From: Lai Jiangshan <jiangshanlai@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: Lai Jiangshan <laijs@linux.alibaba.com>,
Dave Hansen <dave.hansen@linux.intel.com>,
Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Borislav Petkov <bp@alien8.de>,
x86@kernel.org, "H. Peter Anvin" <hpa@zytor.com>
Subject: [PATCH V2 2/3] x86/mm/pti: issue warning when mapping large pmd beyond specifid range
Date: Thu, 10 Dec 2020 22:35:25 +0800 [thread overview]
Message-ID: <20201210143527.2398-2-jiangshanlai@gmail.com> (raw)
In-Reply-To: <20201210143527.2398-1-jiangshanlai@gmail.com>
From: Lai Jiangshan <laijs@linux.alibaba.com>
When PTI_CLONE_PTE, the caller doesn't want to expose pages beyond specifid
range and it worths a warning.
Signed-off-by: Lai Jiangshan <laijs@linux.alibaba.com>
---
arch/x86/mm/pti.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/arch/x86/mm/pti.c b/arch/x86/mm/pti.c
index 7ee99ef13a99..cd6da1d42ba9 100644
--- a/arch/x86/mm/pti.c
+++ b/arch/x86/mm/pti.c
@@ -356,6 +356,13 @@ pti_clone_pgtable(unsigned long start, unsigned long end,
* caller, so we just simply align it here.
*/
addr = round_down(addr, PMD_SIZE);
+ /*
+ * Mapping large pmd beyond [start, end) may expose
+ * secrets to user-space when it wants to clone ptes
+ * only.
+ */
+ WARN_ON_ONCE(level == PTI_CLONE_PTE &&
+ (addr < start || end < addr + PMD_SIZE));
target_pmd = pti_user_pagetable_walk_pmd(addr);
if (WARN_ON(!target_pmd))
--
2.19.1.6.gb485710b
next prev parent reply other threads:[~2020-12-10 13:38 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-11-30 15:25 [PATCH 1/2] x86/mm/pti: Check unaligned address for pmd clone in pti_clone_pagetable() Lai Jiangshan
2020-11-30 15:25 ` [PATCH 2/2] x86/mm/pti: warn and stop when pti_clone_pagetable() is on 1G page Lai Jiangshan
2020-11-30 16:37 ` Dave Hansen
2020-12-01 17:43 ` [PATCH 1/2] x86/mm/pti: Check unaligned address for pmd clone in pti_clone_pagetable() Dave Hansen
2020-12-02 8:55 ` Lai Jiangshan
2020-12-10 14:35 ` [PATCH V2 1/3] x86/mm/pti: handle " Lai Jiangshan
2020-12-10 14:35 ` Lai Jiangshan [this message]
2020-12-10 14:35 ` [PATCH V2 3/3] x86/mm/pti: warn and stop when pti_clone_pagetable() is on 1G page Lai Jiangshan
2020-12-18 13:00 ` [PATCH V2 1/3] x86/mm/pti: handle unaligned address for pmd clone in pti_clone_pagetable() Lai Jiangshan
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