PATCH PTI v3 08/10] x86/mm/64: Improve the memory map documentation Andy Lutomirski
2017-12-12 15:56 ` [PATCH PTI v3 09/10] x86/mm/64: Make a full PGD-entry size hole in the memory map Andy Lutomirski
2017-12-13 13:17 ` Kirill A. Shutemov
2017-12-13 17:04 ` Andy Lutomirski
2017-12-12 15:56 ` [PATCH PTI v3 10/10] x86/pti: Put the LDT in its own PGD if PTI is on Andy Lutomirski
2017-12-15 22:54 ` Thomas Gleixner
2017-12-16 0:39 ` Thomas Gleixner
2017-12-16 6:41 ` Andy Lutomirski [this message]
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