us_manager/helper.c

   1 #include <dbi_kprobes.h>
   2 #include <dbi_kprobes_deps.h>
   3 #include <ksyms.h>
   4 #include "us_proc_inst.h"
   5 #include "us_slot_manager.h"
   6 #include "storage.h"
   7 #include "sspt/sspt.h"
   8 #include "helper.h"
   9
  10 struct task_struct;
  11
  12 struct task_struct *check_task(struct task_struct *task);
  13
  14 /*
  15  ******************************************************************************
  16  *                               do_page_fault()                              *
  17  ******************************************************************************
  18  */
  19
  20 struct pf_data {
  21         unsigned long addr;
  22 };
  23
  24 static int entry_handler_pf(struct kretprobe_instance *ri, struct pt_regs *regs)
  25 {
  26         struct pf_data *data = (struct pf_data *)ri->data;
  27
  28 #if defined(CONFIG_X86)
  29         data->addr = read_cr2();
  30 #elif defined(CONFIG_ARM)
  31         data->addr = regs->ARM_r0;
  32 #else
  33 #error this architecture is not supported
  34 #endif
  35
  36         return 0;
  37 }
  38
  39 /* Detects when IPs are really loaded into phy mem and installs probes. */
  40 static int ret_handler_pf(struct kretprobe_instance *ri, struct pt_regs *regs)
  41 {
  42         struct task_struct *task;
  43         struct sspt_proc *proc;
  44
  45         install_page(((struct pf_data *)ri->data)->addr);
  46         return 0;
  47
  48         /*
  49          * Because process threads have same address space
  50          * we instrument only group_leader of all this threads
  51          */
  52         task = current->group_leader;
  53         if (is_kthread(task))
  54                 return 0;
  55
  56         proc = sspt_proc_get_by_task(task);
  57         if (proc)
  58                 goto install_proc;
  59
  60         task = check_task(task);
  61         if (task) {
  62                 proc = sspt_proc_get_new(task);
  63                 goto install_proc;
  64         }
  65
  66         return 0;
  67
  68 install_proc:
  69         if (proc->first_install) {
  70                 unsigned long page;
  71                 page = ((struct pf_data *)ri->data)->addr & PAGE_MASK;
  72                 sspt_proc_install_page(proc, page);
  73         } else {
  74                 sspt_proc_install(proc);
  75         }
  76
  77         return 0;
  78 }
  79
  80 static struct kretprobe pf_kretprobe = {
  81         .entry_handler = entry_handler_pf,
  82         .handler = ret_handler_pf,
  83         .data_size = sizeof(struct pf_data)
  84 };
  85
  86
  87
  88 /*
  89  ******************************************************************************
  90  *                              copy_process()                                *
  91  ******************************************************************************
  92  */
  93
  94 static void recover_child(struct task_struct *child_task, struct sspt_proc *proc)
  95 {
  96         sspt_proc_uninstall(proc, child_task, US_DISARM);
  97         dbi_disarm_urp_inst_for_task(current, child_task);
  98 }
  99
 100 static void rm_uprobes_child(struct task_struct *task)
 101 {
 102         struct sspt_proc *proc = sspt_proc_get_by_task(current);
 103         if(proc) {
 104                 recover_child(task, proc);
 105         }
 106 }
 107
 108 /* Delete uprobs in children at fork */
 109 static int ret_handler_cp(struct kretprobe_instance *ri, struct pt_regs *regs)
 110 {
 111         struct task_struct *task = (struct task_struct *)regs_return_value(regs);
 112
 113         if(!task || IS_ERR(task))
 114                 goto out;
 115
 116         if(task->mm != current->mm) {   /* check flags CLONE_VM */
 117                 rm_uprobes_child(task);
 118
 119                 if (check_task(current)) {
 120                         struct sspt_proc *proc;
 121
 122                         proc = sspt_proc_get_new(task);
 123                         sspt_proc_install(proc);
 124                 }
 125         }
 126 out:
 127         return 0;
 128 }
 129
 130 static struct kretprobe cp_kretprobe = {
 131         .handler = ret_handler_cp,
