diff options
| author | Anton Arapov <anton@redhat.com> | 2013-04-03 18:00:33 +0200 |
|---|---|---|
| committer | Oleg Nesterov <oleg@redhat.com> | 2013-04-13 15:31:55 +0200 |
| commit | 791eca10107f2886c1915d91c99a3b022a75909c (patch) | |
| tree | eb36692870d6e8e293ca27695b6980dbb6a11394 /arch | |
| parent | e78aebfd27256ca59ccd3e6cf62cfad2a80e02d3 (diff) | |
uretprobes/x86: Hijack return address
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>
Diffstat (limited to 'arch')
| -rw-r--r-- | arch/x86/include/asm/uprobes.h | 1 | ||||
| -rw-r--r-- | arch/x86/kernel/uprobes.c | 29 |
2 files changed, 30 insertions, 0 deletions
diff --git a/arch/x86/include/asm/uprobes.h b/arch/x86/include/asm/uprobes.h index 8ff8be7835ab..6e5197910fd8 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 0ba4cfb4f412..2ed845928b5f 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; +} |