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home:troyeb:intel-gfx
kernel-rh
_service:download_src_package:linux-2.6-i386-nx...
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File _service:download_src_package:linux-2.6-i386-nx-emulation.patch of Package kernel-rh
--- a/arch/x86/include/asm/desc.h +++ b/arch/x86/include/asm/desc.h @@ -5,6 +5,7 @@ #include <asm/ldt.h> #include <asm/mmu.h> +#include <linux/mm_types.h> #include <linux/smp.h> static inline void fill_ldt(struct desc_struct *desc, const struct user_desc *info) @@ -97,6 +98,9 @@ static inline int desc_empty(const void *ptr) #define load_TLS(t, cpu) native_load_tls(t, cpu) #define set_ldt native_set_ldt +#ifdef CONFIG_X86_32 +#define load_user_cs_desc native_load_user_cs_desc +#endif /*CONFIG_X86_32*/ #define write_ldt_entry(dt, entry, desc) native_write_ldt_entry(dt, entry, desc) #define write_gdt_entry(dt, entry, desc, type) native_write_gdt_entry(dt, entry, desc, type) @@ -392,4 +396,25 @@ static inline void set_system_intr_gate_ist(int n, void *addr, unsigned ist) _set_gate(n, GATE_INTERRUPT, addr, 0x3, ist, __KERNEL_CS); } +#ifdef CONFIG_X86_32 +static inline void set_user_cs(struct desc_struct *desc, unsigned long limit) +{ + limit = (limit - 1) / PAGE_SIZE; + desc->a = limit & 0xffff; + desc->b = (limit & 0xf0000) | 0x00c0fb00; +} + +static inline void native_load_user_cs_desc(int cpu, struct mm_struct *mm) +{ + get_cpu_gdt_table(cpu)[GDT_ENTRY_DEFAULT_USER_CS] = (mm)->context.user_cs; +} + +#define arch_add_exec_range arch_add_exec_range +#define arch_remove_exec_range arch_remove_exec_range +#define arch_flush_exec_range arch_flush_exec_range +extern void arch_add_exec_range(struct mm_struct *mm, unsigned long limit); +extern void arch_remove_exec_range(struct mm_struct *mm, unsigned long limit); +extern void arch_flush_exec_range(struct mm_struct *mm); +#endif /* CONFIG_X86_32 */ + #endif /* _ASM_X86_DESC_H */ --- a/arch/x86/include/asm/mmu.h +++ b/arch/x86/include/asm/mmu.h @@ -7,6 +7,9 @@ /* * The x86 doesn't have a mmu context, but * we put the segment information here. + * + * exec_limit is used to track the range PROT_EXEC + * mappings span. */ typedef struct { void *ldt; @@ -19,6 +22,11 @@ typedef struct { struct mutex lock; void *vdso; + +#ifdef CONFIG_X86_32 + struct desc_struct user_cs; + unsigned long exec_limit; +#endif } mm_context_t; #ifdef CONFIG_SMP --- a/arch/x86/include/asm/paravirt.h +++ b/arch/x86/include/asm/paravirt.h @@ -289,6 +289,12 @@ static inline void set_ldt(const void *addr, unsigned entries) { PVOP_VCALL2(pv_cpu_ops.set_ldt, addr, entries); } +#ifdef CONFIG_X86_32 +static inline void load_user_cs_desc(unsigned int cpu, struct mm_struct *mm) +{ + PVOP_VCALL2(pv_cpu_ops.load_user_cs_desc, cpu, mm); +} +#endif /*CONFIG_X86_32*/ static inline void store_gdt(struct desc_ptr *dtr) { PVOP_VCALL1(pv_cpu_ops.store_gdt, dtr); --- a/arch/x86/include/asm/paravirt_types.h +++ b/arch/x86/include/asm/paravirt_types.h @@ -118,6 +118,9 @@ struct pv_cpu_ops { void (*store_gdt)(struct desc_ptr *); void (*store_idt)(struct desc_ptr *); void (*set_ldt)(const void *desc, unsigned entries); +#ifdef CONFIG_X86_32 + void (*load_user_cs_desc)(int cpu, struct mm_struct *mm); +#endif unsigned long (*store_tr)(void); void (*load_tls)(struct thread_struct *t, unsigned int cpu); #ifdef CONFIG_X86_64 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -802,6 +802,22 @@ static void __cpuinit identify_cpu(struct cpuinfo_x86 *c) /* Filter out anything that depends on CPUID levels