x86/fpu: Use validate_xstate_header() to validate the xstate_header in xstateregs_set()

Tighten the checks in xstateregs_set().

Signed-off-by: Eric Biggers <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Dave Hansen <[email protected]>
Cc: Dmitry Vyukov <[email protected]>
Cc: Eric Biggers <[email protected]>
Cc: Fenghua Yu <[email protected]>
Cc: Kees Cook <[email protected]>
Cc: Kevin Hao <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Michael Halcrow <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Rik van Riel <[email protected]>
Cc: Thomas Gleixner <[email protected]>
Cc: Wanpeng Li <[email protected]>
Cc: Yu-cheng Yu <[email protected]>
Cc: [email protected]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

diff --git a/arch/x86/kernel/fpu/regset.c b/arch/x86/kernel/fpu/regset.c
index ee8d2f0498188a4b6a3ae1543f8b70810dad890f..b831d5b9de99c174f0b69b8de62325017e3061db 100644 (file)
--- a/arch/x86/kernel/fpu/regset.c
+++ b/arch/x86/kernel/fpu/regset.c
@@ -141,27 +141,20 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset,
                        ret = copy_user_to_xstate(xsave, ubuf);
        } else {
                ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, xsave, 0, -1);
-
-               /* xcomp_bv must be 0 when using uncompacted format */
-               if (!ret && xsave->header.xcomp_bv)
-                       ret = -EINVAL;
+               if (!ret)
+                       ret = validate_xstate_header(&xsave->header);
        }
 
-       /*
-        * In case of failure, mark all states as init:
-        */
-       if (ret)
-               fpstate_init(&fpu->state);
-
        /*
         * mxcsr reserved bits must be masked to zero for security reasons.
         */
        xsave->i387.mxcsr &= mxcsr_feature_mask;
-       xsave->header.xfeatures &= xfeatures_mask;
+
        /*
-        * These bits must be zero.
+        * In case of failure, mark all states as init:
         */
-       memset(&xsave->header.reserved, 0, 48);
+       if (ret)
+               fpstate_init(&fpu->state);
 
        return ret;
 }