Re: [PATCH 4.9 1/3] ion: Fix use after free during ION_IOC_ALLOC

[Lee Jones <lee.jones@linaro.org>]

On Mon, 24 Jan 2022, Greg KH wrote:

> On Mon, Jan 24, 2022 at 04:12:41PM +0000, Lee Jones wrote:
> > From: Daniel Rosenberg <drosen@google.com>
> > 
> > If a user happens to call ION_IOC_FREE during an ION_IOC_ALLOC
> > on the just allocated id, and the copy_to_user fails, the cleanup
> > code will attempt to free an already freed handle.
> > 
> > This adds a wrapper for ion_alloc that adds an ion_handle_get to
> > avoid this.
> > 
> > Signed-off-by: Daniel Rosenberg <drosen@google.com>
> > Signed-off-by: Dennis Cagle <d-cagle@codeaurora.org>
> > Signed-off-by: Patrick Daly <pdaly@codeaurora.org>
> > Signed-off-by: Lee Jones <lee.jones@linaro.org>
> > ---
> >  drivers/staging/android/ion/ion-ioctl.c | 14 +++++++++-----
> >  drivers/staging/android/ion/ion.c       | 15 ++++++++++++---
> >  drivers/staging/android/ion/ion.h       |  4 ++++
> >  3 files changed, 25 insertions(+), 8 deletions(-)
> 
> What is the git commit id of this in Linus's tree (same for the other
> 2)?

They are not in Linus' tree.

These fixes only made it into Android for some reason.

> And why just 4.9?  What about 4.14 and newer kernels?

The troublesome code was refactored before v4.14.

-- 
Lee Jones [李琼斯]
Principal Technical Lead - Developer Services
Linaro.org │ Open source software for Arm SoCs
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