diff options
| -rw-r--r-- | arch/um/kernel/skas/include/mmu-skas.h | 2 | ||||
| -rw-r--r-- | arch/um/kernel/skas/include/skas.h | 3 | ||||
| -rw-r--r-- | arch/um/kernel/skas/mem.c | 2 | ||||
| -rw-r--r-- | arch/um/kernel/skas/mmu.c | 44 | ||||
| -rw-r--r-- | arch/um/kernel/skas/process.c | 6 | ||||
| -rw-r--r-- | arch/um/kernel/skas/process_kern.c | 2 | ||||
| -rw-r--r-- | arch/um/os-Linux/start_up.c | 75 | ||||
| -rw-r--r-- | arch/um/scripts/Makefile.rules | 7 | ||||
| -rw-r--r-- | arch/um/sys-i386/ldt.c | 506 | ||||
| -rw-r--r-- | arch/um/sys-x86_64/Makefile | 5 | ||||
| -rw-r--r-- | arch/um/sys-x86_64/syscalls.c | 75 | ||||
| -rw-r--r-- | include/asm-um/ldt-i386.h | 69 | ||||
| -rw-r--r-- | include/asm-um/ldt.h | 69 |
13 files changed, 724 insertions, 141 deletions
diff --git a/arch/um/kernel/skas/include/mmu-skas.h b/arch/um/kernel/skas/include/mmu-skas.h index 09536f8..44110c5 100644 --- a/arch/um/kernel/skas/include/mmu-skas.h +++ b/arch/um/kernel/skas/include/mmu-skas.h @@ -8,6 +8,7 @@ #include "linux/config.h" #include "mm_id.h" +#include "asm/ldt.h" struct mmu_context_skas { struct mm_id id; @@ -15,6 +16,7 @@ struct mmu_context_skas { #ifdef CONFIG_3_LEVEL_PGTABLES unsigned long last_pmd; #endif + uml_ldt_t ldt; }; extern void switch_mm_skas(struct mm_id * mm_idp); diff --git a/arch/um/kernel/skas/include/skas.h b/arch/um/kernel/skas/include/skas.h index 0609347..daa2f85 100644 --- a/arch/um/kernel/skas/include/skas.h +++ b/arch/um/kernel/skas/include/skas.h @@ -10,7 +10,8 @@ #include "sysdep/ptrace.h" extern int userspace_pid[]; -extern int proc_mm, ptrace_faultinfo; +extern int proc_mm, ptrace_faultinfo, ptrace_ldt; +extern int skas_needs_stub; extern void switch_threads(void *me, void *next); extern void thread_wait(void *sw, void *fb); diff --git a/arch/um/kernel/skas/mem.c b/arch/um/kernel/skas/mem.c index 147466d..88ab96c 100644 --- a/arch/um/kernel/skas/mem.c +++ b/arch/um/kernel/skas/mem.c @@ -20,7 +20,7 @@ unsigned long set_task_sizes_skas(int arg, unsigned long *host_size_out, *task_size_out = CONFIG_HOST_TASK_SIZE; #else *host_size_out = top; - if (proc_mm && ptrace_faultinfo) + if (!skas_needs_stub) *task_size_out = top; else *task_size_out = CONFIG_STUB_START & PGDIR_MASK; #endif diff --git a/arch/um/kernel/skas/mmu.c b/arch/um/kernel/skas/mmu.c index 9e5e39c..677871f 100644 --- a/arch/um/kernel/skas/mmu.c +++ b/arch/um/kernel/skas/mmu.c @@ -15,6 +15,7 @@ #include "asm/mmu.h" #include "asm/pgalloc.h" #include "asm/pgtable.h" +#include "asm/ldt.h" #include "os.h" #include "skas.h" @@ -74,13 +75,12 @@ static int init_stub_pte(struct mm_struct *mm, unsigned long proc, int init_new_context_skas(struct task_struct *task, struct mm_struct *mm) { - struct mm_struct *cur_mm = current->mm; - struct mm_id *cur_mm_id = &cur_mm->context.skas.id; - struct mm_id *mm_id = &mm->context.skas.id; + struct mmu_context_skas *from_mm = NULL; + struct mmu_context_skas *to_mm = &mm->context.skas; unsigned long stack = 0; - int from, ret = -ENOMEM; + int from_fd, ret = -ENOMEM; - if(!proc_mm || !ptrace_faultinfo){ + if(skas_needs_stub){ stack = get_zeroed_page(GFP_KERNEL); if(stack == 0) goto out; @@ -102,33 +102,43 @@ int init_new_context_skas(struct task_struct *task, struct mm_struct *mm) mm->nr_ptes--; } - mm_id->stack = stack; + + to_mm->id.stack = stack; + if(current->mm != NULL && current->mm != &init_mm) + from_mm = ¤t->mm->context.skas; if(proc_mm){ - if((cur_mm != NULL) && (cur_mm != &init_mm)) - from = cur_mm_id->u.mm_fd; - else from = -1; + if(from_mm) + from_fd = from_mm->id.u.mm_fd; + else from_fd = -1; - ret = new_mm(from, stack); + ret = new_mm(from_fd, stack); if(ret < 0){ printk("init_new_context_skas - new_mm failed, " "errno = %d\n", ret); goto out_free; } - mm_id->u.mm_fd = ret; + to_mm->id.u.mm_fd = ret; } else { - if((cur_mm != NULL) && (cur_mm != &init_mm)) - mm_id->u.pid = copy_context_skas0(stack, - cur_mm_id->u.pid); - else mm_id->u.pid = start_userspace(stack); + if(from_mm) + to_mm->id.u.pid = copy_context_skas0(stack, + from_mm->id.u.pid); + else to_mm->id.u.pid = start_userspace(stack); + } + + ret = init_new_ldt(to_mm, from_mm); + if(ret < 0){ + printk("init_new_context_skas - init_ldt" + " failed, errno = %d\n", ret); + goto out_free; } return 0; out_free: - if(mm_id->stack != 0) - free_page(mm_id->stack); + if(to_mm->id.stack != 0) + free_page(to_mm->id.stack); out: return ret; } diff --git a/arch/um/kernel/skas/process.c b/arch/um/kernel/skas/process.c index 42f2da6..599d679 100644 --- a/arch/um/kernel/skas/process.c +++ b/arch/um/kernel/skas/process.c @@ -381,9 +381,9 @@ int copy_context_skas0(unsigned long new_stack, int pid) } /* - * This is used only, if proc_mm is available, while PTRACE_FAULTINFO - * isn't. Opening /proc/mm creates a new mm_context, which lacks the stub-pages - * Thus, we map them using /proc/mm-fd + * This is used only, if stub pages are needed, while proc_mm is + * availabl. Opening /proc/mm creates a new mm_context, which lacks + * the stub-pages. Thus, we map them using /proc/mm-fd */ void map_stub_pages(int fd, unsigned long code, unsigned long data, unsigned long stack) diff --git a/arch/um/kernel/skas/process_kern.c b/arch/um/kernel/skas/process_kern.c index efe92e8..9c99025 100644 --- a/arch/um/kernel/skas/process_kern.c +++ b/arch/um/kernel/skas/process_kern.c @@ -145,7 +145,7 @@ int new_mm(int from, unsigned long stack) "err = %d\n", -n); } - if(!ptrace_faultinfo) + if(skas_needs_stub) map_stub_pages(fd, CONFIG_STUB_CODE, CONFIG_STUB_DATA, stack); return(fd); diff --git a/arch/um/os-Linux/start_up.c b/arch/um/os-Linux/start_up.c index b99ab41..553a09c 100644 --- a/arch/um/os-Linux/start_up.c +++ b/arch/um/os-Linux/start_up.c @@ -135,7 +135,9 @@ static int stop_ptraced_child(int pid, void *stack, int exitcode, } int ptrace_faultinfo = 1; +int ptrace_ldt = 1; int proc_mm = 1; +int skas_needs_stub = 0; static int __init skas0_cmd_param(char *str, int* add) { @@ -352,14 +354,26 @@ __uml_setup("noptracefaultinfo", noptracefaultinfo_cmd_param, " it. To support PTRACE_FAULTINFO, the host needs to be patched\n" " using the current skas3 patch.\n\n"); +static int __init noptraceldt_cmd_param(char *str, int* add) +{ + ptrace_ldt = 0; + return 0; +} + +__uml_setup("noptraceldt", noptraceldt_cmd_param, +"noptraceldt\n" +" Turns off usage of PTRACE_LDT, even if host supports it.\n" +" To support PTRACE_LDT, the host needs to be patched using\n" +" the current skas3 patch.\n\n"); + #ifdef UML_CONFIG_MODE_SKAS -static inline void check_skas3_ptrace_support(void) +static inline void check_skas3_ptrace_faultinfo(void) { struct ptrace_faultinfo fi; void *stack; int pid, n; - printf("Checking for the skas3 patch in the host..."); + printf(" - PTRACE_FAULTINFO..."); pid = start_ptraced_child(&stack); n = ptrace(PTRACE_FAULTINFO, pid, 0, &fi); @@ -381,9 +395,49 @@ static inline void check_skas3_ptrace_support(void) stop_ptraced_child(pid, stack, 1, 1); } -int can_do_skas(void) +static inline void check_skas3_ptrace_ldt(void) +{ +#ifdef PTRACE_LDT + void *stack; + int pid, n; + unsigned char ldtbuf[40]; + struct ptrace_ldt ldt_op = (struct ptrace_ldt) { + .func = 