Overview
About vulnerability
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().
Details
- Affected product:
- CentOS 6 ELS , CentOS 8.4 ELS , CentOS 8.5 ELS , CloudLinux 6 ELS , Oracle Linux 6 ELS , Oracle Linux 7 ELS , Ubuntu 16.04 ELS
- Affected packages:
- kernel @ 2.6.32 (+7 more)
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().