2e5e55923e
*) Reorganize the two cases of sys_modify_ldt to share all the reasonably
common code.
*) Avoid memory allocation when unneeded (i.e. when we are writing and the
passed buffer size is known), thus not returning ENOMEM (which isn't
allowed for this syscall, even if there is no strict "specification").
*) Add copy_{from,to}_user to modify_ldt for TT mode.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Jeff Dike <jdike@addtoit.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
109 lines
2 KiB
C
109 lines
2 KiB
C
/*
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* Copyright (C) 2001, 2002 Jeff Dike (jdike@karaya.com)
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* Licensed under the GPL
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*/
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#include "linux/config.h"
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#include "linux/sched.h"
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#include "linux/slab.h"
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#include "linux/types.h"
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#include "asm/uaccess.h"
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#include "asm/ptrace.h"
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#include "asm/smp.h"
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#include "asm/ldt.h"
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#include "choose-mode.h"
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#include "kern.h"
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#include "mode_kern.h"
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#ifdef CONFIG_MODE_TT
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extern int modify_ldt(int func, void *ptr, unsigned long bytecount);
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static int do_modify_ldt_tt(int func, void *ptr, unsigned long bytecount)
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{
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return modify_ldt(func, ptr, bytecount);
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}
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#endif
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#ifdef CONFIG_MODE_SKAS
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#include "skas.h"
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#include "skas_ptrace.h"
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static int do_modify_ldt_skas(int func, void *ptr, unsigned long bytecount)
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{
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struct ptrace_ldt ldt;
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u32 cpu;
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int res;
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ldt = ((struct ptrace_ldt) { .func = func,
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.ptr = ptr,
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.bytecount = bytecount });
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cpu = get_cpu();
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res = ptrace(PTRACE_LDT, userspace_pid[cpu], 0, (unsigned long) &ldt);
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put_cpu();
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return res;
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}
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#endif
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int sys_modify_ldt(int func, void __user *ptr, unsigned long bytecount)
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{
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struct user_desc info;
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int res = 0;
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void *buf = NULL;
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void *p = NULL; /* What we pass to host. */
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switch(func){
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case 1:
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case 0x11: /* write_ldt */
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/* Do this check now to avoid overflows. */
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if (bytecount != sizeof(struct user_desc)) {
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res = -EINVAL;
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goto out;
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}
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if(copy_from_user(&info, ptr, sizeof(info))) {
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res = -EFAULT;
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goto out;
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}
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p = &info;
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break;
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case 0:
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case 2: /* read_ldt */
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/* The use of info avoids kmalloc on the write case, not on the
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* read one. */
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buf = kmalloc(bytecount, GFP_KERNEL);
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if (!buf) {
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res = -ENOMEM;
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goto out;
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}
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p = buf;
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default:
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res = -ENOSYS;
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goto out;
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}
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res = CHOOSE_MODE_PROC(do_modify_ldt_tt, do_modify_ldt_skas, func,
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p, bytecount);
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if(res < 0)
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goto out;
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switch(func){
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case 0:
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case 2:
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/* Modify_ldt was for reading and returned the number of read
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* bytes.*/
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if(copy_to_user(ptr, p, res))
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res = -EFAULT;
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break;
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}
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out:
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kfree(buf);
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return res;
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}
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