diff options
Diffstat (limited to 'arch/x86_64/kernel/ptrace.c')
| -rw-r--r-- | arch/x86_64/kernel/ptrace.c | 547 |
1 files changed, 547 insertions, 0 deletions
diff --git a/arch/x86_64/kernel/ptrace.c b/arch/x86_64/kernel/ptrace.c new file mode 100644 index 000000000000..0b7b101debdf --- /dev/null +++ b/arch/x86_64/kernel/ptrace.c @@ -0,0 +1,547 @@ +/* ptrace.c */ +/* By Ross Biro 1/23/92 */ +/* + * Pentium III FXSR, SSE support + * Gareth Hughes <gareth@valinux.com>, May 2000 + * + * x86-64 port 2000-2002 Andi Kleen + */ + +#include <linux/kernel.h> +#include <linux/sched.h> +#include <linux/mm.h> +#include <linux/smp.h> +#include <linux/smp_lock.h> +#include <linux/errno.h> +#include <linux/ptrace.h> +#include <linux/user.h> +#include <linux/security.h> +#include <linux/audit.h> +#include <linux/seccomp.h> + +#include <asm/uaccess.h> +#include <asm/pgtable.h> +#include <asm/system.h> +#include <asm/processor.h> +#include <asm/i387.h> +#include <asm/debugreg.h> +#include <asm/ldt.h> +#include <asm/desc.h> +#include <asm/proto.h> +#include <asm/ia32.h> + +/* + * does not yet catch signals sent when the child dies. + * in exit.c or in signal.c. + */ + +/* determines which flags the user has access to. */ +/* 1 = access 0 = no access */ +#define FLAG_MASK 0x44dd5UL + +/* set's the trap flag. */ +#define TRAP_FLAG 0x100UL + +/* + * eflags and offset of eflags on child stack.. + */ +#define EFLAGS offsetof(struct pt_regs, eflags) +#define EFL_OFFSET ((int)(EFLAGS-sizeof(struct pt_regs))) + +/* + * this routine will get a word off of the processes privileged stack. + * the offset is how far from the base addr as stored in the TSS. + * this routine assumes that all the privileged stacks are in our + * data space. + */ +static inline unsigned long get_stack_long(struct task_struct *task, int offset) +{ + unsigned char *stack; + + stack = (unsigned char *)task->thread.rsp0; + stack += offset; + return (*((unsigned long *)stack)); +} + +/* + * this routine will put a word on the processes privileged stack. + * the offset is how far from the base addr as stored in the TSS. + * this routine assumes that all the privileged stacks are in our + * data space. + */ +static inline long put_stack_long(struct task_struct *task, int offset, + unsigned long data) +{ + unsigned char * stack; + + stack = (unsigned char *) task->thread.rsp0; + stack += offset; + *(unsigned long *) stack = data; + return 0; +} + +/* + * Called by kernel/ptrace.c when detaching.. + * + * Make sure the single step bit is not set. + */ +void ptrace_disable(struct task_struct *child) +{ + long tmp; + + clear_tsk_thread_flag(child, TIF_SINGLESTEP); + tmp = get_stack_long(child, EFL_OFFSET) & ~TRAP_FLAG; + put_stack_long(child, EFL_OFFSET, tmp); +} + +static int putreg(struct task_struct *child, + unsigned long regno, unsigned long value) +{ + unsigned long tmp; + + /* Some code in the 64bit emulation may not be 64bit clean. + Don't take any chances. */ + if (test_tsk_thread_flag(child, TIF_IA32)) + value &= 0xffffffff; + switch (regno) { + case offsetof(struct user_regs_struct,fs): + if (value && (value & 3) != 3) + return -EIO; + child->thread.fsindex = value & 0xffff; + return 0; + case offsetof(struct user_regs_struct,gs): + if (value && (value & 3) != 3) + return -EIO; + child->thread.gsindex = value & 0xffff; + return 0; + case offsetof(struct user_regs_struct,ds): + if (value && (value & 3) != 3) + return -EIO; + child->thread.ds = value & 0xffff; + return 0; + case offsetof(struct user_regs_struct,es): + if (value && (value & 3) != 3) + return -EIO; + child->thread.es = value & 0xffff; + return 0; + case offsetof(struct user_regs_struct,ss): + if ((value & 3) != 3) + return -EIO; + value &= 0xffff; + return 0; + case offsetof(struct user_regs_struct,fs_base): + if (!