diff --git a/arch/arm64/include/asm/pointer_auth.h b/arch/arm64/include/asm/pointer_auth.h new file mode 100644 index 000000000000..91c4185dda5b --- /dev/null +++ b/arch/arm64/include/asm/pointer_auth.h @@ -0,0 +1,79 @@ +// SPDX-License-Identifier: GPL-2.0 +#ifndef __ASM_POINTER_AUTH_H +#define __ASM_POINTER_AUTH_H + +#include + +#include +#include + +#ifdef CONFIG_ARM64_PTR_AUTH +/* + * Each key is a 128-bit quantity which is split across a pair of 64-bit + * registers (Lo and Hi). + */ +struct ptrauth_key { + unsigned long lo, hi; +}; + +/* + * We give each process its own keys, which are shared by all threads. The keys + * are inherited upon fork(), and reinitialised upon exec*(). + */ +struct ptrauth_keys { + struct ptrauth_key apia; + struct ptrauth_key apib; + struct ptrauth_key apda; + struct ptrauth_key apdb; + struct ptrauth_key apga; +}; + +static inline void ptrauth_keys_init(struct ptrauth_keys *keys) +{ + if (system_supports_address_auth()) { + get_random_bytes(&keys->apia, sizeof(keys->apia)); + get_random_bytes(&keys->apib, sizeof(keys->apib)); + get_random_bytes(&keys->apda, sizeof(keys->apda)); + get_random_bytes(&keys->apdb, sizeof(keys->apdb)); + } + + if (system_supports_generic_auth()) + get_random_bytes(&keys->apga, sizeof(keys->apga)); +} + +#define __ptrauth_key_install(k, v) \ +do { \ + struct ptrauth_key __pki_v = (v); \ + write_sysreg_s(__pki_v.lo, SYS_ ## k ## KEYLO_EL1); \ + write_sysreg_s(__pki_v.hi, SYS_ ## k ## KEYHI_EL1); \ +} while (0) + +static inline void ptrauth_keys_switch(struct ptrauth_keys *keys) +{ + if (system_supports_address_auth()) { + __ptrauth_key_install(APIA, keys->apia); + __ptrauth_key_install(APIB, keys->apib); + __ptrauth_key_install(APDA, keys->apda); + __ptrauth_key_install(APDB, keys->apdb); + } + + if (system_supports_generic_auth()) + __ptrauth_key_install(APGA, keys->apga); +} + +#define ptrauth_thread_init_user(tsk) \ +do { \ + struct task_struct *__ptiu_tsk = (tsk); \ + ptrauth_keys_init(&__ptiu_tsk->thread_info.keys_user); \ + ptrauth_keys_switch(&__ptiu_tsk->thread_info.keys_user); \ +} while (0) + +#define ptrauth_thread_switch(tsk) \ + ptrauth_keys_switch(&(tsk)->thread_info.keys_user) + +#else /* CONFIG_ARM64_PTR_AUTH */ +#define ptrauth_thread_init_user(tsk) +#define ptrauth_thread_switch(tsk) +#endif /* CONFIG_ARM64_PTR_AUTH */ + +#endif /* __ASM_POINTER_AUTH_H */ diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h index bbca68b54732..f8f66ad9dd8f 100644 --- a/arch/arm64/include/asm/thread_info.h +++ b/arch/arm64/include/asm/thread_info.h @@ -28,6 +28,7 @@ struct task_struct; #include +#include #include #include @@ -54,6 +55,9 @@ struct thread_info { #endif } preempt; }; +#ifdef CONFIG_ARM64_PTR_AUTH + struct ptrauth_keys keys_user; +#endif }; #define thread_saved_pc(tsk) \ diff --git a/arch/arm64/include/uapi/asm/hwcap.h b/arch/arm64/include/uapi/asm/hwcap.h index 7784f7cba16c..5f0750c2199c 100644 --- a/arch/arm64/include/uapi/asm/hwcap.h +++ b/arch/arm64/include/uapi/asm/hwcap.h @@ -50,5 +50,7 @@ #define HWCAP_FLAGM (1 << 27) #define HWCAP_SSBS (1 << 28) #define HWCAP_SB (1 << 29) +#define HWCAP_PACA (1 << 30) +#define HWCAP_PACG (1UL << 31) #endif /* _UAPI__ASM_HWCAP_H */ diff --git a/arch/arm64/kernel/cpufeature.c b/arch/arm64/kernel/cpufeature.c index c82ebd8f0087..f15000872e08 100644 --- a/arch/arm64/kernel/cpufeature.c +++ b/arch/arm64/kernel/cpufeature.c @@ -1191,6 +1191,12 @@ static void cpu_clear_disr(const struct arm64_cpu_capabilities *__unused) #endif /* CONFIG_ARM64_RAS_EXTN */ #ifdef CONFIG_ARM64_PTR_AUTH +static void cpu_enable_address_auth(struct arm64_cpu_capabilities const *cap) +{ + sysreg_clear_set(sctlr_el1, 0, SCTLR_ELx_ENIA | SCTLR_ELx_ENIB | + SCTLR_ELx_ENDA | SCTLR_ELx_ENDB); +} + static bool has_address_auth(const struct arm64_cpu_capabilities *entry, int __unused) { @@ -1478,6 +1484,7 @@ static const struct arm64_cpu_capabilities arm64_features[] = { .capability = ARM64_HAS_ADDRESS_AUTH, .type = ARM64_CPUCAP_SYSTEM_FEATURE, .matches = has_address_auth, + .cpu_enable = cpu_enable_address_auth, }, { .desc = "Generic authentication (architected algorithm)", @@ -1552,6 +1559,12 @@ static const struct arm64_cpu_capabilities arm64_elf_hwcaps[] = { HWCAP_CAP(SYS_ID_AA64PFR0_EL1, ID_AA64PFR0_SVE_SHIFT, FTR_UNSIGNED, ID_AA64PFR0_SVE, CAP_HWCAP, HWCAP_SVE), #endif HWCAP_CAP(SYS_ID_AA64PFR1_EL1, ID_AA64PFR1_SSBS_SHIFT, FTR_UNSIGNED, ID_AA64PFR1_SSBS_PSTATE_INSNS, CAP_HWCAP, HWCAP_SSBS), +#ifdef CONFIG_ARM64_PTR_AUTH + { .desc = "HWCAP_PACA", .type = ARM64_CPUCAP_SYSTEM_FEATURE, .matches = has_address_auth, + .hwcap_type = CAP_HWCAP, .hwcap = HWCAP_PACA }, + { .desc = "HWCAP_PACG", .type = ARM64_CPUCAP_SYSTEM_FEATURE, .matches = has_generic_auth, + .hwcap_type = CAP_HWCAP, .hwcap = HWCAP_PACG }, +#endif {}, }; diff --git a/arch/arm64/kernel/cpuinfo.c b/arch/arm64/kernel/cpuinfo.c index 7cb0b08ab0a7..ca0685f33900 100644 --- a/arch/arm64/kernel/cpuinfo.c +++ b/arch/arm64/kernel/cpuinfo.c @@ -83,6 +83,8 @@ static const char *const hwcap_str[] = { "flagm", "ssbs", "sb", + "paca", + "pacg", NULL }; diff --git a/arch/arm64/kernel/process.c b/arch/arm64/kernel/process.c index 8a2d68f04e0d..e0a443730e04 100644 --- a/arch/arm64/kernel/process.c +++ b/arch/arm64/kernel/process.c @@ -57,6 +57,7 @@ #include #include #include +#include #include #if defined(CONFIG_STACKPROTECTOR) && !defined(CONFIG_STACKPROTECTOR_PER_TASK) @@ -429,6 +430,7 @@ __notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev, contextidr_thread_switch(next); entry_task_switch(next); uao_thread_switch(next); + ptrauth_thread_switch(next); /* * Complete any pending TLB or cache maintenance on this CPU in case @@ -496,4 +498,6 @@ unsigned long arch_randomize_brk(struct mm_struct *mm) void arch_setup_new_exec(void) { current->mm->context.flags = is_compat_task() ? MMCF_AARCH32 : 0; + + ptrauth_thread_init_user(current); }