Commit 0a06ea87 authored Nov 20, 2007 by David S. Miller

[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>

parent a572da43

net/wireless/wext.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -1094,7 +1094,7 @@ int wext_handle_ioctl(struct net net, struct ifreq ifr, unsigned int cmd,
		rtnl_lock();
		ret = wireless_process_ioctl(net, ifr, cmd);
		rtnl_unlock();
		if (IW_IS_GET(cmd) && copy_to_user(arg, ifr, sizeof(struct ifreq)))
		if (IW_IS_GET(cmd) && copy_to_user(arg, ifr, sizeof(struct iwreq)))
		return -EFAULT;
		return ret;
		}

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