| 1 | |
| 2 |
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| 3 | #include <linux/compat.h>
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| 4 | #include <linux/errno.h>
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| 5 | #include <linux/prctl.h>
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| 6 | #include <linux/random.h>
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| 7 | #include <linux/sched.h>
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| 8 | #include <asm/cpufeature.h>
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| 9 | #include <asm/pointer_auth.h>
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| 10 |
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| 11 | int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg)
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| 12 | {
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| 13 | struct ptrauth_keys_user *keys = &tsk->thread.keys_user;
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| 14 | unsigned long addr_key_mask = PR_PAC_APIAKEY | PR_PAC_APIBKEY |
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| 15 | PR_PAC_APDAKEY | PR_PAC_APDBKEY;
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| 16 | unsigned long key_mask = addr_key_mask | PR_PAC_APGAKEY;
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| 17 |
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| 18 | if (!system_supports_address_auth() && !system_supports_generic_auth())
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| 19 | return -EINVAL;
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| 20 |
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| 21 | if (is_compat_thread(task_thread_info(tsk)))
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| 22 | return -EINVAL;
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| 23 |
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| 24 | if (!arg) {
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| 25 | ptrauth_keys_init_user(keys);
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| 26 | return 0;
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| 27 | }
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| 28 |
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| 29 | if (arg & ~key_mask)
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| 30 | return -EINVAL;
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| 31 |
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| 32 | if (((arg & addr_key_mask) && !system_supports_address_auth()) ||
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| 33 | ((arg & PR_PAC_APGAKEY) && !system_supports_generic_auth()))
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| 34 | return -EINVAL;
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| 35 |
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| 36 | if (arg & PR_PAC_APIAKEY)
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| 37 | get_random_bytes(&keys->apia, sizeof(keys->apia));
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| 38 | if (arg & PR_PAC_APIBKEY)
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| 39 | get_random_bytes(&keys->apib, sizeof(keys->apib));
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| 40 | if (arg & PR_PAC_APDAKEY)
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| 41 | get_random_bytes(&keys->apda, sizeof(keys->apda));
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| 42 | if (arg & PR_PAC_APDBKEY)
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| 43 | get_random_bytes(&keys->apdb, sizeof(keys->apdb));
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| 44 | if (arg & PR_PAC_APGAKEY)
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| 45 | get_random_bytes(&keys->apga, sizeof(keys->apga));
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| 46 | ptrauth_keys_install_user(keys);
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| 47 |
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| 48 | return 0;
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| 49 | }
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| 50 |
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| 51 | static u64 arg_to_enxx_mask(unsigned long arg)
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| 52 | {
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| 53 | u64 sctlr_enxx_mask = 0;
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| 54 |
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| 55 | WARN_ON(arg & ~PR_PAC_ENABLED_KEYS_MASK);
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| 56 | if (arg & PR_PAC_APIAKEY)
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| 57 | sctlr_enxx_mask |= SCTLR_ELx_ENIA;
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| 58 | if (arg & PR_PAC_APIBKEY)
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| 59 | sctlr_enxx_mask |= SCTLR_ELx_ENIB;
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| 60 | if (arg & PR_PAC_APDAKEY)
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| 61 | sctlr_enxx_mask |= SCTLR_ELx_ENDA;
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| 62 | if (arg & PR_PAC_APDBKEY)
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| 63 | sctlr_enxx_mask |= SCTLR_ELx_ENDB;
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| 64 | return sctlr_enxx_mask;
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| 65 | }
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| 66 |
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| 67 | int ptrauth_set_enabled_keys(struct task_struct *tsk, unsigned long keys,
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| 68 | unsigned long enabled)
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| 69 | {
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| 70 | u64 sctlr;
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| 71 |
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| 72 | if (!system_supports_address_auth())
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| 73 | return -EINVAL;
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| 74 |
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| 75 | if (is_compat_thread(task_thread_info(tsk)))
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| 76 | return -EINVAL;
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| 77 |
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| 78 | if ((keys & ~PR_PAC_ENABLED_KEYS_MASK) || (enabled & ~keys))
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| 79 | return -EINVAL;
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| 80 |
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| 81 | preempt_disable();
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| 82 | sctlr = tsk->thread.sctlr_user;
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| 83 | sctlr &= ~arg_to_enxx_mask(keys);
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| 84 | sctlr |= arg_to_enxx_mask(enabled);
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| 85 | tsk->thread.sctlr_user = sctlr;
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| 86 | if (tsk == current)
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| 87 | update_sctlr_el1(sctlr);
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| 88 | preempt_enable();
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| 89 |
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| 90 | return 0;
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| 91 | }
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| 92 |
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| 93 | int ptrauth_get_enabled_keys(struct task_struct *tsk)
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| 94 | {
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| 95 | int retval = 0;
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| 96 |
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| 97 | if (!system_supports_address_auth())
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| 98 | return -EINVAL;
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| 99 |
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| 100 | if (is_compat_thread(task_thread_info(tsk)))
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| 101 | return -EINVAL;
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| 102 |
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| 103 | if (tsk->thread.sctlr_user & SCTLR_ELx_ENIA)
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| 104 | retval |= PR_PAC_APIAKEY;
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| 105 | if (tsk->thread.sctlr_user & SCTLR_ELx_ENIB)
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| 106 | retval |= PR_PAC_APIBKEY;
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| 107 | if (tsk->thread.sctlr_user & SCTLR_ELx_ENDA)
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| 108 | retval |= PR_PAC_APDAKEY;
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| 109 | if (tsk->thread.sctlr_user & SCTLR_ELx_ENDB)
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| 110 | retval |= PR_PAC_APDBKEY;
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| 111 |
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| 112 | return retval;
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| 113 | }
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