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Input: paper over a bug in Synaptics X driver
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
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5402a7349d
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1 changed files with 20 additions and 1 deletions
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@ -647,8 +647,10 @@ static int str_to_user(const char *str, unsigned int maxlen, void __user *p)
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return copy_to_user(p, str, len) ? -EFAULT : len;
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}
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#define OLD_KEY_MAX 0x1ff
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static int handle_eviocgbit(struct input_dev *dev, unsigned int cmd, void __user *p, int compat_mode)
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{
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static unsigned long keymax_warn_time;
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unsigned long *bits;
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int len;
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@ -665,9 +667,26 @@ static int handle_eviocgbit(struct input_dev *dev, unsigned int cmd, void __user
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case EV_SW: bits = dev->swbit; len = SW_MAX; break;
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default: return -EINVAL;
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}
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/*
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* Work around bugs in userspace programs that like to do
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* EVIOCGBIT(EV_KEY, KEY_MAX) and not realize that 'len'
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* should be in bytes, not in bits.
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*/
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if ((_IOC_NR(cmd) & EV_MAX) == EV_KEY && _IOC_SIZE(cmd) == OLD_KEY_MAX) {
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len = OLD_KEY_MAX;
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if (printk_timed_ratelimit(&keymax_warn_time, 10 * 1000))
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printk(KERN_WARNING
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"evdev.c(EVIOCGBIT): Suspicious buffer size %d, "
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"limiting output to %d bytes. See "
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"http://userweb.kernel.org/~dtor/eviocgbit-bug.html\n",
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OLD_KEY_MAX,
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BITS_TO_LONGS(OLD_KEY_MAX) * sizeof(long));
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}
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return bits_to_user(bits, len, _IOC_SIZE(cmd), p, compat_mode);
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}
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#undef OLD_KEY_MAX
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static long evdev_do_ioctl(struct file *file, unsigned int cmd,
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void __user *p, int compat_mode)
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