CVE-2022-48828 Information

Description

In the Linux kernel the following vulnerability has been resolved:

NFSD: Fix ia_size underflow

iattr::ia_size is a loff_t which is a signed 64-bit type. NFSv3 and NFSv4 both define file size as an unsigned 64-bit type. Thus there is a range of valid file size values an NFS client can send that is already larger than Linux can handle.

Currently decode_fattr4() dumps a full u64 value into ia_size. If that value happens to be larger than S64_MAX then ia_size underflows. I’m about to fix up the NFSv3 behavior as well so let’s catch the underflow in the common code path: nfsd_setattr().

Reference

https://git.kernel.org/stable/c/38d02ba22e43b6fc7d291cf724bc6e3b7be6626b https://git.kernel.org/stable/c/8e0ecaf7a7e57b30284d6b3289cc436100fadc48 https://git.kernel.org/stable/c/da22ca1ad548429d7822011c54cfe210718e0aa7 https://git.kernel.org/stable/c/e6faac3f58c7c4176b66f63def17a34232a17b0e