58c0d0b2d4
commit 85cc91e2ba4262a602ec65e2b76c4391a9e60d3d upstream. The implementation of syscall_get_nr on mips used to ignore the task argument and return the syscall number of the calling thread instead of the target thread. The bug was exposed to user space by commit201766a20e("ptrace: add PTRACE_GET_SYSCALL_INFO request") and detected by strace test suite. Link: https://github.com/strace/strace/issues/235 Fixes:c2d9f17757("MIPS: Fix syscall_get_nr for the syscall exit tracing.") Cc: <stable@vger.kernel.org> # v3.19+ Co-developed-by: Dmitry V. Levin <ldv@strace.io> Signed-off-by: Dmitry V. Levin <ldv@strace.io> Signed-off-by: Elvira Khabirova <lineprinter0@gmail.com> Signed-off-by: Thomas Bogendoerfer <tsbogend@alpha.franken.de> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
161 lines
3.6 KiB
C
161 lines
3.6 KiB
C
/*
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* Access to user system call parameters and results
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*
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* This file is subject to the terms and conditions of the GNU General Public
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* License. See the file "COPYING" in the main directory of this archive
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* for more details.
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*
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* See asm-generic/syscall.h for descriptions of what we must do here.
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*
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* Copyright (C) 2012 Ralf Baechle <ralf@linux-mips.org>
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*/
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#ifndef __ASM_MIPS_SYSCALL_H
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#define __ASM_MIPS_SYSCALL_H
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#include <linux/compiler.h>
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#include <uapi/linux/audit.h>
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#include <linux/elf-em.h>
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#include <linux/kernel.h>
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#include <linux/sched.h>
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#include <linux/uaccess.h>
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#include <asm/ptrace.h>
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#include <asm/unistd.h>
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#ifndef __NR_syscall /* Only defined if _MIPS_SIM == _MIPS_SIM_ABI32 */
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#define __NR_syscall 4000
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#endif
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static inline bool mips_syscall_is_indirect(struct task_struct *task,
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struct pt_regs *regs)
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{
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/* O32 ABI syscall() - Either 64-bit with O32 or 32-bit */
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return (IS_ENABLED(CONFIG_32BIT) ||
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test_tsk_thread_flag(task, TIF_32BIT_REGS)) &&
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(regs->regs[2] == __NR_syscall);
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}
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static inline long syscall_get_nr(struct task_struct *task,
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struct pt_regs *regs)
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{
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return task_thread_info(task)->syscall;
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}
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static inline void mips_syscall_update_nr(struct task_struct *task,
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struct pt_regs *regs)
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{
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/*
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* v0 is the system call number, except for O32 ABI syscall(), where it
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* ends up in a0.
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*/
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if (mips_syscall_is_indirect(task, regs))
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task_thread_info(task)->syscall = regs->regs[4];
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else
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task_thread_info(task)->syscall = regs->regs[2];
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}
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static inline void mips_get_syscall_arg(unsigned long *arg,
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struct task_struct *task, struct pt_regs *regs, unsigned int n)
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{
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unsigned long usp __maybe_unused = regs->regs[29];
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switch (n) {
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case 0: case 1: case 2: case 3:
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*arg = regs->regs[4 + n];
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return;
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#ifdef CONFIG_32BIT
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case 4: case 5: case 6: case 7:
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get_user(*arg, (int *)usp + n);
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return;
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#endif
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#ifdef CONFIG_64BIT
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case 4: case 5: case 6: case 7:
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#ifdef CONFIG_MIPS32_O32
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if (test_tsk_thread_flag(task, TIF_32BIT_REGS))
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get_user(*arg, (int *)usp + n);
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else
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#endif
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*arg = regs->regs[4 + n];
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return;
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#endif
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default:
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BUG();
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}
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unreachable();
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}
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static inline long syscall_get_error(struct task_struct *task,
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struct pt_regs *regs)
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{
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return regs->regs[7] ? -regs->regs[2] : 0;
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}
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static inline long syscall_get_return_value(struct task_struct *task,
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struct pt_regs *regs)
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{
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return regs->regs[2];
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}
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static inline void syscall_rollback(struct task_struct *task,
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struct pt_regs *regs)
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{
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/* Do nothing */
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}
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static inline void syscall_set_return_value(struct task_struct *task,
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struct pt_regs *regs,
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int error, long val)
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{
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if (error) {
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regs->regs[2] = -error;
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regs->regs[7] = 1;
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} else {
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regs->regs[2] = val;
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regs->regs[7] = 0;
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}
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}
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static inline void syscall_get_arguments(struct task_struct *task,
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struct pt_regs *regs,
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unsigned long *args)
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{
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unsigned int i = 0;
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unsigned int n = 6;
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/* O32 ABI syscall() */
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if (mips_syscall_is_indirect(task, regs))
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i++;
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while (n--)
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mips_get_syscall_arg(args++, task, regs, i++);
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}
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extern const unsigned long sys_call_table[];
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extern const unsigned long sys32_call_table[];
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extern const unsigned long sysn32_call_table[];
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static inline int syscall_get_arch(struct task_struct *task)
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{
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int arch = AUDIT_ARCH_MIPS;
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#ifdef CONFIG_64BIT
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if (!test_tsk_thread_flag(task, TIF_32BIT_REGS)) {
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arch |= __AUDIT_ARCH_64BIT;
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/* N32 sets only TIF_32BIT_ADDR */
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if (test_tsk_thread_flag(task, TIF_32BIT_ADDR))
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arch |= __AUDIT_ARCH_CONVENTION_MIPS64_N32;
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}
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#endif
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#if defined(__LITTLE_ENDIAN)
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arch |= __AUDIT_ARCH_LE;
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#endif
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return arch;
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}
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#endif /* __ASM_MIPS_SYSCALL_H */
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