we don't have */ filter_cpuid_features(c, true); +#ifdef CONFIG_X86_32 + /* + * emulation of NX with segment limits unfortunately means + * we have to disable the fast system calls, due to the way that + * sysexit clears the segment limits on return. + * If we have either disabled exec-shield on the boot command line, + * or we have NX, then we don't need to do this. + */ + if (!disable_nx) { +#ifdef CONFIG_X86_PAE + if (!test_cpu_cap(c, X86_FEATURE_NX)) +#endif + clear_cpu_cap(c, X86_FEATURE_SEP); + } +#endif + /* If the model name is still unset, do table lookup. */ if (!c->x86_model_id[0]) { const char *p; --- a/arch/x86/kernel/paravirt.c +++ b/arch/x86/kernel/paravirt.c @@ -345,6 +345,9 @@ struct pv_cpu_ops pv_cpu_ops = { .read_tscp = native_read_tscp, .load_tr_desc = native_load_tr_desc, .set_ldt = native_set_ldt, +#ifdef CONFIG_X86_32 + .load_user_cs_desc = native_load_user_cs_desc, +#endif /*CONFIG_X86_32*/ .load_gdt = native_load_gdt, .load_idt = native_load_idt, .store_gdt = native_store_gdt, --- a/arch/x86/kernel/process_32.c +++ b/arch/x86/kernel/process_32.c @@ -243,7 +243,10 @@ int copy_thread(unsigned long clone_flags, unsigned long sp, void start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp) { + int cpu; + set_user_gs(regs, 0); + regs->fs = 0; regs->ds = __USER_DS; regs->es = __USER_DS; @@ -252,6 +255,11 @@ start_thread(struct pt_regs *regs, unsigned long new_ip, unsigned long new_sp) regs->cs = __USER_CS; regs->ip = new_ip; regs->sp = new_sp; + + cpu = get_cpu(); + load_user_cs_desc(cpu, current->mm); + put_cpu(); + /* * Free the old FP and other extended state */ @@ -311,6 +319,9 @@ __switch_to(struct task_struct *prev_p, struct task_struct *next_p) if (preload_fpu) prefetch(next->fpu.state); + if (next_p->mm) + load_user_cs_desc(cpu, next_p->mm); + /* * Reload esp0. */ @@ -404,3 +415,40 @@ unsigned long get_wchan(struct task_struct *p) return 0; } +static void modify_cs(struct mm_struct *mm, unsigned long limit) +{ + mm->context.exec_limit = limit; + set_user_cs(&mm->context.user_cs, limit); + if (mm == current->mm) { + int cpu; + + cpu = get_cpu(); + load_user_cs_desc(cpu, mm); + put_cpu(); + } +} + +void arch_add_exec_range(struct mm_struct *mm, unsigned long limit) +{ + if (limit > mm->context.exec_limit) + modify_cs(mm, limit); +} + +void arch_remove_exec_range(struct mm_struct *mm, unsigned long old_end) +{ + struct vm_area_struct *vma; + unsigned long limit = PAGE_SIZE; + + if (old_end == mm->context.exec_limit) { + for (vma = mm->mmap; vma; vma = vma->vm_next) + if ((vma->vm_flags & VM_EXEC) && (vma->vm_end > limit)) + limit = vma->vm_end; + modify_cs(mm, limit); + } +} + +void arch_flush_exec_range(struct mm_struct *mm) +{ + mm->context.exec_limit = 0; + set_user_cs(&mm->context.user_cs, 0); +} --- a/arch/x86/kernel/traps.c +++ b/arch/x86/kernel/traps.c @@ -109,6 +109,78 @@ static inline void preempt_conditional_cli(struct pt_regs *regs) dec_preempt_count(); } +#ifdef CONFIG_X86_32 +static inline int +__compare_user_cs_desc(const struct desc_struct *desc1, + const struct desc_struct *desc2) +{ + return ((desc1->limit0 != desc2->limit0) || + (desc1->limit != desc2->limit) || + (desc1->base0 != desc2->base0) || + (desc1->base1 != desc2->base1) || + (desc1->base2 != desc2->base2)); +} + +/* + * lazy-check for CS validity on exec-shield binaries: + * + * the original non-exec stack patch was written by + * Solar Designer <solar at openwall.com>. Thanks! + */ +static int +check_lazy_exec_limit(int cpu, struct pt_regs *regs, long