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Merge branch 'for-next/pac-set-get-enabled-keys' into for-next/core

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* for-next/pac-set-get-enabled-keys:
  : Introduce arm64 prctl(PR_PAC_{SET,GET}_ENABLED_KEYS).
  arm64: pac: Optimize kernel entry/exit key installation code paths
  arm64: Introduce prctl(PR_PAC_{SET,GET}_ENABLED_KEYS)
  arm64: mte: make the per-task SCTLR_EL1 field usable elsewhere
This commit is contained in:
Catalin Marinas 2021-04-15 14:00:48 +01:00
commit a27a881656
16 changed files with 316 additions and 83 deletions
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34
Documentation/arm64/pointer-authentication.rst
View File

@ -107,3 +107,37 @@ filter out the Pointer Authentication system key registers from
KVM_GET/SET_REG_* ioctls and mask those features from cpufeature ID
register. Any attempt to use the Pointer Authentication instructions will
result in an UNDEFINED exception being injected into the guest.
Enabling and disabling keys
---------------------------
The prctl PR_PAC_SET_ENABLED_KEYS allows the user program to control which
PAC keys are enabled in a particular task. It takes two arguments, the
first being a bitmask of PR_PAC_APIAKEY, PR_PAC_APIBKEY, PR_PAC_APDAKEY
and PR_PAC_APDBKEY specifying which keys shall be affected by this prctl,
and the second being a bitmask of the same bits specifying whether the key
should be enabled or disabled. For example::
prctl(PR_PAC_SET_ENABLED_KEYS,
PR_PAC_APIAKEY | PR_PAC_APIBKEY | PR_PAC_APDAKEY | PR_PAC_APDBKEY,
PR_PAC_APIBKEY, 0, 0);
disables all keys except the IB key.
The main reason why this is useful is to enable a userspace ABI that uses PAC
instructions to sign and authenticate function pointers and other pointers
exposed outside of the function, while still allowing binaries conforming to
the ABI to interoperate with legacy binaries that do not sign or authenticate
pointers.
The idea is that a dynamic loader or early startup code would issue this
prctl very early after establishing that a process may load legacy binaries,
but before executing any PAC instructions.
For compatibility with previous kernel versions, processes start up with IA,
IB, DA and DB enabled, and are reset to this state on exec(). Processes created
via fork() and clone() inherit the key enabled state from the calling process.
It is recommended to avoid disabling the IA key, as this has higher performance
overhead than disabling any of the other keys.

20
arch/arm64/include/asm/asm_pointer_auth.h
View File

@ -13,30 +13,12 @@
* so use the base value of ldp as thread.keys_user and offset as
* thread.keys_user.ap*.
*/
.macro ptrauth_keys_install_user tsk, tmp1, tmp2, tmp3
.macro __ptrauth_keys_install_user tsk, tmp1, tmp2, tmp3
mov \tmp1, #THREAD_KEYS_USER
add \tmp1, \tsk, \tmp1
alternative_if_not ARM64_HAS_ADDRESS_AUTH
b .Laddr_auth_skip_\@
alternative_else_nop_endif
ldp \tmp2, \tmp3, [\tmp1, #PTRAUTH_USER_KEY_APIA]
msr_s SYS_APIAKEYLO_EL1, \tmp2
msr_s SYS_APIAKEYHI_EL1, \tmp3
ldp \tmp2, \tmp3, [\tmp1, #PTRAUTH_USER_KEY_APIB]
msr_s SYS_APIBKEYLO_EL1, \tmp2
msr_s SYS_APIBKEYHI_EL1, \tmp3
ldp \tmp2, \tmp3, [\tmp1, #PTRAUTH_USER_KEY_APDA]
msr_s SYS_APDAKEYLO_EL1, \tmp2
msr_s SYS_APDAKEYHI_EL1, \tmp3
ldp \tmp2, \tmp3, [\tmp1, #PTRAUTH_USER_KEY_APDB]
msr_s SYS_APDBKEYLO_EL1, \tmp2
msr_s SYS_APDBKEYHI_EL1, \tmp3
.Laddr_auth_skip_\@:
alternative_if ARM64_HAS_GENERIC_AUTH
ldp \tmp2, \tmp3, [\tmp1, #PTRAUTH_USER_KEY_APGA]
msr_s SYS_APGAKEYLO_EL1, \tmp2
msr_s SYS_APGAKEYHI_EL1, \tmp3
alternative_else_nop_endif
.endm
.macro __ptrauth_keys_install_kernel_nosync tsk, tmp1, tmp2, tmp3

