Messages in this thread Patch in this message | | | From | Ingo Molnar <> | Subject | [PATCH 09/10] x86/fpu: Use validate_xstate_header() to validate the xstate_header in copy_user_to_xstate() | Date | Sun, 24 Sep 2017 12:59:12 +0200 |
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From: Eric Biggers <ebiggers@google.com>
Tighten the checks in copy_user_to_xstate().
Signed-off-by: Eric Biggers <ebiggers@google.com> Cc: Andy Lutomirski <luto@kernel.org> Cc: Dave Hansen <dave.hansen@linux.intel.com> Cc: Dmitry Vyukov <dvyukov@google.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 Signed-off-by: Ingo Molnar <mingo@kernel.org> --- arch/x86/kernel/fpu/xstate.c | 16 +++++----------- 1 file changed, 5 insertions(+), 11 deletions(-)
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++) { -- 2.11.0
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