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-rw-r--r--arch/arm64/mm/fault.c31
1 files changed, 25 insertions, 6 deletions
diff --git a/arch/arm64/mm/fault.c b/arch/arm64/mm/fault.c
index 92ddac1e8ca2..820d47353cf0 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 +233,10 @@ 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 (!search_exception_tables(regs->pc))
+ panic("Accessing user space memory outside uaccess.h routines");
+ }
/*
* As per x86, we may deadlock here. However, since the kernel only
@@ -561,3 +567,16 @@ 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 */