Commit cf9df81b 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 xstateregs_set()



Tighten the checks in xstateregs_set().

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/20170924105913.9157-3-mingo@kernel.org


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

parent e63e5d5c

arch/x86/kernel/fpu/regset.c

+6 −13

Original line number	Diff line number	Diff line
		@@ -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;
		}

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