4
arch/arm64/include/asm/mte.h
View File

@ -39,7 +39,7 @@ void mte_free_tag_storage(char *storage);
void mte_sync_tags(pte_t *ptep, pte_t pte);
void mte_copy_page_tags(void *kto, const void *kfrom);
void flush_mte_state(void);
void mte_thread_init_user(void);
void mte_thread_switch(struct task_struct *next);
void mte_suspend_enter(void);
void mte_suspend_exit(void);
@ -59,7 +59,7 @@ static inline void mte_sync_tags(pte_t *ptep, pte_t pte)
static inline void mte_copy_page_tags(void *kto, const void *kfrom)
{
}
static inline void flush_mte_state(void)
static inline void mte_thread_init_user(void)
{
}
static inline void mte_thread_switch(struct task_struct *next)

61
arch/arm64/include/asm/pointer_auth.h
View File

@ -3,6 +3,7 @@
#define __ASM_POINTER_AUTH_H
#include <linux/bitops.h>
#include <linux/prctl.h>
#include <linux/random.h>
#include <asm/cpufeature.h>
@ -34,6 +35,25 @@ struct ptrauth_keys_kernel {
struct ptrauth_key apia;
};
#define __ptrauth_key_install_nosync(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_install_user(struct ptrauth_keys_user *keys)
{
if (system_supports_address_auth()) {
__ptrauth_key_install_nosync(APIB, keys->apib);
__ptrauth_key_install_nosync(APDA, keys->apda);
__ptrauth_key_install_nosync(APDB, keys->apdb);
}
if (system_supports_generic_auth())
__ptrauth_key_install_nosync(APGA, keys->apga);
}
static inline void ptrauth_keys_init_user(struct ptrauth_keys_user *keys)
{
if (system_supports_address_auth()) {
@ -45,14 +65,9 @@ static inline void ptrauth_keys_init_user(struct ptrauth_keys_user *keys)
if (system_supports_generic_auth())
get_random_bytes(&keys->apga, sizeof(keys->apga));
}
#define __ptrauth_key_install_nosync(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)
ptrauth_keys_install_user(keys);
}
static __always_inline void ptrauth_keys_init_kernel(struct ptrauth_keys_kernel *keys)
{
@ -71,6 +86,10 @@ static __always_inline void ptrauth_keys_switch_kernel(struct ptrauth_keys_kerne
extern int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg);
extern int ptrauth_set_enabled_keys(struct task_struct *tsk, unsigned long keys,
unsigned long enabled);
extern int ptrauth_get_enabled_keys(struct task_struct *tsk);
static inline unsigned long ptrauth_strip_insn_pac(unsigned long ptr)
{
return ptrauth_clear_pac(ptr);
@ -85,8 +104,23 @@ static __always_inline void ptrauth_enable(void)
isb();
}
#define ptrauth_thread_init_user(tsk) \
ptrauth_keys_init_user(&(tsk)->thread.keys_user)
#define ptrauth_suspend_exit() \
ptrauth_keys_install_user(&current->thread.keys_user)
#define ptrauth_thread_init_user() \
do { \
ptrauth_keys_init_user(&current->thread.keys_user); \
\
/* enable all keys */ \
if (system_supports_address_auth()) \
set_task_sctlr_el1(current->thread.sctlr_user | \
SCTLR_ELx_ENIA | SCTLR_ELx_ENIB | \
SCTLR_ELx_ENDA | SCTLR_ELx_ENDB); \
} while (0)
#define ptrauth_thread_switch_user(tsk) \
ptrauth_keys_install_user(&(tsk)->thread.keys_user)
#define ptrauth_thread_init_kernel(tsk) \
ptrauth_keys_init_kernel(&(tsk)->thread.keys_kernel)
#define ptrauth_thread_switch_kernel(tsk) \
@ -95,10 +129,17 @@ static __always_inline void ptrauth_enable(void)
#else /* CONFIG_ARM64_PTR_AUTH */
#define ptrauth_enable()
#define ptrauth_prctl_reset_keys(tsk, arg) (-EINVAL)
#define ptrauth_set_enabled_keys(tsk, keys, enabled) (-EINVAL)
#define ptrauth_get_enabled_keys(tsk) (-EINVAL)
#define ptrauth_strip_insn_pac(lr) (lr)
#define ptrauth_thread_init_user(tsk)
#define ptrauth_suspend_exit()
#define ptrauth_thread_init_user()
#define ptrauth_thread_init_kernel(tsk)
#define ptrauth_thread_switch_user(tsk)
#define ptrauth_thread_switch_kernel(tsk)
#endif /* CONFIG_ARM64_PTR_AUTH */
#define PR_PAC_ENABLED_KEYS_MASK \
(PR_PAC_APIAKEY | PR_PAC_APIBKEY | PR_PAC_APDAKEY | PR_PAC_APDBKEY)
#endif /* __ASM_POINTER_AUTH_H */

