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arm64: ptr auth: Move per-thread keys from thread_info to thread_struct 

We don't need to get at the per-thread keys from assembly at all, so
they can live alongside the rest of the per-thread register state in
thread_struct instead of thread_info.

This will also allow straighforward whitelisting of the keys for
hardened usercopy should we expose them via a ptrace request later on.

Signed-off-by: Will Deacon <will.deacon@arm.com>
hifive-unleashed-5.1
Will Deacon 2018-12-13 13:14:06 +00:00
parent 04ca3204fa
commit 84931327a8
4 changed files with 7 additions and 8 deletions
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6
arch/arm64/include/asm/pointer_auth.h
View File

@ -80,12 +80,12 @@ static inline unsigned long ptrauth_strip_insn_pac(unsigned long ptr)
#define ptrauth_thread_init_user(tsk) \ #define ptrauth_thread_init_user(tsk) \
do { \ do { \
struct task_struct *__ptiu_tsk = (tsk); \ struct task_struct *__ptiu_tsk = (tsk); \
ptrauth_keys_init(&__ptiu_tsk->thread_info.keys_user); \ ptrauth_keys_init(&__ptiu_tsk->thread.keys_user); \
ptrauth_keys_switch(&__ptiu_tsk->thread_info.keys_user); \ ptrauth_keys_switch(&__ptiu_tsk->thread.keys_user); \
} while (0) } while (0)
#define ptrauth_thread_switch(tsk) \ #define ptrauth_thread_switch(tsk) \
ptrauth_keys_switch(&(tsk)->thread_info.keys_user) ptrauth_keys_switch(&(tsk)->thread.keys_user)
#else /* CONFIG_ARM64_PTR_AUTH */ #else /* CONFIG_ARM64_PTR_AUTH */
#define ptrauth_prctl_reset_keys(tsk, arg) (-EINVAL) #define ptrauth_prctl_reset_keys(tsk, arg) (-EINVAL)

3
arch/arm64/include/asm/processor.h
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@ -147,6 +147,9 @@ struct thread_struct {
unsigned long fault_address; /* fault info */ unsigned long fault_address; /* fault info */
unsigned long fault_code; /* ESR_EL1 value */ unsigned long fault_code; /* ESR_EL1 value */
struct debug_info debug; /* debugging */ struct debug_info debug; /* debugging */
#ifdef CONFIG_ARM64_PTR_AUTH
struct ptrauth_keys keys_user;
#endif
}; };
static inline void arch_thread_struct_whitelist(unsigned long *offset, static inline void arch_thread_struct_whitelist(unsigned long *offset,

4
arch/arm64/include/asm/thread_info.h
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@ -28,7 +28,6 @@
struct task_struct; struct task_struct;
#include <asm/memory.h> #include <asm/memory.h>
#include <asm/pointer_auth.h>
#include <asm/stack_pointer.h> #include <asm/stack_pointer.h>
#include <asm/types.h> #include <asm/types.h>
@ -55,9 +54,6 @@ struct thread_info {
#endif #endif
} preempt; } preempt;
}; };
#ifdef CONFIG_ARM64_PTR_AUTH
struct ptrauth_keys keys_user;
#endif
}; };
#define thread_saved_pc(tsk) \ #define thread_saved_pc(tsk) \

2
arch/arm64/kernel/pointer_auth.c
View File

@ -9,7 +9,7 @@
int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg) int ptrauth_prctl_reset_keys(struct task_struct *tsk, unsigned long arg)
{ {
struct ptrauth_keys *keys = &tsk->thread_info.keys_user; struct ptrauth_keys *keys = &tsk->thread.keys_user;
unsigned long addr_key_mask = PR_PAC_APIAKEY | PR_PAC_APIBKEY | unsigned long addr_key_mask = PR_PAC_APIAKEY | PR_PAC_APIBKEY |
PR_PAC_APDAKEY | PR_PAC_APDBKEY; PR_PAC_APDAKEY | PR_PAC_APDBKEY;
unsigned long key_mask = addr_key_mask | PR_PAC_APGAKEY; unsigned long key_mask = addr_key_mask | PR_PAC_APGAKEY;