Commit | Line | Data |
---|---|---|
1da177e4 | 1 | /* |
1da177e4 | 2 | * This contains the io-permission bitmap code - written by obz, with changes |
ccafa59a | 3 | * by Linus. 32/64 bits code unification by Miguel Botón. |
1da177e4 LT |
4 | */ |
5 | ||
6 | #include <linux/sched.h> | |
7 | #include <linux/kernel.h> | |
a9415644 | 8 | #include <linux/capability.h> |
1da177e4 LT |
9 | #include <linux/errno.h> |
10 | #include <linux/types.h> | |
11 | #include <linux/ioport.h> | |
12 | #include <linux/smp.h> | |
1da177e4 LT |
13 | #include <linux/stddef.h> |
14 | #include <linux/slab.h> | |
15 | #include <linux/thread_info.h> | |
ca906e42 | 16 | #include <linux/syscalls.h> |
1da177e4 LT |
17 | |
18 | /* Set EXTENT bits starting at BASE in BITMAP to value TURN_ON. */ | |
f2f58178 TG |
19 | static void set_bitmap(unsigned long *bitmap, unsigned int base, |
20 | unsigned int extent, int new_value) | |
1da177e4 | 21 | { |
f2f58178 | 22 | unsigned int i; |
1da177e4 | 23 | |
f2f58178 | 24 | for (i = base; i < base + extent; i++) { |
1da177e4 | 25 | if (new_value) |
f2f58178 | 26 | __set_bit(i, bitmap); |
1da177e4 | 27 | else |
f2f58178 | 28 | __clear_bit(i, bitmap); |
1da177e4 LT |
29 | } |
30 | } | |
31 | ||
1da177e4 LT |
32 | /* |
33 | * this changes the io permissions bitmap in the current task. | |
34 | */ | |
35 | asmlinkage long sys_ioperm(unsigned long from, unsigned long num, int turn_on) | |
36 | { | |
1da177e4 LT |
37 | struct thread_struct * t = ¤t->thread; |
38 | struct tss_struct * tss; | |
ccafa59a | 39 | unsigned int i, max_long, bytes, bytes_updated; |
1da177e4 LT |
40 | |
41 | if ((from + num <= from) || (from + num > IO_BITMAP_BITS)) | |
42 | return -EINVAL; | |
43 | if (turn_on && !capable(CAP_SYS_RAWIO)) | |
44 | return -EPERM; | |
45 | ||
46 | /* | |
47 | * If it's the first ioperm() call in this thread's lifetime, set the | |
48 | * IO bitmap up. ioperm() is much less timing critical than clone(), | |
49 | * this is why we delay this operation until now: | |
50 | */ | |
51 | if (!t->io_bitmap_ptr) { | |
9a211abe TG |
52 | unsigned long *bitmap = kmalloc(IO_BITMAP_BYTES, GFP_KERNEL); |
53 | ||
1da177e4 LT |
54 | if (!bitmap) |
55 | return -ENOMEM; | |
56 | ||
57 | memset(bitmap, 0xff, IO_BITMAP_BYTES); | |
58 | t->io_bitmap_ptr = bitmap; | |
b3cf2576 | 59 | set_thread_flag(TIF_IO_BITMAP); |
1da177e4 LT |
60 | } |
61 | ||
62 | /* | |
63 | * do it in the per-thread copy and in the TSS ... | |
64 | * | |
65 | * Disable preemption via get_cpu() - we must not switch away | |
66 | * because the ->io_bitmap_max value must match the bitmap | |
67 | * contents: | |
68 | */ | |
69 | tss = &per_cpu(init_tss, get_cpu()); | |
70 | ||
71 | set_bitmap(t->io_bitmap_ptr, from, num, !turn_on); | |
72 | ||
73 | /* | |
74 | * Search for a (possibly new) maximum. This is simple and stupid, | |