13
arch/arm64/include/asm/processor.h
View File

@ -151,11 +151,15 @@ struct thread_struct {
struct ptrauth_keys_kernel keys_kernel;
#endif
#ifdef CONFIG_ARM64_MTE
u64 sctlr_tcf0;
u64 gcr_user_excl;
#endif
u64 sctlr_user;
};
#define SCTLR_USER_MASK \
(SCTLR_ELx_ENIA | SCTLR_ELx_ENIB | SCTLR_ELx_ENDA | SCTLR_ELx_ENDB | \
SCTLR_EL1_TCF0_MASK)
static inline void arch_thread_struct_whitelist(unsigned long *offset,
unsigned long *size)
{
@ -247,6 +251,8 @@ extern void release_thread(struct task_struct *);
unsigned long get_wchan(struct task_struct *p);
void set_task_sctlr_el1(u64 sctlr);
/* Thread switching */
extern struct task_struct *cpu_switch_to(struct task_struct *prev,
struct task_struct *next);
@ -301,6 +307,11 @@ extern void __init minsigstksz_setup(void);
/* PR_PAC_RESET_KEYS prctl */
#define PAC_RESET_KEYS(tsk, arg) ptrauth_prctl_reset_keys(tsk, arg)
/* PR_PAC_{SET,GET}_ENABLED_KEYS prctl */
#define PAC_SET_ENABLED_KEYS(tsk, keys, enabled) \
ptrauth_set_enabled_keys(tsk, keys, enabled)
#define PAC_GET_ENABLED_KEYS(tsk) ptrauth_get_enabled_keys(tsk)
#ifdef CONFIG_ARM64_TAGGED_ADDR_ABI
/* PR_{SET,GET}_TAGGED_ADDR_CTRL prctl */
long set_tagged_addr_ctrl(struct task_struct *task, unsigned long arg);

4
arch/arm64/include/asm/sysreg.h
View File

@ -571,8 +571,10 @@
#define SCTLR_ELx_TCF_ASYNC (UL(0x2) << SCTLR_ELx_TCF_SHIFT)
#define SCTLR_ELx_TCF_MASK (UL(0x3) << SCTLR_ELx_TCF_SHIFT)
#define SCTLR_ELx_ENIA_SHIFT 31
#define SCTLR_ELx_ITFSB (BIT(37))
#define SCTLR_ELx_ENIA (BIT(31))
#define SCTLR_ELx_ENIA (BIT(SCTLR_ELx_ENIA_SHIFT))
#define SCTLR_ELx_ENIB (BIT(30))
#define SCTLR_ELx_ENDA (BIT(27))
#define SCTLR_ELx_EE (BIT(25))

5
arch/arm64/kernel/asm-offsets.c
View File

@ -43,6 +43,7 @@ int main(void)
#endif
BLANK();
DEFINE(THREAD_CPU_CONTEXT, offsetof(struct task_struct, thread.cpu_context));
DEFINE(THREAD_SCTLR_USER, offsetof(struct task_struct, thread.sctlr_user));
#ifdef CONFIG_ARM64_PTR_AUTH
DEFINE(THREAD_KEYS_USER, offsetof(struct task_struct, thread.keys_user));
DEFINE(THREAD_KEYS_KERNEL, offsetof(struct task_struct, thread.keys_kernel));
@ -149,10 +150,6 @@ int main(void)
#endif
#ifdef CONFIG_ARM64_PTR_AUTH
DEFINE(PTRAUTH_USER_KEY_APIA, offsetof(struct ptrauth_keys_user, apia));
DEFINE(PTRAUTH_USER_KEY_APIB, offsetof(struct ptrauth_keys_user, apib));
DEFINE(PTRAUTH_USER_KEY_APDA, offsetof(struct ptrauth_keys_user, apda));
DEFINE(PTRAUTH_USER_KEY_APDB, offsetof(struct ptrauth_keys_user, apdb));
DEFINE(PTRAUTH_USER_KEY_APGA, offsetof(struct ptrauth_keys_user, apga));
DEFINE(PTRAUTH_KERNEL_KEY_APIA, offsetof(struct ptrauth_keys_kernel, apia));
BLANK();
#endif

