--- zzzz-none-000/linux-3.10.107/arch/x86/um/ldt.c 2017-06-27 09:49:32.000000000 +0000 +++ scorpion-7490-727/linux-3.10.107/arch/x86/um/ldt.c 2021-02-04 17:41:59.000000000 +0000 @@ -6,118 +6,35 @@ #include #include #include +#include #include #include -#include #include -#include #include -extern int modify_ldt(int func, void *ptr, unsigned long bytecount); +static inline int modify_ldt (int func, void *ptr, unsigned long bytecount) +{ + return syscall(__NR_modify_ldt, func, ptr, bytecount); +} static 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(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 unsure: should interrupts be disabled here? - */ - if (!current->active_mm || current->active_mm == &init_mm || - mm_idp != ¤t->active_mm->context.id) - __switch_mm(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 = os_ptrace_ldt(pid, 0, (unsigned long) &ldt_op); - - 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); - } + 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.id) - __switch_mm(¤t->active_mm->context.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 = 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 = os_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; } @@ -145,9 +62,6 @@ bytecount = LDT_ENTRY_SIZE*LDT_ENTRIES; err = bytecount; - if (ptrace_ldt) - return read_ldt_from_host(ptr, bytecount); - mutex_lock(&ldt->lock); if (ldt->entry_count <= LDT_DIRECT_ENTRIES) { size = LDT_ENTRY_SIZE*LDT_DIRECT_ENTRIES; @@ -229,17 +143,11 @@ goto out; } - if (!ptrace_ldt) - mutex_lock(&ldt->lock); + mutex_lock(&ldt->lock); 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) { @@ -393,91 +301,56 @@ int i; long page, err=0; void *addr = NULL; - struct proc_mm_op copy; - if (!ptrace_ldt) - mutex_init(&new_mm->arch.ldt.lock); + mutex_init(&new_mm->arch.ldt.lock); if (!from_mm) { memset(&desc, 0, sizeof(desc)); /* - * We have to initialize a clean ldt. + * 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 (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 - */ - 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; - } + 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->arch.ldt.entry_count = 0; goto out; } - if (proc_mm) { - /* - * We have a valid from_mm, so we now have to copy the LDT of - * from_mm to new_mm, because using proc_mm an new mm with - * an empty/default LDT was created in new_mm() - */ - copy = ((struct proc_mm_op) { .op = MM_COPY_SEGMENTS, - .u = - { .copy_segments = - from_mm->id.u.mm_fd } } ); - i = os_write_file(new_mm->id.u.mm_fd, ©, sizeof(copy)); - if (i != sizeof(copy)) - printk(KERN_ERR "new_mm : /proc/mm copy_segments " - "failed, err = %d\n", -i); - } - - 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. - */ - mutex_lock(&from_mm->arch.ldt.lock); - if (from_mm->arch.ldt.entry_count <= LDT_DIRECT_ENTRIES) - memcpy(new_mm->arch.ldt.u.entries, from_mm->arch.ldt.u.entries, - sizeof(new_mm->arch.ldt.u.entries)); - else { - i = from_mm->arch.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->arch.ldt.u.pages[i] = - (struct ldt_entry *) page; - memcpy(new_mm->arch.ldt.u.pages[i], - from_mm->arch.ldt.u.pages[i], PAGE_SIZE); + /* + * 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. + */ + mutex_lock(&from_mm->arch.ldt.lock); + if (from_mm->arch.ldt.entry_count <= LDT_DIRECT_ENTRIES) + memcpy(new_mm->arch.ldt.u.entries, from_mm->arch.ldt.u.entries, + sizeof(new_mm->arch.ldt.u.entries)); + else { + i = from_mm->arch.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->arch.ldt.u.pages[i] = + (struct ldt_entry *) page; + memcpy(new_mm->arch.ldt.u.pages[i], + from_mm->arch.ldt.u.pages[i], PAGE_SIZE); } - new_mm->arch.ldt.entry_count = from_mm->arch.ldt.entry_count; - mutex_unlock(&from_mm->arch.ldt.lock); } + new_mm->arch.ldt.entry_count = from_mm->arch.ldt.entry_count; + mutex_unlock(&from_mm->arch.ldt.lock); out: return err; @@ -488,7 +361,7 @@ { int i; - if (!ptrace_ldt && mm->arch.ldt.entry_count > LDT_DIRECT_ENTRIES) { + if (mm->arch.ldt.entry_count > LDT_DIRECT_ENTRIES) { i = mm->arch.ldt.entry_count / LDT_ENTRIES_PER_PAGE; while (i-- > 0) free_page((long) mm->arch.ldt.u.pages[i]);