Andy Lutomirski
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65973dd3fd
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selftests/x86/ldt_gdt_32: Work around a glibc sigaction() bug
i386 glibc is buggy and calls the sigaction syscall incorrectly.
This is asymptomatic for normal programs, but it blows up on
programs that do evil things with segmentation. The ldt_gdt
self-test is an example of such an evil program.
This doesn't appear to be a regression -- I think I just got lucky
with the uninitialized memory that glibc threw at the kernel when I
wrote the test.
This hackish fix manually issues sigaction(2) syscalls to undo the
damage. Without the fix, ldt_gdt_32 segfaults; with the fix, it
passes for me.
See: https://sourceware.org/bugzilla/show_bug.cgi?id=21269
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Juergen Gross <jgross@suse.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Garnier <thgarnie@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: stable@vger.kernel.org
Link: http://lkml.kernel.org/r/aaab0f9f93c9af25396f01232608c163a760a668.1490218061.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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2017-03-23 08:25:07 +01:00 |
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Dmitry Safonov
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2a4d0c627f
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x86/selftests: Add clobbers for int80 on x86_64
Kernel erases R8..R11 registers prior returning to userspace
from int80:
https://lkml.org/lkml/2009/10/1/164
GCC can reuse these registers and doesn't expect them to change
during syscall invocation. I met this kind of bug in CRIU once
GCC 6.1 and CLANG stored local variables in those registers
and the kernel zerofied them during syscall:
990d33f1a1
By that reason I suggest to add those registers to clobbers
in selftests. Also, as noted by Andy - removed unneeded clobber
for flags in INT $0x80 inline asm.
Signed-off-by: Dmitry Safonov <dsafonov@virtuozzo.com>
Acked-by: Andy Lutomirski <luto@kernel.org>
Cc: 0x7f454c46@gmail.com
Cc: Borislav Petkov <bp@alien8.de>
Cc: Borislav Petkov <bp@suse.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kselftest@vger.kernel.org
Link: http://lkml.kernel.org/r/20170213101336.20486-1-dsafonov@virtuozzo.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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2017-03-01 10:24:56 +01:00 |
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Andy Lutomirski
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d63f4b5269
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selftests/x86/ldt_gdt: Test set_thread_area() deletion of an active segment
Now that set_thread_area() is supposed to give deterministic behavior
when it modifies in-use segments, test it.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/f2bc11af1ee1a0f815ed910840cbdba06b640a20.1461698311.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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2016-04-29 11:56:42 +02:00 |
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Andy Lutomirski
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014dc90b66
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selftests/x86, x86/ldt: Add a selftest for modify_ldt()
This tests general modify_ldt() behavior (only writes, so far) as
well as synchronous updates via IPI. It fails on old kernels.
I called this ldt_gdt because I'll add set_thread_area() tests to
it at some point.
Signed-off-by: Andy Lutomirski <luto@kernel.org>
Reviewed-by: Kees Cook <keescook@chromium.org>
Cc: Andrew Cooper <andrew.cooper3@citrix.com>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Boris Ostrovsky <boris.ostrovsky@oracle.com>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Brian Gerst <brgerst@gmail.com>
Cc: Denys Vlasenko <dvlasenk@redhat.com>
Cc: H. Peter Anvin <hpa@zytor.com>
Cc: Jan Beulich <jbeulich@suse.com>
Cc: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Sasha Levin <sasha.levin@oracle.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: security@kernel.org <security@kernel.org>
Cc: xen-devel <xen-devel@lists.xen.org>
Link: http://lkml.kernel.org/r/dcfda65dad07ff5a3ea97a9172b5963bf8031b2e.1438291540.git.luto@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
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2015-07-31 10:24:37 +02:00 |
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