46
arch/arm64/kernel/entry.S
View File

@ -247,7 +247,29 @@ alternative_else_nop_endif
check_mte_async_tcf x19, x22
apply_ssbd 1, x22, x23
ptrauth_keys_install_kernel tsk, x20, x22, x23
#ifdef CONFIG_ARM64_PTR_AUTH
alternative_if ARM64_HAS_ADDRESS_AUTH
/*
* Enable IA for in-kernel PAC if the task had it disabled. Although
* this could be implemented with an unconditional MRS which would avoid
* a load, this was measured to be slower on Cortex-A75 and Cortex-A76.
*
* Install the kernel IA key only if IA was enabled in the task. If IA
* was disabled on kernel exit then we would have left the kernel IA
* installed so there is no need to install it again.
*/
ldr x0, [tsk, THREAD_SCTLR_USER]
tbz x0, SCTLR_ELx_ENIA_SHIFT, 1f
__ptrauth_keys_install_kernel_nosync tsk, x20, x22, x23
b 2f
1:
mrs x0, sctlr_el1
orr x0, x0, SCTLR_ELx_ENIA
msr sctlr_el1, x0
2:
isb
alternative_else_nop_endif
#endif
mte_set_kernel_gcr x22, x23
@ -351,8 +373,26 @@ alternative_else_nop_endif
3:
scs_save tsk, x0
/* No kernel C function calls after this as user keys are set. */
ptrauth_keys_install_user tsk, x0, x1, x2
#ifdef CONFIG_ARM64_PTR_AUTH
alternative_if ARM64_HAS_ADDRESS_AUTH
/*
* IA was enabled for in-kernel PAC. Disable it now if needed, or
* alternatively install the user's IA. All other per-task keys and
* SCTLR bits were updated on task switch.
*
* No kernel C function calls after this.
*/
ldr x0, [tsk, THREAD_SCTLR_USER]
tbz x0, SCTLR_ELx_ENIA_SHIFT, 1f
__ptrauth_keys_install_user tsk, x0, x1, x2
b 2f
1:
mrs x0, sctlr_el1
bic x0, x0, SCTLR_ELx_ENIA
msr sctlr_el1, x0
2:
alternative_else_nop_endif
#endif
mte_set_user_gcr tsk, x0, x1

