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3Description
In the Linux kernel, the following vulnerability has been resolved: s390/vfio-ap: fix memory leak in vfio_ap device driver The device release callback function invoked to release the matrix device uses the dev_get_drvdata(device *dev) function to retrieve the pointer to the vfio_matrix_dev object in order to free its storage. The problem is, this object is not stored as drvdata with the device; since the kfree function will accept a NULL pointer, the memory for the vfio_matrix_dev object is never freed. Since the device being released is contained within the vfio_matrix_dev object, the container_of macro will be used to retrieve its pointer.
Analysis
In the Linux kernel, the following vulnerability has been resolved:
s390/vfio-ap: fix memory leak in vfio_ap device driver
The device release callback function invoked to release the matrix device uses the dev_get_drvdata(device *dev) function to retrieve the pointer to the vfio_matrix_dev object in order to free its storage. The problem is, this object is not stored as drvdata with the device; since the kfree function will accept a NULL pointer, the memory for the vfio_matrix_dev object is never freed.
Since the device being released is contained within the vfio_matrix_dev object, the container_of macro will be used to retrieve its pointer.
Technical Context
A NULL pointer dereference occurs when the application attempts to use a pointer that has not been initialized or has been set to NULL.
Remediation
Add NULL checks before pointer dereference operations. Use static analysis to identify potential NULL pointer issues. Enable compiler warnings.
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External POC / Exploit Code
Leaving vuln.today
EUVD-2023-60082