diff options
| -rw-r--r-- | arch/x86/entry/entry_64.S | 19 | ||||
| -rw-r--r-- | arch/x86/entry/entry_64_compat.S | 6 | ||||
| -rw-r--r-- | arch/x86/include/asm/hw_irq.h | 2 | ||||
| -rw-r--r-- | arch/x86/include/asm/kaiser.h | 113 | ||||
| -rw-r--r-- | arch/x86/include/asm/pgtable.h | 4 | ||||
| -rw-r--r-- | arch/x86/include/asm/pgtable_64.h | 21 | ||||
| -rw-r--r-- | arch/x86/include/asm/pgtable_types.h | 12 | ||||
| -rw-r--r-- | arch/x86/include/asm/processor.h | 7 | ||||
| -rw-r--r-- | arch/x86/kernel/cpu/common.c | 4 | ||||
| -rw-r--r-- | arch/x86/kernel/espfix_64.c | 6 | ||||
| -rw-r--r-- | arch/x86/kernel/head_64.S | 16 | ||||
| -rw-r--r-- | arch/x86/kernel/irqinit.c | 2 | ||||
| -rw-r--r-- | arch/x86/kernel/process.c | 2 | ||||
| -rw-r--r-- | arch/x86/mm/Makefile | 1 | ||||
| -rw-r--r-- | arch/x86/mm/kaiser.c | 160 | ||||
| -rw-r--r-- | arch/x86/mm/pageattr.c | 2 | ||||
| -rw-r--r-- | arch/x86/mm/pgtable.c | 26 | ||||
| -rw-r--r-- | include/asm-generic/vmlinux.lds.h | 11 | ||||
| -rw-r--r-- | include/linux/percpu-defs.h | 30 | ||||
| -rw-r--r-- | init/main.c | 6 | ||||
| -rw-r--r-- | kernel/fork.c | 8 | ||||
| -rw-r--r-- | security/Kconfig | 7 |
22 files changed, 449 insertions, 16 deletions
diff --git a/arch/x86/entry/entry_64.S b/arch/x86/entry/entry_64.S index cc0f2f5da19b..273bc5b8d491 100644 --- a/arch/x86/entry/entry_64.S +++ b/arch/x86/entry/entry_64.S @@ -35,6 +35,7 @@ #include <asm/asm.h> #include <asm/smap.h> #include <asm/pgtable_types.h> +#include <asm/kaiser.h> #include <linux/err.h> /* Avoid __ASSEMBLER__'ifying <linux/audit.h> just for this. */ @@ -135,6 +136,7 @@ ENTRY(entry_SYSCALL_64) * it is too small to ever cause noticeable irq latency. */ SWAPGS_UNSAFE_STACK + SWITCH_KERNEL_CR3_NO_STACK /* * A hypervisor implementation might want to use a label * after the swapgs, so that it can do the swapgs @@ -207,9 +209,10 @@ entry_SYSCALL_64_fastpath: testl $_TIF_ALLWORK_MASK, ASM_THREAD_INFO(TI_flags, %rsp, SIZEOF_PTREGS) jnz int_ret_from_sys_call_irqs_off /* Go to the slow path */ - RESTORE_C_REGS_EXCEPT_RCX_R11 movq RIP(%rsp), %rcx movq EFLAGS(%rsp), %r11 + RESTORE_C_REGS_EXCEPT_RCX_R11 + SWITCH_USER_CR3 movq RSP(%rsp), %rsp /* * 64-bit SYSRET restores rip from rcx, @@ -347,10 +350,12 @@ GLOBAL(int_ret_from_sys_call) syscall_return_via_sysret: /* rcx and r11 are already restored (see code above) */ RESTORE_C_REGS_EXCEPT_RCX_R11 + SWITCH_USER_CR3 movq RSP(%rsp), %rsp USERGS_SYSRET64 opportunistic_sysret_failed: + SWITCH_USER_CR3 SWAPGS jmp restore_c_regs_and_iret END(entry_SYSCALL_64) @@ -509,6 +514,7 @@ END(irq_entries_start) * tracking that we're in kernel mode. */ SWAPGS + SWITCH_KERNEL_CR3 /* * We need to tell lockdep that IRQs are off. We can't do this until @@ -568,6 +574,7 @@ GLOBAL(retint_user) mov %rsp,%rdi call prepare_exit_to_usermode TRACE_IRQS_IRETQ + SWITCH_USER_CR3 SWAPGS jmp restore_regs_and_iret @@ -625,6 +632,7 @@ native_irq_return_ldt: pushq %rax pushq %rdi SWAPGS + SWITCH_KERNEL_CR3 movq PER_CPU_VAR(espfix_waddr), %rdi movq %rax, (0*8)(%rdi) /* RAX */ movq (2*8)(%rsp), %rax /* RIP */ @@ -640,6 +648,7 @@ native_irq_return_ldt: andl $0xffff0000, %eax popq %rdi orq PER_CPU_VAR(espfix_stack), %rax + SWITCH_USER_CR3 SWAPGS movq %rax, %rsp popq %rax @@ -1007,6 +1016,7 @@ ENTRY(paranoid_entry) testl %edx, %edx js 1f /* negative -> in kernel */ SWAPGS + SWITCH_KERNEL_CR3 xorl %ebx, %ebx 1: ret END(paranoid_entry) @@ -1029,6 +1039,7 @@ ENTRY(paranoid_exit) testl %ebx, %ebx /* swapgs needed? */ jnz paranoid_exit_no_swapgs TRACE_IRQS_IRETQ + SWITCH_USER_CR3_NO_STACK SWAPGS_UNSAFE_STACK jmp paranoid_exit_restore paranoid_exit_no_swapgs: @@ -1058,6 +1069,7 @@ ENTRY(error_entry) * from user mode due to an IRET fault. */ SWAPGS + SWITCH_KERNEL_CR3 .Lerror_entry_from_usermode_after_swapgs: /* @@ -1110,7 +1122,7 @@ ENTRY(error_entry) * Switch to kernel gsbase: */ SWAPGS - + SWITCH_KERNEL_CR3 /* * Pretend that the exception came from user mode: set up pt_regs * as if we faulted immediately after IRET and clear EBX so that @@ -1210,6 +1222,7 @@ ENTRY(nmi) */ SWAPGS_UNSAFE_STACK + SWITCH_KERNEL_CR3_NO_STACK cld movq %rsp, %rdx movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp @@ -1250,6 +1263,7 @@ ENTRY(nmi) * work, because we don't want to enable interrupts. Fortunately, * do_nmi doesn't modify pt_regs. */ + SWITCH_USER_CR3 SWAPGS jmp restore_c_regs_and_iret @@ -1461,6 +1475,7 @@ end_repeat_nmi: testl %ebx, %ebx /* swapgs needed? */ jnz nmi_restore nmi_swapgs: + SWITCH_USER_CR3_NO_STACK SWAPGS_UNSAFE_STACK nmi_restore: RESTORE_EXTRA_REGS diff --git a/arch/x86/entry/entry_64_compat.S b/arch/x86/entry/entry_64_compat.S index 15cfebaa7688..fe1911930b52 100644 --- a/arch/x86/entry/entry_64_compat.S +++ b/arch/x86/entry/entry_64_compat.S @@ -13,6 +13,7 @@ #include <asm/irqflags.h> #include <asm/asm.h> #include <asm/smap.h> +#include <asm/kaiser.h> #include <linux/linkage.h> #include <linux/err.h> @@ -50,6 +51,7 @@ ENDPROC(native_usergs_sysret32) ENTRY(entry_SYSENTER_compat) /* Interrupts are off on entry. */ SWAPGS_UNSAFE_STACK + SWITCH_KERNEL_CR3_NO_STACK movq PER_CPU_VAR(cpu_current_top_of_stack), %rsp /* @@ -161,6 +163,7 @@ ENDPROC(entry_SYSENTER_compat) ENTRY(entry_SYSCALL_compat) /* Interrupts are off on entry. */ SWAPGS_UNSAFE_STACK + SWITCH_KERNEL_CR3_NO_STACK /* Stash user ESP and switch to the kernel stack. */ movl %esp, %r8d @@ -208,6 +211,7 @@ ENTRY(entry_SYSCALL_compat) /* Opportunistic SYSRET */ sysret32_from_system_call: TRACE_IRQS_ON /* User mode traces as IRQs on. */ + SWITCH_USER_CR3 movq RBX(%rsp), %rbx /* pt_regs->rbx */ movq RBP(%rsp), %rbp /* pt_regs->rbp */ movq EFLAGS(%rsp), %r11 /* pt_regs->flags (in r11) */ @@ -269,6 +273,7 @@ ENTRY(entry_INT80_compat) PARAVIRT_ADJUST_EXCEPTION_FRAME ASM_CLAC /* Do this early to minimize exposure */ SWAPGS + SWITCH_KERNEL_CR3_NO_STACK /* * User tracing code (ptrace or signal handlers) might assume that @@ -311,6 +316,7 @@ ENTRY(entry_INT80_compat) /* Go back to user mode. */ TRACE_IRQS_ON + SWITCH_USER_CR3 SWAPGS jmp restore_regs_and_iret END(entry_INT80_compat) diff --git a/arch/x86/include/asm/hw_irq.h b/arch/x86/include/asm/hw_irq.h index 59caa55fb9b5..ee52ff858699 100644 --- a/arch/x86/include/asm/hw_irq.h +++ b/arch/x86/include/asm/hw_irq.h @@ -187,7 +187,7 @@ extern char irq_entries_start[]; #define VECTOR_RETRIGGERED ((void *)~0UL) typedef struct irq_desc* vector_irq_t[NR_VECTORS]; -DECLARE_PER_CPU(vector_irq_t, vector_irq); +DECLARE_PER_CPU_USER_MAPPED(vector_irq_t, vector_irq); #endif /* !ASSEMBLY_ */ diff --git a/arch/x86/include/asm/kaiser.h b/arch/x86/include/asm/kaiser.h new file mode 100644 index 000000000000..63ee8309b35b --- /dev/null +++ b/arch/x86/include/asm/kaiser.h @@ -0,0 +1,113 @@ +#ifndef _ASM_X86_KAISER_H +#define _ASM_X86_KAISER_H + +/* This file includes the definitions for the KAISER feature. + * KAISER is a counter measure against x86_64 side channel attacks on the kernel virtual memory. + * It has a shodow-pgd for every process. the shadow-pgd has a minimalistic kernel-set mapped, + * but includes the whole user memory. Within a kernel context switch, or when an interrupt is handled, + * the pgd is switched to the normal one. When the system switches to user mode, the shadow pgd is enabled. + * By this, the virtual