arch/arm64/kernel/pointer_auth.c

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