51
arch/arm64/kernel/mte.c
View File

@ -185,26 +185,6 @@ void mte_check_tfsr_el1(void)
}
#endif
static void update_sctlr_el1_tcf0(u64 tcf0)
{
/* ISB required for the kernel uaccess routines */
sysreg_clear_set(sctlr_el1, SCTLR_EL1_TCF0_MASK, tcf0);
isb();
}
static void set_sctlr_el1_tcf0(u64 tcf0)
{
/*
* mte_thread_switch() checks current->thread.sctlr_tcf0 as an
* optimisation. Disable preemption so that it does not see
* the variable update before the SCTLR_EL1.TCF0 one.
*/
preempt_disable();
current->thread.sctlr_tcf0 = tcf0;
update_sctlr_el1_tcf0(tcf0);
preempt_enable();
}
static void update_gcr_el1_excl(u64 excl)
{
@ -227,7 +207,7 @@ static void set_gcr_el1_excl(u64 excl)
*/
}
void flush_mte_state(void)
void mte_thread_init_user(void)
{
if (!system_supports_mte())
return;
@ -237,31 +217,22 @@ void flush_mte_state(void)
write_sysreg_s(0, SYS_TFSRE0_EL1);
clear_thread_flag(TIF_MTE_ASYNC_FAULT);
/* disable tag checking */
set_sctlr_el1_tcf0(SCTLR_EL1_TCF0_NONE);
set_task_sctlr_el1((current->thread.sctlr_user & ~SCTLR_EL1_TCF0_MASK) |
SCTLR_EL1_TCF0_NONE);
/* reset tag generation mask */
set_gcr_el1_excl(SYS_GCR_EL1_EXCL_MASK);
}
void mte_thread_switch(struct task_struct *next)
{
if (!system_supports_mte())
return;
/* avoid expensive SCTLR_EL1 accesses if no change */
if (current->thread.sctlr_tcf0 != next->thread.sctlr_tcf0)
update_sctlr_el1_tcf0(next->thread.sctlr_tcf0);
else
isb();
/*
* Check if an async tag exception occurred at EL1.
*
* Note: On the context switch path we rely on the dsb() present
* in __switch_to() to guarantee that the indirect writes to TFSR_EL1
* are synchronized before this point.
* isb() above is required for the same reason.
*
*/
isb();
mte_check_tfsr_el1();
}
@ -291,7 +262,7 @@ void mte_suspend_exit(void)
long set_mte_ctrl(struct task_struct *task, unsigned long arg)
{
u64 tcf0;
u64 sctlr = task->thread.sctlr_user & ~SCTLR_EL1_TCF0_MASK;
u64 gcr_excl = ~((arg & PR_MTE_TAG_MASK) >> PR_MTE_TAG_SHIFT) &
SYS_GCR_EL1_EXCL_MASK;
@ -300,23 +271,23 @@ long set_mte_ctrl(struct task_struct *task, unsigned long arg)
switch (arg & PR_MTE_TCF_MASK) {
case PR_MTE_TCF_NONE:
tcf0 = SCTLR_EL1_TCF0_NONE;
sctlr |= SCTLR_EL1_TCF0_NONE;
break;
case PR_MTE_TCF_SYNC:
tcf0 = SCTLR_EL1_TCF0_SYNC;
sctlr |= SCTLR_EL1_TCF0_SYNC;
break;
case PR_MTE_TCF_ASYNC:
tcf0 = SCTLR_EL1_TCF0_ASYNC;
sctlr |= SCTLR_EL1_TCF0_ASYNC;
break;
default:
return -EINVAL;
}
if (task != current) {
task->thread.sctlr_tcf0 = tcf0;
task->thread.sctlr_user = sctlr;
task->thread.gcr_user_excl = gcr_excl;
} else {
set_sctlr_el1_tcf0(tcf0);
set_task_sctlr_el1(sctlr);
set_gcr_el1_excl(gcr_excl);
}
@ -333,7 +304,7 @@ long get_mte_ctrl(struct task_struct *task)
ret = incl << PR_MTE_TAG_SHIFT;
switch (task->thread.sctlr_tcf0) {
switch (task->thread.sctlr_user & SCTLR_EL1_TCF0_MASK) {
case SCTLR_EL1_TCF0_NONE:
ret |= PR_MTE_TCF_NONE;
break;

63
arch/arm64/kernel/pointer_auth.c
View File

@ -43,6 +43,69 @@ int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg)
get_random_bytes(&keys->apdb, sizeof(keys->apdb));
if (arg & PR_PAC_APGAKEY)
get_random_bytes(&keys->apga, sizeof(keys->apga));
ptrauth_keys_install_user(keys);
return 0;
}
static u64 arg_to_enxx_mask(unsigned long arg)
{
u64 sctlr_enxx_mask = 0;
WARN_ON(arg & ~PR_PAC_ENABLED_KEYS_MASK);
if (arg & PR_PAC_APIAKEY)
sctlr_enxx_mask |= SCTLR_ELx_ENIA;
if (arg & PR_PAC_APIBKEY)
sctlr_enxx_mask |= SCTLR_ELx_ENIB;
if (arg & PR_PAC_APDAKEY)
sctlr_enxx_mask |= SCTLR_ELx_ENDA;
if (arg & PR_PAC_APDBKEY)
sctlr_enxx_mask |= SCTLR_ELx_ENDB;
return sctlr_enxx_mask;
}
int ptrauth_set_enabled_keys(struct task_struct *tsk, unsigned long keys,
unsigned long enabled)
{
u64 sctlr = tsk->thread.sctlr_user;
if (!system_supports_address_auth())
return -EINVAL;
if (is_compat_thread(task_thread_info(tsk)))
return -EINVAL;
if ((keys & ~PR_PAC_ENABLED_KEYS_MASK) || (enabled & ~keys))
return -EINVAL;
sctlr &= ~arg_to_enxx_mask(keys);
sctlr |= arg_to_enxx_mask(enabled);
if (tsk == current)
set_task_sctlr_el1(sctlr);
else
tsk->thread.sctlr_user = sctlr;
return 0;
}
int ptrauth_get_enabled_keys(struct task_struct *tsk)
{
int retval = 0;
if (!system_supports_address_auth())
return -EINVAL;
if (is_compat_thread(task_thread_info(tsk)))
return -EINVAL;
if (tsk->thread.sctlr_user & SCTLR_ELx_ENIA)
retval |= PR_PAC_APIAKEY;
if (tsk->thread.sctlr_user & SCTLR_ELx_ENIB)
retval |= PR_PAC_APIBKEY;
if (tsk->thread.sctlr_user & SCTLR_ELx_ENDA)
retval |= PR_PAC_APDAKEY;
if (tsk->thread.sctlr_user & SCTLR_ELx_ENDB)
retval |= PR_PAC_APDBKEY;
return retval;
}

