Re: [PATCH v3] nfp: fix use-after-free in area_cache_get()

[Lee Jones]

On Thu, 15 Dec 2022, Greg KH wrote:

> On Thu, Dec 15, 2022 at 09:25:23AM +0000, Lee Jones wrote:
> > Dear Stable,
> > 
> > [NB: Re-poking Stable with the correct contact address this time! :)]
> > 
> > > > > area_cache_get() is used to distribute cache->area and set cache->id,
> > > > >  and if cache->id is not 0 and cache->area->kref refcount is 0, it will
> > > > >  release the cache->area by nfp_cpp_area_release(). area_cache_get()
> > > > >  set cache->id before cpp->op->area_init() and nfp_cpp_area_acquire().
> > > > >
> > > > > But if area_init() or nfp_cpp_area_acquire() fails, the cache->id is
> > > > >  is already set but the refcount is not increased as expected. At this
> > > > >  time, calling the nfp_cpp_area_release() will cause use-after-free.
> > > > >
> > > > > To avoid the use-after-free, set cache->id after area_init() and
> > > > >  nfp_cpp_area_acquire() complete successfully.
> > > > >
> > > > > Note: This vulnerability is triggerable by providing emulated device
> > > > >  equipped with specified configuration.
> > > > >
> > > > >  BUG: KASAN: use-after-free in nfp6000_area_init (/home/user/Kernel/v5.19
> > > > > /x86_64/src/drivers/net/ethernet/netronome/nfp/nfpcore/nfp6000_pcie.c:760)
> > > > >   Write of size 4 at addr ffff888005b7f4a0 by task swapper/0/1
> > > > >
> > > > >  Call Trace:
> > > > >   <TASK>
> > > > >  nfp6000_area_init (/home/user/Kernel/v5.19/x86_64/src/drivers/net
> > > > > /ethernet/netronome/nfp/nfpcore/nfp6000_pcie.c:760)
> > > > >  area_cache_get.constprop.8 (/home/user/Kernel/v5.19/x86_64/src/drivers
> > > > > /net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c:884)
> > > > >
> > > > >  Allocated by task 1:
> > > > >  nfp_cpp_area_alloc_with_name (/home/user/Kernel/v5.19/x86_64/src/drivers
> > > > > /net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c:303)
> > > > >  nfp_cpp_area_cache_add (/home/user/Kernel/v5.19/x86_64/src/drivers/net
> > > > > /ethernet/netronome/nfp/nfpcore/nfp_cppcore.c:802)
> > > > >  nfp6000_init (/home/user/Kernel/v5.19/x86_64/src/drivers/net/ethernet
> > > > > /netronome/nfp/nfpcore/nfp6000_pcie.c:1230)
> > > > >  nfp_cpp_from_operations (/home/user/Kernel/v5.19/x86_64/src/drivers/net
> > > > > /ethernet/netronome/nfp/nfpcore/nfp_cppcore.c:1215)
> > > > >  nfp_pci_probe (/home/user/Kernel/v5.19/x86_64/src/drivers/net/ethernet
> > > > > /netronome/nfp/nfp_main.c:744)
> > > > >
> > > > >  Freed by task 1:
> > > > >  kfree (/home/user/Kernel/v5.19/x86_64/src/mm/slub.c:4562)
> > > > >  area_cache_get.constprop.8 (/home/user/Kernel/v5.19/x86_64/src/drivers
> > > > > /net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c:873)
> > > > >  nfp_cpp_read (/home/user/Kernel/v5.19/x86_64/src/drivers/net/ethernet
> > > > > /netronome/nfp/nfpcore/nfp_cppcore.c:924 /home/user/Kernel/v5.19/x86_64
> > > > > /src/drivers/net/ethernet/netronome/nfp/nfpcore/nfp_cppcore.c:973)
> > > > >  nfp_cpp_readl (/home/user/Kernel/v5.19/x86_64/src/drivers/net/ethernet
> > > > > /netronome/nfp/nfpcore/nfp_cpplib.c:48)
> > > > >
> > > > > Signed-off-by: Jialiang Wang <wangjialiang0806@xxxxxxx>
> > > > 
> > > > Any reason why this doesn't have a Fixes: tag applied and/or didn't
> > > > get sent to Stable?
> > > > 
> > > > Looks as if this needs to go back as far as v4.19.
> > > > 
> > > > Fixes: 4cb584e0ee7df ("nfp: add CPP access core")
> > > > 
> > > > commit 02e1a114fdb71e59ee6770294166c30d437bf86a upstream.
> > 
> > Would you be able to take this with the information provided please?
> 
> You really want this back to 4.14.y, as 4cb584e0ee7df ("nfp: add CPP
> access core") showed up in the 4.11 release, right?

Yes please.  Brain said one thing, fingers typed another!

> if so, now queued up.

Thank you.

-- 
Lee Jones [李琼斯]