diff options
Diffstat (limited to 'arch/x86/kernel/ptrace_64.c')
-rw-r--r-- | arch/x86/kernel/ptrace_64.c | 626 |
1 files changed, 626 insertions, 0 deletions
diff --git a/arch/x86/kernel/ptrace_64.c b/arch/x86/kernel/ptrace_64.c new file mode 100644 index 000000000000..c0cac42df3b6 --- /dev/null +++ b/arch/x86/kernel/ptrace_64.c @@ -0,0 +1,626 @@ +/* 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/errno.h> +#include <linux/ptrace.h> +#include <linux/user.h> +#include <linux/security.h> +#include <linux/audit.h> +#include <linux/seccomp.h> +#include <linux/signal.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]. + * Prohibits changing ID(21), VIP(20), VIF(19), VM(17), IOPL(12-13), IF(9). + * Also masks reserved bits (63-22, 15, 5, 3, 1). + */ +#define FLAG_MASK 0x54dd5UL + +/* 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; +} + +#define LDT_SEGMENT 4 + +unsigned long convert_rip_to_linear(struct task_struct *child, struct pt_regs *regs) +{ + unsigned long addr, seg; + + addr = regs->rip; + seg = regs->cs & 0xffff; + + /* + * We'll assume that the code segments in the GDT + * are all zero-based. That is largely true: the + * TLS segments are used for data, and the PNPBIOS + * and APM bios ones we just ignore here. + */ + if (seg & LDT_SEGMENT) { + u32 *desc; + unsigned long base; + + seg &= ~7UL; + + down(&child->mm->context.sem); + if (unlikely((seg >> 3) >= child->mm->context.size)) + addr = -1L; /* bogus selector, access would fault */ + else { + desc = child->mm->context.ldt + seg; + base = ((desc[0] >> 16) | + ((desc[1] & 0xff) << 16) | + (desc[1] & 0xff000000)); + + /* 16-bit code segment? */ + if (!((desc[1] >> 22) & 1)) + addr &= 0xffff; + addr += base; + } + up(&child->mm->context.sem); + } + + return addr; +} + +static int is_setting_trap_flag(struct task_struct *child, struct pt_regs *regs) +{ + int i, copied; + unsigned char opcode[15]; + unsigned long addr = convert_rip_to_linear(child, regs); + + copied = access_process_vm(child, addr, opcode, sizeof(opcode), 0); + for (i = 0; i < copied; i++) { + switch (opcode[i]) { + /* popf and iret */ + case 0x9d: case 0xcf: + return 1; + + /* CHECKME: 64 65 */ + + /* opcode and address size prefixes */ + case 0x66: case 0x67: + continue; + /* irrelevant prefixes (segment overrides and repeats) */ + case 0x26: case 0x2e: + case 0x36: case 0x3e: + case 0x64: case 0x65: + case 0xf2: case 0xf3: + continue; + + case 0x40 ... 0x4f: + if (regs->cs != __USER_CS) + /* 32-bit mode: register increment */ + return 0; + /* 64-bit mode: REX prefix */ + continue; + + /* CHECKME: f2, f3 */ + + /* + * pushf: NOTE! We should probably not let + * the user see the TF bit being set. But + * it's more pain than it's worth to avoid + * it, and a debugger could emulate this + * all in user space if it _really_ cares. + */ + case 0x9c: + default: + return 0; + } + } + return 0; +} + +static void set_singlestep(struct task_struct *child) +{ + struct pt_regs *regs = task_pt_regs(child); + + /* + * Always set TIF_SINGLESTEP - this guarantees that + * we single-step system calls etc.. This will also + * cause us to set TF when returning to user mode. + */ + set_tsk_thread_flag(child, TIF_SINGLESTEP); + + /* + * If TF was already set, don't do anything else + */ + if (regs->eflags & TRAP_FLAG) + return; + + /* Set TF on the kernel stack.. */ + regs->eflags |= TRAP_FLAG; + + /* + * ..but if TF is changed by the instruction we will trace, + * don't mark it as being "us" that set it, so that we + * won't clear it by hand later. + */ + if (is_setting_trap_flag(child, regs)) + return; + + child->ptrace |= PT_DTRACE; +} + +static void clear_singlestep(struct task_struct *child) +{ + /* Always clear TIF_SINGLESTEP... */ + clear_tsk_thread_flag(child, TIF_SINGLESTEP); + + /* But touch TF only if it was set by us.. */ + if (child->ptrace & PT_DTRACE) { + struct pt_regs *regs = task_pt_regs(child); + regs->eflags &= ~TRAP_FLAG; + child->ptrace &= ~PT_DTRACE; + } +} + +/* + * Called by kernel/ptrace.c when detaching.. + * + * Make sure the single step bit is not set. + */ +void ptrace_disable(struct task_struct *child) +{ + clear_singlestep(child); +} + +static int putreg(struct task_struct *child, + unsigned long regno, unsigned long value) +{ + unsigned long tmp; + + 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 >= TASK_SIZE_OF(child)) + return -EIO; + child->thread.fs = value; + return 0; + case offsetof(struct user_regs_struct,gs_base): + if (value >= TASK_SIZE_OF(child)) + 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; + } + +} + +long arch_ptrace(struct task_struct *child, long request, long addr, long data) +{ + long i, ret; + unsigned ui; + + 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: + ret = generic_ptrace_peekdata(child, addr, 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) - sizeof(long): + 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 = generic_ptrace_pokedata(child, addr, data); + break; + + case PTRACE_POKEUSR: /* write the word at location addr in the USER area */ + { + int dsize = test_tsk_thread_flag(child, TIF_IA32) ? 3 : 7; + ret = -EIO; + if ((addr & 7) || + addr > sizeof(struct user) - 7) + break; + + switch (addr) { + case 0 ... sizeof(struct user_regs_struct) - sizeof(long): + 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_OF(child) - dsize) break; + child->thread.debugreg0 = data; + ret = 0; + break; + case offsetof(struct user, u_debugreg[1]): + if (data >= TASK_SIZE_OF(child) - dsize) break; + child->thread.debugreg1 = data; + ret = 0; + break; + case offsetof(struct user, u_debugreg[2]): + if (data >= TASK_SIZE_OF(child) - dsize) break; + child->thread.debugreg2 = data; + ret = 0; + break; + case offsetof(struct user, u_debugreg[3]): + if (data >= TASK_SIZE_OF(child) - dsize) 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 ((0x5554 >> ((data >> (16 + 4*i)) & 0xf)) & 1) + break; + if (i == 4) { + child->thread.debugreg7 = data; + if (data) + set_tsk_thread_flag(child, TIF_DEBUG); + else + clear_tsk_thread_flag(child, TIF_DEBUG); + ret = 0; + } + break; + } + break; + } + case PTRACE_SYSCALL: /* continue and stop at next (return from) syscall */ + case PTRACE_CONT: /* restart after signal. */ + + ret = -EIO; + if (!valid_signal(data)) + 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. */ + clear_singlestep(child); + 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: + 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. */ + clear_singlestep(child); + wake_up_process(child); + break; + + case PTRACE_SINGLESTEP: /* set the trap flag. */ + ret = -EIO; + if (!valid_signal(data)) + break; + clear_tsk_thread_flag(child,TIF_SYSCALL_TRACE); + set_singlestep(child); + 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); + if (ret) + break; + ret = putreg(child, ui, tmp); + if (ret) + break; + 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; + } + 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 (test_thread_flag(TIF_SYSCALL_TRACE) + && (current->ptrace & PT_PTRACED)) + syscall_trace(regs); + + if (unlikely(current->audit_context)) { + if (test_thread_flag(TIF_IA32)) { + audit_syscall_entry(AUDIT_ARCH_I386, + regs->orig_rax, + regs->rbx, regs->rcx, + regs->rdx, regs->rsi); + } else { + audit_syscall_entry(AUDIT_ARCH_X86_64, + regs->orig_rax, + regs->rdi, regs->rsi, + regs->rdx, regs->r10); + } + } +} + +asmlinkage void syscall_trace_leave(struct pt_regs *regs) +{ + if (unlikely(current->audit_context)) + audit_syscall_exit(AUDITSC_RESULT(regs->rax), regs->rax); + + if ((test_thread_flag(TIF_SYSCALL_TRACE) + || test_thread_flag(TIF_SINGLESTEP)) + && (current->ptrace & PT_PTRACED)) + syscall_trace(regs); +} |