From 0ce105bf9723e9a2dc7ec0a1e164c1b63aa64546 Mon Sep 17 00:00:00 2001 From: Matt Redfearn Date: Tue, 29 Mar 2016 09:35:29 +0100 Subject: [PATCH] selftests/seccomp: add MIPS self-test support This adds self-test support on MIPS, based on RFC patch from Kees Cook. Modifications from the RFC: - support the O32 syscall which passes the real syscall number in a0. - Use PTRACE_{GET,SET}REGS - Because SYSCALL_NUM and SYSCALL_RET are the same register, it is not possible to test modifying the syscall return value when skipping, since both would need to set the same register. Therefore modify that test case to just detect the skipped test. Tested on MIPS32r2 / MIPS64r2 with O32, N32 and N64 userlands. Signed-off-by: Matt Redfearn Acked-by: Kees Cook Cc: Andy Lutomirski Cc: Shuah Khan Cc: Will Drewry Cc: IMG-MIPSLinuxKerneldevelopers@imgtec.com Cc: linux-kernel@vger.kernel.org Cc: linux-kselftest@vger.kernel.org Patchwork: https://patchwork.linux-mips.org/patch/12977/ Signed-off-by: Ralf Baechle --- tools/testing/selftests/seccomp/seccomp_bpf.c | 30 +++++++++++++++++-- 1 file changed, 28 insertions(+), 2 deletions(-) diff --git a/tools/testing/selftests/seccomp/seccomp_bpf.c b/tools/testing/selftests/seccomp/seccomp_bpf.c index 150829dd7998..7947e568e057 100644 --- a/tools/testing/selftests/seccomp/seccomp_bpf.c +++ b/tools/testing/selftests/seccomp/seccomp_bpf.c @@ -5,6 +5,7 @@ * Test code for seccomp bpf. */ +#include #include #define __have_siginfo_t 1 #define __have_sigval_t 1 @@ -14,7 +15,6 @@ #include #include #include -#include #include #include #include @@ -1242,6 +1242,12 @@ TEST_F(TRACE_poke, getpid_runs_normally) # define ARCH_REGS s390_regs # define SYSCALL_NUM gprs[2] # define SYSCALL_RET gprs[2] +#elif defined(__mips__) +# define ARCH_REGS struct pt_regs +# define SYSCALL_NUM regs[2] +# define SYSCALL_SYSCALL_NUM regs[4] +# define SYSCALL_RET regs[2] +# define SYSCALL_NUM_RET_SHARE_REG #else # error "Do not know how to find your architecture's registers and syscalls" #endif @@ -1249,7 +1255,7 @@ TEST_F(TRACE_poke, getpid_runs_normally) /* Use PTRACE_GETREGS and PTRACE_SETREGS when available. This is useful for * architectures without HAVE_ARCH_TRACEHOOK (e.g. User-mode Linux). */ -#if defined(__x86_64__) || defined(__i386__) +#if defined(__x86_64__) || defined(__i386__) || defined(__mips__) #define HAVE_GETREGS #endif @@ -1273,6 +1279,10 @@ int get_syscall(struct __test_metadata *_metadata, pid_t tracee) } #endif +#if defined(__mips__) + if (regs.SYSCALL_NUM == __NR_O32_Linux) + return regs.SYSCALL_SYSCALL_NUM; +#endif return regs.SYSCALL_NUM; } @@ -1297,6 +1307,13 @@ void change_syscall(struct __test_metadata *_metadata, { regs.SYSCALL_NUM = syscall; } +#elif defined(__mips__) + { + if (regs.SYSCALL_NUM == __NR_O32_Linux) + regs.SYSCALL_SYSCALL_NUM = syscall; + else + regs.SYSCALL_NUM = syscall; + } #elif defined(__arm__) # ifndef PTRACE_SET_SYSCALL @@ -1327,7 +1344,11 @@ void change_syscall(struct __test_metadata *_metadata, /* If syscall is skipped, change return value. */ if (syscall == -1) +#ifdef SYSCALL_NUM_RET_SHARE_REG + TH_LOG("Can't modify syscall return on this architecture"); +#else regs.SYSCALL_RET = 1; +#endif #ifdef HAVE_GETREGS ret = ptrace(PTRACE_SETREGS, tracee, 0, ®s); @@ -1465,8 +1486,13 @@ TEST_F(TRACE_syscall, syscall_dropped) ret = prctl(PR_SET_SECCOMP, SECCOMP_MODE_FILTER, &self->prog, 0, 0); ASSERT_EQ(0, ret); +#ifdef SYSCALL_NUM_RET_SHARE_REG + /* gettid has been skipped */ + EXPECT_EQ(-1, syscall(__NR_gettid)); +#else /* gettid has been skipped and an altered return value stored. */ EXPECT_EQ(1, syscall(__NR_gettid)); +#endif EXPECT_NE(self->mytid, syscall(__NR_gettid)); } -- 2.39.5