memory chaches are freed, and the user may not attack the whole kernel memory. + * + * A minimalistic kernel mapping holds the parts needed to be mapped in user mode, as the entry/exit functions + * of the user space, or the stacks. + */ +#ifdef __ASSEMBLY__ +#ifdef CONFIG_KAISER + +.macro _SWITCH_TO_KERNEL_CR3 reg +movq %cr3, \reg +andq $(~0x1000), \reg +movq \reg, %cr3 +.endm + +.macro _SWITCH_TO_USER_CR3 reg +movq %cr3, \reg +orq $(0x1000), \reg +movq \reg, %cr3 +.endm + +.macro SWITCH_KERNEL_CR3 +pushq %rax +_SWITCH_TO_KERNEL_CR3 %rax +popq %rax +.endm + +.macro SWITCH_USER_CR3 +pushq %rax +_SWITCH_TO_USER_CR3 %rax +popq %rax +.endm + +.macro SWITCH_KERNEL_CR3_NO_STACK +movq %rax, PER_CPU_VAR(unsafe_stack_register_backup) +_SWITCH_TO_KERNEL_CR3 %rax +movq PER_CPU_VAR(unsafe_stack_register_backup), %rax +.endm + + +.macro SWITCH_USER_CR3_NO_STACK + +movq %rax, PER_CPU_VAR(unsafe_stack_register_backup) +_SWITCH_TO_USER_CR3 %rax +movq PER_CPU_VAR(unsafe_stack_register_backup), %rax + +.endm + +#else /* CONFIG_KAISER */ + +.macro SWITCH_KERNEL_CR3 reg +.endm +.macro SWITCH_USER_CR3 reg +.endm +.macro SWITCH_USER_CR3_NO_STACK +.endm +.macro SWITCH_KERNEL_CR3_NO_STACK +.endm + +#endif /* CONFIG_KAISER */ +#else /* __ASSEMBLY__ */ + + +#ifdef CONFIG_KAISER +// Upon kernel/user mode switch, it may happen that +// the address space has to be switched before the registers have been stored. +// To change the address space, another register is needed. +// A register therefore has to be stored/restored. +// +DECLARE_PER_CPU_USER_MAPPED(unsigned long, unsafe_stack_register_backup); + +#endif /* CONFIG_KAISER */ + +/** + * shadowmem_add_mapping - map a virtual memory part to the shadow mapping + * @addr: the start address of the range + * @size: the size of the range + * @flags: The mapping flags of the pages + * + * the mapping is done on a global scope, so no bigger synchronization has to be done. + * the pages have to be manually unmapped again when they are not needed any longer. + */ +extern void kaiser_add_mapping(unsigned long addr, unsigned long size, unsigned long flags); + + +/** + * shadowmem_remove_mapping - unmap a virtual memory part of the shadow mapping + * @addr: the start address of the range + * @size: the size of the range + */ +extern void kaiser_remove_mapping(unsigned long start, unsigned long size); + +/** + * shadowmem_initialize_mapping - Initalize the shadow mapping + * + * most parts of the shadow mapping can be mapped upon boot time. + * only the thread stacks have to be mapped on runtime. + * the mapped regions are not unmapped at all. + */ +extern void kaiser_init(void); + +#endif + + + +#endif /* _ASM_X86_KAISER_H */ diff --git a/arch/x86/include/asm/pgtable.h b/arch/x86/include/asm/pgtable.h index 6ec0c8b2e9df..6a843d254114 100644 --- a/arch/x86/include/asm/pgtable.h +++ b/arch/x86/include/asm/pgtable.h @@ -856,6 +856,10 @@ static inline void pmdp_set_wrprotect(struct mm_struct *mm, static inline void clone_pgd_range(pgd_t *dst, pgd_t *src, int count) { memcpy(dst, src, count * sizeof(pgd_t)); +#ifdef CONFIG_KAISER + // clone the shadow pgd part as well + memcpy(native_get_shadow_pgd(dst), native_get_shadow_pgd(src), count * sizeof(pgd_t)); +#endif } #define PTE_SHIFT ilog2(PTRS_PER_PTE) diff --git a/arch/x86/include/asm/pgtable_64.h b/arch/x86/include/asm/pgtable_64.h index 2ee781114d34..2131edda6620 100644 --- a/arch/x86/include/asm/pgtable_64.h +++ b/arch/x86/include/asm/pgtable_64.h @@ -106,9 +106,30 @@ static inline void native_pud_clear(pud_t *pud) native_set_pud(pud, native_make_pud(0)); } +#ifdef CONFIG_KAISER +static inline pgd_t * native_get_shadow_pgd(pgd_t *pgdp) { + return (pgd_t *)(void*)((unsigned long)(void*)pgdp | (unsigned long)PAGE_SIZE); +} + +static inline pgd_t * native_get_normal_pgd(pgd_t *pgdp) { + return (pgd_t *)(void*)((unsigned long)(void*)pgdp & ~(unsigned long)PAGE_SIZE); +} +#endif /* CONFIG_KAISER */ + static inline void native_set_pgd(pgd_t *pgdp, pgd_t pgd) { +#ifdef CONFIG_KAISER + // We know that a pgd is page aligned. + // Therefore the lower indices have to be mapped to user space. + // These pages are mapped to the shadow mapping. + if ((((unsigned long)pgdp) % PAGE_SIZE) < (PAGE_SIZE / 2)) { + native_get_shadow_pgd(pgdp)->pgd = pgd.pgd; + } + + pgdp->pgd = pgd.pgd & ~_PAGE_USER; +#else /* CONFIG_KAISER */ *pgdp = pgd; +#endif } static inline void native_pgd_clear(pgd_t *pgd) diff --git a/arch/x86/include/asm/pgtable_types.h b/arch/x86/include/asm/pgtable_types.h index 79c91853e50e..984670491901 100644 --- a/arch/x86/include/asm/pgtable_types.h +++ b/arch/x86/include/asm/pgtable_types.h @@ -39,7 +39,11 @@ #define _PAGE_ACCESSED (_AT(pteval_t, 1) << _PAGE_BIT_ACCESSED) #define _PAGE_DIRTY (_AT(pteval_t, 1) << _PAGE_BIT_DIRTY) #define _PAGE_PSE (_AT(pteval_t, 1) << _PAGE_BIT_PSE) -#define _PAGE_GLOBAL (_AT(pteval_t, 1) << _PAGE_BIT_GLOBAL) +#ifdef CONFIG_KAISER +#define _PAGE_GLOBAL (_AT(pteval_t, 0)) +#else +#define _PAGE_GLOBAL (_AT(pteval_t, 1) << _PAGE_BIT_GLOBAL) +#endif #define _PAGE_SOFTW1 (_AT(pteval_t, 1) << _PAGE_BIT_SOFTW1) #define _PAGE_SOFTW2 (_AT(pteval_t, 1) << _PAGE_BIT_SOFTW2) #define _PAGE_PAT (_AT(pteval_t, 1) << _PAGE_BIT_PAT) @@ -89,7 +93,11 @@ #define _PAGE_NX (_AT(pteval_t, 0)) #endif -#define _PAGE_PROTNONE (_AT(pteval_t, 1) << _PAGE_BIT_PROTNONE) +#ifdef CONFIG_KAISER +#define _PAGE_PROTNONE (_AT(pteval_t, 0)) +#else +#define _PAGE_PROTNONE (_AT(pteval_t, 1) << _PAGE_BIT_PROTNONE) +#endif #define _PAGE_TABLE (_PAGE_PRESENT | _PAGE_RW | _PAGE_USER | \ _PAGE_ACCESSED | _PAGE_DIRTY) diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 2d5a50cb61a2..6a2e0a0b4a96 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -305,7 +305,7 @@ struct tss_struct { } ____cacheline_aligned; -DECLARE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss); +DECLARE_PER_CPU_SHARED_ALIGNED_USER_MAPPED(struct tss_struct, cpu_tss); #ifdef CONFIG_X86_32 DECLARE_PER_CPU(unsigned long, cpu_current_top_of_stack); @@ -332,6 +332,11 @@ union irq_stack_union { char gs_base[40]; unsigned long stack_canary; }; + + struct { + char irq_stack_pointer[64]; + char unused[IRQ_STACK_SIZE - 64]; + }; }; DECLARE_PER_CPU_FIRST(union irq_stack_union, irq_stack_union) __visible; diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index aa1e7246b06b..e5ba9701ee6c 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -92,7 +92,7 @@ static const struct cpu_dev default_cpu = { static const struct cpu_dev *this_cpu = &default_cpu; -DEFINE_PER_CPU_PAGE_ALIGNED(struct gdt_page, gdt_page) = { .gdt = { +DEFINE_PER_CPU_PAGE_ALIGNED_USER_MAPPED(struct gdt_page, gdt_page) = { .gdt = { #ifdef CONFIG_X86_64 /* * We need valid kernel segments for data and code in long mode too @@ -1229,7 +1229,7 @@ static const unsigned int exception_stack_sizes[N_EXCEPTION_STACKS] = { [DEBUG_STACK - 1] = DEBUG_STKSZ }; -static DEFINE_PER_CPU_PAGE_ALIGNED(char, exception_stacks +DEFINE_PER_CPU_PAGE_ALIGNED_USER_MAPPED(char, exception_stacks [(N_EXCEPTION_STACKS - 1) * EXCEPTION_STKSZ + DEBUG_STKSZ]); /* May not be marked __init: used by software suspend */ diff --git a/arch/x86/kernel/espfix_64.c b/arch/x86/kernel/espfix_64.c index 4d38416e2a7f..bd1358d55146 100644 --- a/arch/x86/kernel/espfix_64.c +++ b/arch/x86/kernel/espfix_64.c @@ -41,6 +41,7 @@ #include <asm/pgalloc.h> #include <asm/setup.h> #include <asm/espfix.h> +#include <asm/kaiser.h> /* * Note: we only need 6*8 = 48 bytes for the espfix stack, but round @@ -126,6 +127,11 @@ void __init init_espfix_bsp(void) /* Install the espfix pud into the kernel page directory */ pgd_p = &init_level4_pgt[pgd_index(ESPFIX_BASE_ADDR)]; pgd_populate(&init_mm, pgd_p, (pud_t *)espfix_pud_page); +#ifdef CONFIG_KAISER + // add the esp stack pud to the shadow mapping here. + // This can be done directly, because the fixup stack has its own pud + set_pgd(native_get_shadow_pgd(pgd_p), __pgd(_PAGE_TABLE | __pa((pud_t *)espfix_pud_page))); +#endif /* Randomize the locations */ init_espfix_random(); diff --git a/arch/x86/kernel/head_64.S b/arch/x86/kernel/head_64.S index ffdc0e860390..0a8d18ac63eb 100644 --- a/arch/x86/kernel/head_64.S +++ b/arch/x86/kernel/head_64.S @@ -441,6 +441,14 @@ early_idt_ripmsg: .balign PAGE_SIZE; \ GLOBAL(name) +#ifdef CONFIG_KAISER +#define NEXT_PGD_PAGE(name) \ + .balign 2 * PAGE_SIZE; \ +GLOBAL(name) +#else +#define NEXT_PGD_PAGE(name) NEXT_PAGE(name) +#endif + /* Automate the creation of 1 to 1 mapping pmd entries */ #define PMDS(START, PERM, COUNT) \ i = 0 ; \ @@ -450,7 +458,7 @@ GLOBAL(name) .endr __INITDATA -NEXT_PAGE(early_level4_pgt) +NEXT_PGD_PAGE(early_level4_pgt) .fill 511,8,0 .quad level3_kernel_pgt - __START_KERNEL_map + _PAGE_TABLE @@ -460,10 +468,10 @@ NEXT_PAGE(early_dynamic_pgts) .data #ifndef CONFIG_XEN -NEXT_PAGE(init_level4_pgt) - .fill 512,8,0 +NEXT_PGD_PAGE(init_level4_pgt) + .fill 2*512,8,0 #else -NEXT_PAGE(init_level4_pgt) +NEXT_PGD_PAGE(init_level4_pgt) .quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE .org init_level4_pgt + L4_PAGE_OFFSET*8, 0 .quad level3_ident_pgt - __START_KERNEL_map + _KERNPG_TABLE diff --git a/arch/x86/kernel/irqinit.c b/arch/x86/kernel/irqinit.c index 1423ab1b0312..f480b38a03c3 100644 --- a/arch/x86/kernel/irqinit.c +++ b/arch/x86/kernel/irqinit.c @@ -51,7 +51,7 @@ static struct irqaction irq2 = { .flags = IRQF_NO_THREAD, }; -DEFINE_PER_CPU(vector_irq_t, vector_irq) = { +DEFINE_PER_CPU_USER_MAPPED(vector_irq_t, vector_irq) = { [0 ... NR_VECTORS - 1] = VECTOR_UNUSED, }; diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 9f7c21c22477..7c5c5dc90ffa 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -39,7 +39,7 @@ * section. Since TSS's are completely CPU-local, we want them * on exact cacheline boundaries, to eliminate cacheline ping-pong. */ -__visible DEFINE_PER_CPU_SHARED_ALIGNED(struct tss_struct, cpu_tss) = { +__visible DEFINE_PER_CPU_SHARED_ALIGNED_USER_MAPPED(struct tss_struct, cpu_tss) = { .x86_tss = { .sp0 = TOP_OF_INIT_STACK, #ifdef CONFIG_X86_32 diff --git a/arch/x86/mm/Makefile b/arch/x86/mm/Makefile index 1ae7c141f778..978156081bed 100644 --- a/arch/x86/mm/Makefile +++ b/arch/x86/mm/Makefile @@ -32,3 +32,4 @@ obj-$(CONFIG_ACPI_NUMA) += srat.o obj-$(CONFIG_NUMA_EMU) += numa_emulation.o obj-$(CONFIG_X86_INTEL_MPX) += mpx.o +obj-$(CONFIG_KAISER) += kaiser.o diff --git a/arch/x86/mm/kaiser.c b/arch/x86/mm/kaiser.c new file mode 100644 index 000000000000..cf1bb922d467 --- /dev/null +++ b/arch/x86/mm/kaiser.c @@ -0,0 +1,160 @@ + + +#include <linux/kernel.h> +#include <linux/errno.h> +#include <linux/string.h> +#include <linux/types.h> +#include <linux/bug.h> +#include <linux/init.h> +#include <linux/spinlock.h> +#include <linux/mm.h> + +#include <linux/uaccess.h> +#include <asm/pgtable.h> +#include <asm/pgalloc.h> +#include <asm/desc.h> +#ifdef CONFIG_KAISER + +__visible DEFINE_PER_CPU_USER_MAPPED(unsigned long, unsafe_stack_register_backup); + +/** + * Get