| From | Greg Kroah-Hartman <> | Subject | [PATCH 4.14 13/74] x86/vsyscall/64: Warn and fail vsyscall emulation in NATIVE mode | Date | Wed, 27 Dec 2017 17:45:46 +0100 |
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4.14-stable review patch. If anyone has any objections, please let me know.
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From: Andy Lutomirski <luto@kernel.org>
commit 4831b779403a836158917d59a7ca880483c67378 upstream.
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> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Cc: Borislav Petkov <bp@alien8.de> Cc: Brian Gerst <brgerst@gmail.com> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: David Laight <David.Laight@aculab.com> Cc: H. Peter Anvin <hpa@zytor.com> Cc: Josh Poimboeuf <jpoimboe@redhat.com> Cc: Juergen Gross <jgross@suse.com> Cc: Kees Cook <keescook@chromium.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Peter Zijlstra <peterz@infradead.org> Signed-off-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
--- arch/x86/entry/vsyscall/vsyscall_64.c | 4 ++++ 1 file changed, 4 insertions(+)
--- a/arch/x86/entry/vsyscall/vsyscall_64.c +++ b/arch/x86/entry/vsyscall/vsyscall_64.c @@ -139,6 +139,10 @@ bool emulate_vsyscall(struct pt_regs *re 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");
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