diff options
| author | Marc Zyngier <marc.zyngier@arm.com> | 2016-09-29 18:18:23 -0400 |
|---|---|---|
| committer | Alex Shi <alex.shi@linaro.org> | 2016-10-20 15:38:13 +0800 |
| commit | 71b5200f5f0c1e9966dd7d238526e85f4fbf8089 (patch) | |
| tree | 646ad74f9223604b1fb76820dfd8cc86e83d48cd | |
| parent | a1961c0da3b0e3fa8bd803547f96963bf31b69a4 (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>
| -rw-r--r-- | arch/arm64/kernel/probes/kprobes.c | 16 |
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); preempt_disable(); @@ -545,7 +551,7 @@ int __kprobes longjmp_break_handler(struct kprobe *p, struct pt_regs *regs) unpause_graph_tracing(); *regs = kcb->jprobe_saved_regs; memcpy((void *)stack_addr, kcb->jprobes_stack, - MIN_STACK_SIZE(stack_addr)); + min_stack_size(stack_addr)); preempt_enable_no_resched(); return 1; } |