33
arch/arm64/kernel/process.c
View File

@ -339,7 +339,6 @@ void flush_thread(void)
tls_thread_flush();
flush_ptrace_hw_breakpoint(current);
flush_tagged_addr_state();
flush_mte_state();
}
void release_thread(struct task_struct *dead_task)
@ -529,6 +528,31 @@ static void erratum_1418040_thread_switch(struct task_struct *prev,
write_sysreg(val, cntkctl_el1);
}
static void update_sctlr_el1(u64 sctlr)
{
/*
* EnIA must not be cleared while in the kernel as this is necessary for
* in-kernel PAC. It will be cleared on kernel exit if needed.
*/
sysreg_clear_set(sctlr_el1, SCTLR_USER_MASK & ~SCTLR_ELx_ENIA, sctlr);
/* ISB required for the kernel uaccess routines when setting TCF0. */
isb();
}
void set_task_sctlr_el1(u64 sctlr)
{
/*
* __switch_to() checks current->thread.sctlr as an
* optimisation. Disable preemption so that it does not see
* the variable update before the SCTLR_EL1 one.
*/
preempt_disable();
current->thread.sctlr_user = sctlr;
update_sctlr_el1(sctlr);
preempt_enable();
}
/*
* Thread switching.
*/
@ -544,6 +568,7 @@ __notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev,
entry_task_switch(next);
ssbs_thread_switch(next);
erratum_1418040_thread_switch(prev, next);
ptrauth_thread_switch_user(next);
/*
* Complete any pending TLB or cache maintenance on this CPU in case
@ -559,6 +584,9 @@ __notrace_funcgraph struct task_struct *__switch_to(struct task_struct *prev,
* registers.
*/
mte_thread_switch(next);
/* avoid expensive SCTLR_EL1 accesses if no change */
if (prev->thread.sctlr_user != next->thread.sctlr_user)
update_sctlr_el1(next->thread.sctlr_user);
/* the actual thread switch */
last = cpu_switch_to(prev, next);
@ -608,7 +636,8 @@ void arch_setup_new_exec(void)
{
current->mm->context.flags = is_compat_task() ? MMCF_AARCH32 : 0;
ptrauth_thread_init_user(current);
ptrauth_thread_init_user();
mte_thread_init_user();
if (task_spec_ssb_noexec(current)) {
arch_prctl_spec_ctrl_set(current, PR_SPEC_STORE_BYPASS,

