Commit af95774b authored Sep 24, 2017 by Eric Biggers Committed by Ingo Molnar Sep 26, 2017

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



Tighten the checks in copy_kernel_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/20170924105913.9157-7-mingo@kernel.org


Signed-off-by: Ingo Molnar <mingo@kernel.org>

parent b89eda48

arch/x86/kernel/fpu/xstate.c

+2 −10

Original line number	Diff line number	Diff line
		@@ -1138,15 +1138,12 @@ int copy_xstate_to_user(void __user ubuf, struct xregs_state xsave, unsigned i

		/*
		* 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.
		* and copy to the target thread. This is called from xstateregs_set().
		*/
		int copy_kernel_to_xstate(struct xregs_state xsave, const void kbuf)
		{
		unsigned int offset, size;
		int i;
		u64 allowed_features;
		struct xstate_header hdr;

		offset = offsetof(struct xregs_state, header);
		@@ -1154,12 +1151,7 @@ int copy_kernel_to_xstate(struct xregs_state xsave, const void kbuf)

		memcpy(&hdr, kbuf + offset, size);

		/*
		* 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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