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 } 49 50 static u64 arg_to_enxx_mask(unsigned long arg) 51 { 52 u64 sctlr_enxx_mask = 0; 53 54 WARN_ON(arg & ~PR_PAC_ENABLED_KEYS_MASK); 55 if (arg & PR_PAC_APIAKEY) 56 sctlr_enxx_mask |= SCTLR_ELx_ENIA; 57 if (arg & PR_PAC_APIBKEY) 58 sctlr_enxx_mask |= SCTLR_ELx_ENIB; 59 if (arg & PR_PAC_APDAKEY) 60 sctlr_enxx_mask |= SCTLR_ELx_ENDA; 61 if (arg & PR_PAC_APDBKEY) 62 sctlr_enxx_mask |= SCTLR_ELx_ENDB; 63 return sctlr_enxx_mask; 64 } 65 66 int ptrauth_set_enabled_keys(struct task_struct *tsk, unsigned long keys, 67 unsigned long enabled) 68 { 69 u64 sctlr = tsk->thread.sctlr_user; 70 71 if (!system_supports_address_auth()) 72 return -EINVAL; 73 74 if (is_compat_thread(task_thread_info(tsk))) 75 return -EINVAL; 76 77 if ((keys & ~PR_PAC_ENABLED_KEYS_MASK) || (enabled & ~keys)) 78 return -EINVAL; 79 80 sctlr &= ~arg_to_enxx_mask(keys); 81 sctlr |= arg_to_enxx_mask(enabled); 82 if (tsk == current) 83 set_task_sctlr_el1(sctlr); 84 else 85 tsk->thread.sctlr_user = sctlr; 86 87 return 0; 88 } 89 90 int ptrauth_get_enabled_keys(struct task_struct *tsk) 91 { 92 int retval = 0; 93 94 if (!system_supports_address_auth()) 95 return -EINVAL; 96 97 if (is_compat_thread(task_thread_info(tsk))) 98 return -EINVAL; 99 100 if (tsk->thread.sctlr_user & SCTLR_ELx_ENIA) 101 retval |= PR_PAC_APIAKEY; 102 if (tsk->thread.sctlr_user & SCTLR_ELx_ENIB) 103 retval |= PR_PAC_APIBKEY; 104 if (tsk->thread.sctlr_user & SCTLR_ELx_ENDA) 105 retval |= PR_PAC_APDAKEY; 106 if (tsk->thread.sctlr_user & SCTLR_ELx_ENDB) 107 retval |= PR_PAC_APDBKEY; 108 109 return retval; 110 } 111