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 8fc842dae3b390a49c5147255129d98c8ad88eaf..9a1489b9278271b9e8d3930291f84581db180c7d 100644 (file)
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -262,15 +262,23 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
                return 0;
        }
 
-       if (!access_ok(VERIFY_READ, buf, size))
+       if (!access_ok(VERIFY_READ, buf, size)) {
+               fpu__clear(fpu);
                return -EACCES;
+       }
 
        fpu__activate_curr(fpu);
 
-       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)) {
+               int ret = fpregs_soft_set(current, NULL, 0,
+                                         sizeof(struct user_i387_ia32_struct),
+                                         NULL, buf);
+
+               if (ret)
+                       fpu__clear(fpu);
+
+               return ret != 0;
+       }
 
        if (use_xsave()) {
                struct _fpx_sw_bytes fx_sw_user;