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-rw-r--r--arch/x86/kernel/uprobes.c551
1 files changed, 349 insertions, 202 deletions
diff --git a/arch/x86/kernel/uprobes.c b/arch/x86/kernel/uprobes.c
index 2ed845928b5f..ace22916ade3 100644
--- a/arch/x86/kernel/uprobes.c
+++ b/arch/x86/kernel/uprobes.c
@@ -53,7 +53,7 @@
#define OPCODE1(insn) ((insn)->opcode.bytes[0])
#define OPCODE2(insn) ((insn)->opcode.bytes[1])
#define OPCODE3(insn) ((insn)->opcode.bytes[2])
-#define MODRM_REG(insn) X86_MODRM_REG(insn->modrm.value)
+#define MODRM_REG(insn) X86_MODRM_REG((insn)->modrm.value)
#define W(row, b0, b1, b2, b3, b4, b5, b6, b7, b8, b9, ba, bb, bc, bd, be, bf)\
(((b0##UL << 0x0)|(b1##UL << 0x1)|(b2##UL << 0x2)|(b3##UL << 0x3) | \
@@ -229,63 +229,6 @@ static int validate_insn_32bits(struct arch_uprobe *auprobe, struct insn *insn)
return -ENOTSUPP;
}
-/*
- * Figure out which fixups arch_uprobe_post_xol() will need to perform, and
- * annotate arch_uprobe->fixups accordingly. To start with,
- * arch_uprobe->fixups is either zero or it reflects rip-related fixups.
- */
-static void prepare_fixups(struct arch_uprobe *auprobe, struct insn *insn)
-{
- bool fix_ip = true, fix_call = false; /* defaults */
- int reg;
-
- insn_get_opcode(insn); /* should be a nop */
-
- switch (OPCODE1(insn)) {
- case 0x9d:
- /* popf */
- auprobe->fixups |= UPROBE_FIX_SETF;
- break;
- case 0xc3: /* ret/lret */
- case 0xcb:
- case 0xc2:
- case 0xca:
- /* ip is correct */
- fix_ip = false;
- break;
- case 0xe8: /* call relative - Fix return addr */
- fix_call = true;
- break;
- case 0x9a: /* call absolute - Fix return addr, not ip */
- fix_call = true;
- fix_ip = false;
- break;
- case 0xff:
- insn_get_modrm(insn);
- reg = MODRM_REG(insn);
- if (reg == 2 || reg == 3) {
- /* call or lcall, indirect */
- /* Fix return addr; ip is correct. */
- fix_call = true;
- fix_ip = false;
- } else if (reg == 4 || reg == 5) {
- /* jmp or ljmp, indirect */
- /* ip is correct. */
- fix_ip = false;
- }
- break;
- case 0xea: /* jmp absolute -- ip is correct */
- fix_ip = false;
- break;
- default:
- break;
- }
- if (fix_ip)
- auprobe->fixups |= UPROBE_FIX_IP;
- if (fix_call)
- auprobe->fixups |= UPROBE_FIX_CALL;
-}
-
#ifdef CONFIG_X86_64
/*
* If arch_uprobe->insn doesn't use rip-relative addressing, return
@@ -310,15 +253,11 @@ static void prepare_fixups(struct arch_uprobe *auprobe, struct insn *insn)
* - The displacement is always 4 bytes.
*/
static void
-handle_riprel_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, struct insn *insn)
+handle_riprel_insn(struct arch_uprobe *auprobe, struct insn *insn)
{
u8 *cursor;
u8 reg;
- if (mm->context.ia32_compat)
- return;
-
- auprobe->rip_rela_target_address = 0x0;
if (!insn_rip_relative(insn))
return;
@@ -372,7 +311,48 @@ handle_riprel_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, struct ins
cursor++;
memmove(cursor, cursor + insn->displacement.nbytes, insn->immediate.nbytes);
}
- return;
+}
+
+/*
+ * If we're emulating a rip-relative instruction, save the contents
+ * of the scratch register and store the target address in that register.
