diff options
Diffstat (limited to 'arch/arm64/mm/fault.c')
| -rw-r--r-- | arch/arm64/mm/fault.c | 34 |
1 files changed, 28 insertions, 6 deletions
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c index abe2a9542b3a..0077674b2b38 100644 --- a/arch/arm64/mm/fault.c +++ b/arch/arm64/mm/fault.c @@ -192,6 +192,14 @@ out: return fault; } +static inline int permission_fault(unsigned int esr) +{ + unsigned int ec = (esr & ESR_ELx_EC_MASK) >> ESR_ELx_EC_SHIFT; + unsigned int fsc_type = esr & ESR_ELx_FSC_TYPE; + + return (ec == ESR_ELx_EC_DABT_CUR && fsc_type == ESR_ELx_FSC_PERM); +} + static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, struct pt_regs *regs) { @@ -225,12 +233,13 @@ static int __kprobes do_page_fault(unsigned long addr, unsigned int esr, mm_flags |= FAULT_FLAG_WRITE; } - /* - * PAN bit set implies the fault happened in kernel space, but not - * in the arch's user access functions. - */ - if (IS_ENABLED(CONFIG_ARM64_PAN) && (regs->pstate & PSR_PAN_BIT)) - goto no_context; + if (permission_fault(esr) && (addr < USER_DS)) { + if (get_fs() == KERNEL_DS) + die("Accessing user space memory with fs=KERNEL_DS", regs, esr); + + if (!search_exception_tables(regs->pc)) + die("Accessing user space memory outside uaccess.h routines", regs, esr); + } /* * As per x86, we may deadlock here. However, since the kernel only @@ -568,3 +577,16 @@ void cpu_enable_pan(void *__unused) config_sctlr_el1(SCTLR_EL1_SPAN, 0); } #endif /* CONFIG_ARM64_PAN */ + +#ifdef CONFIG_ARM64_UAO +/* + * Kernel threads have fs=KERNEL_DS by default, and don't need to call + * set_fs(), devtmpfs in particular relies on this behaviour. + * We need to enable the feature at runtime (instead of adding it to + * PSR_MODE_EL1h) as the feature may not be implemented by the cpu. + */ +void cpu_enable_uao(void *__unused) +{ + asm(SET_PSTATE_UAO(1)); +} +#endif /* CONFIG_ARM64_UAO */ |