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-rw-r--r--arch/x86/kernel/ptrace_64.c627
1 files changed, 627 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..eea3702427b4
--- /dev/null
+++ b/arch/x86/kernel/ptrace_64.c
@@ -0,0 +1,627 @@
+/* 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/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);
+}
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.