+ */
+static void
+pre_xol_rip_insn(struct arch_uprobe *auprobe, struct pt_regs *regs,
+ struct arch_uprobe_task *autask)
+{
+ if (auprobe->fixups & UPROBE_FIX_RIP_AX) {
+ autask->saved_scratch_register = regs->ax;
+ regs->ax = current->utask->vaddr;
+ regs->ax += auprobe->rip_rela_target_address;
+ } else if (auprobe->fixups & UPROBE_FIX_RIP_CX) {
+ autask->saved_scratch_register = regs->cx;
+ regs->cx = current->utask->vaddr;
+ regs->cx += auprobe->rip_rela_target_address;
+ }
+}
+
+static void
+handle_riprel_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs, long *correction)
+{
+ if (auprobe->fixups & (UPROBE_FIX_RIP_AX | UPROBE_FIX_RIP_CX)) {
+ struct arch_uprobe_task *autask;
+
+ autask = &current->utask->autask;
+ if (auprobe->fixups & UPROBE_FIX_RIP_AX)
+ regs->ax = autask->saved_scratch_register;
+ else
+ regs->cx = autask->saved_scratch_register;
+
+ /*
+ * The original instruction includes a displacement, and so
+ * is 4 bytes longer than what we've just single-stepped.
+ * Caller may need to apply other fixups to handle stuff
+ * like "jmpq *...(%rip)" and "callq *...(%rip)".
+ */
+ if (correction)
+ *correction += 4;
+ }
}
static int validate_insn_64bits(struct arch_uprobe *auprobe, struct insn *insn)
@@ -401,9 +381,19 @@ static int validate_insn_bits(struct arch_uprobe *auprobe, struct mm_struct *mm,
return validate_insn_64bits(auprobe, insn);
}
#else /* 32-bit: */
-static void handle_riprel_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, struct insn *insn)
+/*
+ * No RIP-relative addressing on 32-bit
+ */
+static void handle_riprel_insn(struct arch_uprobe *auprobe, struct insn *insn)
+{
+}
+static void pre_xol_rip_insn(struct arch_uprobe *auprobe, struct pt_regs *regs,
+ struct arch_uprobe_task *autask)
+{
+}
+static void handle_riprel_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs,
+ long *correction)
{
- /* No RIP-relative addressing on 32-bit */
}
static int validate_insn_bits(struct arch_uprobe *auprobe, struct mm_struct *mm, struct insn *insn)
@@ -412,141 +402,311 @@ static int validate_insn_bits(struct arch_uprobe *auprobe, struct mm_struct *mm,
}
#endif /* CONFIG_X86_64 */
-/**
- * arch_uprobe_analyze_insn - instruction analysis including validity and fixups.
- * @mm: the probed address space.
- * @arch_uprobe: the probepoint information.
- * @addr: virtual address at which to install the probepoint
- * Return 0 on success or a -ve number on error.
+struct uprobe_xol_ops {
+ bool (*emulate)(struct arch_uprobe *, struct pt_regs *);
+ int (*pre_xol)(struct arch_uprobe *, struct pt_regs *);
+ int (*post_xol)(struct arch_uprobe *, struct pt_regs *);
+};
+
+static inline int sizeof_long(void)
+{
+ return is_ia32_task() ? 4 : 8;
+}
+
+static int default_pre_xol_op(struct arch_uprobe *auprobe, struct pt_regs *regs)
+{
+ pre_xol_rip_insn(auprobe, regs, &current->utask->autask);
+ return 0;
+}
+
+/*
+ * Adjust the return address pushed by a call insn executed out of line.
*/
-int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long addr)
+static int adjust_ret_addr(unsigned long sp, long correction)
{
- int ret;
- struct insn insn;
+ int rasize = sizeof_long();
+ long ra;
- auprobe->fixups = 0;
- ret = validate_insn_bits(auprobe, mm, &insn);
- if (ret != 0)
- return ret;
+ if (copy_from_user(&ra, (void __user *)sp, rasize))
+ return -EFAULT;
- handle_riprel_insn(auprobe, mm, &insn);
- prepare_fixups(auprobe, &insn);
+ ra += correction;
+ if (copy_to_user((void __user *)sp, &ra, rasize))
+ return -EFAULT;
return 0;
}
-#ifdef CONFIG_X86_64
-/*
- * If we're emulating a rip-relative instruction, save the contents
- * of the scratch register and store the target address in that register.
