x86/fpu: Use validate_xstate_header() to validate the xstate_header in copy_user_to_xstate() (98c0fad9) · Commits · 戴 / test

Tighten the checks in copy_user_to_xstate(). Signed-off-by:

Eric Biggers <ebiggers@google.com> 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: Dmitry Vyukov <dvyukov@google.com> Cc: Eric Biggers <ebiggers3@gmail.com> Cc: Fenghua Yu <fenghua.yu@intel.com> Cc: Kees Cook <keescook@chromium.org> Cc: Kevin Hao <haokexin@gmail.com> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Michael Halcrow <mhalcrow@google.com> 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: Wanpeng Li <wanpeng.li@hotmail.com> Cc: Yu-cheng Yu <yu-cheng.yu@intel.com> Cc: kernel-hardening@lists.openwall.com Link: http://lkml.kernel.org/r/20170924105913.9157-10-mingo@kernel.org Signed-off-by:

Ingo Molnar <mingo@kernel.org>

arch/x86/kernel/fpu/xstate.c

+5 −11

Original line number	Diff line number	Diff line
		@@ -1188,16 +1188,15 @@ int copy_kernel_to_xstate(struct xregs_state xsave, const void kbuf)
		}

		/*
		* 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.
		* Convert from a ptrace or sigreturn standard-format user-space buffer to
		* kernel XSAVES format and copy to the target thread. This is called from
		* xstateregs_set(), as well as potentially from the sigreturn() and
		* rt_sigreturn() system calls.
		*/
		int copy_user_to_xstate(struct xregs_state xsave, const void __user ubuf)
		{
		unsigned int offset, size;
		int i;
		u64 allowed_features;
		struct xstate_header hdr;

		offset = offsetof(struct xregs_state, header);
		@@ -1206,12 +1205,7 @@ int copy_user_to_xstate(struct xregs_state xsave, const void __user ubuf)
		if (__copy_from_user(&hdr, ubuf + offset, size))
		return -EFAULT;

		/*
		* Reject if the user sets any disabled or supervisor features:
		*/
		allowed_features = xfeatures_mask & ~XFEATURE_MASK_SUPERVISOR;

		if (hdr.xfeatures & ~allowed_features)
		if (validate_xstate_header(&hdr))
		return -EINVAL;

		for (i = 0; i < XFEATURE_MAX; i++) {

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