((value >> 48) == 0 || (value >> 48) == 0xffff)) + return -EIO; + child->thread.fs = value; + return 0; + case offsetof(struct user_regs_struct,gs_base): + if (!((value >> 48) == 0 || (value >> 48) == 0xffff)) + return -EIO; + child->thread.gs = value; + return 0; + case offsetof(struct user_regs_struct, eflags): + value &= FLAG_MASK; + tmp = get_stack_long(child, EFL_OFFSET); + tmp &= ~FLAG_MASK; + value |= tmp; + break; + case offsetof(struct user_regs_struct,cs): + if ((value & 3) != 3) + return -EIO; + value &= 0xffff; + break; + } + put_stack_long(child, regno - sizeof(struct pt_regs), value); + return 0; +} + +static unsigned long getreg(struct task_struct *child, unsigned long regno) +{ + unsigned long val; + switch (regno) { + case offsetof(struct user_regs_struct, fs): + return child->thread.fsindex; + case offsetof(struct user_regs_struct, gs): + return child->thread.gsindex; + case offsetof(struct user_regs_struct, ds): + return child->thread.ds; + case offsetof(struct user_regs_struct, es): + return child->thread.es; + case offsetof(struct user_regs_struct, fs_base): + return child->thread.fs; + case offsetof(struct user_regs_struct, gs_base): + return child->thread.gs; + default: + regno = regno - sizeof(struct pt_regs); + val = get_stack_long(child, regno); + if (test_tsk_thread_flag(child, TIF_IA32)) + val &= 0xffffffff; + return val; + } + +} + +asmlinkage long sys_ptrace(long request, long pid, unsigned long addr, long data) +{ + struct task_struct *child; + long i, ret; + unsigned ui; + + /* This lock_kernel fixes a subtle race with suid exec */ + lock_kernel(); + ret = -EPERM; + if (request == PTRACE_TRACEME) { + /* are we already being traced? */ + if (current->ptrace & PT_PTRACED) + goto out; + ret = security_ptrace(current->parent, current); + if (ret) + goto out; + /* set the ptrace bit in the process flags. */ + current->ptrace |= PT_PTRACED; + ret = 0; + goto out; + } + ret = -ESRCH; + read_lock(&tasklist_lock); + child = find_task_by_pid(pid); + if (child) + get_task_struct(child); + read_unlock(&tasklist_lock); + if (!child) + goto out; + + ret = -EPERM; + if (pid == 1) /* you may not mess with init */ + goto out_tsk; + + if (request == PTRACE_ATTACH) { + ret = ptrace_attach(child); + goto out_tsk; + } + ret = ptrace_check_attach(child, request == PTRACE_KILL); + if (ret < 0) + goto out_tsk; + + switch (request) { + /* when I and D space are separate, these will need to be fixed. */ + case PTRACE_PEEKTEXT: /* read word at location addr. */ + case PTRACE_PEEKDATA: { + unsigned long tmp; + int copied; + + copied = access_process_vm(child, addr, &tmp, sizeof(tmp), 0); + ret = -EIO; + if (copied != sizeof(tmp)) + break; + ret = put_user(tmp,(unsigned long __user *) data); + break; + } + + /* read the word at location addr in the USER area. */ + case PTRACE_PEEKUSR: { + unsigned long tmp; + + ret = -EIO; + if ((addr & 7) || + addr > sizeof(struct user) - 7) + break; + + switch (addr) { + case 0 ... sizeof(struct user_regs_struct): + tmp = getreg(child, addr); + break; + case offsetof(struct user, u_debugreg[0]): + tmp = child->thread.debugreg0; + break; + case offsetof(struct user, u_debugreg[1]): + tmp = child->thread.debugreg1; + break; + case offsetof(struct user, u_debugreg[2]): + tmp = child->thread.debugreg2; + break; + case offsetof(struct user, u_debugreg[3]): + tmp = child->thread.debugreg3; + break; + case offsetof(struct user, u_debugreg[6]): + tmp = child->thread.debugreg6; + break; + case offsetof(struct user, u_debugreg[7]): + tmp = child->thread.debugreg7; + break; + default: + tmp = 0; + break; + } + ret = put_user(tmp,(unsigned long __user *) data); + break; + } + + /* when I and D space are separate, this will have to be fixed. */ + case PTRACE_POKETEXT: /* write the word at location addr. */ + case PTRACE_POKEDATA: + ret = 0; + if (access_process_vm(child, addr, &data, sizeof(data), 1) == sizeof(data)) + break; + ret = -EIO; + break; + + case PTRACE_POKEUSR: /* write the word at location addr in the USER area */ + ret = -EIO; + if ((addr & 7) || + addr > sizeof(struct user) - 7) + break; + + switch (addr) { + case 0 ... sizeof(struct user_regs_struct): + ret = putreg(child, addr, data); + break; + /* Disallows to set a breakpoint into the vsyscall */ + case offsetof(struct user, u_debugreg[0]): + if (data >= TASK_SIZE-7) break; + child->thread.debugreg0 = data; + ret = 0; + break; + case offsetof(struct user, u_debugreg[1]): + if (data >= TASK_SIZE-7) break; + child->thread.debugreg1 = data; + ret = 0; + break; + case offsetof(struct user, u_debugreg[2]): + if (data >= TASK_SIZE-7) break; + child->thread.debugreg2 = data; + ret = 0; + break; + case offsetof(struct user, u_debugreg[3]): + if (data >= TASK_SIZE-7) break; + child->thread.debugreg3 = data; + ret = 0; + break; + case offsetof(struct user, u_debugreg[6]): + if (data >> 32) + break; + child->thread.debugreg6 = data; + ret = 0; + break; + case offsetof(struct user, u_debugreg[7]): + /* See arch/i386/kernel/ptrace.c for an explanation of + * this awkward check.*/ + data &= ~DR_CONTROL_RESERVED; + for(i=0; i<4; i++) + if ((0x5454 >> ((data >> (16 + 4*i)) & 0xf)) & 1) + break; + if (i == 4) { + child->thread.debugreg7 = data; + ret = 0; + } + break; + } + break; + case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */ + case PTRACE_CONT: { /* restart after signal. */ + long tmp; + + ret = -EIO; + if ((unsigned long) data > _NSIG) + break; + if (request == PTRACE_SYSCALL) + set_tsk_thread_flag(child,TIF_SYSCALL_TRACE); + else + clear_tsk_thread_flag(child,TIF_SYSCALL_TRACE); + clear_tsk_thread_flag(child, TIF_SINGLESTEP); + child->exit_code = data; + /* make sure the single step bit is not set. */ + tmp = get_stack_long(child, EFL_OFFSET); + tmp &= ~TRAP_FLAG; + put_stack_long(child, EFL_OFFSET,tmp); + wake_up_process(child); + ret = 0; + break; + } + +#ifdef CONFIG_IA32_EMULATION + /* This makes only sense with 32bit programs. Allow a + 64bit debugger to fully examine them too. Better + don't use it against 64bit processes, use + PTRACE_ARCH_PRCTL instead. */ + case PTRACE_SET_THREAD_AREA: { + struct user_desc __user *p; + int old; + p = (struct user_desc __user *)data; + get_user(old, &p->entry_number); + put_user(addr, &p->entry_number); + ret = do_set_thread_area(&child->thread, p); + put_user(old, &p->entry_number); + break; + case PTRACE_GET_THREAD_AREA: + p = (struct user_desc __user *)data; + get_user(old, &p->entry_number); + put_user(addr, &p->entry_number); + ret = do_get_thread_area(&child->thread, p); + put_user(old, &p->entry_number); + break; + } +#endif + /* normal 64bit interface to access TLS data. + Works just like arch_prctl, except that the arguments + are reversed. */ + case PTRACE_ARCH_PRCTL: + ret = do_arch_prctl(child, data, addr); + break; + +/* + * make the child exit. Best I can do is send it a sigkill. + * perhaps it should be put in the status that it wants to + * exit. + */ + case PTRACE_KILL: { + long tmp; + + ret = 0; + if (child->exit_state == EXIT_ZOMBIE) /* already dead */ + break; + clear_tsk_thread_flag(child, TIF_SINGLESTEP); + child->exit_code = SIGKILL; + /* make sure the single step bit is not set. */ + tmp = get_stack_long(child, EFL_OFFSET) & ~TRAP_FLAG; + put_stack_long(child, EFL_OFFSET, tmp); + wake_up_process(child); + break; + } + + case PTRACE_SINGLESTEP: { /* set the trap flag. */ + long tmp; + + ret = -EIO; + if ((unsigned long) data > _NSIG) + break; + clear_tsk_thread_flag(child,TIF_SYSCALL_TRACE); + if ((child->ptrace & PT_DTRACE) == 0) { + /* Spurious delayed TF traps may occur */ + child->ptrace |= PT_DTRACE; + } + tmp = get_stack_long(child, EFL_OFFSET) | TRAP_FLAG; + put_stack_long(child, EFL_OFFSET, tmp); + set_tsk_thread_flag(child, TIF_SINGLESTEP); + child->exit_code = data; + /* give it a chance to run. */ + wake_up_process(child); + ret = 0; + break; + } + + case PTRACE_DETACH: + /* detach a process that was attached. */ + ret = ptrace_detach(child, data); + break; + + case PTRACE_GETREGS: { /* Get all gp regs from the child. */ + if (!access_ok(VERIFY_WRITE, (unsigned __user *)data, + sizeof(struct user_regs_struct))) { + ret = -EIO; + break; + } + ret = 0; + for (ui = 0; ui < sizeof(struct user_regs_struct); ui += sizeof(long)) { + ret |= __put_user(getreg(child, ui),(unsigned long __user *) data); + data += sizeof(long); + } + break; + } + + case PTRACE_SETREGS: { /* Set all gp regs in the child. */ + unsigned long tmp; + if (!access_ok(VERIFY_READ, (unsigned __user *)data, + sizeof(struct user_regs_struct))) { + ret = -EIO; + break; + } + ret = 0; + for (ui = 0; ui < sizeof(struct user_regs_struct); ui += sizeof(long)) { + ret |= __get_user(tmp, (unsigned long __user *) data); + putreg(child, ui, tmp); + data += sizeof(long); + } + break; + } + + case PTRACE_GETFPREGS: { /* Get the child extended FPU state. */ + if (!access_ok(VERIFY_WRITE, (unsigned __user *)data, + sizeof(struct user_i387_struct))) { + ret = -EIO; + break; + } + ret = get_fpregs((struct user_i387_struct __user *)data, child); + break; + } + + case PTRACE_SETFPREGS: { /* Set the child extended FPU state. */ + if (!access_ok(VERIFY_READ, (unsigned __user *)data, + sizeof(struct user_i387_struct))) { + ret = -EIO; + break; + } + set_stopped_child_used_math(child); + ret = set_fpregs(child, (struct user_i387_struct __user *)data); + break; + } + + default: + ret = ptrace_request(child, request, addr, data); + break; + } +out_tsk: + put_task_struct(child); +out: + unlock_kernel(); + return ret; +} + +static void syscall_trace(struct pt_regs *regs) +{ + +#if 0 + printk("trace %s rip %lx rsp %lx rax %d origrax %d caller %lx tiflags %x ptrace %x\n", + current->comm, + regs->rip, regs->rsp, regs->rax, regs->orig_rax, __builtin_return_address(0), + current_thread_info()->flags, current->ptrace); +#endif + + ptrace_notify(SIGTRAP | ((current->ptrace & PT_TRACESYSGOOD) + ? 0x80 : 0)); + /* + * this isn't the same as continuing with a signal, but it will do + * for normal use. strace only continues with a signal if the + * stopping signal is not SIGTRAP. -brl + */ + if (current->exit_code) { + send_sig(current->exit_code, current, 1); + current->exit_code = 0; + } +} + +asmlinkage void syscall_trace_enter(struct pt_regs *regs) +{ + /* do the secure computing check first */ + secure_computing(regs->orig_rax); + + if (unlikely(current->audit_context)) + audit_syscall_entry(current, regs->orig_rax, + regs->rdi, regs->rsi, + regs->rdx, regs->r10); + + if (test_thread_flag(TIF_SYSCALL_TRACE) + && (current->ptrace & PT_PTRACED)) + syscall_trace(regs); +} + +asmlinkage void syscall_trace_leave(struct pt_regs *regs) +{ + if (unlikely(current->audit_context)) + audit_syscall_exit(current, regs->rax); + + if ((test_thread_flag(TIF_SYSCALL_TRACE) + || test_thread_flag(TIF_SINGLESTEP)) + && (current->ptrace & PT_PTRACED)) + syscall_trace(regs); +} |