- */
-static void
-pre_xol_rip_insn(struct arch_uprobe *auprobe, struct pt_regs *regs,
- struct arch_uprobe_task *autask)
+static int default_post_xol_op(struct arch_uprobe *auprobe, struct pt_regs *regs)
{
- if (auprobe->fixups & UPROBE_FIX_RIP_AX) {
- autask->saved_scratch_register = regs->ax;
- regs->ax = current->utask->vaddr;
- regs->ax += auprobe->rip_rela_target_address;
- } else if (auprobe->fixups & UPROBE_FIX_RIP_CX) {
- autask->saved_scratch_register = regs->cx;
- regs->cx = current->utask->vaddr;
- regs->cx += auprobe->rip_rela_target_address;
+ struct uprobe_task *utask = current->utask;
+ long correction = (long)(utask->vaddr - utask->xol_vaddr);
+
+ handle_riprel_post_xol(auprobe, regs, &correction);
+ if (auprobe->fixups & UPROBE_FIX_IP)
+ regs->ip += correction;
+
+ if (auprobe->fixups & UPROBE_FIX_CALL) {
+ if (adjust_ret_addr(regs->sp, correction)) {
+ regs->sp += sizeof_long();
+ return -ERESTART;
+ }
}
+
+ return 0;
}
-#else
-static void
-pre_xol_rip_insn(struct arch_uprobe *auprobe, struct pt_regs *regs,
- struct arch_uprobe_task *autask)
+
+static struct uprobe_xol_ops default_xol_ops = {
+ .pre_xol = default_pre_xol_op,
+ .post_xol = default_post_xol_op,
+};
+
+static bool branch_is_call(struct arch_uprobe *auprobe)
{
- /* No RIP-relative addressing on 32-bit */
+ return auprobe->branch.opc1 == 0xe8;
}
-#endif
-/*
- * arch_uprobe_pre_xol - prepare to execute out of line.
- * @auprobe: the probepoint information.
- * @regs: reflects the saved user state of current task.
- */
-int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
-{
- struct arch_uprobe_task *autask;
+#define CASE_COND \
+ COND(70, 71, XF(OF)) \
+ COND(72, 73, XF(CF)) \
+ COND(74, 75, XF(ZF)) \
+ COND(78, 79, XF(SF)) \
+ COND(7a, 7b, XF(PF)) \
+ COND(76, 77, XF(CF) || XF(ZF)) \
+ COND(7c, 7d, XF(SF) != XF(OF)) \
+ COND(7e, 7f, XF(ZF) || XF(SF) != XF(OF))
- autask = &current->utask->autask;
- autask->saved_trap_nr = current->thread.trap_nr;
- current->thread.trap_nr = UPROBE_TRAP_NR;
- regs->ip = current->utask->xol_vaddr;
- pre_xol_rip_insn(auprobe, regs, autask);
+#define COND(op_y, op_n, expr) \
+ case 0x ## op_y: DO((expr) != 0) \
+ case 0x ## op_n: DO((expr) == 0)
- autask->saved_tf = !!(regs->flags & X86_EFLAGS_TF);
- regs->flags |= X86_EFLAGS_TF;
- if (test_tsk_thread_flag(current, TIF_BLOCKSTEP))
- set_task_blockstep(current, false);
+#define XF(xf) (!!(flags & X86_EFLAGS_ ## xf))
- return 0;
+static bool is_cond_jmp_opcode(u8 opcode)
+{
+ switch (opcode) {
+ #define DO(expr) \
+ return true;
+ CASE_COND
+ #undef DO
+
+ default:
+ return false;
+ }
}
-/*
- * This function is called by arch_uprobe_post_xol() to adjust the return
- * address pushed by a call instruction executed out of line.
