commit f3bc432aa8a7a2bfe9ebb432502be5c5d979d7fe upstream.
Commit 2f964780c03b ("USB: core: replace %p with %pK") used the %pK
format specifier for a bunch of __user pointers. But as the 'K' in
the specifier indicates, it is meant for kernel pointers. The reason
for the %pK specifier is to avoid leaks of kernel addresses, but when
the pointer is to an address in userspace the security implications
are minimal. In particular, no kernel information is leaked.
This patch changes the __user %pK specifiers (used in a bunch of
debugging output lines) to %px, which will always print the actual
address with no mangling. (Notably, there is no printk format
specifier particularly intended for __user pointers.)
Fixes: 2f964780c03b ("USB: core: replace %p with %pK")
CC: Vamsi Krishna Samavedam <vskrishn@codeaurora.org>
CC: <stable@vger.kernel.org>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Link: https://lore.kernel.org/r/20201119170228.GB576844@rowland.harvard.edu
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit a0e710a7def471b8eb779ff551fc27701da49599 upstream.
In commit 2bef9aed6f0e ("usb: usbfs: correct kernel->user page attribute
mismatch") we switched from always calling remap_pfn_range() to call
dma_mmap_coherent() to handle issues with systems with non-coherent USB host
controller drivers. Unfortunatly, as syzbot quickly told us, not all the world
is host controllers with DMA support, so we need to check what host controller
we are attempting to talk to before doing this type of allocation.
Thanks to Christoph for the quick idea of how to fix this.
Fixes: 2bef9aed6f0e ("usb: usbfs: correct kernel->user page attribute mismatch")
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hillf Danton <hdanton@sina.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Jeremy Linton <jeremy.linton@arm.com>
Cc: stable <stable@vger.kernel.org>
Reported-by: syzbot+353be47c9ce21b68b7ed@syzkaller.appspotmail.com
Reviewed-by: Jeremy Linton <jeremy.linton@arm.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20200514112711.1858252-1-gregkh@linuxfoundation.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
commit 2bef9aed6f0e22391c8d4570749b1acc9bc3981e upstream.
On some architectures (e.g. arm64) requests for
IO coherent memory may use non-cachable attributes if
the relevant device isn't cache coherent. If these
pages are then remapped into userspace as cacheable,
they may not be coherent with the non-cacheable mappings.
In particular this happens with libusb, when it attempts
to create zero-copy buffers for use by rtl-sdr
(https://github.com/osmocom/rtl-sdr/). On low end arm
devices with non-coherent USB ports, the application will
be unexpectedly killed, while continuing to work fine on
arm machines with coherent USB controllers.
This bug has been discovered/reported a few times over
the last few years. In the case of rtl-sdr a compile time
option to enable/disable zero copy was implemented to
work around it.
Rather than relaying on application specific workarounds,
dma_mmap_coherent() can be used instead of remap_pfn_range().
The page cache/etc attributes will then be correctly set in
userspace to match the kernel mapping.
Signed-off-by: Jeremy Linton <jeremy.linton@arm.com>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20200504201348.1183246-1-jeremy.linton@arm.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Alan Stern