[v2,8/8] selftests/x86: Add a test for process_vm_readv() on the vsyscall page
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Message ID 0fe34229a9330e8f9de9765967939cc4f1cf26b1.1561610354.git.luto@kernel.org
State New
Headers show
Series
  • [v2,1/8] x86/vsyscall: Remove the vsyscall=native documentation
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Commit Message

Andy Lutomirski June 27, 2019, 4:45 a.m. UTC
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@chromium.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Kernel Hardening <kernel-hardening@lists.openwall.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Andy Lutomirski <luto@kernel.org>
---
 tools/testing/selftests/x86/test_vsyscall.c | 35 +++++++++++++++++++++
 1 file changed, 35 insertions(+)

Comments

Kees Cook June 27, 2019, 5:30 p.m. UTC | #1
On Wed, Jun 26, 2019 at 09:45:09PM -0700, Andy Lutomirski wrote:
> 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@chromium.org>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: Kernel Hardening <kernel-hardening@lists.openwall.com>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Signed-off-by: Andy Lutomirski <luto@kernel.org>

Reviewed-by: Kees Cook <keescook@chromium.org>

-Kees

> ---
>  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
>

Patch
diff mbox series

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