- */
-static int adjust_ret_addr(unsigned long sp, long correction)
+static bool check_jmp_cond(struct arch_uprobe *auprobe, struct pt_regs *regs)
{
- int rasize, ncopied;
- long ra = 0;
+ unsigned long flags = regs->flags;
- if (is_ia32_task())
- rasize = 4;
- else
- rasize = 8;
+ switch (auprobe->branch.opc1) {
+ #define DO(expr) \
+ return expr;
+ CASE_COND
+ #undef DO
- ncopied = copy_from_user(&ra, (void __user *)sp, rasize);
- if (unlikely(ncopied))
- return -EFAULT;
+ default: /* not a conditional jmp */
+ return true;
+ }
+}
- ra += correction;
- ncopied = copy_to_user((void __user *)sp, &ra, rasize);
- if (unlikely(ncopied))
- return -EFAULT;
+#undef XF
+#undef COND
+#undef CASE_COND
- return 0;
+static bool branch_emulate_op(struct arch_uprobe *auprobe, struct pt_regs *regs)
+{
+ unsigned long new_ip = regs->ip += auprobe->branch.ilen;
+ unsigned long offs = (long)auprobe->branch.offs;
+
+ if (branch_is_call(auprobe)) {
+ unsigned long new_sp = regs->sp - sizeof_long();
+ /*
+ * If it fails we execute this (mangled, see the comment in
+ * branch_clear_offset) insn out-of-line. In the likely case
+ * this should trigger the trap, and the probed application
+ * should die or restart the same insn after it handles the
+ * signal, arch_uprobe_post_xol() won't be even called.
+ *
+ * But there is corner case, see the comment in ->post_xol().
+ */
+ if (copy_to_user((void __user *)new_sp, &new_ip, sizeof_long()))
+ return false;
+ regs->sp = new_sp;
+ } else if (!check_jmp_cond(auprobe, regs)) {
+ offs = 0;
+ }
+
+ regs->ip = new_ip + offs;
+ return true;
}
-#ifdef CONFIG_X86_64
-static bool is_riprel_insn(struct arch_uprobe *auprobe)
+static int branch_post_xol_op(struct arch_uprobe *auprobe, struct pt_regs *regs)
{
- return ((auprobe->fixups & (UPROBE_FIX_RIP_AX | UPROBE_FIX_RIP_CX)) != 0);
+ BUG_ON(!branch_is_call(auprobe));
+ /*
+ * We can only get here if branch_emulate_op() failed to push the ret
+ * address _and_ another thread expanded our stack before the (mangled)
+ * "call" insn was executed out-of-line. Just restore ->sp and restart.
+ * We could also restore ->ip and try to call branch_emulate_op() again.
+ */
+ regs->sp += sizeof_long();
+ return -ERESTART;
}
-static void
-handle_riprel_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs, long *correction)
+static void branch_clear_offset(struct arch_uprobe *auprobe, struct insn *insn)
{
- if (is_riprel_insn(auprobe)) {
- struct arch_uprobe_task *autask;
+ /*
+ * Turn this insn into "call 1f; 1:", this is what we will execute
+ * out-of-line if ->emulate() fails. We only need this to generate
+ * a trap, so that the probed task receives the correct signal with
+ * the properly filled siginfo.
+ *
+ * But see the comment in ->post_xol(), in the unlikely case it can
+ * succeed. So we need to ensure that the new ->ip can not fall into
+ * the non-canonical area and trigger #GP.
+ *
+ * We could turn it into (say) "pushf", but then we would need to
+ * divorce ->insn[] and ->ixol[]. We need to preserve the 1st byte
+ * of ->insn[] for set_orig_insn().
+ */
+ memset(auprobe->insn + insn_offset_immediate(insn),
+ 0, insn->immediate.nbytes);
+}
- autask = &current->utask->autask;
- if (auprobe->fixups & UPROBE_FIX_RIP_AX)
- regs->ax = autask->saved_scratch_register;
- else
- regs->cx = autask->saved_scratch_register;
+static struct uprobe_xol_ops branch_xol_ops = {
+ .emulate = branch_emulate_op,
+ .post_xol = branch_post_xol_op,
+};
+
+/* Returns -ENOSYS if branch_xol_ops doesn't handle this insn */
+static int branch_setup_xol_ops(struct arch_uprobe *auprobe, struct insn *insn)
+{
+ u8 opc1 = OPCODE1(insn);
+
+ /* has the side-effect of processing the entire instruction */
+ insn_get_length(insn);
+ if (WARN_ON_ONCE(!insn_complete(insn)))
+ return -ENOEXEC;
+
+ switch (opc1) {
+ case 0xeb: /* jmp 8 */
+ case 0xe9: /* jmp 32 */
+ case 0x90: /* prefix* + nop; same as jmp with .offs = 0 */
+ break;
+
+ case 0xe8: /* call relative */
+ branch_clear_offset(auprobe, insn);
+ break;
+ case 0x0f:
+ if (insn->opcode.nbytes != 2)
+ return -ENOSYS;
/*
- * The original instruction includes a displacement, and so
- * is 4 bytes longer than what we've just single-stepped.
