CVE-2024-26692

/// Technical description

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

smb: Fix regression in writes when non-standard maximum write size negotiated

The conversion to netfs in the 6.3 kernel caused a regression when

maximum write size is set by the server to an unexpected value which is

not a multiple of 4096 (similarly if the user overrides the maximum

write size by setting mount parm "wsize", but sets it to a value that

is not a multiple of 4096). When negotiated write size is not a

multiple of 4096 the netfs code can skip the end of the final

page when doing large sequential writes, causing data corruption.

This section of code is being rewritten/removed due to a large

netfs change, but until that point (ie for the 6.3 kernel until now)

we can not support non-standard maximum write sizes.

Add a warning if a user specifies a wsize on mount that is not

a multiple of 4096 (and round down), also add a change where we

round down the maximum write size if the server negotiates a value

t

/// 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