• Denys Vlasenko's avatar
    x86/asm/entry/32, selftests: Add 'test_syscall_vdso' test · c25be94f
    Denys Vlasenko authored
    This new test checks that all x86 registers are preserved across
    32-bit syscalls. It tests syscalls through VDSO (if available)
    and through INT 0x80, normally and under ptrace.
    
    If kernel is a 64-bit one, high registers (r8..r15) are poisoned
    before the syscall is called and are checked afterwards.
    
    They must be either preserved, or cleared to zero (but r11 is
    special); r12..15 must be preserved for INT 0x80.
    
    EFLAGS is checked for changes too, but change there is not
    considered to be a bug (paravirt kernels do not preserve
    arithmetic flags).
    
    Run-tested on 64-bit kernel:
    
    	$ ./test_syscall_vdso_32
    	[RUN]	Executing 6-argument 32-bit syscall via VDSO
    	[OK]	Arguments are preserved across syscall
    	[NOTE]	R11 has changed:0000000000200ed7 - assuming clobbered by
    	SYSRET insn [OK]	R8..R15 did not leak kernel data
    	[RUN]	Executing 6-argument 32-bit syscall via INT 80
    	[OK]	Arguments are preserved across syscall
    	[OK]	R8..R15 did not leak kernel data
    	[RUN]	Running tests under ptrace
    	[RUN]	Executing 6-argument 32-bit syscall via VDSO
    	[OK]	Arguments are preserved across syscall
    	[OK]	R8..R15 did not leak kernel data
    	[RUN]	Executing 6-argument 32-bit syscall via INT 80
    	[OK]	Arguments are preserved across syscall
    	[OK]	R8..R15 did not leak kernel data
    
    On 32-bit paravirt kernel:
    
    	$ ./test_syscall_vdso_32
    	[NOTE]	Not a 64-bit kernel, won't test R8..R15 leaks
    	[RUN]	Executing 6-argument 32-bit syscall via VDSO
    	[WARN]	Flags before=0000000000200ed7 id 0 00 o d i s z 0 a 0 p 1 c
    	[WARN]	Flags  after=0000000000200246 id 0 00 i z 0 0 p 1
    	[WARN]	Flags change=0000000000000c91 0 00 o d s 0 a 0 0 c
    	[OK]	Arguments are preserved across syscall
    	[RUN]	Executing 6-argument 32-bit syscall via INT 80
    	[OK]	Arguments are preserved across syscall
    	[RUN]	Running tests under ptrace
    	[RUN]	Executing 6-argument 32-bit syscall via VDSO
    	[OK]	Arguments are preserved across syscall
    	[RUN]	Executing 6-argument 32-bit syscall via INT 80
    	[OK]	Arguments are preserved across syscall
    Signed-off-by: default avatarDenys Vlasenko <dvlasenk@redhat.com>
    Acked-by: default avatarAndy Lutomirski <luto@amacapital.net>
    Cc: Alexei Starovoitov <ast@plumgrid.com>
    Cc: Borislav Petkov <bp@alien8.de>
    Cc: Brian Gerst <brgerst@gmail.com>
    Cc: Frederic Weisbecker <fweisbec@gmail.com>
    Cc: H. Peter Anvin <hpa@zytor.com>
    Cc: Kees Cook <keescook@chromium.org>
    Cc: Linus Torvalds <torvalds@linux-foundation.org>
    Cc: Oleg Nesterov <oleg@redhat.com>
    Cc: Peter Zijlstra <peterz@infradead.org>
    Cc: Shuah Khan <shuahkh@osg.samsung.com>
    Cc: Steven Rostedt <rostedt@goodmis.org>
    Cc: Thomas Gleixner <tglx@linutronix.de>
    Cc: Will Drewry <wad@chromium.org>
    Cc: linux-kernel@vger.kernel.org
    Link: http://lkml.kernel.org/r/1442427809-2027-1-git-send-email-dvlasenk@redhat.comSigned-off-by: default avatarIngo Molnar <mingo@kernel.org>
    c25be94f
Makefile 1.76 KB