x86/fpu: Reset state for all signal restore failures

commit efa165504943f2128d50f63de0c02faf6dcceb0d upstream.

If access_ok() or fpregs_soft_set() fails in __fpu__restore_sig() then the
function just returns but does not clear the FPU state as it does for all
other fatal failures.

Clear the FPU state for these failures as well.

Fixes: 72a671ced66d ("x86, fpu: Unify signal handling code paths for x86 and x86_64 kernels")
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Borislav Petkov <bp@suse.de>
Cc: stable@vger.kernel.org
Link: https://lkml.kernel.org/r/87mtryyhhz.ffs@nanos.tec.linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index 4ab9aeb..ec3ae30 100644 (file)
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -307,13 +307,17 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
                return 0;
        }
 
-       if (!access_ok(buf, size))
-               return -EACCES;
+       if (!access_ok(buf, size)) {
+               ret = -EACCES;
+               goto out;
+       }
 
-       if (!static_cpu_has(X86_FEATURE_FPU))
-               return fpregs_soft_set(current, NULL,
-                                      0, sizeof(struct user_i387_ia32_struct),
-                                      NULL, buf) != 0;
+       if (!static_cpu_has(X86_FEATURE_FPU)) {
+               ret = fpregs_soft_set(current, NULL, 0,
+                                     sizeof(struct user_i387_ia32_struct),
+                                     NULL, buf);
+               goto out;
+       }
 
        if (use_xsave()) {
                struct _fpx_sw_bytes fx_sw_user;
@@ -396,7 +400,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
                 */
                ret = __copy_from_user(&env, buf, sizeof(env));
                if (ret)
-                       goto err_out;
+                       goto out;
                envp = &env;
        }
 
@@ -426,7 +430,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
 
                ret = copy_user_to_xstate(&fpu->state.xsave, buf_fx);
                if (ret)
-                       goto err_out;
+                       goto out;
 
                sanitize_restored_user_xstate(&fpu->state, envp, user_xfeatures,
                                              fx_only);
@@ -446,7 +450,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
                ret = __copy_from_user(&fpu->state.fxsave, buf_fx, state_size);
                if (ret) {
                        ret = -EFAULT;
-                       goto err_out;
+                       goto out;
                }
 
                sanitize_restored_user_xstate(&fpu->state, envp, user_xfeatures,
@@ -464,7 +468,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
        } else {
                ret = __copy_from_user(&fpu->state.fsave, buf_fx, state_size);
                if (ret)
-                       goto err_out;
+                       goto out;
 
                fpregs_lock();
                ret = copy_kernel_to_fregs_err(&fpu->state.fsave);
@@ -475,7 +479,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
                fpregs_deactivate(fpu);
        fpregs_unlock();
 
-err_out:
+out:
        if (ret)
                fpu__clear_user_states(fpu);
        return ret;