- * Fall through to handle stuff like "jmpq *...(%rip)" and
- * "callq *...(%rip)".
+ * If it is a "near" conditional jmp, OPCODE2() - 0x10 matches
+ * OPCODE1() of the "short" jmp which checks the same condition.
*/
- if (correction)
- *correction += 4;
+ opc1 = OPCODE2(insn) - 0x10;
+ default:
+ if (!is_cond_jmp_opcode(opc1))
+ return -ENOSYS;
}
+
+ auprobe->branch.opc1 = opc1;
+ auprobe->branch.ilen = insn->length;
+ auprobe->branch.offs = insn->immediate.value;
+
+ auprobe->ops = &branch_xol_ops;
+ return 0;
}
-#else
-static void
-handle_riprel_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs, long *correction)
+
+/**
+ * arch_uprobe_analyze_insn - instruction analysis including validity and fixups.
+ * @mm: the probed address space.
+ * @arch_uprobe: the probepoint information.
+ * @addr: virtual address at which to install the probepoint
+ * Return 0 on success or a -ve number on error.
+ */
+int arch_uprobe_analyze_insn(struct arch_uprobe *auprobe, struct mm_struct *mm, unsigned long addr)
+{
+ struct insn insn;
+ bool fix_ip = true, fix_call = false;
+ int ret;
+
+ ret = validate_insn_bits(auprobe, mm, &insn);
+ if (ret)
+ return ret;
+
+ ret = branch_setup_xol_ops(auprobe, &insn);
+ if (ret != -ENOSYS)
+ return ret;
+
+ /*
+ * Figure out which fixups arch_uprobe_post_xol() will need to perform,
+ * and annotate arch_uprobe->fixups accordingly. To start with, ->fixups
+ * is either zero or it reflects rip-related fixups.
+ */
+ switch (OPCODE1(&insn)) {
+ case 0x9d: /* popf */
+ auprobe->fixups |= UPROBE_FIX_SETF;
+ break;
+ case 0xc3: /* ret or lret -- ip is correct */
+ case 0xcb:
+ case 0xc2:
+ case 0xca:
+ fix_ip = false;
+ break;
+ case 0x9a: /* call absolute - Fix return addr, not ip */
+ fix_call = true;
+ fix_ip = false;
+ break;
+ case 0xea: /* jmp absolute -- ip is correct */
+ fix_ip = false;
+ break;
+ case 0xff:
+ insn_get_modrm(&insn);
+ switch (MODRM_REG(&insn)) {
+ case 2: case 3: /* call or lcall, indirect */
+ fix_call = true;
+ case 4: case 5: /* jmp or ljmp, indirect */
+ fix_ip = false;
+ }
+ /* fall through */
+ default:
+ handle_riprel_insn(auprobe, &insn);
+ }
+
+ if (fix_ip)
+ auprobe->fixups |= UPROBE_FIX_IP;
+ if (fix_call)
+ auprobe->fixups |= UPROBE_FIX_CALL;
+
+ auprobe->ops = &default_xol_ops;
+ return 0;
+}
+
+/*
+ * arch_uprobe_pre_xol - prepare to execute out of line.
+ * @auprobe: the probepoint information.
+ * @regs: reflects the saved user state of current task.
