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From: Kees Cook <keescook@chromium.org>
To: linux-kernel@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>,
	Thadeu Lima de Souza Cascardo <cascardo@canonical.com>,
	Max Filippov <jcmvbkbc@gmail.com>,
	Michael Ellerman <mpe@ellerman.id.au>,
	Christian Brauner <christian@brauner.io>,
	Andy Lutomirski <luto@amacapital.net>,
	Will Drewry <wad@chromium.org>,
	linux-kselftest@vger.kernel.org, linux-mips@vger.kernel.org,
	linux-xtensa@linux-xtensa.org,
	linux-arm-kernel@lists.infradead.org,
	linuxppc-dev@lists.ozlabs.org
Subject: [PATCH 10/15] selftests/seccomp: Avoid redundant register flushes
Date: Sat, 12 Sep 2020 04:08:15 -0700	[thread overview]
Message-ID: <20200912110820.597135-11-keescook@chromium.org> (raw)
In-Reply-To: <20200912110820.597135-1-keescook@chromium.org>

When none of the registers have changed, don't flush them back. This can
happen if the architecture uses a non-register way to change the syscall
(e.g. arm64) , and a return value hasn't been written.

Signed-off-by: Kees Cook <keescook@chromium.org>
---
 tools/testing/selftests/seccomp/seccomp_bpf.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c
index d9346121b89b..2790d9cd50f4 100644
--- a/tools/testing/selftests/seccomp/seccomp_bpf.c
+++ b/tools/testing/selftests/seccomp/seccomp_bpf.c
@@ -1859,11 +1859,12 @@ int get_syscall(struct __test_metadata *_metadata, pid_t tracee)
 void change_syscall(struct __test_metadata *_metadata,
 		    pid_t tracee, int syscall, int result)
 {
-	ARCH_REGS regs;
+	ARCH_REGS orig, regs;
 
 	EXPECT_EQ(0, ARCH_GETREGS(regs)) {
 		return;
 	}
+	orig = regs;
 
 	SYSCALL_NUM_SET(regs, syscall);
 
@@ -1876,7 +1877,8 @@ void change_syscall(struct __test_metadata *_metadata,
 #endif
 
 	/* Flush any register changes made. */
-	EXPECT_EQ(0, ARCH_SETREGS(regs));
+	if (memcmp(&orig, &regs, sizeof(orig)) != 0)
+		EXPECT_EQ(0, ARCH_SETREGS(regs));
 }
 
 void tracer_seccomp(struct __test_metadata *_metadata, pid_t tracee,
-- 
2.25.1


  parent reply	other threads:[~2020-09-12 11:10 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-09-12 11:08 [PATCH 00/15] selftests/seccomp: Refactor change_syscall() Kees Cook
2020-09-12 11:08 ` [PATCH 01/15] selftests/seccomp: Refactor arch register macros to avoid xtensa special case Kees Cook
2020-09-15 15:51   ` Christian Brauner
2020-09-12 11:08 ` [PATCH 02/15] selftests/seccomp: Provide generic syscall setting macro Kees Cook
2020-09-15 15:53   ` Christian Brauner
2020-09-12 11:08 ` [PATCH 03/15] selftests/seccomp: mips: Define SYSCALL_NUM_SET macro Kees Cook
2020-09-15 15:55   ` Christian Brauner
2020-09-18 22:00     ` Kees Cook
2020-09-12 11:08 ` [PATCH 04/15] selftests/seccomp: arm: " Kees Cook
2020-09-15 15:56   ` Christian Brauner
2020-09-12 11:08 ` [PATCH 05/15] selftests/seccomp: arm64: " Kees Cook
2020-09-15 15:58   ` Christian Brauner
2020-09-12 11:08 ` [PATCH 06/15] selftests/seccomp: mips: Remove O32-specific macro Kees Cook
2020-09-15 16:00   ` Christian Brauner
2020-09-12 11:08 ` [PATCH 07/15] selftests/seccomp: Remove syscall setting #ifdefs Kees Cook
2020-09-15 16:01   ` Christian Brauner
2020-09-12 11:08 ` [PATCH 08/15] selftests/seccomp: Convert HAVE_GETREG into ARCH_GETREG/ARCH_SETREG Kees Cook
2020-09-15 16:03   ` Christian Brauner
2020-09-12 11:08 ` [PATCH 09/15] selftests/seccomp: Convert REGSET calls " Kees Cook
2020-09-15 16:05   ` Christian Brauner
2020-09-12 11:08 ` Kees Cook [this message]
2020-09-15 16:08   ` [PATCH 10/15] selftests/seccomp: Avoid redundant register flushes Christian Brauner
2020-09-12 11:08 ` [PATCH 11/15] selftests/seccomp: Remove SYSCALL_NUM_RET_SHARE_REG in favor of SYSCALL_RET_SET Kees Cook
2020-09-15 16:11   ` Christian Brauner
2020-09-12 11:08 ` [PATCH 12/15] selftests/seccomp: powerpc: Fix seccomp return value testing Kees Cook
2020-09-14  3:38   ` Michael Ellerman
2020-09-12 11:08 ` [PATCH 13/15] selftests/seccomp: powerpc: Set syscall return during ptrace syscall exit Kees Cook
2020-09-14  5:47   ` Michael Ellerman
2020-09-14 20:20     ` Kees Cook
2020-09-12 11:08 ` [PATCH 14/15] selftests/clone3: Avoid OS-defined clone_args Kees Cook
2020-09-15 16:25   ` Christian Brauner
2020-09-18 22:00     ` Kees Cook
2020-09-12 11:08 ` [PATCH 15/15] selftests/seccomp: Use __NR_mknodat instead of __NR_mknod Kees Cook
2020-09-15 16:16   ` Christian Brauner
2020-09-14 12:15 ` [PATCH 00/15] selftests/seccomp: Refactor change_syscall() Michael Ellerman
2020-09-14 20:32   ` Kees Cook
2020-09-15 11:12     ` Max Filippov
2020-09-15 12:52     ` Michael Ellerman
2020-09-15  8:45 ` Max Filippov

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