mirror of
https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
synced 2026-08-14 06:22:34 +02:00
Mukesh Kumar Chaurasiya (IBM)
263e5159e0
Commitd7a6797e0b("powerpc: add exit_flags field in pt_regs") added the exit_flags field to struct pt_regs to pass internal exit control flags (e.g. _TIF_RESTOREALL) from syscall_exit_prepare() to the low-level assembly exit path. However, the field was placed in a way that was visible to userspace tools such as strace via PTRACE_GETREGS, or caused a struct layout or size regression observable through ptrace. The field is purely kernel-internal and must not be exposed beyond the user_pt_regs boundary. Move exit_flags into struct thread_info where it is only accessible to the kernel, and keep it out of the ptrace-visible register window entirely. Fixes:d7a6797e0b("powerpc: add exit_flags field in pt_regs") Reported-by: Dmitry V. Levin <ldv@strace.io> Closes: https://lore.kernel.org/all/20260722070155.GA11808@strace.io/ Signed-off-by: Mukesh Kumar Chaurasiya (IBM) <mkchauras@gmail.com> Signed-off-by: Madhavan Srinivasan <maddy@linux.ibm.com> Link: https://patch.msgid.link/20260723194809.4046600-1-mkchauras@gmail.com
307 lines
8.3 KiB
C
307 lines
8.3 KiB
C
// SPDX-License-Identifier: GPL-2.0-or-later
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/*
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* PowerPC version
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* Copyright (C) 1995-1996 Gary Thomas (gdt@linuxppc.org)
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*
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* Derived from "arch/m68k/kernel/ptrace.c"
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* Copyright (C) 1994 by Hamish Macdonald
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* Taken from linux/kernel/ptrace.c and modified for M680x0.
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* linux/kernel/ptrace.c is by Ross Biro 1/23/92, edited by Linus Torvalds
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*
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* Modified by Cort Dougan (cort@hq.fsmlabs.com)
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* and Paul Mackerras (paulus@samba.org).
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*/
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#include <linux/regset.h>
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#include <linux/ptrace.h>
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#include <linux/audit.h>
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#include <linux/context_tracking.h>
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#include <linux/syscalls.h>
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#include <asm/switch_to.h>
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#include <asm/debug.h>
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#include "ptrace-decl.h"
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/*
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* Called by kernel/ptrace.c when detaching..
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*
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* Make sure single step bits etc are not set.
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*/
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void ptrace_disable(struct task_struct *child)
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{
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/* make sure the single step bit is not set. */
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user_disable_single_step(child);
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}
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long arch_ptrace(struct task_struct *child, long request,
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unsigned long addr, unsigned long data)
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{
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int ret = -EPERM;
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void __user *datavp = (void __user *) data;
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unsigned long __user *datalp = datavp;
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switch (request) {
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/* read the word at location addr in the USER area. */
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case PTRACE_PEEKUSR: {
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unsigned long index, tmp;
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ret = -EIO;
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/* convert to index and check */
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index = addr / sizeof(long);
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if ((addr & (sizeof(long) - 1)) || !child->thread.regs)
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break;
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if (index < PT_FPR0)
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ret = ptrace_get_reg(child, (int) index, &tmp);
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else
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ret = ptrace_get_fpr(child, index, &tmp);
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if (ret)
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break;
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ret = put_user(tmp, datalp);
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break;
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}
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/* write the word at location addr in the USER area */
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case PTRACE_POKEUSR: {
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unsigned long index;
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ret = -EIO;
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/* convert to index and check */
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index = addr / sizeof(long);
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if ((addr & (sizeof(long) - 1)) || !child->thread.regs)
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break;
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if (index < PT_FPR0)
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ret = ptrace_put_reg(child, index, data);
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else
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ret = ptrace_put_fpr(child, index, data);
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break;
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}
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case PPC_PTRACE_GETHWDBGINFO: {
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struct ppc_debug_info dbginfo;
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ppc_gethwdinfo(&dbginfo);
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if (copy_to_user(datavp, &dbginfo,
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sizeof(struct ppc_debug_info)))
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return -EFAULT;
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return 0;
