From: Andy Lutomirski <luto@kernel.org>
To: x86@kernel.org
Cc: 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>,
Andy Lutomirski <luto@kernel.org>
Subject: [PATCH PTI v2 4/6] x86/vsyscall/64: Warn and fail vsyscall emulation in NATIVE mode
Date: Sun, 10 Dec 2017 22:47:20 -0800 [thread overview]
Message-ID: <504ef309a222b2d0712e2d4ef87dae749ec13b6c.1512974667.git.luto@kernel.org> (raw)
In-Reply-To: <cover.1512974667.git.luto@kernel.org>
In-Reply-To: <cover.1512974667.git.luto@kernel.org>
If something goes wrong with pagetable setup, vsyscall=native will
accidentally fall back to emulation. Make it warn and fail so that
we notice.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
arch/x86/entry/vsyscall/vsyscall_64.c | 4 ++++
1 file changed, 4 insertions(+)
diff --git a/arch/x86/entry/vsyscall/vsyscall_64.c b/arch/x86/entry/vsyscall/vsyscall_64.c
index bc88a0540347..a06f2ae09ad6 100644
--- a/arch/x86/entry/vsyscall/vsyscall_64.c
+++ b/arch/x86/entry/vsyscall/vsyscall_64.c
@@ -138,6 +138,10 @@ bool emulate_vsyscall(struct pt_regs *regs, unsigned long address)
WARN_ON_ONCE(address != regs->ip);
+ /* This should be unreachable in NATIVE mode. */
+ if (WARN_ON(vsyscall_mode == NATIVE))
+ return false;
+
if (vsyscall_mode == NONE) {
warn_bad_vsyscall(KERN_INFO, regs,
"vsyscall attempted with vsyscall=none");
--
2.13.6
next prev parent reply other threads:[~2017-12-11 6:48 UTC|newest]
Thread overview: 18+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-12-11 6:47 [PATCH PTI v2 0/6] Clean up pgd handling and fix VSYSCALL and LDT Andy Lutomirski
2017-12-11 6:47 ` [PATCH PTI v2 1/6] x86/pti: Vastly simplify pgd synchronization Andy Lutomirski
2017-12-11 6:47 ` [PATCH PTI v2 2/6] Revert "x86/mm/pti: Disable native VSYSCALL" Andy Lutomirski
2017-12-11 6:47 ` [PATCH PTI v2 3/6] x86/vsyscall/64: Explicitly set _PAGE_USER in the pagetable hierarchy Andy Lutomirski
2017-12-11 13:39 ` Ingo Molnar
2017-12-11 16:01 ` Andy Lutomirski
2017-12-11 16:24 ` Ingo Molnar
2017-12-11 6:47 ` Andy Lutomirski [this message]
2017-12-11 6:47 ` [PATCH PTI v2 5/6] x86/pti: Map the vsyscall page if needed Andy Lutomirski
2017-12-11 6:47 ` [PATCH PTI v2 6/6] x86/pti: Put the LDT in its own PGD if PTI is on Andy Lutomirski
2017-12-11 17:49 ` Dave Hansen
2017-12-11 18:40 ` Andy Lutomirski
2017-12-11 19:32 ` Dave Hansen
2017-12-11 19:39 ` Andy Lutomirski
2017-12-11 19:47 ` Dave Hansen
2017-12-11 20:06 ` Andy Lutomirski
2017-12-11 6:54 ` [PATCH PTI v2 0/6] Clean up pgd handling and fix VSYSCALL and LDT Andy Lutomirski
2017-12-12 16:01 ` Kirill A. Shutemov
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