Re: dev_ifname32() fails on 32->64bit calls in copy_in_user().

From: Benjamin Herrenschmidt
Date: Tue Oct 30 2007 - 22:35:55 EST


Bug is in the new dev_ifname32:

uifr = compat_alloc_user_space(sizeof(struct ifreq));
if (copy_in_user(uifr, compat_ptr(arg), sizeof(struct ifreq32)));
return -EFAULT;

There's a stray ";" after the if statement, that was obviously not
tested :-)

This fixes it here (tested):
----------------------------------------------------------------------------
[PATCH] Fix new dev_ifname32 returning -EFAULT

A stray semicolon slipped in the patch that updated dev_ifname32 to
not be inline, causing it to always return -EFAULT. This fixes it.

Signed-off-by: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
---

Index: linux-work/fs/compat_ioctl.c
===================================================================
--- linux-work.orig/fs/compat_ioctl.c 2007-10-31 13:30:42.000000000 +1100
+++ linux-work/fs/compat_ioctl.c 2007-10-31 13:30:46.000000000 +1100
@@ -322,7 +322,7 @@ static int dev_ifname32(unsigned int fd,
int err;

uifr = compat_alloc_user_space(sizeof(struct ifreq));
- if (copy_in_user(uifr, compat_ptr(arg), sizeof(struct ifreq32)));
+ if (copy_in_user(uifr, compat_ptr(arg), sizeof(struct ifreq32)))
return -EFAULT;

err = sys_ioctl(fd, SIOCGIFNAME, (unsigned long)uifr);


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