arch/arm64/kernel/pointer_auth.c

   1 // SPDX-License-Identifier: GPL-2.0
   2
   3 #include <linux/compat.h>
   4 #include <linux/errno.h>
   5 #include <linux/prctl.h>
   6 #include <linux/random.h>
   7 #include <linux/sched.h>
   8 #include <asm/cpufeature.h>
   9 #include <asm/pointer_auth.h>
  10
  11 int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg)
  12 {
  13         struct ptrauth_keys_user *keys = &tsk->thread.keys_user;
  14         unsigned long addr_key_mask = PR_PAC_APIAKEY | PR_PAC_APIBKEY |
  15                                       PR_PAC_APDAKEY | PR_PAC_APDBKEY;
  16         unsigned long key_mask = addr_key_mask | PR_PAC_APGAKEY;
  17
  18         if (!system_supports_address_auth() && !system_supports_generic_auth())
  19                 return -EINVAL;
  20
  21         if (is_compat_thread(task_thread_info(tsk)))
  22                 return -EINVAL;
  23
  24         if (!arg) {
  25                 ptrauth_keys_init_user(keys);
  26                 return 0;
  27         }
  28
  29         if (arg & ~key_mask)
  30                 return -EINVAL;
  31
  32         if (((arg & addr_key_mask) && !system_supports_address_auth()) ||
  33             ((arg & PR_PAC_APGAKEY) && !system_supports_generic_auth()))
  34                 return -EINVAL;
  35
  36         if (arg & PR_PAC_APIAKEY)
  37                 get_random_bytes(&keys->apia, sizeof(keys->apia));
  38         if (arg & PR_PAC_APIBKEY)
  39                 get_random_bytes(&keys->apib, sizeof(keys->apib));
  40         if (arg & PR_PAC_APDAKEY)
  41                 get_random_bytes(&keys->apda, sizeof(keys->apda));
  42         if (arg & PR_PAC_APDBKEY)
  43                 get_random_bytes(&keys->apdb, sizeof(keys->apdb));
  44         if (arg & PR_PAC_APGAKEY)
  45                 get_random_bytes(&keys->apga, sizeof(keys->apga));
  46
  47         return 0;
  48 }