Messages in this thread | | | Date | Sun, 24 Mar 2013 15:59:42 +0100 | From | Oleg Nesterov <> | Subject | Re: [PATCH 3/7] uretprobes/x86: hijack return address |
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On 03/22, Anton Arapov wrote: > > +arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr, struct pt_regs *regs) > +{ > + int rasize, ncopied; > + unsigned long orig_ret_vaddr = 0; /* clear high bits for 32-bit apps */ > + > + rasize = is_ia32_task() ? 4 : 8;
Hmm.. I guess you need is_compat_task() here.
> + ncopied = copy_from_user(&orig_ret_vaddr, (void __user *)regs->sp, rasize); > + if (unlikely(ncopied)) > + return -1; > + > + /* check whether address has been already hijacked */ > + if (orig_ret_vaddr == trampoline_vaddr) > + return orig_ret_vaddr; > + > + ncopied = copy_to_user((void __user *)regs->sp, &trampoline_vaddr, rasize); > + if (unlikely(ncopied)) { > + if (ncopied != rasize) { > + printk(KERN_ERR "uprobe: return address clobbered: "
Cosmetic, but we have pr_err().
> + "pid=%d, %%sp=%#lx, %%ip=%#lx\n", > + current->pid, regs->sp, regs->ip); > + /* kill task immediately */ > + send_sig(SIGSEGV, current, 0);
probably force_sig_info() makes more sense, but this is minor
> + }
You need to retun -1 here.
Cosmetic again, but since this function should be updated anyway, I'd suggest
ncopied = copy_to_user(...);
if (likely(!ncopied)) return orig_ret_vaddr;
if (ncopied != rasize) { ... }
return -1;
Oleg.
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