[WIRELESS] WEXT: Fix userspace corruption on 64-bit.
On 64-bit systems sizeof(struct ifreq) is 8 bytes larger than sizeof(struct iwreq). For GET calls, the wireless extension code copies back into userspace using sizeof(struct ifreq) but userspace and elsewhere only allocates a "struct iwreq". Thus, this copy writes past the end of the iwreq object and corrupts whatever sits after it in memory. Fix the copy_to_user() length. This particularly hurts the compat case because the wireless compat code uses compat_alloc_userspace() and right after this allocated buffer is the current bottom of the user stack, and that's what gets overwritten by the copy_to_user() call. Signed-off-by: David S. Miller <davem@davemloft.net>
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@ -1094,7 +1094,7 @@ int wext_handle_ioctl(struct net *net, struct ifreq *ifr, unsigned int cmd,
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rtnl_lock();
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ret = wireless_process_ioctl(net, ifr, cmd);
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rtnl_unlock();
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if (IW_IS_GET(cmd) && copy_to_user(arg, ifr, sizeof(struct ifreq)))
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if (IW_IS_GET(cmd) && copy_to_user(arg, ifr, sizeof(struct iwreq)))
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return -EFAULT;
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return ret;
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}
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