 132 };
 133
 134
 135
 136 /*
 137  ******************************************************************************
 138  *                                mm_release()                                *
 139  ******************************************************************************
 140  */
 141
 142 /* Detects when target process removes IPs. */
 143 static int mr_pre_handler(struct kprobe *p, struct pt_regs *regs)
 144 {
 145         struct sspt_proc *proc = NULL;
 146         struct task_struct *task;
 147
 148 #if defined(CONFIG_X86)
 149         task = (struct task_struct *)regs->EREG(ax);
 150 #elif defined(CONFIG_ARM)
 151         task = (struct task_struct *)regs->ARM_r0;
 152 #else
 153 #error this architecture is not supported
 154 #endif
 155
 156         if (is_kthread(task))
 157                 goto out;
 158
 159         if (task->tgid != task->pid) {
 160                 goto out;
 161         }
 162
 163         proc = sspt_proc_get_by_task(task);
 164         if (proc) {
 165                 int ret = sspt_proc_uninstall(proc, task, US_UNREGS_PROBE);
 166                 if (ret != 0) {
 167                         printk("failed to uninstall IPs (%d)!\n", ret);
 168                 }
 169
 170                 dbi_unregister_all_uprobes(task);
 171         }
 172
 173 out:
 174         return 0;
 175 }
 176
 177 static struct kprobe mr_kprobe = {
 178         .pre_handler = mr_pre_handler
 179 };
 180
 181
 182
 183 /*
 184  ******************************************************************************
 185  *                                 do_munmap()                                *
 186  ******************************************************************************
 187  */
 188
 189 static int remove_unmap_probes(struct task_struct *task, struct sspt_proc *proc, unsigned long start, size_t len)
 190 {
 191         struct mm_struct *mm = task->mm;
 192         struct vm_area_struct *vma;
 193
 194         if ((start & ~PAGE_MASK) || start > TASK_SIZE || len > TASK_SIZE - start) {
 195                 return -EINVAL;
 196         }
 197
 198         if ((len = PAGE_ALIGN(len)) == 0) {
 199                 return -EINVAL;
 200         }
 201
 202         vma = find_vma(mm, start);
 203         if (vma && check_vma(vma)) {
 204                 struct sspt_file *file;
 205                 unsigned long end = start + len;
 206                 struct dentry *dentry = vma->vm_file->f_dentry;
 207
 208                 file = sspt_proc_find_file(proc, dentry);
 209                 if (file) {
 210                         if (vma->vm_start == start || vma->vm_end == end) {
 211                                 sspt_file_uninstall(file, task, US_UNREGS_PROBE);
 212                                 file->loaded = 0;
 213                         } else {
 214                                 unsigned long page_addr;
 215                                 struct sspt_page *page;
 216
 217                                 for (page_addr = vma->vm_start; page_addr < vma->vm_end; page_addr += PAGE_SIZE) {
 218                                         page = sspt_find_page_mapped(file, page_addr);
 219                                         if (page) {
 220                                                 sspt_unregister_page(page, US_UNREGS_PROBE, task);
 221                                         }
 222                                 }
 223
 224                                 if (sspt_file_check_install_pages(file)) {
 225                                         file->loaded = 0;
 226                                 }
 227                         }
 228                 }
 229         }
 230
 231         return 0;
 232 }
 233
 234 /* Detects when target removes IPs. */
 235 static int unmap_pre_handler(struct kprobe *p, struct pt_regs *regs)
 236 {
 237         /* for ARM */
 238         struct mm_struct *mm;
 239         unsigned long start;
 240         size_t len;
 241
 242 #if defined(CONFIG_X86)
 243         mm = (struct mm_struct *)regs->EREG(ax);
 244         start = regs->EREG(dx);
 245         len = (size_t)regs->EREG(cx);
 246 #elif defined(CONFIG_ARM)