2, /* read default ldt */ + .ptr = ldtbuf, + .bytecount = sizeof(ldtbuf)}; + + printf(" - PTRACE_LDT..."); + pid = start_ptraced_child(&stack); + + n = ptrace(PTRACE_LDT, pid, 0, (unsigned long) &ldt_op); + if (n < 0) { + if(errno == EIO) + printf("not found\n"); + else { + perror("not found"); + } + ptrace_ldt = 0; + } + else { + if(ptrace_ldt) + printf("found\n"); + else + printf("found, but use is disabled\n"); + } + + stop_ptraced_child(pid, stack, 1, 1); +#else + /* PTRACE_LDT might be disabled via cmdline option. + * We want to override this, else we might use the stub + * without real need + */ + ptrace_ldt = 1; +#endif +} + +static inline void check_skas3_proc_mm(void) { - printf("Checking for /proc/mm..."); + printf(" - /proc/mm..."); if (os_access("/proc/mm", OS_ACC_W_OK) < 0) { proc_mm = 0; printf("not found\n"); @@ -394,8 +448,19 @@ int can_do_skas(void) else printf("found\n"); } +} + +int can_do_skas(void) +{ + printf("Checking for the skas3 patch in the host:\n"); + + check_skas3_proc_mm(); + check_skas3_ptrace_faultinfo(); + check_skas3_ptrace_ldt(); + + if(!proc_mm || !ptrace_faultinfo || !ptrace_ldt) + skas_needs_stub = 1; - check_skas3_ptrace_support(); return 1; } #else diff --git a/arch/um/scripts/Makefile.rules b/arch/um/scripts/Makefile.rules index 651d9d8..b3fbf12 100644 --- a/arch/um/scripts/Makefile.rules +++ b/arch/um/scripts/Makefile.rules @@ -26,8 +26,13 @@ define unprofile $(patsubst -pg,,$(patsubst -fprofile-arcs -ftest-coverage,,$(1))) endef +# cmd_make_link checks to see if the $(foo-dir) variable starts with a /. If +# so, it's considered to be a path relative to $(srcdir) rather than +# $(srcdir)/arch/$(SUBARCH). This is because x86_64 wants to get ldt.c from +# arch/um/sys-i386 rather than arch/i386 like the other borrowed files. So, +# it sets $(ldt.c-dir) to /arch/um/sys-i386. quiet_cmd_make_link = SYMLINK $@ -cmd_make_link = ln -sf $(srctree)/arch/$(SUBARCH)/$($(notdir $@)-dir)/$(notdir $@) $@ +cmd_make_link = rm -f $@; ln -sf $(srctree)$(if $(filter-out /%,$($(notdir $@)-dir)),/arch/$(SUBARCH))/$($(notdir $@)-dir)/$(notdir $@) $@ # this needs to be before the foreach, because targets does not accept # complete paths like $(obj)/$(f). To make sure this works, use a := assignment diff --git a/arch/um/sys-i386/ldt.c b/arch/um/sys-i386/ldt.c index 36b5c2c..6360f1c 100644 --- a/arch/um/sys-i386/ldt.c +++ b/arch/um/sys-i386/ldt.c @@ -3,53 +3,26 @@ * Licensed under the GPL */ +#include "linux/stddef.h" #include "linux/config.h" #include "linux/sched.h" #include "linux/slab.h" #include "linux/types.h" +#include "linux/errno.h" #include "asm/uaccess.h" -#include "asm/ptrace.h" #include "asm/smp.h" #include "asm/ldt.h" +#include "asm/unistd.h" #include "choose-mode.h" #include "kern.h" #include "mode_kern.h" -#ifdef CONFIG_MODE_TT - extern int modify_ldt(int func, void *ptr, unsigned long bytecount); -static int do_modify_ldt_tt(int func, void *ptr, unsigned long bytecount) -{ - return modify_ldt(func, ptr, bytecount); -} - -#endif - -#ifdef CONFIG_MODE_SKAS - -#include "skas.h" -#include "skas_ptrace.h" - -static int do_modify_ldt_skas(int func, void *ptr, unsigned long bytecount) -{ - struct ptrace_ldt ldt; - u32 cpu; - int res; - - ldt = ((struct ptrace_ldt) { .func = func, - .ptr = ptr, - .bytecount = bytecount }); - - cpu = get_cpu(); - res = ptrace(PTRACE_LDT, userspace_pid[cpu], 0, (unsigned long) &ldt); - put_cpu(); - - return res; -} -#endif +#ifdef CONFIG_MODE_TT -int sys_modify_ldt(int func, void __user *ptr, unsigned long bytecount) +static long do_modify_ldt_tt(int func, void __user *ptr, + unsigned long bytecount) { struct user_desc info; int res = 0; @@ -89,8 +62,7 @@ int sys_modify_ldt(int func, void __user *ptr, unsigned long bytecount) goto out; } - res = CHOOSE_MODE_PROC(do_modify_ldt_tt, do_modify_ldt_skas, func, - p, bytecount); + res = modify_ldt(func, p, bytecount); if(res < 0) goto out; @@ -108,3 +80,467 @@ out: kfree(buf); return res; } + +#endif + +#ifdef CONFIG_MODE_SKAS + +#include "skas.h" +#include "skas_ptrace.h" +#include "asm/mmu_context.h" + +long write_ldt_entry(struct mm_id * mm_idp, int func, struct user_desc * desc, + void **addr, int done) +{ + long res; + + if(proc_mm){ + /* This is a special handling for the case, that the mm to + * modify isn't current->active_mm. + * If this is called directly by modify_ldt, + * (current->active_mm->context.skas.u == mm_idp) + * will be true. So no call to switch_mm_skas(mm_idp) is done. + * If this is called in case of init_new_ldt or PTRACE_LDT, + * mm_idp won't belong to current->active_mm, but child->mm. + * So we need to switch child's mm into our userspace, then + * later switch back. + * + * Note: I'm unshure: should interrupts be disabled here? + */ + if(!current->active_mm || current->active_mm == &init_mm || + mm_idp != ¤t->active_mm->context.skas.id) + switch_mm_skas(mm_idp); + } + + if(ptrace_ldt) { + struct ptrace_ldt ldt_op = (struct ptrace_ldt) { + .func = func, + .ptr = desc, + .bytecount = sizeof(*desc)}; + u32 cpu; + int pid; + + if(!proc_mm) + pid = mm_idp->u.pid; + else { + cpu = get_cpu(); + pid = userspace_pid[cpu]; + } + + res = ptrace(PTRACE_LDT, pid, 0, (unsigned long) &ldt_op); + if(res) + res = errno; + + if(proc_mm) + put_cpu(); + } + else { + void *stub_addr; + res = syscall_stub_data(mm_idp, (unsigned long *)desc, + (sizeof(*desc) + sizeof(long) - 1) & + ~(sizeof(long) - 1), + addr, &stub_addr); + if(!res){ + unsigned long args[] = { func, + (unsigned long)stub_addr, + sizeof(*desc), + 0, 0, 0 }; + res = run_syscall_stub(mm_idp, __NR_modify_ldt, args, + 0, addr, done); + } + } + + if(proc_mm){ + /* This is the second part of special handling, that makes + * PTRACE_LDT possible to implement. + */ + if(current->active_mm && current->active_mm != &init_mm && + mm_idp != ¤t->active_mm->context.skas.id) + switch_mm_skas(¤t->active_mm->context.skas.id); + } + + return res; +} + +static long read_ldt_from_host(void __user * ptr, unsigned long bytecount) +{ + int res, n; + struct ptrace_ldt ptrace_ldt = (struct ptrace_ldt) { + .func = 0, + .bytecount = bytecount, + .ptr = (void *)kmalloc(bytecount, GFP_KERNEL)}; + u32 cpu; + + if(ptrace_ldt.ptr == NULL) + return -ENOMEM; + + /* This is called from sys_modify_ldt only, so userspace_pid gives + * us the right number + */ + + cpu = get_cpu(); + res = ptrace(PTRACE_LDT, userspace_pid[cpu], 0, + (unsigned long) &ptrace_ldt); + put_cpu(); + if(res < 0) + goto out; + + n = copy_to_user(ptr, ptrace_ldt.ptr, res); + if(n != 0) + res = -EFAULT; + + out: + kfree(ptrace_ldt.ptr); + + return res; +} + +/* + * In skas mode, we hold our own ldt data in UML. + * Thus, the code implementing sys_modify_ldt_skas + * is very similar to (and mostly stolen from) sys_modify_ldt + * for arch/i386/kernel/ldt.c + * The routines copied and modified in part are: + * - read_ldt + * - read_default_ldt + * - write_ldt + * - sys_modify_ldt_skas + */ + +static int read_ldt(void __user * ptr, unsigned long bytecount) +{ + int i, err = 0; + unsigned long size; + uml_ldt_t * ldt = ¤t->mm->context.skas.ldt; + + if(!ldt->entry_count) + goto out; + if(bytecount > LDT_ENTRY_SIZE*LDT_ENTRIES) + bytecount = LDT_ENTRY_SIZE*LDT_ENTRIES; + err = bytecount; + + if(ptrace_ldt){ + return read_ldt_from_host(ptr, bytecount); + } + + down(&ldt->semaphore); + if(ldt->entry_count <= LDT_DIRECT_ENTRIES){ + size = LDT_ENTRY_SIZE*LDT_DIRECT_ENTRIES; + if(size > bytecount) + size = bytecount; + if(copy_to_user(ptr, ldt->entries, size)) + err = -EFAULT; + bytecount -= size; + ptr += size; + } + else { + for(i=0; i<ldt->entry_count/LDT_ENTRIES_PER_PAGE && bytecount; + i++){ + size = PAGE_SIZE; + if(size > bytecount) + size = bytecount; + if(copy_to_user(ptr, ldt->pages[i], size)){ + err = -EFAULT; + break; + } + bytecount -= size; + ptr += size; + } + } + up(&ldt->semaphore); + + if(bytecount == 0 || err == -EFAULT) + goto out; + + if(clear_user(ptr, bytecount)) + err = -EFAULT; + +out: + return err; +} + +static int read_default_ldt(void __user * ptr, unsigned long bytecount) +{ + int err; + + if(bytecount > 5*LDT_ENTRY_SIZE) + bytecount = 5*LDT_ENTRY_SIZE; + + err = bytecount; + /* UML doesn't support lcall7 and lcall27. + * So, we don't really have a default ldt, but emulate + * an empty ldt of common host default ldt size. + */ + if(clear_user(ptr, bytecount)) + err = -EFAULT; + + return err; +} + +static int write_ldt(void __user * ptr, unsigned long bytecount, int func) +{ + uml_ldt_t * ldt = ¤t->mm->context.skas.ldt; + struct mm_id * mm_idp = ¤t->mm->context.skas.id; + int i, err; + struct user_desc ldt_info; + struct ldt_entry entry0, *ldt_p; + void *addr = NULL; + + err = -EINVAL; + if(bytecount != sizeof(ldt_info)) + goto out; + err = -EFAULT; + if(copy_from_user(&ldt_info, ptr, sizeof(ldt_info))) + goto out; + + err = -EINVAL; + if(ldt_info.entry_number >= LDT_ENTRIES) + goto out; + if(ldt_info.contents == 3){ + if (func == 1) + goto out; + if (ldt_info.seg_not_present == 0) + goto out; + } + + if(!ptrace_ldt) + down(&ldt->semaphore); + + err = write_ldt_entry(mm_idp, func, &ldt_info, &addr, 1); + if(err) + goto out_unlock; + else if(ptrace_ldt) { + /* With PTRACE_LDT available, this is used as a flag only */ + ldt->entry_count = 1; + goto out; + } + + if(ldt_info.entry_number >= ldt->entry_count && + ldt_info.entry_number >= LDT_DIRECT_ENTRIES){ + for(i=ldt->entry_count/LDT_ENTRIES_PER_PAGE; + i*LDT_ENTRIES_PER_PAGE <= ldt_info.entry_number; + i++){ + if(i == 0) + memcpy(&entry0, ldt->entries, sizeof(entry0)); + ldt->pages[i] = (struct ldt_entry *) + __get_free_page(GFP_KERNEL|__GFP_ZERO); + if(!ldt->pages[i]){ + err = -ENOMEM; + /* Undo the change in host */ + memset(&ldt_info, 0, sizeof(ldt_info)); + write_ldt_entry(mm_idp, 1, &ldt_info, &addr, 1); + goto out_unlock; + } + if(i == 0) { + memcpy(ldt->pages[0], &entry0, sizeof(entry0)); + memcpy(ldt->pages[0]+1, ldt->entries+1, + sizeof(entry0)*(LDT_DIRECT_ENTRIES-1)); + } + ldt->entry_count = (i + 1) * LDT_ENTRIES_PER_PAGE; + } + } + if(ldt->entry_count <= ldt_info.entry_number) + ldt->entry_count = ldt_info.entry_number + 1; + + if(ldt->entry_count <= LDT_DIRECT_ENTRIES) + ldt_p = ldt->entries + ldt_info.entry_number; + else + ldt_p = ldt->pages[ldt_info.entry_number/LDT_ENTRIES_PER_PAGE] + + ldt_info.entry_number%LDT_ENTRIES_PER_PAGE; + + if(ldt_info.base_addr == 0 && ldt_info.limit == 0 && + (func == 1 || LDT_empty(&ldt_info))){ + ldt_p->a = 0; + ldt_p->b = 0; + } + else{ + if (func == 1) + ldt_info.useable = 0; + ldt_p->a = LDT_entry_a(&ldt_info); + ldt_p->b = LDT_entry_b(&ldt_info); + } + err = 0; + +out_unlock: + up(&ldt->semaphore); +out: + return err; +} + +static long do_modify_ldt_skas(int func, void __user *ptr, + unsigned long