From af2c4322d986a08a6e793b74b83a62b325019c20 Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Sun, 24 Sep 2017 12:59:10 +0200 Subject: [PATCH] x86/fpu: Copy the full header in copy_user_to_xstate() This is in preparation to verify the full xstate header as supplied by user-space. Signed-off-by: Eric Biggers Cc: Andrew Morton Cc: Andy Lutomirski Cc: Andy Lutomirski Cc: Borislav Petkov Cc: Dave Hansen Cc: Dmitry Vyukov Cc: Eric Biggers Cc: Fenghua Yu Cc: Kees Cook Cc: Kevin Hao Cc: Linus Torvalds Cc: Michael Halcrow Cc: Oleg Nesterov Cc: Peter Zijlstra Cc: Rik van Riel Cc: Thomas Gleixner Cc: Wanpeng Li Cc: Yu-cheng Yu Cc: kernel-hardening@lists.openwall.com Link: http://lkml.kernel.org/r/20170924105913.9157-8-mingo@kernel.org Signed-off-by: Ingo Molnar --- arch/x86/kernel/fpu/xstate.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index 325db7850335..0cd7b73c25e8 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -1199,13 +1199,16 @@ int copy_user_to_xstate(struct xregs_state *xsave, const void __user *ubuf) int i; u64 xfeatures; u64 allowed_features; + struct xstate_header hdr; offset = offsetof(struct xregs_state, header); - size = sizeof(xfeatures); + size = sizeof(hdr); - if (__copy_from_user(&xfeatures, ubuf + offset, size)) + if (__copy_from_user(&hdr, ubuf + offset, size)) return -EFAULT; + xfeatures = hdr.xfeatures; + /* * Reject if the user sets any disabled or supervisor features: */ -- 2.20.1