41
arch/arm64/kernel/ptrace.c
View File

@ -909,6 +909,38 @@ static int pac_mask_get(struct task_struct *target,
return membuf_write(&to, &uregs, sizeof(uregs));
}
static int pac_enabled_keys_get(struct task_struct *target,
const struct user_regset *regset,
struct membuf to)
{
long enabled_keys = ptrauth_get_enabled_keys(target);
if (IS_ERR_VALUE(enabled_keys))
return enabled_keys;
return membuf_write(&to, &enabled_keys, sizeof(enabled_keys));
}
static int pac_enabled_keys_set(struct task_struct *target,
const struct user_regset *regset,
unsigned int pos, unsigned int count,
const void *kbuf, const void __user *ubuf)
{
int ret;
long enabled_keys = ptrauth_get_enabled_keys(target);
if (IS_ERR_VALUE(enabled_keys))
return enabled_keys;
ret = user_regset_copyin(&pos, &count, &kbuf, &ubuf, &enabled_keys, 0,
sizeof(long));
if (ret)
return ret;
return ptrauth_set_enabled_keys(target, PR_PAC_ENABLED_KEYS_MASK,
enabled_keys);
}
#ifdef CONFIG_CHECKPOINT_RESTORE
static __uint128_t pac_key_to_user(const struct ptrauth_key *key)
{
@ -1074,6 +1106,7 @@ enum aarch64_regset {
#endif
#ifdef CONFIG_ARM64_PTR_AUTH
REGSET_PAC_MASK,
REGSET_PAC_ENABLED_KEYS,
#ifdef CONFIG_CHECKPOINT_RESTORE
REGSET_PACA_KEYS,
REGSET_PACG_KEYS,
@ -1160,6 +1193,14 @@ static const struct user_regset aarch64_regsets[] = {
.regset_get = pac_mask_get,
/* this cannot be set dynamically */
},
[REGSET_PAC_ENABLED_KEYS] = {
.core_note_type = NT_ARM_PAC_ENABLED_KEYS,
.n = 1,
.size = sizeof(long),
.align = sizeof(long),
.regset_get = pac_enabled_keys_get,
.set = pac_enabled_keys_set,
},
#ifdef CONFIG_CHECKPOINT_RESTORE
[REGSET_PACA_KEYS] = {
.core_note_type = NT_ARM_PACA_KEYS,

3
arch/arm64/kernel/suspend.c
View File

@ -74,8 +74,9 @@ void notrace __cpu_suspend_exit(void)
*/
spectre_v4_enable_mitigation(NULL);
/* Restore additional MTE-specific configuration */
/* Restore additional feature-specific configuration */
mte_suspend_exit();
ptrauth_suspend_exit();
}
/*

1
include/uapi/linux/elf.h
View File

@ -426,6 +426,7 @@ typedef struct elf64_shdr {
#define NT_ARM_PACA_KEYS 0x407 /* ARM pointer authentication address keys */
#define NT_ARM_PACG_KEYS 0x408 /* ARM pointer authentication generic key */
#define NT_ARM_TAGGED_ADDR_CTRL 0x409 /* arm64 tagged address control (prctl()) */
#define NT_ARM_PAC_ENABLED_KEYS 0x40a /* arm64 ptr auth enabled keys (prctl()) */
#define NT_ARC_V2 0x600 /* ARCv2 accumulator/extra registers */
#define NT_VMCOREDD 0x700 /* Vmcore Device Dump Note */
#define NT_MIPS_DSP 0x800 /* MIPS DSP ASE registers */

4
include/uapi/linux/prctl.h
View File

@ -255,4 +255,8 @@ struct prctl_mm_map {
# define SYSCALL_DISPATCH_FILTER_ALLOW 0
# define SYSCALL_DISPATCH_FILTER_BLOCK 1
/* Set/get enabled arm64 pointer authentication keys */
#define PR_PAC_SET_ENABLED_KEYS 60
#define PR_PAC_GET_ENABLED_KEYS 61
#endif /* _LINUX_PRCTL_H */

16
kernel/sys.c
View File

@ -119,6 +119,12 @@
#ifndef PAC_RESET_KEYS
# define PAC_RESET_KEYS(a, b) (-EINVAL)
#endif
#ifndef PAC_SET_ENABLED_KEYS
# define PAC_SET_ENABLED_KEYS(a, b, c) (-EINVAL)
#endif
#ifndef PAC_GET_ENABLED_KEYS
# define PAC_GET_ENABLED_KEYS(a) (-EINVAL)
#endif
#ifndef SET_TAGGED_ADDR_CTRL
# define SET_TAGGED_ADDR_CTRL(a) (-EINVAL)
#endif
@ -2497,6 +2503,16 @@ SYSCALL_DEFINE5(prctl, int, option, unsigned long, arg2, unsigned long, arg3,
return -EINVAL;
error = PAC_RESET_KEYS(me, arg2);
break;
case PR_PAC_SET_ENABLED_KEYS:
if (arg4 || arg5)
return -EINVAL;
error = PAC_SET_ENABLED_KEYS(me, arg2, arg3);
break;
case PR_PAC_GET_ENABLED_KEYS:
if (arg2 || arg3 || arg4 || arg5)
return -EINVAL;
error = PAC_GET_ENABLED_KEYS(me);
break;
case PR_SET_TAGGED_ADDR_CTRL:
if (arg3 || arg4 || arg5)
return -EINVAL;