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b3b4efa2e6
[ Upstream commit 408c97c4a5e0b634dcd15bf8b8808b382e888164 ]
While enable active config via cscfg_csdev_enable_active_config(),
active config could be deactivated via configfs' sysfs interface.
This could make UAF issue in below scenario:
CPU0 CPU1
(sysfs enable) load module
cscfg_load_config_sets()
activate config. // sysfs
(sys_active_cnt == 1)
...
cscfg_csdev_enable_active_config()
lock(csdev->cscfg_csdev_lock)
// here load config activate by CPU1
unlock(csdev->cscfg_csdev_lock)
deactivate config // sysfs
(sys_activec_cnt == 0)
cscfg_unload_config_sets()
unload module
// access to config_desc which freed
// while unloading module.
cscfg_csdev_enable_config
To address this, use cscfg_config_desc's active_cnt as a reference count
which will be holded when
- activate the config.
- enable the activated config.
and put the module reference when config_active_cnt == 0.
Fixes: f8cce2ff3c ("coresight: syscfg: Add API to activate and enable configurations")
Suggested-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Signed-off-by: Yeoreum Yun <yeoreum.yun@arm.com>
Reviewed-by: Leo Yan <leo.yan@arm.com>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
Link: https://lore.kernel.org/r/20250514161951.3427590-4-yeoreum.yun@arm.com
Signed-off-by: Sasha Levin <sashal@kernel.org>
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.
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.