platform/x86: p2sb: Fix UAF when caller uses resource name

We have to copy only selected fields from the original resource.
Because a PCI device will be removed immediately after getting
its resources, we may not use any allocated data, hence we may
not copy any pointers.

Consider the following scenario:

  1/ a caller of p2sb_bar() gets the resource;

  2/ the resource has been copied by platform_device_add_data()
     in order to create a platform device;

  3/ the platform device creation will call for the device driver's
     ->probe() as soon as a match found;

  4/ the ->probe() takes given resources (see 2/) and tries to
     access one of its field, i.e. 'name', in the
     __devm_ioremap_resource() to create a pretty looking output;

  5/ but the 'name' is a dangling pointer because p2sb_bar()
     removed a PCI device, which 'name' had been copied to
     the caller's memory.

  6/ UAF (Use-After-Free) as a result.

Kudos to Mika for the initial analisys of the issue.

Fixes: 9745fb07474f ("platform/x86/intel: Add Primary to Sideband (P2SB) bridge support")
Reported-by: kernel test robot <[email protected]>
Suggested-by: Mika Westerberg <[email protected]>
Link: https://lore.kernel.org/linux-i2c/YvPCbnKqDiL2XEKp@xsang-OptiPlex-9020/
Link: https://lore.kernel.org/linux-i2c/YtjAswDKfiuDfWYs@xsang-OptiPlex-9020/
Signed-off-by: Andy Shevchenko <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Reviewed-by: Hans de Goede <[email protected]>
Signed-off-by: Hans de Goede <[email protected]>

0 files changed, 0 insertions, 0 deletions