CVE-2023-52749

About vulnerability

In the Linux kernel, the following vulnerability has been resolved:

spi: Fix null dereference on suspend

A race condition exists where a synchronous (noqueue) transfer can be active during a system suspend. This can cause a null pointer dereference exception to occur when the system resumes.

Example order of events leading to the exception:

1. spi_sync() calls __spi_transfer_message_noqueue() which sets ctlr->cur_msg
2. Spi transfer begins via spi_transfer_one_message()
3. System is suspended interrupting the transfer context
4. System is resumed
5. spi_controller_resume() calls spi_start_queue() which resets cur_msg to NULL
6. Spi transfer context resumes and spi_finalize_current_message() is called which dereferences cur_msg (which is now NULL)

Wait for synchronous transfers to complete before suspending by acquiring the bus mutex and setting/checking a suspend flag.

Affected product:

AlmaLinux 9.2 ESU , CentOS 6 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CloudLinux 6 ELS , Oracle Linux 6 ELS , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS

Affected packages:

kernel @ 2.6.32 (+9 more)

In the Linux kernel, the following vulnerability has been resolved:

spi: Fix null dereference on suspend

A race condition exists where a synchronous (noqueue) transfer can be active during a system suspend. This can cause a null pointer dereference exception to occur when the system resumes.

Example order of events leading to the exception:

1. spi_sync() calls __spi_transfer_message_noqueue() which sets ctlr->cur_msg
2. Spi transfer begins via spi_transfer_one_message()
3. System is suspended interrupting the transfer context
4. System is resumed
5. spi_controller_resume() calls spi_start_queue() which resets cur_msg to NULL
6. Spi transfer context resumes and spi_finalize_current_message() is called which dereferences cur_msg (which is now NULL)

Wait for synchronous transfers to complete before suspending by acquiring the bus mutex and setting/checking a suspend flag.