1 files changed, 21 insertions, 16 deletions

diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c
index 83c23c230b4c..fb639e70048f 100644
--- a/arch/x86/kernel/fpu/signal.c
+++ b/arch/x86/kernel/fpu/signal.c
@@ -155,7 +155,8 @@ static inline int copy_fpregs_to_sigframe(struct xregs_state __user *buf)
  */
 int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
 {
-        struct xregs_state *xsave = &current->thread.fpu.state.xsave;
+        struct fpu *fpu = &current->thread.fpu;
+        struct xregs_state *xsave = &fpu->state.xsave;
         struct task_struct *tsk = current;
         int ia32_fxstate = (buf != buf_fx);
 
@@ -170,13 +171,13 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
                         sizeof(struct user_i387_ia32_struct), NULL,
                         (struct _fpstate_32 __user *) buf) ? -1 : 1;
 
-        if (fpregs_active() || using_compacted_format()) {
+        if (fpu->initialized || using_compacted_format()) {
                 /* Save the live register state to the user directly. */
                 if (copy_fpregs_to_sigframe(buf_fx))
                         return -1;
                 /* Update the thread's fxstate to save the fsave header. */
                 if (ia32_fxstate)
-                        copy_fxregs_to_kernel(&tsk->thread.fpu);
+                        copy_fxregs_to_kernel(fpu);
         } else {
                 /*
                  * It is a *bug* if kernel uses compacted-format for xsave
@@ -189,7 +190,7 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size)
                         return -1;
                 }
 
-                fpstate_sanitize_xstate(&tsk->thread.fpu);
+                fpstate_sanitize_xstate(fpu);
                 if (__copy_to_user(buf_fx, xsave, fpu_user_xstate_size))
                         return -1;
         }
@@ -213,8 +214,11 @@ sanitize_restored_xstate(struct task_struct *tsk,
         struct xstate_header *header = &xsave->header;
 
         if (use_xsave()) {
-                /* These bits must be zero. */
-                memset(header->reserved, 0, 48);
+                /*
+                 * Note: we don't need to zero the reserved bits in the
+                 * xstate_header here because we either didn't copy them at all,
+                 * or we checked earlier that they aren't set.
+                 */
 
                 /*
                  * Init the state that is not present in the memory
@@ -223,7 +227,7 @@ sanitize_restored_xstate(struct task_struct *tsk,
                 if (fx_only)
                         header->xfeatures = XFEATURE_MASK_FPSSE;
                 else
-                        header->xfeatures &= (xfeatures_mask & xfeatures);
+                        header->xfeatures &= xfeatures;
         }
 
         if (use_fxsr()) {
@@ -279,7 +283,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
         if (!access_ok(VERIFY_READ, buf, size))
                 return -EACCES;
 
-        fpu__activate_curr(fpu);
+        fpu__initialize(fpu);
 
         if (!static_cpu_has(X86_FEATURE_FPU))
                 return fpregs_soft_set(current, NULL,
@@ -307,28 +311,29 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
                 /*
                  * For 32-bit frames with fxstate, copy the user state to the
                  * thread's fpu state, reconstruct fxstate from the fsave
-                 * header. Sanitize the copied state etc.
+                 * header. Validate and sanitize the copied state.
                  */
                 struct fpu *fpu = &tsk->thread.fpu;
                 struct user_i387_ia32_struct env;
                 int err = 0;
 
                 /*
-                 * Drop the current fpu which clears fpu->fpstate_active. This ensures
+                 * Drop the current fpu which clears fpu->initialized. This ensures
                  * that any context-switch during the copy of the new state,
                  * avoids the intermediate state from getting restored/saved.
                  * Thus avoiding the new restored state from getting corrupted.
                  * We will be ready to restore/save the state only after
-                 * fpu->fpstate_active is again set.
+                 * fpu->initialized is again set.
                  */
                 fpu__drop(fpu);
 
                 if (using_compacted_format()) {
-                        err = copyin_to_xsaves(NULL, buf_fx,
-                                               &fpu->state.xsave);
+                        err = copy_user_to_xstate(&fpu->state.xsave, buf_fx);
                 } else {
-                        err = __copy_from_user(&fpu->state.xsave,
-                                               buf_fx, state_size);
+                        err = __copy_from_user(&fpu->state.xsave, buf_fx, state_size);
+
+                        if (!err && state_size > offsetof(struct xregs_state, header))
+                                err = validate_xstate_header(&fpu->state.xsave.header);
                 }
 
                 if (err || __copy_from_user(&env, buf, sizeof(env))) {
@@ -339,7 +344,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size)
                         sanitize_restored_xstate(tsk, &env, xfeatures, fx_only);
                 }
 
-                fpu->fpstate_active = 1;
+                fpu->initialized = 1;
                 preempt_disable();
                 fpu__restore(fpu);
                 preempt_enable();