syscalls/mprotect.c

   1 /*
   2  * sys_mprotect(unsigned long start, size_t len, unsigned long prot)
   3  */
   4 #include <asm/mman.h>
   5 #include "trinity.h"    // page_size
   6 #include "arch.h"
   7 #include "random.h"
   8 #include "sanitise.h"
   9 #include "shm.h"
  10
  11 static void sanitise_mprotect(int childno)
  12 {
  13         unsigned long end;
  14
  15         shm->a1[childno] &= PAGE_MASK;
  16
  17 retry_end:
  18         end = shm->a1[childno] + shm->a2[childno];
  19         /* Length must not be zero. */
  20         if (shm->a2[childno] == 0) {
  21                 shm->a2[childno] = rand64();
  22                 goto retry_end;
  23         }
  24
  25         /* End must be after start */
  26         if (end <= shm->a1[childno]) {
  27                 shm->a2[childno] = rand64();
  28                 goto retry_end;
  29         }
  30 }
  31
  32 struct syscall syscall_mprotect = {
  33         .name = "mprotect",
  34         .num_args = 3,
  35         .arg1name = "start",
  36         .arg1type = ARG_MMAP,
  37         .arg2name = "len",
  38         .arg2type = ARG_LEN,
  39         .arg3name = "prot",
  40         .arg3type = ARG_LIST,
  41         .arg3list = {
  42                 .num = 6,
  43                 .values = { PROT_READ, PROT_WRITE, PROT_EXEC, PROT_SEM, PROT_GROWSDOWN, PROT_GROWSUP },
  44         },
  45         .sanitise = sanitise_mprotect,
  46         .group = GROUP_VM,
  47
  48         .flags = AVOID_SYSCALL, // hopefully temporary.
  49 };