the real ppn from a address in kernel mapping. + * @param address The virtual adrress + * @return the physical address + */ +static inline unsigned long get_pa_from_mapping (unsigned long address) +{ + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + + pgd = pgd_offset_k(address); + BUG_ON(pgd_none(*pgd) || pgd_large(*pgd)); + + pud = pud_offset(pgd, address); + BUG_ON(pud_none(*pud)); + + if (pud_large(*pud)) { + return (pud_pfn(*pud) << PAGE_SHIFT) | (address & ~PUD_PAGE_MASK); + } + + pmd = pmd_offset(pud, address); + BUG_ON(pmd_none(*pmd)); + + if (pmd_large(*pmd)) { + return (pmd_pfn(*pmd) << PAGE_SHIFT) | (address & ~PMD_PAGE_MASK); + } + + pte = pte_offset_kernel(pmd, address); + BUG_ON(pte_none(*pte)); + + return (pte_pfn(*pte) << PAGE_SHIFT) | (address & ~PAGE_MASK); +} + +void _kaiser_copy (unsigned long start_addr, unsigned long size, + unsigned long flags) +{ + pgd_t *pgd; + pud_t *pud; + pmd_t *pmd; + pte_t *pte; + unsigned long address; + unsigned long end_addr = start_addr + size; + unsigned long target_address; + + for (address = PAGE_ALIGN(start_addr - (PAGE_SIZE - 1)); + address < PAGE_ALIGN(end_addr); address += PAGE_SIZE) { + target_address = get_pa_from_mapping(address); + + pgd = native_get_shadow_pgd(pgd_offset_k(address)); + + BUG_ON(pgd_none(*pgd) && "All shadow pgds should be mapped at this time\n"); + BUG_ON(pgd_large(*pgd)); + + pud = pud_offset(pgd, address); + if (pud_none(*pud)) { + set_pud(pud, __pud(_PAGE_TABLE | __pa(pmd_alloc_one(0, address)))); + } + BUG_ON(pud_large(*pud)); + + pmd = pmd_offset(pud, address); + if (pmd_none(*pmd)) { + set_pmd(pmd, __pmd(_PAGE_TABLE | __pa(pte_alloc_one_kernel(0, address)))); + } + BUG_ON(pmd_large(*pmd)); + + pte = pte_offset_kernel(pmd, address); + if (pte_none(*pte)) { + set_pte(pte, __pte(flags | target_address)); + } else { + BUG_ON(__pa(pte_page(*pte)) != target_address); + } + } +} + +// at first, add a pmd for every pgd entry in the shadowmem-kernel-part of the kernel mapping +static inline void __init _kaiser_init(void) +{ + pgd_t *pgd; + int i = 0; + + pgd = native_get_shadow_pgd(pgd_offset_k((unsigned long )0)); + for (i = PTRS_PER_PGD / 2; i < PTRS_PER_PGD; i++) { + set_pgd(pgd + i, __pgd(_PAGE_TABLE |__pa(pud_alloc_one(0, 0)))); + } +} + +extern char __per_cpu_user_mapped_start[], __per_cpu_user_mapped_end[]; +spinlock_t shadow_table_lock; +void __init kaiser_init(void) +{ + int cpu; + spin_lock_init(&shadow_table_lock); + + spin_lock(&shadow_table_lock); + + _kaiser_init(); + + for_each_possible_cpu(cpu) { + // map the per cpu user variables + _kaiser_copy( + (unsigned long) (__per_cpu_user_mapped_start + per_cpu_offset(cpu)), + (unsigned long) __per_cpu_user_mapped_end - (unsigned long) __per_cpu_user_mapped_start, + __PAGE_KERNEL); + } + + // map the entry/exit text section, which is responsible to switch between user- and kernel mode + _kaiser_copy( + (unsigned long) __entry_text_start, + (unsigned long) __entry_text_end - (unsigned long) __entry_text_start, + __PAGE_KERNEL_RX); + + // the fixed map address of the idt_table + _kaiser_copy( + (unsigned long) idt_descr.address, + sizeof(gate_desc) * NR_VECTORS, + __PAGE_KERNEL_RO); + + spin_unlock(&shadow_table_lock); +} + +// add a mapping to the shadow-mapping, and synchronize the mappings +void kaiser_add_mapping(unsigned long addr, unsigned long size, unsigned long flags) +{ + spin_lock(&shadow_table_lock); + _kaiser_copy(addr, size, flags); + spin_unlock(&shadow_table_lock); +} + +extern void unmap_pud_range(pgd_t *pgd, unsigned long start, unsigned long end); +void kaiser_remove_mapping(unsigned long start, unsigned