75 | * to keep it obviously correct: | |
76 | */ | |
77 | max_long = 0; | |
78 | for (i = 0; i < IO_BITMAP_LONGS; i++) | |
79 | if (t->io_bitmap_ptr[i] != ~0UL) | |
80 | max_long = i; | |
81 | ||
ccafa59a | 82 | bytes = (max_long + 1) * sizeof(unsigned long); |
83 | bytes_updated = max(bytes, t->io_bitmap_max); | |
1da177e4 | 84 | |
ccafa59a | 85 | t->io_bitmap_max = bytes; |
86 | ||
87 | #ifdef CONFIG_X86_32 | |
1da177e4 LT |
88 | /* |
89 | * Sets the lazy trigger so that the next I/O operation will | |
90 | * reload the correct bitmap. | |
f912696a BO |
91 | * Reset the owner so that a process switch will not set |
92 | * tss->io_bitmap_base to IO_BITMAP_OFFSET. | |
1da177e4 | 93 | */ |
a75c54f9 | 94 | tss->x86_tss.io_bitmap_base = INVALID_IO_BITMAP_OFFSET_LAZY; |
f912696a | 95 | tss->io_bitmap_owner = NULL; |
ccafa59a | 96 | #else |
97 | /* Update the TSS: */ | |
98 | memcpy(tss->io_bitmap, t->io_bitmap_ptr, bytes_updated); | |
99 | #endif | |
1da177e4 LT |
100 | |
101 | put_cpu(); | |
102 | ||
103 | return 0; | |
104 | } | |
105 | ||
106 | /* | |
107 | * sys_iopl has to be used when you want to access the IO ports | |
108 | * beyond the 0x3ff range: to get the full 65536 ports bitmapped | |
109 | * you'd need 8kB of bitmaps/process, which is a bit excessive. | |
110 | * | |
65ea5b03 | 111 | * Here we just change the flags value on the stack: we allow |
1da177e4 LT |
112 | * only the super-user to do it. This depends on the stack-layout |
113 | * on system-call entry - see also fork() and the signal handling | |
114 | * code. | |
115 | */ | |
a1bf250a | 116 | static int do_iopl(unsigned int level, struct pt_regs *regs) |
1da177e4 | 117 | { |
65ea5b03 | 118 | unsigned int old = (regs->flags >> 12) & 3; |
1da177e4 LT |
119 | |
120 | if (level > 3) | |
121 | return -EINVAL; | |
122 | /* Trying to gain more privileges? */ | |
123 | if (level > old) { | |
124 | if (!capable(CAP_SYS_RAWIO)) | |
125 | return -EPERM; | |
126 | } | |
ccafa59a | 127 | regs->flags = (regs->flags & ~X86_EFLAGS_IOPL) | (level << 12); |
a1bf250a | 128 | |
ccafa59a | 129 | return 0; |
130 | } | |
a1bf250a CW |
131 | |
132 | #ifdef CONFIG_X86_32 | |
133 | asmlinkage long sys_iopl(unsigned long regsp) | |
ccafa59a | 134 | { |
a1bf250a CW |
135 | struct pt_regs *regs = (struct pt_regs *)®sp; |
136 | unsigned int level = regs->bx; | |
137 | struct thread_struct *t = ¤t->thread; | |
138 | int rc; | |
9a211abe | 139 | |
a1bf250a CW |
140 | rc = do_iopl(level, regs); |
141 | if (rc < 0) | |
142 | goto out; | |
9a211abe | 143 | |
a1bf250a CW |
144 | t->iopl = level << 12; |
145 | set_iopl_mask(t->iopl); | |
146 | out: | |
147 | return rc; | |
148 | } | |
149 | #else | |
150 | asmlinkage long sys_iopl(unsigned int level, struct pt_regs *regs) | |
151 | { | |
152 | return do_iopl(level, regs); | |
1da177e4 | 153 | } |
ccafa59a | 154 | #endif |