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647e82dbf8
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: 9745fb0747 ("platform/x86/intel: Add Primary to Sideband (P2SB) bridge support")
Reported-by: kernel test robot <oliver.sang@intel.com>
Suggested-by: Mika Westerberg <mika.westerberg@linux.intel.com>
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 <andriy.shevchenko@linux.intel.com>
Link: https://lore.kernel.org/r/20220901113406.65876-1-andriy.shevchenko@linux.intel.com
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
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Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
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https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.