 247         mm = (struct mm_struct *)regs->ARM_r0;
 248         start = regs->ARM_r1;
 249         len = (size_t)regs->ARM_r2;
 250 #else
 251 #error this architecture is not supported
 252 #endif
 253
 254         struct sspt_proc *proc = NULL;
 255         struct task_struct *task = current;
 256
 257         if (is_kthread(task))
 258                 goto out;
 259
 260         proc = sspt_proc_get_by_task(task);
 261         if (proc) {
 262                 if (remove_unmap_probes(task, proc, start, len)) {
 263                         printk("ERROR do_munmap: start=%lx, len=%x\n", start, len);
 264                 }
 265         }
 266
 267 out:
 268         return 0;
 269 }
 270
 271 static struct kprobe unmap_kprobe = {
 272         .pre_handler = unmap_pre_handler
 273 };
 274
 275
 276
 277 int register_helper(void)
 278 {
 279         int ret = 0;
 280
 281         /* install kprobe on 'do_munmap' to detect when for remove user space probes */
 282         ret = dbi_register_kprobe(&unmap_kprobe);
 283         if (ret) {
 284                 printk("dbi_register_kprobe(do_munmap) result=%d!\n", ret);
 285                 return ret;
 286         }
 287
 288         /* install kprobe on 'mm_release' to detect when for remove user space probes */
 289         ret = dbi_register_kprobe(&mr_kprobe);
 290         if (ret != 0) {
 291                 printk("dbi_register_kprobe(mm_release) result=%d!\n", ret);
 292                 goto unregister_unmap;
 293         }
 294
 295
 296         /* install kretprobe on 'copy_process' */
 297         ret = dbi_register_kretprobe(&cp_kretprobe);
 298         if (ret) {
 299                 printk("dbi_register_kretprobe(copy_process) result=%d!\n", ret);
 300                 goto unregister_mr;
 301         }
 302
 303         /* install kretprobe on 'do_page_fault' to detect when they will be loaded */
 304         ret = dbi_register_kretprobe(&pf_kretprobe);
 305         if (ret) {
 306                 printk("dbi_register_kretprobe(do_page_fault) result=%d!\n", ret);
 307                 goto unregister_cp;
 308         }
 309
 310         return ret;
 311
 312 unregister_cp:
 313         dbi_unregister_kretprobe(&cp_kretprobe);
 314
 315 unregister_mr:
 316         dbi_unregister_kprobe(&mr_kprobe, NULL);
 317
 318 unregister_unmap:
 319         dbi_unregister_kprobe(&unmap_kprobe, NULL);
 320
 321         return ret;
 322 }
 323
 324 void unregister_helper(void)
 325 {
 326         /* uninstall kretprobe with 'do_page_fault' */
 327         dbi_unregister_kretprobe(&pf_kretprobe);
 328
 329         /* uninstall kretprobe with 'copy_process' */
 330         dbi_unregister_kretprobe(&cp_kretprobe);
 331
 332         /* uninstall kprobe with 'mm_release' */
 333         dbi_unregister_kprobe(&mr_kprobe, NULL);
 334
 335         /* uninstall kprobe with 'do_munmap' */
 336         dbi_unregister_kprobe(&unmap_kprobe, NULL);
 337 }
 338
 339 int init_helper(void)
 340 {
 341         unsigned long addr;
 342         addr = swap_ksyms("do_page_fault");
 343         if (addr == 0) {
 344                 printk("Cannot find address for page fault function!\n");
 345                 return -EINVAL;
 346         }
 347         pf_kretprobe.kp.addr = (kprobe_opcode_t *)addr;
 348
 349         addr = swap_ksyms("copy_process");
 350         if (addr == 0) {
 351                 printk("Cannot find address for copy_process function!\n");
 352                 return -EINVAL;
 353         }
 354         cp_kretprobe.kp.addr = (kprobe_opcode_t *)addr;
 355
 356         addr = swap_ksyms("mm_release");
 357         if (addr == 0) {
 358                 printk("Cannot find address for mm_release function!\n");
 359                 return -EINVAL;
 360         }
 361         mr_kprobe.addr = (kprobe_opcode_t *)addr;
 362
 363         addr = swap_ksyms("do_munmap");
 364         if (addr == 0) {
 365                 printk("Cannot find address for do_munmap function!\n");
 366                 return -EINVAL;
 367         }
 368         unmap_kprobe.addr = (kprobe_opcode_t *)addr;
 369
 370         return 0;
 371 }
 372
 373 void uninit_helper(void)
 374 {
 375 }