From 98c0fad9d60e8b2cd47e15b7bee7df343648f5bb Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Sun, 24 Sep 2017 12:59:12 +0200 Subject: x86/fpu: Use validate_xstate_header() to validate the xstate_header in copy_user_to_xstate() Tighten the checks in copy_user_to_xstate(). 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/20170924105913.9157-10-mingo@kernel.org Signed-off-by: Ingo Molnar --- arch/x86/kernel/fpu/xstate.c | 16 +++++----------- 1 file changed, 5 insertions(+), 11 deletions(-) (limited to 'arch/x86') diff --git a/arch/x86/kernel/fpu/xstate.c b/arch/x86/kernel/fpu/xstate.c index b6d78b78b5c2..f1d5476c9022 100644 --- a/arch/x86/kernel/fpu/xstate.c +++ b/arch/x86/kernel/fpu/xstate.c @@ -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++) { -- cgit v1.2.3