[PATCH v1 1/2] Missing instruction_pointer_set() instances

Jin Yao
2020-07-31T02:57:43Z

There is a potential security issue that perf kernel samples
may be leaked even though kernel sampling is disabled. For fixing
the potential leakage, the idea is to use instruction_pointer_set
to set invalid ip address in leaked perf samples in some cases.

But instruction_pointer_set is missing on some architectures.
Define instruction_pointer_set for these architectures.

Signed-off-by: Jin Yao <yao.jin@linux.intel.com>
---
arch/alpha/include/asm/ptrace.h | 6 ++++++
arch/arc/include/asm/ptrace.h | 6 ++++++
arch/nds32/include/asm/ptrace.h | 7 +++++++
arch/xtensa/include/asm/ptrace.h | 6 ++++++
4 files changed, 25 insertions(+)

diff --git a/arch/alpha/include/asm/ptrace.h b/arch/alpha/include/asm/ptrace.h
index df5f317ab3fc..c464d525c110 100644
--- a/arch/alpha/include/asm/ptrace.h
+++ b/arch/alpha/include/asm/ptrace.h
@@ -25,4 +25,10 @@ static inline unsigned long regs_return_value(struct pt_regs *regs)
return regs->r0;
}

+static inline void instruction_pointer_set(struct pt_regs *regs,
+ unsigned long val)
+{
+ regs->pc = val;
+}
+
#endif
diff --git a/arch/arc/include/asm/ptrace.h b/arch/arc/include/asm/ptrace.h
index 2fdb87addadc..8869a6c0fe8c 100644
--- a/arch/arc/include/asm/ptrace.h
+++ b/arch/arc/include/asm/ptrace.h
@@ -154,6 +154,12 @@ static inline long regs_return_value(struct pt_regs *regs)
return (long)regs->r0;
}

+static inline void instruction_pointer_set(struct pt_regs *regs,
+ unsigned long val)
+{
+ regs->ret = val;
+}
+
#endif /* !__ASSEMBLY__ */

#endif /* __ASM_PTRACE_H */
diff --git a/arch/nds32/include/asm/ptrace.h b/arch/nds32/include/asm/ptrace.h
index 919ee223620c..19a916bef7f5 100644
--- a/arch/nds32/include/asm/ptrace.h
+++ b/arch/nds32/include/asm/ptrace.h
@@ -62,6 +62,13 @@ static inline unsigned long regs_return_value(struct pt_regs *regs)
{
return regs->uregs[0];
}
+
+static inline void instruction_pointer_set(struct pt_regs *regs,
+ unsigned long val)
+{
+ regs->ipc = val;
+}
+
extern void show_regs(struct pt_regs *);
/* Avoid circular header include via sched.h */
struct task_struct;
diff --git a/arch/xtensa/include/asm/ptrace.h b/arch/xtensa/include/asm/ptrace.h
index b109416dc07e..82ab1ba99259 100644
--- a/arch/xtensa/include/asm/ptrace.h
+++ b/arch/xtensa/include/asm/ptrace.h
@@ -90,6 +90,12 @@ struct pt_regs {
# define return_pointer(regs) (MAKE_PC_FROM_RA((regs)->areg[0], \
(regs)->areg[1]))

+static inline void instruction_pointer_set(struct pt_regs *regs,
+ unsigned long val)
+{
+ regs->pc = val;
+}
+
# ifndef CONFIG_SMP
# define profile_pc(regs) instruction_pointer(regs)
# else
--
2.17.1