bytecount) +{ + int ret = -ENOSYS; + + switch (func) { + case 0: + ret = read_ldt(ptr, bytecount); + break; + case 1: + case 0x11: + ret = write_ldt(ptr, bytecount, func); + break; + case 2: + ret = read_default_ldt(ptr, bytecount); + break; + } + return ret; +} + +short dummy_list[9] = {0, -1}; +short * host_ldt_entries = NULL; + +void ldt_get_host_info(void) +{ + long ret; + struct ldt_entry * ldt; + int i, size, k, order; + + host_ldt_entries = dummy_list+1; + + for(i = LDT_PAGES_MAX-1, order=0; i; i>>=1, order++); + + ldt = (struct ldt_entry *) + __get_free_pages(GFP_KERNEL|__GFP_ZERO, order); + if(ldt == NULL) { + printk("ldt_get_host_info: couldn't allocate buffer for host ldt\n"); + return; + } + + ret = modify_ldt(0, ldt, (1<<order)*PAGE_SIZE); + if(ret < 0) { + printk("ldt_get_host_info: couldn't read host ldt\n"); + goto out_free; + } + if(ret == 0) { + /* default_ldt is active, simply write an empty entry 0 */ + host_ldt_entries = dummy_list; + goto out_free; + } + + for(i=0, size=0; i<ret/LDT_ENTRY_SIZE; i++){ + if(ldt[i].a != 0 || ldt[i].b != 0) + size++; + } + + if(size < sizeof(dummy_list)/sizeof(dummy_list[0])) { + host_ldt_entries = dummy_list; + } + else { + size = (size + 1) * sizeof(dummy_list[0]); + host_ldt_entries = (short *)kmalloc(size, GFP_KERNEL); + if(host_ldt_entries == NULL) { + printk("ldt_get_host_info: couldn't allocate host ldt list\n"); + goto out_free; + } + } + + for(i=0, k=0; i<ret/LDT_ENTRY_SIZE; i++){ + if(ldt[i].a != 0 || ldt[i].b != 0) { + host_ldt_entries[k++] = i; + } + } + host_ldt_entries[k] = -1; + +out_free: + free_pages((unsigned long)ldt, order); +} + +long init_new_ldt(struct mmu_context_skas * new_mm, + struct mmu_context_skas * from_mm) +{ + struct user_desc desc; + short * num_p; + int i; + long page, err=0; + void *addr = NULL; + + memset(&desc, 0, sizeof(desc)); + + if(!ptrace_ldt) + init_MUTEX(&new_mm->ldt.semaphore); + + if(!from_mm){ + /* + * We have to initialize a clean ldt. + */ + if(proc_mm) { + /* + * If the new mm was created using proc_mm, host's + * default-ldt currently is assigned, which normally + * contains the call-gates for lcall7 and lcall27. + * To remove these gates, we simply write an empty + * entry as number 0 to the host. + */ + err = write_ldt_entry(&new_mm->id, 1, &desc, + &addr, 1); + } + else{ + /* + * Now we try to retrieve info about the ldt, we + * inherited from the host. All ldt-entries found + * will be reset in the following loop + */ + if(host_ldt_entries == NULL) + ldt_get_host_info(); + for(num_p=host_ldt_entries; *num_p != -1; num_p++){ + desc.entry_number = *num_p; + err = write_ldt_entry(&new_mm->id, 1, &desc, + &addr, *(num_p + 1) == -1); + if(err) + break; + } + } + new_mm->ldt.entry_count = 0; + } + else if (!ptrace_ldt) { + /* Our local LDT is used to supply the data for + * modify_ldt(READLDT), if PTRACE_LDT isn't available, + * i.e., we have to use the stub for modify_ldt, which + * can't handle the big read buffer of up to 64kB. + */ + down(&from_mm->ldt.semaphore); + if(from_mm->ldt.entry_count <= LDT_DIRECT_ENTRIES){ + memcpy(new_mm->ldt.entries, from_mm->ldt.entries, + sizeof(new_mm->ldt.entries)); + } + else{ + i = from_mm->ldt.entry_count / LDT_ENTRIES_PER_PAGE; + while(i-->0){ + page = __get_free_page(GFP_KERNEL|__GFP_ZERO); + if (!page){ + err = -ENOMEM; + break; + } + new_mm->ldt.pages[i] = (struct ldt_entry*)page; + memcpy(new_mm->ldt.pages[i], + from_mm->ldt.pages[i], PAGE_SIZE); + } + } + new_mm->ldt.entry_count = from_mm->ldt.entry_count; + up(&from_mm->ldt.semaphore); + } + + return err; +} + + +void