Commit-ID: 791eca10107f2886c1915d91c99a3b022a75909c Gitweb: http://git.kernel.org/tip/791eca10107f2886c1915d91c99a3b022a75909c Author: Anton Arapov <anton@xxxxxxxxxx> AuthorDate: Wed, 3 Apr 2013 18:00:33 +0200 Committer: Oleg Nesterov <oleg@xxxxxxxxxx> CommitDate: Sat, 13 Apr 2013 15:31:55 +0200 uretprobes/x86: Hijack return address Hijack the return address and replace it with a trampoline address. Signed-off-by: Anton Arapov <anton@xxxxxxxxxx> Acked-by: Srikar Dronamraju <srikar@xxxxxxxxxxxxxxxxxx> Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx> --- arch/x86/include/asm/uprobes.h | 1 + arch/x86/kernel/uprobes.c | 29 +++++++++++++++++++++++++++++ 2 files changed, 30 insertions(+) diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h index 8ff8be7..6e51979 100644 --- a/arch/x86/include/asm/uprobes.h +++ b/arch/x86/include/asm/uprobes.h @@ -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 */ diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c index 0ba4cfb..2ed8459 100644 --- a/arch/x86/kernel/uprobes.c +++ b/arch/x86/kernel/uprobes.c @@ -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; +} -- To unsubscribe from this list: send the line "unsubscribe linux-tip-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html