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uretprobes/x86: Hijack return address

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Hijack the return address and replace it with a trampoline address.

Signed-off-by: Anton Arapov <anton@redhat.com>
Acked-by: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
This commit is contained in:
Anton Arapov 2013-04-03 18:00:33 +02:00 committed by Oleg Nesterov
parent e78aebfd27
commit 791eca1010
2 changed files with 30 additions and 0 deletions
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1
arch/x86/include/asm/uprobes.h
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@ -55,4 +55,5 @@ extern int arch_uprobe_post_xol(struct arch_uprobe *aup, struct pt_regs *regs);
extern bool arch_uprobe_xol_was_trapped(struct task_struct *tsk);
extern int arch_uprobe_exception_notify(struct notifier_block *self, unsigned long val, void *data);
extern void arch_uprobe_abort_xol(struct arch_uprobe *aup, struct pt_regs *regs);
extern unsigned long arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr, struct pt_regs *regs);
#endif /* _ASM_UPROBES_H */

29
arch/x86/kernel/uprobes.c
View File

@ -697,3 +697,32 @@ bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
send_sig(SIGTRAP, current, 0);
return ret;
}
unsigned long
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;
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 (likely(!ncopied))
return orig_ret_vaddr;
if (ncopied != rasize) {
pr_err("uprobe: return address clobbered: pid=%d, %%sp=%#lx, "
"%%ip=%#lx\n", current->pid, regs->sp, regs->ip);
force_sig_info(SIGSEGV, SEND_SIG_FORCED, current);
}
return -1;
}