free_ldt(struct mmu_context_skas * mm) +{ + int i; + + if(!ptrace_ldt && mm->ldt.entry_count > LDT_DIRECT_ENTRIES){ + i = mm->ldt.entry_count / LDT_ENTRIES_PER_PAGE; + while(i-- > 0){ + free_page((long )mm->ldt.pages[i]); + } + } + mm->ldt.entry_count = 0; +} +#endif + +int sys_modify_ldt(int func, void __user *ptr, unsigned long bytecount) +{ + return(CHOOSE_MODE_PROC(do_modify_ldt_tt, do_modify_ldt_skas, func, + ptr, bytecount)); +} diff --git a/arch/um/sys-x86_64/Makefile b/arch/um/sys-x86_64/Makefile index 06c3633..ea977df 100644 --- a/arch/um/sys-x86_64/Makefile +++ b/arch/um/sys-x86_64/Makefile @@ -5,7 +5,7 @@ # #XXX: why into lib-y? -lib-y = bitops.o bugs.o csum-partial.o delay.o fault.o mem.o memcpy.o \ +lib-y = bitops.o bugs.o csum-partial.o delay.o fault.o ldt.o mem.o memcpy.o \ ptrace.o ptrace_user.o sigcontext.o signal.o stub.o \ stub_segv.o syscalls.o syscall_table.o sysrq.o thunk.o @@ -14,7 +14,7 @@ obj-$(CONFIG_MODULES) += module.o um_module.o USER_OBJS := ptrace_user.o sigcontext.o -SYMLINKS = bitops.c csum-copy.S csum-partial.c csum-wrappers.c memcpy.S \ +SYMLINKS = bitops.c csum-copy.S csum-partial.c csum-wrappers.c ldt.c memcpy.S \ thunk.S module.c include arch/um/scripts/Makefile.rules @@ -23,6 +23,7 @@ bitops.c-dir = lib csum-copy.S-dir = lib csum-partial.c-dir = lib csum-wrappers.c-dir = lib +ldt.c-dir = /arch/um/sys-i386 memcpy.S-dir = lib thunk.S-dir = lib module.c-dir = kernel diff --git a/arch/um/sys-x86_64/syscalls.c b/arch/um/sys-x86_64/syscalls.c index 3259a4d..6acee5c 100644 --- a/arch/um/sys-x86_64/syscalls.c +++ b/arch/um/sys-x86_64/syscalls.c @@ -29,81 +29,6 @@ asmlinkage long sys_uname64(struct new_utsname __user * name) } #ifdef CONFIG_MODE_TT -extern int modify_ldt(int func, void *ptr, unsigned long bytecount); - -long sys_modify_ldt_tt(int func, void *ptr, unsigned long bytecount) -{ - /* XXX This should check VERIFY_WRITE depending on func, check this - * in i386 as well. - */ - if (!access_ok(VERIFY_READ, ptr, bytecount)) - return -EFAULT; - return(modify_ldt(func, ptr, bytecount)); -} -#endif - -#ifdef CONFIG_MODE_SKAS -extern int userspace_pid[]; - -#include "skas_ptrace.h" - -long sys_modify_ldt_skas(int func, void *ptr, unsigned long bytecount) -{ - struct ptrace_ldt ldt; - void *buf; - int res, n; - - buf = kmalloc(bytecount, GFP_KERNEL); - if(buf == NULL) - return(-ENOMEM); - - res = 0; - - switch(func){ - case 1: - case 0x11: - res = copy_from_user(buf, ptr, bytecount); - break; - } - - if(res != 0){ - res = -EFAULT; - goto out; - } - - ldt = ((struct ptrace_ldt) { .func = func, - .ptr = buf, - .bytecount = bytecount }); -#warning Need to look up userspace_pid by cpu - res = ptrace(PTRACE_LDT, userspace_pid[0], 0, (unsigned long) &ldt); - if(res < 0) - goto out; - - switch(func){ - case 0: - case 2: - n = res; - res = copy_to_user(ptr, buf, n); - if(res != 0) - res = -EFAULT; - else - res = n; - break; - } - - out: - kfree(buf); - return(res); -} -#endif - -long sys_modify_ldt(int func, void *ptr, unsigned long bytecount) -{ - return(CHOOSE_MODE_PROC(sys_modify_ldt_tt, sys_modify_ldt_skas, func, - ptr, bytecount)); -} - -#ifdef CONFIG_MODE_TT extern long arch_prctl(int code, unsigned long addr); static long arch_prctl_tt(int code, unsigned long addr) diff --git a/include/asm-um/ldt-i386.h b/include/asm-um/ldt-i386.h new file mode 100644 index 0000000..b426629 --- /dev/null +++ b/include/asm-um/ldt-i386.h @@ -0,0 +1,69 @@ +/* + * Copyright (C) 2004 Fujitsu Siemens Computers GmbH + * Licensed under the GPL + * + * Author: Bodo Stroesser <bstroesser@fujitsu-siemens.com> + */ + +#ifndef __ASM_LDT_I386_H +#define __ASM_LDT_I386_H + +#include "asm/semaphore.h" +#include "asm/arch/ldt.h" + +struct mmu_context_skas; +extern void ldt_host_info(void); +extern long init_new_ldt(struct mmu_context_skas * to_mm, + struct mmu_context_skas * from_mm); +extern void free_ldt(struct mmu_context_skas * mm); + +#define LDT_PAGES_MAX \ + ((LDT_ENTRIES * LDT_ENTRY_SIZE)/PAGE_SIZE) +#define LDT_ENTRIES_PER_PAGE \ + (PAGE_SIZE/LDT_ENTRY_SIZE) +#define LDT_DIRECT_ENTRIES \ + ((LDT_PAGES_MAX*sizeof(void *))/LDT_ENTRY_SIZE) + +struct ldt_entry { + __u32 a; + __u32 b; +}; + +typedef struct uml_ldt { + int entry_count; + struct semaphore semaphore; + union { + struct ldt_entry * pages[LDT_PAGES_MAX]; + struct ldt_entry entries[LDT_DIRECT_ENTRIES]; + }; +} uml_ldt_t; + +/* + * macros stolen from include/asm-i386/desc.h + */ +#define LDT_entry_a(info) \ + ((((info)->base_addr & 0x0000ffff) << 16) | ((info)->limit & 0x0ffff)) + +#define LDT_entry_b(info) \ + (((info)->base_addr & 0xff000000) | \ + (((info)->base_addr & 0x00ff0000) >> 16) | \ + ((info)->limit & 0xf0000) | \ + (((info)->read_exec_only ^ 1) << 9) | \ + ((info)->contents << 10) | \ + (((info)->seg_not_present ^ 1) << 15) | \ + ((info)->seg_32bit << 22) | \ + ((info)->limit_in_pages << 23) | \ + ((info)->useable << 20) | \ + 0x7000) + +#define LDT_empty(info) (\ + (info)->base_addr == 0 && \ + (info)->limit == 0 && \ + (info)->contents == 0 && \ + (info)->read_exec_only == 1 && \ + (info)->seg_32bit == 0 && \ + (info)->limit_in_pages == 0 && \ + (info)->seg_not_present == 1 && \ + (info)->useable == 0 ) + +#endif diff --git a/include/asm-um/ldt.h b/include/asm-um/ldt.h index e908439..4466ff6 100644 --- a/include/asm-um/ldt.h +++ b/include/asm-um/ldt.h @@ -1,3 +1,72 @@ +/* + * Copyright (C) 2004 Fujitsu Siemens Computers GmbH + * Licensed under the GPL + * + * Author: Bodo Stroesser <bstroesser@fujitsu-siemens.com> + */ + +#ifndef __ASM_LDT_I386_H +#define __ASM_LDT_I386_H + +#include "asm/semaphore.h" +#include "asm/arch/ldt.h" + +struct mmu_context_skas; +extern void ldt_host_info(void); +extern long init_new_ldt(struct mmu_context_skas * to_mm, + struct mmu_context_skas * from_mm); +extern void free_ldt(struct mmu_context_skas * mm); + +#define LDT_PAGES_MAX \ + ((LDT_ENTRIES * LDT_ENTRY_SIZE)/PAGE_SIZE) +#define LDT_ENTRIES_PER_PAGE \ + (PAGE_SIZE/LDT_ENTRY_SIZE) +#define LDT_DIRECT_ENTRIES \ + ((LDT_PAGES_MAX*sizeof(void *))/LDT_ENTRY_SIZE) + +struct ldt_entry { + __u32 a; + __u32 b; +}; + +typedef struct uml_ldt { + int entry_count; + struct semaphore semaphore; + union { + struct ldt_entry * pages[LDT_PAGES_MAX]; + struct ldt_entry entries[LDT_DIRECT_ENTRIES]; + }; +} uml_ldt_t; + +/* + * macros stolen from include/asm-i386/desc.h + */ +#define LDT_entry_a(info) \ + ((((info)->base_addr & 0x0000ffff) << 16) | ((info)->limit & 0x0ffff)) + +#define LDT_entry_b(info) \ + (((info)->base_addr & 0xff000000) | \ + (((info)->base_addr & 0x00ff0000) >> 16) | \ + ((info)->limit & 0xf0000) | \ + (((info)->read_exec_only ^ 1) << 9) | \ + ((info)->contents << 10) | \ + (((info)->seg_not_present ^ 1) << 15) | \ + ((info)->seg_32bit << 22) | \ + ((info)->limit_in_pages << 23) | \ + ((info)->useable << 20) | \ + 0x7000) + +#define LDT_empty(info) (\ + (info)->base_addr == 0 && \ + (info)->limit == 0 && \ + (info)->contents == 0 && \ + (info)->read_exec_only == 1 && \ + (info)->seg_32bit == 0 && \ + (info)->limit_in_pages == 0 && \ + (info)->seg_not_present == 1 && \ + (info)->useable == 0 ) + +#endif #ifndef __UM_LDT_H #define __UM_LDT_H |