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}
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case PPC_PTRACE_SETHWDEBUG: {
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struct ppc_hw_breakpoint bp_info;
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if (copy_from_user(&bp_info, datavp,
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sizeof(struct ppc_hw_breakpoint)))
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return -EFAULT;
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return ppc_set_hwdebug(child, &bp_info);
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}
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case PPC_PTRACE_DELHWDEBUG: {
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ret = ppc_del_hwdebug(child, data);
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break;
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}
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case PTRACE_GET_DEBUGREG:
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ret = ptrace_get_debugreg(child, addr, datalp);
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break;
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case PTRACE_SET_DEBUGREG:
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ret = ptrace_set_debugreg(child, addr, data);
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break;
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#ifdef CONFIG_PPC64
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case PTRACE_GETREGS64:
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#endif
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case PTRACE_GETREGS: /* Get all pt_regs from the child. */
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return copy_regset_to_user(child, &user_ppc_native_view,
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REGSET_GPR,
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0, sizeof(struct user_pt_regs),
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datavp);
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#ifdef CONFIG_PPC64
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case PTRACE_SETREGS64:
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#endif
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case PTRACE_SETREGS: /* Set all gp regs in the child. */
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return copy_regset_from_user(child, &user_ppc_native_view,
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REGSET_GPR,
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0, sizeof(struct user_pt_regs),
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datavp);
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case PTRACE_GETFPREGS: /* Get the child FPU state (FPR0...31 + FPSCR) */
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return copy_regset_to_user(child, &user_ppc_native_view,
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REGSET_FPR,
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0, sizeof(elf_fpregset_t),
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datavp);
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case PTRACE_SETFPREGS: /* Set the child FPU state (FPR0...31 + FPSCR) */
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return copy_regset_from_user(child, &user_ppc_native_view,
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REGSET_FPR,
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0, sizeof(elf_fpregset_t),
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datavp);
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#ifdef CONFIG_ALTIVEC
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case PTRACE_GETVRREGS:
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return copy_regset_to_user(child, &user_ppc_native_view,
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REGSET_VMX,
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0, (33 * sizeof(vector128) +
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sizeof(u32)),
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datavp);
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case PTRACE_SETVRREGS:
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return copy_regset_from_user(child, &user_ppc_native_view,
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REGSET_VMX,
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0, (33 * sizeof(vector128) +
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sizeof(u32)),
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datavp);
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#endif
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#ifdef CONFIG_VSX
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case PTRACE_GETVSRREGS:
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return copy_regset_to_user(child, &user_ppc_native_view,
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REGSET_VSX,
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0, 32 * sizeof(double),
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datavp);
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case PTRACE_SETVSRREGS:
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return copy_regset_from_user(child, &user_ppc_native_view,
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REGSET_VSX,
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0, 32 * sizeof(double),
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datavp);
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#endif
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#ifdef CONFIG_SPE
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case PTRACE_GETEVRREGS:
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/* Get the child spe register state. */
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return copy_regset_to_user(child, &user_ppc_native_view,
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REGSET_SPE, 0, 35 * sizeof(u32),
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datavp);
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case PTRACE_SETEVRREGS:
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/* Set the child spe register state. */
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return copy_regset_from_user(child, &user_ppc_native_view,
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REGSET_SPE, 0, 35 * sizeof(u32),
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datavp);
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#endif
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default:
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ret = ptrace_request(child, request, addr, data);
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break;
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}
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return ret;
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}
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void __init pt_regs_check(void);
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/*
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* Dummy function, its purpose is to break the build if struct pt_regs and
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* struct user_pt_regs don't match.