long size) +{ + pgd_t *pgd = native_get_shadow_pgd(pgd_offset_k(start)); + spin_lock(&shadow_table_lock); + do { + unmap_pud_range(pgd, start, start + size); + } while (pgd++ != native_get_shadow_pgd(pgd_offset_k(start + size))); + spin_unlock(&shadow_table_lock); +} +#endif /* CONFIG_KAISER */ diff --git a/arch/x86/mm/pageattr.c b/arch/x86/mm/pageattr.c index b599a780a5a9..4fe616bd2586 100644 --- a/arch/x86/mm/pageattr.c +++ b/arch/x86/mm/pageattr.c @@ -829,7 +829,7 @@ static void unmap_pmd_range(pud_t *pud, unsigned long start, unsigned long end) pud_clear(pud); } -static void unmap_pud_range(pgd_t *pgd, unsigned long start, unsigned long end) +void unmap_pud_range(pgd_t *pgd, unsigned long start, unsigned long end) { pud_t *pud = pud_offset(pgd, start); diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c index fb0a9dd1d6e4..087d3e1e7125 100644 --- a/arch/x86/mm/pgtable.c +++ b/arch/x86/mm/pgtable.c @@ -342,12 +342,38 @@ static inline void _pgd_free(pgd_t *pgd) #else static inline pgd_t *_pgd_alloc(void) { +#ifdef CONFIG_KAISER + // Instead of one PML4, we aquire two PML4s and, thus, an 8kb-aligned memory + // block. Therefore, we have to allocate at least 3 pages. However, the + // __get_free_pages returns us 4 pages. Hence, we store the base pointer at + // the beginning of the page of our 8kb-aligned memory block in order to + // correctly free it afterwars. + + unsigned long pages = __get_free_pages(PGALLOC_GFP, get_order(4*PAGE_SIZE)); + + if(native_get_normal_pgd((pgd_t*) pages) == (pgd_t*) pages) + { + *((unsigned long*)(pages + 2 * PAGE_SIZE)) = pages; + return (pgd_t *) pages; + } + else + { + *((unsigned long*)(pages + 3 * PAGE_SIZE)) = pages; + return (pgd_t *) (pages + PAGE_SIZE); + } +#else return (pgd_t *)__get_free_page(PGALLOC_GFP); +#endif } static inline void _pgd_free(pgd_t *pgd) { +#ifdef CONFIG_KAISER + unsigned long pages = *((unsigned long*) ((char*) pgd + 2 * PAGE_SIZE)); + free_pages(pages, get_order(4*PAGE_SIZE)); +#else free_page((unsigned long)pgd); +#endif } #endif /* CONFIG_X86_PAE */ diff --git a/include/asm-generic/vmlinux.lds.h b/include/asm-generic/vmlinux.lds.h index ef2e8c97e183..cc1c6628e0ae 100644 --- a/include/asm-generic/vmlinux.lds.h +++ b/include/asm-generic/vmlinux.lds.h @@ -725,7 +725,16 @@ */ #define PERCPU_INPUT(cacheline) \ VMLINUX_SYMBOL(__per_cpu_start) = .; \ - *(.data..percpu..first) \ + \ + VMLINUX_SYMBOL(__per_cpu_user_mapped_start) = .; \ + *(.data..percpu..first) \ + . = ALIGN(cacheline); \ + *(.data..percpu..user_mapped) \ + *(.data..percpu..user_mapped..shared_aligned) \ + . = ALIGN(PAGE_SIZE); \ + *(.data..percpu..user_mapped..page_aligned) \ + VMLINUX_SYMBOL(__per_cpu_user_mapped_end) = .; \ + \ . = ALIGN(PAGE_SIZE); \ *(.data..percpu..page_aligned) \ . = ALIGN(cacheline); \ diff --git a/include/linux/percpu-defs.h b/include/linux/percpu-defs.h index 8f16299ca068..8ea945f63a05 100644 --- a/include/linux/percpu-defs.h +++ b/include/linux/percpu-defs.h @@ -35,6 +35,12 @@ #endif +#ifdef CONFIG_KAISER +#define USER_MAPPED_SECTION "..user_mapped" +#else +#define USER_MAPPED_SECTION "" +#endif + /* * Base implementations of per-CPU variable declarations and definitions, where * the section in which the variable is to be placed is provided by the @@ -115,6 +121,12 @@ #define DEFINE_PER_CPU(type, name) \ DEFINE_PER_CPU_SECTION(type, name, "") +#define DECLARE_PER_CPU_USER_MAPPED(type, name) \ + DECLARE_PER_CPU_SECTION(type, name, USER_MAPPED_SECTION) + +#define DEFINE_PER_CPU_USER_MAPPED(type, name) \ + DEFINE_PER_CPU_SECTION(type, name, USER_MAPPED_SECTION) + /* * Declaration/definition used for per-CPU variables