diff options
authorMarc Zyngier <marc.zyngier@arm.com>2016-09-29 18:18:23 -0400
committerAlex Shi <alex.shi@linaro.org>2016-10-20 15:38:13 +0800
commit71b5200f5f0c1e9966dd7d238526e85f4fbf8089 (patch)
parenta1961c0da3b0e3fa8bd803547f96963bf31b69a4 (diff)
arm64: kprobes: Fix overflow when saving stack
commit ab4c1325d4bf111a590a1f773e3d93bde7f40201 upstream. The MIN_STACK_SIZE macro tries evaluate how much stack space needs to be saved in the jprobes_stack array, sized at 128 bytes. When using the IRQ stack, said macro can happily return up to IRQ_STACK_SIZE, which is 16kB. Mayhem follows. This patch fixes things by getting rid of the crazy macro and limiting the copy to be at most the size of the jprobes_stack array, no matter which stack we're on. [dave.long@linaro.org: Since there is no irq_stack in this kernel version this fix is not strictly necessary, but is included for completeness.] Signed-off-by: Marc Zyngier <marc.zyngier@arm.com> Signed-off-by: Catalin Marinas <catalin.marinas@arm.com> Signed-off-by: David A. Long <dave.long@linaro.org>
1 files changed, 11 insertions, 5 deletions
diff --git a/arch/arm64/kernel/probes/kprobes.c b/arch/arm64/kernel/probes/kprobes.c
index a9b274c99519..b1189741dbb0 100644
--- a/arch/arm64/kernel/probes/kprobes.c
+++ b/arch/arm64/kernel/probes/kprobes.c
@@ -34,9 +34,6 @@
#include "decode-insn.h"
-#define MIN_STACK_SIZE(addr) min((unsigned long)MAX_STACK_SIZE, \
- (unsigned long)current_thread_info() + THREAD_START_SP - (addr))
void jprobe_return_break(void);
DEFINE_PER_CPU(struct kprobe *, current_kprobe) = NULL;
@@ -45,6 +42,15 @@ DEFINE_PER_CPU(struct kprobe_ctlblk, kprobe_ctlblk);
static void __kprobes
post_kprobe_handler(struct kprobe_ctlblk *, struct pt_regs *);
+static inline unsigned long min_stack_size(unsigned long addr)
+ unsigned long size;
+ size = (unsigned long)current_thread_info() + THREAD_START_SP - addr;
+ return min(size, FIELD_SIZEOF(struct kprobe_ctlblk, jprobes_stack));
static void __kprobes arch_prepare_ss_slot(struct kprobe *p)
/* prepare insn slot */
@@ -492,7 +498,7 @@ int __kprobes setjmp_pre_handler(struct kprobe *p, struct pt_regs *regs)
* the argument area.
memcpy(kcb->jprobes_stack, (void *)stack_ptr,
- MIN_STACK_SIZE(stack_ptr));
+ min_stack_size(stack_ptr));
instruction_pointer_set(regs, (unsigned long) jp->entry);
@@ -545,7 +551,7 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs)
*regs = kcb->jprobe_saved_regs;
memcpy((void *)stack_addr, kcb->jprobes_stack,
- MIN_STACK_SIZE(stack_addr));
+ min_stack_size(stack_addr));
return 1;