x86/fpu: Split copy_user_to_xstate() into copy_kernel_to_xstate() & copy_user_to_xstate()

Similar to:

  x86/fpu: Split copy_xstate_to_user() into copy_xstate_to_kernel() & copy_xstate_to_user()

No change in functionality.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andy Lutomirski <luto@amacapital.net>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Eric Biggers <ebiggers3@gmail.com>
Cc: Fenghua Yu <fenghua.yu@intel.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yu-cheng Yu <yu-cheng.yu@intel.com>
Link: http://lkml.kernel.org/r/20170923130016.21448-12-mingo@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/arch/x86/include/asm/fpu/xstate.h b/arch/x86/include/asm/fpu/xstate.h
index fed6617a1079b0b94ab65cb214a7865cac8eddda..79af79dbcab6770eea8e8831843d57244e913357 100644 (file)
--- a/arch/x86/include/asm/fpu/xstate.h
+++ b/arch/x86/include/asm/fpu/xstate.h
@@ -50,6 +50,6 @@ const void *get_xsave_field_ptr(int xstate_field);
 int using_compacted_format(void);
 int copy_xstate_to_kernel(void *kbuf, struct xregs_state *xsave, unsigned int offset, unsigned int size);
 int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned int offset, unsigned int size);
-int copy_user_to_xstate(const void *kbuf, const void __user *ubuf,
-                    struct xregs_state *xsave);
+int copy_kernel_to_xstate(const void *kbuf, const void __user *ubuf, struct xregs_state *xsave);
+int copy_user_to_xstate(const void *kbuf, const void __user *ubuf, struct xregs_state *xsave);
 #endif

diff --git a/arch/x86/kernel/fpu/regset.c b/arch/x86/kernel/fpu/regset.c
index ec1404194b658b5d30ef8e6f774d07d71c2de2b5..cb45dd81d6170c0225deba4b9d833098632e83a5 100644 (file)
--- a/arch/x86/kernel/fpu/regset.c
+++ b/arch/x86/kernel/fpu/regset.c
@@ -134,10 +134,14 @@ int xstateregs_set(struct task_struct *target, const struct user_regset *regset,
 
        fpu__activate_fpstate_write(fpu);
 
-       if (boot_cpu_has(X86_FEATURE_XSAVES))
-               ret = copy_user_to_xstate(kbuf, ubuf, xsave);
-       else
+       if (boot_cpu_has(X86_FEATURE_XSAVES)) {
+               if (kbuf)
+                       ret = copy_kernel_to_xstate(kbuf, ubuf, xsave);
+               else
+                       ret = copy_user_to_xstate(kbuf, ubuf, xsave);
+       } else {
                ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, xsave, 0, -1);
+       }
 
        /*
         * In case of failure, mark all states as init:

diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c
index 00c3b41c3cf1aa95e62a72e65545896d5b85ce49..1ad25d1b805612289d8fdc16016d91949104fa44 100644 (file)
--- a/arch/x86/kernel/fpu/xstate.c
+++ b/arch/x86/kernel/fpu/xstate.c
@@ -1084,7 +1084,71 @@ int copy_xstate_to_user(void __user *ubuf, struct xregs_state *xsave, unsigned i
 }
 
 /*
- * Convert from a ptrace standard-format buffer to kernel XSAVES format
+ * Convert from a ptrace standard-format kernel buffer to kernel XSAVES format
+ * and copy to the target thread. This is called from xstateregs_set() and
+ * there we check the CPU has XSAVES and a whole standard-sized buffer
+ * exists.
+ */
+int copy_kernel_to_xstate(const void *kbuf, const void __user *ubuf,
+                    struct xregs_state *xsave)
+{
+       unsigned int offset, size;
+       int i;
+       u64 xfeatures;
+       u64 allowed_features;
+
+       offset = offsetof(struct xregs_state, header);
+       size = sizeof(xfeatures);
+
+       if (kbuf) {
+               memcpy(&xfeatures, kbuf + offset, size);
+       } else {
+               if (__copy_from_user(&xfeatures, ubuf + offset, size))
+                       return -EFAULT;
+       }
+
+       /*
+        * Reject if the user sets any disabled or supervisor features:
+        */
+       allowed_features = xfeatures_mask & ~XFEATURE_MASK_SUPERVISOR;
+
+       if (xfeatures & ~allowed_features)
+               return -EINVAL;
+
+       for (i = 0; i < XFEATURE_MAX; i++) {
+               u64 mask = ((u64)1 << i);
+
+               if (xfeatures & mask) {
+                       void *dst = __raw_xsave_addr(xsave, 1 << i);
+
+                       offset = xstate_offsets[i];
+                       size = xstate_sizes[i];
+
+                       if (kbuf) {
+                               memcpy(dst, kbuf + offset, size);
+                       } else {
+                               if (__copy_from_user(dst, ubuf + offset, size))
+                                       return -EFAULT;
+                       }
+               }
+       }
+
+       /*
+        * The state that came in from userspace was user-state only.
+        * Mask all the user states out of 'xfeatures':
+        */
+       xsave->header.xfeatures &= XFEATURE_MASK_SUPERVISOR;
+
+       /*
+        * Add back in the features that came in from userspace:
+        */
+       xsave->header.xfeatures |= xfeatures;
+
+       return 0;
+}
+
+/*
+ * Convert from a ptrace standard-format user-space buffer to kernel XSAVES format
  * and copy to the target thread. This is called from xstateregs_set() and
  * there we check the CPU has XSAVES and a whole standard-sized buffer
  * exists.