lists.openwall.net   lists  /  announce  owl-users  owl-dev  john-users  john-dev  passwdqc-users  yescrypt  popa3d-users  /  oss-security  kernel-hardening  musl  sabotage  tlsify  passwords  /  crypt-dev  xvendor  /  Bugtraq  Full-Disclosure  linux-kernel  linux-netdev  linux-ext4  linux-hardening  linux-cve-announce  PHC 
Open Source and information security mailing list archives
 
Hash Suite: Windows password security audit tool. GUI, reports in PDF.
[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]
Message-Id: <20230530114247.21821-11-alexander.shishkin@linux.intel.com>
Date:   Tue, 30 May 2023 14:42:45 +0300
From:   Alexander Shishkin <alexander.shishkin@...ux.intel.com>
To:     linux-kernel@...r.kernel.org, x86@...nel.org,
        Andy Lutomirski <luto@...nel.org>,
        Dave Hansen <dave.hansen@...ux.intel.com>,
        Ravi Shankar <ravi.v.shankar@...el.com>,
        Tony Luck <tony.luck@...el.com>,
        Sohil Mehta <sohil.mehta@...el.com>,
        Paul Lai <paul.c.lai@...el.com>
Cc:     Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Dave Hansen <dave.hansen@...el.com>
Subject: [PATCH v2 10/12] x86/vsyscall: Document the fact that vsyscall=emulate disables LASS

Since EMULATE mode of vsyscall disables LASS, because fixing the LASS
violations during the EMULATE mode would need complex instruction
decoding, document this fact in kernel-parameters.txt.

Cc: Andy Lutomirski <luto@...nel.org>
Suggested-by: Dave Hansen <dave.hansen@...el.com>
Signed-off-by: Alexander Shishkin <alexander.shishkin@...ux.intel.com>
---
 Documentation/admin-guide/kernel-parameters.txt | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 9e5bab29685f..efed9193107e 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -6850,7 +6850,9 @@
 
 			emulate     Vsyscalls turn into traps and are emulated
 			            reasonably safely.  The vsyscall page is
-				    readable.
+				    readable.  This also disables the LASS
+				    feature to allow userspace to poke around
+				    the vsyscall page.
 
 			xonly       [default] Vsyscalls turn into traps and are
 			            emulated reasonably safely.  The vsyscall
-- 
2.39.2

Powered by blists - more mailing lists

Powered by Openwall GNU/*/Linux Powered by OpenVZ