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*/
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void __init pt_regs_check(void)
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{
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BUILD_BUG_ON(offsetof(struct pt_regs, gpr) !=
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offsetof(struct user_pt_regs, gpr));
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BUILD_BUG_ON(offsetof(struct pt_regs, nip) !=
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offsetof(struct user_pt_regs, nip));
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BUILD_BUG_ON(offsetof(struct pt_regs, msr) !=
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offsetof(struct user_pt_regs, msr));
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BUILD_BUG_ON(offsetof(struct pt_regs, orig_gpr3) !=
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offsetof(struct user_pt_regs, orig_gpr3));
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BUILD_BUG_ON(offsetof(struct pt_regs, ctr) !=
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offsetof(struct user_pt_regs, ctr));
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BUILD_BUG_ON(offsetof(struct pt_regs, link) !=
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offsetof(struct user_pt_regs, link));
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BUILD_BUG_ON(offsetof(struct pt_regs, xer) !=
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offsetof(struct user_pt_regs, xer));
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BUILD_BUG_ON(offsetof(struct pt_regs, ccr) !=
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offsetof(struct user_pt_regs, ccr));
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#ifdef __powerpc64__
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BUILD_BUG_ON(offsetof(struct pt_regs, softe) !=
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offsetof(struct user_pt_regs, softe));
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#else
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BUILD_BUG_ON(offsetof(struct pt_regs, mq) !=
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offsetof(struct user_pt_regs, mq));
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#endif
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BUILD_BUG_ON(offsetof(struct pt_regs, trap) !=
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offsetof(struct user_pt_regs, trap));
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BUILD_BUG_ON(offsetof(struct pt_regs, dar) !=
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offsetof(struct user_pt_regs, dar));
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BUILD_BUG_ON(offsetof(struct pt_regs, dear) !=
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offsetof(struct user_pt_regs, dar));
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BUILD_BUG_ON(offsetof(struct pt_regs, dsisr) !=
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offsetof(struct user_pt_regs, dsisr));
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BUILD_BUG_ON(offsetof(struct pt_regs, esr) !=
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offsetof(struct user_pt_regs, dsisr));
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BUILD_BUG_ON(offsetof(struct pt_regs, result) !=
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offsetof(struct user_pt_regs, result));
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BUILD_BUG_ON(sizeof(struct user_pt_regs) > sizeof(struct pt_regs));
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// Now check that the pt_regs offsets match the uapi #defines
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#define CHECK_REG(_pt, _reg) \
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BUILD_BUG_ON(_pt != (offsetof(struct user_pt_regs, _reg) / \
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sizeof(unsigned long)));
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CHECK_REG(PT_R0, gpr[0]);
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CHECK_REG(PT_R1, gpr[1]);
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CHECK_REG(PT_R2, gpr[2]);
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CHECK_REG(PT_R3, gpr[3]);
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CHECK_REG(PT_R4, gpr[4]);
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CHECK_REG(PT_R5, gpr[5]);
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CHECK_REG(PT_R6, gpr[6]);
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CHECK_REG(PT_R7, gpr[7]);
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CHECK_REG(PT_R8, gpr[8]);
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CHECK_REG(PT_R9, gpr[9]);
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CHECK_REG(PT_R10, gpr[10]);
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CHECK_REG(PT_R11, gpr[11]);
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CHECK_REG(PT_R12, gpr[12]);
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CHECK_REG(PT_R13, gpr[13]);
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CHECK_REG(PT_R14, gpr[14]);
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CHECK_REG(PT_R15, gpr[15]);
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CHECK_REG(PT_R16, gpr[16]);
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CHECK_REG(PT_R17, gpr[17]);
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CHECK_REG(PT_R18, gpr[18]);
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CHECK_REG(PT_R19, gpr[19]);
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CHECK_REG(PT_R20, gpr[20]);
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CHECK_REG(PT_R21, gpr[21]);
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CHECK_REG(PT_R22, gpr[22]);
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CHECK_REG(PT_R23, gpr[23]);
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CHECK_REG(PT_R24, gpr[24]);
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CHECK_REG(PT_R25, gpr[25]);
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CHECK_REG(PT_R26, gpr[26]);
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CHECK_REG(PT_R27, gpr[27]);
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CHECK_REG(PT_R28, gpr[28]);
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CHECK_REG(PT_R29, gpr[29]);
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CHECK_REG(PT_R30, gpr[30]);
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CHECK_REG(PT_R31, gpr[31]);
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CHECK_REG(PT_NIP, nip);
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CHECK_REG(PT_MSR, msr);
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CHECK_REG(PT_ORIG_R3, orig_gpr3);
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CHECK_REG(PT_CTR, ctr);
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CHECK_REG(PT_LNK, link);
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CHECK_REG(PT_XER, xer);
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CHECK_REG(PT_CCR, ccr);
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#ifdef CONFIG_PPC64
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CHECK_REG(PT_SOFTE, softe);
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#else
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CHECK_REG(PT_MQ, mq);
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#endif
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CHECK_REG(PT_TRAP, trap);
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CHECK_REG(PT_DAR, dar);
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CHECK_REG(PT_DSISR, dsisr);
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CHECK_REG(PT_RESULT, result);
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#undef CHECK_REG
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BUILD_BUG_ON(PT_REGS_COUNT != sizeof(struct user_pt_regs) / sizeof(unsigned long));
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/*
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* PT_DSCR isn't a real reg, but it's important that it doesn't overlap the
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* real registers.
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*/
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BUILD_BUG_ON(PT_DSCR < sizeof(struct user_pt_regs) / sizeof(unsigned long));
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// ptrace_get/put_fpr() rely on PPC32 and VSX being incompatible
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BUILD_BUG_ON(IS_ENABLED(CONFIG_PPC32) && IS_ENABLED(CONFIG_VSX));
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}
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