title: smb: Fix regression in writes when non-standard maximum write size negotiated
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
that is not a multiple of 4096 (we also have to check to make sure that
we do not round it down to zero).
affected:
{
product: Linux
vendor: Linux
defaultStatus: unaffected
repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
versions:
version: d08089f649a0, lessThan: 4145ccff546e, status: affected, versionType: git
version: d08089f649a0, lessThan: 63c35afd50e2, status: affected, versionType: git
version: d08089f649a0, lessThan: 4860abb91f3d, status: affected, versionType: git
}
{
product: Linux
vendor: Linux
defaultStatus: affected
repo: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
versions:
version: 6.3, status: affected
version: 0, lessThan: 6.3, status: unaffected, versionType: custom
version: 6.6.18, lessThanOrEqual: 6.6.*, status: unaffected, versionType: custom
version: 6.7.6, lessThanOrEqual: 6.7.*, status: unaffected, versionType: custom
version: 6.8, lessThanOrEqual: *, status: unaffected, versionType: original_commit_for_fix
}
