CVE-2023-52786

/// Technical description

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

ext4: fix racy may inline data check in dio write

syzbot reports that the following warning from ext4_iomap_begin()

triggers as of the commit referenced below:

if (WARN_ON_ONCE(ext4_has_inline_data(inode)))

return -ERANGE;

This occurs during a dio write, which is never expected to encounter

an inode with inline data. To enforce this behavior,

ext4_dio_write_iter() checks the current inline state of the inode

and clears the MAY_INLINE_DATA state flag to either fall back to

buffered writes, or enforce that any other writers in progress on

the inode are not allowed to create inline data.

The problem is that the check for existing inline data and the state

flag can span a lock cycle. For example, if the ilock is originally

locked shared and subsequently upgraded to exclusive, another writer

may have reacquired the lock and created inline data before the dio

write task acquires the lock and proc

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References