error_code) +{ + struct desc_struct *desc1, *desc2; + struct vm_area_struct *vma; + unsigned long limit; + + if (current->mm == NULL) + return 0; + + limit = -1UL; + if (current->mm->context.exec_limit != -1UL) { + limit = PAGE_SIZE; + spin_lock(¤t->mm->page_table_lock); + for (vma = current->mm->mmap; vma; vma = vma->vm_next) + if ((vma->vm_flags & VM_EXEC) && (vma->vm_end > limit)) + limit = vma->vm_end; + vma = get_gate_vma(current->mm); + if (vma && (vma->vm_flags & VM_EXEC) && (vma->vm_end > limit)) + limit = vma->vm_end; + spin_unlock(¤t->mm->page_table_lock); + if (limit >= TASK_SIZE) + limit = -1UL; + current->mm->context.exec_limit = limit; + } + set_user_cs(¤t->mm->context.user_cs, limit); + + desc1 = ¤t->mm->context.user_cs; + desc2 = get_cpu_gdt_table(cpu) + GDT_ENTRY_DEFAULT_USER_CS; + + if (__compare_user_cs_desc(desc1, desc2)) { + /* + * The CS was not in sync - reload it and retry the + * instruction. If the instruction still faults then + * we won't hit this branch next time around. + */ + if (print_fatal_signals >= 2) { + printk(KERN_ERR "#GPF fixup (%ld[seg:%lx]) at %08lx, CPU#%d.\n", + error_code, error_code/8, regs->ip, + smp_processor_id()); + printk(KERN_ERR "exec_limit: %08lx, user_cs: %08x/%08x, CPU_cs: %08x/%08x.\n", + current->mm->context.exec_limit, + desc1->a, desc1->b, desc2->a, desc2->b); + } + + load_user_cs_desc(cpu, current->mm); + + return 1; + } + + return 0; +} +#endif + static void __kprobes do_trap(int trapnr, int signr, char *str, struct pt_regs *regs, long error_code, siginfo_t *info) @@ -265,6 +337,29 @@ do_general_protection(struct pt_regs *regs, long error_code) if (!user_mode(regs)) goto gp_in_kernel; +#ifdef CONFIG_X86_32 +{ + int cpu; + int ok; + + cpu = get_cpu(); + ok = check_lazy_exec_limit(cpu, regs, error_code); + put_cpu(); + + if (ok) + return; + + if (print_fatal_signals) { + printk(KERN_ERR "#GPF(%ld[seg:%lx]) at %08lx, CPU#%d.\n", + error_code, error_code/8, regs->ip, smp_processor_id()); + printk(KERN_ERR "exec_limit: %08lx, user_cs: %08x/%08x.\n", + current->mm->context.exec_limit, + current->mm->context.user_cs.a, + current->mm->context.user_cs.b); + } +} +#endif /*CONFIG_X86_32*/ + tsk->thread.error_code = error_code; tsk->thread.trap_no = 13; @@ -792,19 +887,37 @@ do_device_not_available(struct pt_regs *regs, long error_code) } #ifdef CONFIG_X86_32 +/* + * The fixup code for errors in iret jumps to here (iret_exc). It loses + * the original trap number and erorr code. The bogus trap 32 and error + * code 0 are what the vanilla kernel delivers via: + * DO_ERROR_INFO(32, SIGSEGV, "iret exception", iret_error, ILL_BADSTK, 0, 1) + * + * NOTE: Because of the final "1" in the macro we need to enable interrupts. + * + * In case of a general protection fault in the iret instruction, we + * need to check for a lazy CS update for exec-shield. + */ dotraplinkage void do_iret_error(struct pt_regs *regs, long error_code) { - siginfo_t info; + int ok; + int cpu; + local_irq_enable(); - info.si_signo = SIGILL; - info.si_errno = 0; - info.si_code = ILL_BADSTK; - info.si_addr = NULL; - if (notify_die(DIE_TRAP, "iret exception", - regs, error_code, 32, SIGILL) == NOTIFY_STOP) - return; - do_trap(32, SIGILL, "iret exception", regs, error_code, &info); + cpu = get_cpu(); + ok = check_lazy_exec_limit(cpu, regs, error_code); + put_cpu(); + + if (!ok && notify_die(DIE_TRAP, "iret exception", regs, + error_code, 32, SIGSEGV) != NOTIFY_STOP) { + siginfo_t info; + info.si_signo = SIGSEGV; + info.si_errno = 0; + info.si_code = ILL_BADSTK; + info.si_addr = 0; + do_trap(32, SIGSEGV, "iret exception", regs, error_code, &info); + } } #endif --- a/arch/x86/mm/setup_nx.c +++ b/arch/x86/mm/setup_nx.c @@ -1,3 +1,4 @@ +#include <linux/sched.h> #include <linux/spinlock.h> #include <linux/errno.h> #include <linux/init.h> @@ -6,7 +6,7 @@ #include <asm/pgtable.h> #include <asm/proto.h> -static int disable_nx __cpuinitdata; +int disable_nx __cpuinitdata; /* * noexec = on|off @@ -40,6 +42,10 @@ void __cpuinit x86_configure_nx(void) void __init x86_report_nx(void) { if (!cpu_has_nx) { + if (!disable_nx) + printk(KERN_INFO "Using x86 segment limits to approximate NX protection\n"); + else + printk(KERN_NOTICE "Notice: NX (Execute Disable) protection " "missing in CPU!\n"); } else { --- a/arch/x86/mm/tlb.c +++ b/arch/x86/mm/tlb.c @@ -6,6 +6,7 @@ #include <linux/module.h> #include <linux/cpu.h> +#include <asm/desc.h> #include <asm/tlbflush.h> #include <asm/mmu_context.h> #include <asm/cache.h> @@ -131,6 +132,12 @@ void smp_invalidate_interrupt(struct pt_regs *regs) union smp_flush_state *f; cpu = smp_processor_id(); + +#ifdef CONFIG_X86_32 + if (current->active_mm) + load_user_cs_desc(cpu, current->active_mm); +#endif + /* * orig_rax contains the negated interrupt vector. * Use that to determine where the sender put the data. --- a/arch/x86/xen/enlighten.c +++ b/arch/x86/xen/enlighten.c @@ -335,6 +335,24 @@ static void xen_set_ldt(const void *addr, unsigned entries) xen_mc_issue(PARAVIRT_LAZY_CPU); } +#ifdef CONFIG_X86_32 +static void xen_load_user_cs_desc(int cpu, struct mm_struct *mm) +{ + void *gdt; + xmaddr_t mgdt; + u64 descriptor; + struct desc_struct user_cs; + + gdt = &get_cpu_gdt_table(cpu)[GDT_ENTRY_DEFAULT_USER_CS]; + mgdt = virt_to_machine(gdt); + + user_cs = mm->context.user_cs; + descriptor = (u64) user_cs.a | ((u64) user_cs.b) << 32; + + HYPERVISOR_update_descriptor(mgdt.maddr, descriptor); +} +#endif /*CONFIG_X86_32*/ + static void xen_load_gdt(const struct desc_ptr *dtr) { unsigned long va = dtr->address; @@ -961,6 +979,9 @@ static const struct pv_cpu_ops xen_cpu_ops __initdata = { .load_tr_desc = paravirt_nop, .set_ldt = xen_set_ldt, +#ifdef CONFIG_X86_32 + .load_user_cs_desc = xen_load_user_cs_desc, +#endif /*CONFIG_X86_32*/ .load_gdt = xen_load_gdt, .load_idt = xen_load_idt, .load_tls = xen_load_tls, --- a/fs/binfmt_elf.c +++ b/fs/binfmt_elf.c @@ -717,6 +722,15 @@ static int load_elf_binary(struct linux_binprm *bprm, struct pt_regs *regs) if (retval) goto out_free_dentry; +#ifdef CONFIG_X86_32 + /* + * Turn off the CS limit completely if exec-shield disabled or + * NX active: + */ + if (disable_nx || executable_stack != EXSTACK_DISABLE_X || (__supported_pte_mask & _PAGE_NX)) + arch_add_exec_range(current->mm, -1); +#endif + /* OK, This is the point of no return */ current->flags &= ~PF_FORKNOEXEC; current->mm->def_flags = def_flags; --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -101,6 +101,9 @@ struct bio_list; struct perf_event_context; struct blk_plug; +extern int disable_nx; +extern int print_fatal_signals; + /* * List of flags we want to share for kernel threads, * if only because they are not used by them anyway. --- b/mm/mmap.c +++ b/mm/mmap.c @@ -44,6 +45,18 @@ #define arch_rebalance_pgtables(addr, len) (addr) #endif +/* No sane architecture will #define these to anything else */ +#ifndef arch_add_exec_range +#define arch_add_exec_range(mm, limit) do { ; } while (0) +#endif +#ifndef arch_flush_exec_range +#define arch_flush_exec_range(mm) do { ; } while (0) +#endif +#ifndef arch_remove_exec_range +#define arch_remove_exec_range(mm, limit) do { ; } while (0) +#endif + + static void unmap_region(struct mm_struct *mm, struct vm_area_struct *vma, struct vm_area_struct *prev, unsigned long start, unsigned long end); @@ -432,6 +432,8 @@ __vma_link(struct mm_struct *mm, struct vm_area_struct *vma, struct vm_area_struct *prev, struct rb_node **rb_link, struct rb_node *rb_parent) { + if (vma->vm_flags & VM_EXEC) + arch_add_exec_range(mm, vma->vm_end); __vma_link_list(mm, vma, prev, rb_parent); __vma_link_rb(mm, vma, rb_link, rb_parent); } @@ -489,6 +504,8 @@ rb_erase(&vma->vm_rb, &mm->mm_rb); if (mm->mmap_cache == vma) mm->mmap_cache = prev; + if (vma->vm_flags & VM_EXEC) + arch_remove_exec_range(mm, vma->vm_end); } /* @@ -790,6 +807,8 @@ } else /* cases 2, 5, 7 */ err = vma_adjust(prev, prev->vm_start, end, prev->vm_pgoff, NULL); + if (prev->vm_flags & VM_EXEC) + arch_add_exec_range(mm, prev->vm_end); if (err) return NULL; return prev; @@ -1966,10 +2075,14 @@ if (new->vm_ops && new->vm_ops->open) new->vm_ops->open(new); - if (new_below) + if (new_below) { + unsigned long old_end = vma->vm_end; + err = vma_adjust(vma, addr, vma->vm_end, vma->vm_pgoff + ((addr - new->vm_start) >> PAGE_SHIFT), new); - else + if (vma->vm_flags & VM_EXEC) + arch_remove_exec_range(mm, old_end); + } else err = vma_adjust(vma, vma->vm_start, addr, vma->vm_pgoff, new); /* Success. */ @@ -2254,6 +2367,7 @@ free_pgtables(&tlb, vma, FIRST_USER_ADDRESS, 0); tlb_finish_mmu(&tlb, 0, end); + arch_flush_exec_range(mm); /* * Walk the list again, actually closing and freeing it, --- a/mm/mprotect.c +++ b/mm/mprotect.c @@ -25,9 +25,14 @@ #include <linux/perf_event.h> #include <asm/uaccess.h> #include <asm/pgtable.h> +#include <asm/pgalloc.h> #include <asm/cacheflush.h> #include <asm/tlbflush.h> +#ifndef arch_remove_exec_range +#define arch_remove_exec_range(mm, limit) do { ; } while (0) +#endif + #ifndef pgprot_modify static inline pgprot_t pgprot_modify(pgprot_t oldprot, pgprot_t newprot) { @@ -138,7 +143,7 @@ mprotect_fixup(struct vm_area_struct *vma, struct vm_area_struct **pprev, struct mm_struct *mm = vma->vm_mm; unsigned long oldflags = vma->vm_flags; long nrpages = (end - start) >> PAGE_SHIFT; - unsigned long charged = 0; + unsigned long charged = 0, old_end = vma->vm_end; pgoff_t pgoff; int error; int dirty_accountable = 0; @@ -203,6 +208,9 @@ success: dirty_accountable = 1; } + if (oldflags & VM_EXEC) + arch_remove_exec_range(current->mm, old_end); + mmu_notifier_invalidate_range_start(mm, start, end); if (is_vm_hugetlb_page(vma)) hugetlb_change_protection(vma, start, end, vma->vm_page_prot); diff --git a/arch/x86/kernel/process.c b/arch/x86/kernel/process.c index 57d1868..29c0c35 100644 --- a/arch/x86/kernel/process.c +++ b/arch/x86/kernel/process.c @@ -669,6 +669,16 @@ unsigned long arch_align_stack(unsigned long sp) unsigned long arch_randomize_brk(struct mm_struct *mm) { unsigned long range_end = mm->brk + 0x02000000; - return randomize_range(mm->brk, range_end, 0) ? : mm->brk; + unsigned long bump = 0; +#ifdef CONFIG_X86_32 + /* in the case of NX emulation, shove the brk segment way out of the + way of the exec randomization area, since it can collide with + future allocations if not. */ + if ( (mm->get_unmapped_exec_area == arch_get_unmapped_exec_area) && + (mm->brk < 0x08000000) ) { + bump = (TASK_SIZE/6); + } +#endif + return bump + (randomize_range(mm->brk, range_end, 0) ? : mm->brk); }
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