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When populating the pinctrl mapping table entries for a device, the
'dev_name' field for each entry is initialised to point directly at the
string returned by 'dev_name()' for the device and subsequently used by
'create_pinctrl()' when looking up the mappings for the device being
probed.
This is unreliable in the presence of calls to 'dev_set_name()', which may
reallocate the device name string leaving the pinctrl mappings with a
dangling reference. This then leads to a use-after-free every time the
name is dereferenced by a device probe:
| BUG: KASAN: invalid-access in strcmp+0x20/0x64
| Read of size 1 at addr 13ffffc153494b00 by task modprobe/590
| Pointer tag: [13], memory tag: [fe]
|
| Call trace:
| __kasan_report+0x16c/0x1dc
| kasan_report+0x10/0x18
| check_memory_region
| __hwasan_load1_noabort+0x4c/0x54
| strcmp+0x20/0x64
| create_pinctrl+0x18c/0x7f4
| pinctrl_get+0x90/0x114
| devm_pinctrl_get+0x44/0x98
| pinctrl_bind_pins+0x5c/0x450
| really_probe+0x1c8/0x9a4
| driver_probe_device+0x120/0x1d8
Follow the example of sysfs, and duplicate the device name string before
stashing it away in the pinctrl mapping entries.
Cc: Linus Walleij <linus.walleij@linaro.org>
Reported-by: Elena Petrova <lenaptr@google.com>
Tested-by: Elena Petrova <lenaptr@google.com>
Signed-off-by: Will Deacon <will@kernel.org>
Link: https://lore.kernel.org/r/20191002124206.22928-1-will@kernel.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
(cherry picked from commit be4c60b563
https: //git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl.git
devel)
Bug: 140550171
Signed-off-by: Elena Petrova <lenaptr@google.com>
Change-Id: Ia54c7088590ab0f9adc7753c191bba85c06dfdc1
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
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.
See Documentation/00-INDEX for a list of what is contained in each file.
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.