From bippy-c9c4e1df01b2 Mon Sep 17 00:00:00 2001 From: Greg Kroah-Hartman To: Reply-to: , Subject: CVE-2022-48828: NFSD: Fix ia_size underflow 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(). The Linux kernel CVE team has assigned CVE-2022-48828 to this issue. Affected and fixed versions =========================== Fixed in 5.10.220 with commit 38d02ba22e43 Fixed in 5.15.24 with commit 8e0ecaf7a7e5 Fixed in 5.16.10 with commit da22ca1ad548 Fixed in 5.17 with commit e6faac3f58c7 Please see https://www.kernel.org for a full list of currently supported kernel versions by the kernel community. Unaffected versions might change over time as fixes are backported to older supported kernel versions. The official CVE entry at https://cve.org/CVERecord/?id=CVE-2022-48828 will be updated if fixes are backported, please check that for the most up to date information about this issue. Affected files ============== The file(s) affected by this issue are: fs/nfsd/vfs.c Mitigation ========== The Linux kernel CVE team recommends that you update to the latest stable kernel version for this, and many other bugfixes. Individual changes are never tested alone, but rather are part of a larger kernel release. Cherry-picking individual commits is not recommended or supported by the Linux kernel community at all. If however, updating to the latest release is impossible, the individual changes to resolve this issue can be found at these commits: 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