+ */
+int arch_uprobe_pre_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
{
- /* No RIP-relative addressing on 32-bit */
+ struct uprobe_task *utask = current->utask;
+
+ regs->ip = utask->xol_vaddr;
+ utask->autask.saved_trap_nr = current->thread.trap_nr;
+ current->thread.trap_nr = UPROBE_TRAP_NR;
+
+ utask->autask.saved_tf = !!(regs->flags & X86_EFLAGS_TF);
+ regs->flags |= X86_EFLAGS_TF;
+ if (test_tsk_thread_flag(current, TIF_BLOCKSTEP))
+ set_task_blockstep(current, false);
+
+ if (auprobe->ops->pre_xol)
+ return auprobe->ops->pre_xol(auprobe, regs);
+ return 0;
}
-#endif
/*
* If xol insn itself traps and generates a signal(Say,
@@ -592,22 +752,25 @@ bool arch_uprobe_xol_was_trapped(struct task_struct *t)
*/
int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
{
- struct uprobe_task *utask;
- long correction;
- int result = 0;
+ struct uprobe_task *utask = current->utask;
WARN_ON_ONCE(current->thread.trap_nr != UPROBE_TRAP_NR);
- utask = current->utask;
- current->thread.trap_nr = utask->autask.saved_trap_nr;
- correction = (long)(utask->vaddr - utask->xol_vaddr);
- handle_riprel_post_xol(auprobe, regs, &correction);
- if (auprobe->fixups & UPROBE_FIX_IP)
- regs->ip += correction;
-
- if (auprobe->fixups & UPROBE_FIX_CALL)
- result = adjust_ret_addr(regs->sp, correction);
+ if (auprobe->ops->post_xol) {
+ int err = auprobe->ops->post_xol(auprobe, regs);
+ if (err) {
+ arch_uprobe_abort_xol(auprobe, regs);
+ /*
+ * Restart the probed insn. ->post_xol() must ensure
+ * this is really possible if it returns -ERESTART.
+ */
+ if (err == -ERESTART)
+ return 0;
+ return err;
+ }
+ }
+ current->thread.trap_nr = utask->autask.saved_trap_nr;
/*
* arch_uprobe_pre_xol() doesn't save the state of TIF_BLOCKSTEP
* so we can get an extra SIGTRAP if we do not clear TF. We need
@@ -618,7 +781,7 @@ int arch_uprobe_post_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
else if (!(auprobe->fixups & UPROBE_FIX_SETF))
regs->flags &= ~X86_EFLAGS_TF;
- return result;
+ return 0;
}
/* callback routine for handling exceptions. */
@@ -652,8 +815,9 @@ int arch_uprobe_exception_notify(struct notifier_block *self, unsigned long val,
/*
* This function gets called when XOL instruction either gets trapped or
- * the thread has a fatal signal, so reset the instruction pointer to its
- * probed address.
+ * the thread has a fatal signal, or if arch_uprobe_post_xol() failed.
+ * Reset the instruction pointer to its probed address for the potential
+ * restart or for post mortem analysis.
*/
void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
{
@@ -668,25 +832,10 @@ void arch_uprobe_abort_xol(struct arch_uprobe *auprobe, struct pt_regs *regs)
regs->flags &= ~X86_EFLAGS_TF;
}
-/*
- * Skip these instructions as per the currently known x86 ISA.
- * rep=0x66*; nop=0x90
- */
static bool __skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
{
- int i;
-
- for (i = 0; i < MAX_UINSN_BYTES; i++) {
- if (auprobe->insn[i] == 0x66)
- continue;
-
- if (auprobe->insn[i] == 0x90) {
- regs->ip += i + 1;
- return true;
- }
-
- break;
- }
+ if (auprobe->ops->emulate)
+ return auprobe->ops->emulate(auprobe, regs);
return false;
}
@@ -701,23 +850,21 @@ bool arch_uprobe_skip_sstep(struct arch_uprobe *auprobe, struct pt_regs *regs)
unsigned long
arch_uretprobe_hijack_return_addr(unsigned long trampoline_vaddr, struct pt_regs *regs)
{
- int rasize, ncopied;
+ int rasize = sizeof_long(), nleft;
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))
+ if (copy_from_user(&orig_ret_vaddr, (void __user *)regs->sp, rasize))
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))
+ nleft = copy_to_user((void __user *)regs->sp, &trampoline_vaddr, rasize);
+ if (likely(!nleft))
return orig_ret_vaddr;
- if (ncopied != rasize) {
+ if (nleft != rasize) {
pr_err("uprobe: return address clobbered: pid=%d, %%sp=%#lx, "
"%%ip=%#lx\n", current->pid, regs->sp, regs->ip);