CVE-2024-53131

About vulnerability

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

nilfs2: fix null-ptr-deref in block_touch_buffer tracepoint

Patch series “nilfs2: fix null-ptr-deref bugs on block tracepoints”.

This series fixes null pointer dereference bugs that occur when using nilfs2 and two block-related tracepoints.

This patch (of 2):

It has been reported that when using “block:block_touch_buffer” tracepoint, touch_buffer() called from __nilfs_get_folio_block() causes a NULL pointer dereference, or a general protection fault when KASAN is enabled.

This happens because since the tracepoint was added in touch_buffer(), it references the dev_t member bh->b_bdev->bd_dev regardless of whether the buffer head has a pointer to a block_device structure. In the current implementation, the block_device structure is set after the function returns to the caller.

Here, touch_buffer() is used to mark the folio/page that owns the buffer head as accessed, but the common search helper for folio/page used by the caller function was optimized to mark the folio/page as accessed when it was reimplemented a long time ago, eliminating the need to call touch_buffer() here in the first place.

So this solves the issue by eliminating the touch_buffer() call itself.

Affected product:

AlmaLinux 9.2 ESU , Amazon Linux 2 ELS , CentOS 7 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CentOS Stream 8 ELS , CloudLinux 7 ELS , Debian 10 ELS , Oracle Linux 7 ELS , RHEL 7 ELS , TuxCare 9.6 ESU , Ubuntu 16.04 ELS , Ubuntu 18.04 ELS , Ubuntu 20.04 ELS

Affected packages:

kernel @ 5.14.0-11 (+16 more)

Live-patch status from KernelCare for each operating system.