diff --git a/arch/x86/kernel/fpu/signal.c b/arch/x86/kernel/fpu/signal.c index cd6eafba12da..77e5c2e34ee6 100644 --- a/arch/x86/kernel/fpu/signal.c +++ b/arch/x86/kernel/fpu/signal.c @@ -211,9 +211,9 @@ int copy_fpstate_to_sigframe(void __user *buf, void __user *buf_fx, int size) } static inline void -sanitize_restored_xstate(union fpregs_state *state, - struct user_i387_ia32_struct *ia32_env, - u64 xfeatures, int fx_only) +sanitize_restored_user_xstate(union fpregs_state *state, + struct user_i387_ia32_struct *ia32_env, + u64 user_xfeatures, int fx_only) { struct xregs_state *xsave = &state->xsave; struct xstate_header *header = &xsave->header; @@ -226,13 +226,22 @@ sanitize_restored_xstate(union fpregs_state *state, */ /* - * Init the state that is not present in the memory - * layout and not enabled by the OS. + * 'user_xfeatures' might have bits clear which are + * set in header->xfeatures. This represents features that + * were in init state prior to a signal delivery, and need + * to be reset back to the init state. Clear any user + * feature bits which are set in the kernel buffer to get + * them back to the init state. + * + * Supervisor state is unchanged by input from userspace. + * Ensure supervisor state bits stay set and supervisor + * state is not modified. */ if (fx_only) header->xfeatures = XFEATURE_MASK_FPSSE; else - header->xfeatures &= xfeatures; + header->xfeatures &= user_xfeatures | + xfeatures_mask_supervisor(); } if (use_fxsr()) { @@ -281,7 +290,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) struct task_struct *tsk = current; struct fpu *fpu = &tsk->thread.fpu; struct user_i387_ia32_struct env; - u64 xfeatures = 0; + u64 user_xfeatures = 0; int fx_only = 0; int ret = 0; @@ -314,7 +323,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) trace_x86_fpu_xstate_check_failed(fpu); } else { state_size = fx_sw_user.xstate_size; - xfeatures = fx_sw_user.xfeatures; + user_xfeatures = fx_sw_user.xfeatures; } } @@ -349,7 +358,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) */ fpregs_lock(); pagefault_disable(); - ret = copy_user_to_fpregs_zeroing(buf_fx, xfeatures, fx_only); + ret = copy_user_to_fpregs_zeroing(buf_fx, user_xfeatures, fx_only); pagefault_enable(); if (!ret) { fpregs_mark_activate(); @@ -362,7 +371,7 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) if (use_xsave() && !fx_only) { - u64 init_bv = xfeatures_mask_user() & ~xfeatures; + u64 init_bv = xfeatures_mask_user() & ~user_xfeatures; if (using_compacted_format()) { ret = copy_user_to_xstate(&fpu->state.xsave, buf_fx); @@ -375,12 +384,13 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) if (ret) goto err_out; - sanitize_restored_xstate(&fpu->state, envp, xfeatures, fx_only); + sanitize_restored_user_xstate(&fpu->state, envp, user_xfeatures, + fx_only); fpregs_lock(); if (unlikely(init_bv)) copy_kernel_to_xregs(&init_fpstate.xsave, init_bv); - ret = copy_kernel_to_xregs_err(&fpu->state.xsave, xfeatures); + ret = copy_kernel_to_xregs_err(&fpu->state.xsave, user_xfeatures); } else if (use_fxsr()) { ret = __copy_from_user(&fpu->state.fxsave, buf_fx, state_size); @@ -389,7 +399,8 @@ static int __fpu__restore_sig(void __user *buf, void __user *buf_fx, int size) goto err_out; } - sanitize_restored_xstate(&fpu->state, envp, xfeatures, fx_only); + sanitize_restored_user_xstate(&fpu->state, envp, user_xfeatures, + fx_only); fpregs_lock(); if (use_xsave()) {