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Message-Id: <0fe34229a9330e8f9de9765967939cc4f1cf26b1.1561610354.git.luto@kernel.org> Date: Wed, 26 Jun 2019 21:45:09 -0700 From: Andy Lutomirski <luto@...nel.org> To: x86@...nel.org Cc: LKML <linux-kernel@...r.kernel.org>, Kees Cook <keescook@...omium.org>, Florian Weimer <fweimer@...hat.com>, Jann Horn <jannh@...gle.com>, Andy Lutomirski <luto@...nel.org>, Borislav Petkov <bp@...en8.de>, Kernel Hardening <kernel-hardening@...ts.openwall.com>, Peter Zijlstra <peterz@...radead.org>, Thomas Gleixner <tglx@...utronix.de> Subject: [PATCH v2 8/8] selftests/x86: Add a test for process_vm_readv() on the vsyscall page get_gate_page() is a piece of somewhat alarming code to make get_user_pages() work on the vsyscall page. Test it via process_vm_readv(). Cc: Kees Cook <keescook@...omium.org> Cc: Borislav Petkov <bp@...en8.de> Cc: Kernel Hardening <kernel-hardening@...ts.openwall.com> Cc: Peter Zijlstra <peterz@...radead.org> Cc: Thomas Gleixner <tglx@...utronix.de> Signed-off-by: Andy Lutomirski <luto@...nel.org> --- tools/testing/selftests/x86/test_vsyscall.c | 35 +++++++++++++++++++++ 1 file changed, 35 insertions(+) diff --git a/tools/testing/selftests/x86/test_vsyscall.c b/tools/testing/selftests/x86/test_vsyscall.c index 34a1d35995ef..4602326b8f5b 100644 --- a/tools/testing/selftests/x86/test_vsyscall.c +++ b/tools/testing/selftests/x86/test_vsyscall.c @@ -18,6 +18,7 @@ #include <sched.h> #include <stdbool.h> #include <setjmp.h> +#include <sys/uio.h> #ifdef __x86_64__ # define VSYS(x) (x) @@ -459,6 +460,38 @@ static int test_vsys_x(void) return 0; } +static int test_process_vm_readv(void) +{ +#ifdef __x86_64__ + char buf[4096]; + struct iovec local, remote; + int ret; + + printf("[RUN]\tprocess_vm_readv() from vsyscall page\n"); + + local.iov_base = buf; + local.iov_len = 4096; + remote.iov_base = (void *)0xffffffffff600000; + remote.iov_len = 4096; + ret = process_vm_readv(getpid(), &local, 1, &remote, 1, 0); + if (ret != 4096) { + printf("[OK]\tprocess_vm_readv() failed (ret = %d, errno = %d)\n", ret, errno); + return 0; + } + + if (vsyscall_map_r) { + if (!memcmp(buf, (const void *)0xffffffffff600000, 4096)) { + printf("[OK]\tIt worked and read correct data\n"); + } else { + printf("[FAIL]\tIt worked but returned incorrect data\n"); + return 1; + } + } +#endif + + return 0; +} + #ifdef __x86_64__ #define X86_EFLAGS_TF (1UL << 8) static volatile sig_atomic_t num_vsyscall_traps; @@ -533,6 +566,8 @@ int main(int argc, char **argv) nerrs += test_vsys_r(); nerrs += test_vsys_x(); + nerrs += test_process_vm_readv(); + #ifdef __x86_64__ nerrs += test_emulation(); #endif -- 2.21.0
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