that must come first in * the set of variables. @@ -144,6 +156,14 @@ DEFINE_PER_CPU_SECTION(type, name, PER_CPU_SHARED_ALIGNED_SECTION) \ ____cacheline_aligned_in_smp +#define DECLARE_PER_CPU_SHARED_ALIGNED_USER_MAPPED(type, name) \ + DECLARE_PER_CPU_SECTION(type, name, USER_MAPPED_SECTION PER_CPU_SHARED_ALIGNED_SECTION) \ + ____cacheline_aligned_in_smp + +#define DEFINE_PER_CPU_SHARED_ALIGNED_USER_MAPPED(type, name) \ + DEFINE_PER_CPU_SECTION(type, name, USER_MAPPED_SECTION PER_CPU_SHARED_ALIGNED_SECTION) \ + ____cacheline_aligned_in_smp + #define DECLARE_PER_CPU_ALIGNED(type, name) \ DECLARE_PER_CPU_SECTION(type, name, PER_CPU_ALIGNED_SECTION) \ ____cacheline_aligned @@ -162,6 +182,16 @@ #define DEFINE_PER_CPU_PAGE_ALIGNED(type, name) \ DEFINE_PER_CPU_SECTION(type, name, "..page_aligned") \ __aligned(PAGE_SIZE) +/* + * Declaration/definition used for per-CPU variables that must be page aligned and need to be mapped in user mode. + */ +#define DECLARE_PER_CPU_PAGE_ALIGNED_USER_MAPPED(type, name) \ + DECLARE_PER_CPU_SECTION(type, name, USER_MAPPED_SECTION"..page_aligned") \ + __aligned(PAGE_SIZE) + +#define DEFINE_PER_CPU_PAGE_ALIGNED_USER_MAPPED(type, name) \ + DEFINE_PER_CPU_SECTION(type, name, USER_MAPPED_SECTION"..page_aligned") \ + __aligned(PAGE_SIZE) /* * Declaration/definition used for per-CPU variables that must be read mostly. diff --git a/init/main.c b/init/main.c index 9e64d7097f1a..0cc5c4b6841f 100644 --- a/init/main.c +++ b/init/main.c @@ -87,6 +87,9 @@ #include <asm/setup.h> #include <asm/sections.h> #include <asm/cacheflush.h> +#ifdef CONFIG_KAISER +#include <asm/kaiser.h> +#endif static int kernel_init(void *); @@ -492,6 +495,9 @@ static void __init mm_init(void) pgtable_init(); vmalloc_init(); ioremap_huge_init(); +#ifdef CONFIG_KAISER + kaiser_init(); +#endif } asmlinkage __visible void __init start_kernel(void) diff --git a/kernel/fork.c b/kernel/fork.c index 68cfda1c1800..8f1931f5b0a5 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -167,8 +167,12 @@ static struct thread_info *alloc_thread_info_node(struct task_struct *tsk, return page ? page_address(page) : NULL; } +extern void kaiser_remove_mapping(unsigned long start_addr, unsigned long size); static inline void free_thread_info(struct thread_info *ti) { +#ifdef CONFIG_KAISER + kaiser_remove_mapping((unsigned long)ti, THREAD_SIZE); +#endif free_kmem_pages((unsigned long)ti, THREAD_SIZE_ORDER); } # else @@ -331,6 +335,7 @@ void set_task_stack_end_magic(struct task_struct *tsk) *stackend = STACK_END_MAGIC; /* for overflow detection */ } +extern void kaiser_add_mapping(unsigned long addr, unsigned long size, unsigned long flags); static struct task_struct *dup_task_struct(struct task_struct *orig, int node) { struct task_struct *tsk; @@ -352,6 +357,9 @@ static struct task_struct *dup_task_struct(struct task_struct *orig, int node) goto free_ti; tsk->stack = ti; +#ifdef CONFIG_KAISER + kaiser_add_mapping((unsigned long)tsk->stack, THREAD_SIZE, __PAGE_KERNEL); +#endif #ifdef CONFIG_SECCOMP /* * We must handle setting up seccomp filters once we're under diff --git a/security/Kconfig b/security/Kconfig index e45237897b43..cb2a9bcff063 100644 --- a/security/Kconfig +++ b/security/Kconfig @@ -30,6 +30,13 @@ config SECURITY model will be used. If you are unsure how to answer this question, answer N. +config KAISER + bool "Remove the kernel mapping in user mode" + depends on X86_64 + depends on !PARAVIRT + help + This enforces a strict kernel and user space isolation in order to close + hardware side channels on kernel address information. config SECURITYFS bool "Enable the securityfs filesystem" |