CVE-2022-48827

Description

In the Linux kernel, the following vulnerability has been resolved: NFSD: Fix the behavior of READ near OFFSET_MAX Dan Aloni reports: > Due to commit 8cfb9015280d ("NFS: Always provide aligned buffers to > the RPC read layers") on the client, a read of 0xfff is aligned up > to server rsize of 0x1000. > > As a result, in a test where the server has a file of size > 0x7fffffffffffffff, and the client tries to read from the offset > 0x7ffffffffffff000, the read causes loff_t overflow in the server > and it returns an NFS code of EINVAL to the client. The client as > a result indefinitely retries the request. The Linux NFS client does not handle NFS?ERR_INVAL, even though all NFS specifications permit servers to return that status code for a READ. Instead of NFS?ERR_INVAL, have out-of-range READ requests succeed and return a short result. Set the EOF flag in the result to prevent the client from retrying the READ request. This behavior appears to be consistent with Solaris NFS servers. Note that NFSv3 and NFSv4 use u64 offset values on the wire. These must be converted to loff_t internally before use -- an implicit type cast is not adequate for this purpose. Otherwise VFS checks against sb->s_maxbytes do not work properly.

Gravité et risque d'exploitation

CVE-2022-48827 obtient un score CVSS de 7.5/10, soit une gravité élevée. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.62 %, ce qui la place devant 48.8 % des CVE référencées.

Que faire ?

• Vérifiez si Linux (versions <2.6.12, 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, <44502aca8e02ab32d6b0eb52e006a5ec9402719b, <=*, <c6eff5c4277146a78b4fb8c9b668dd64542c41b0, <1726a39b0879acfb490b22dca643f26f4f907da9, 2.6.12, <=5.15.*, 5.15.24, 5.16.10, <=5.10.*, 0, 5.17, <0cb4d23ae08c48f6bf3c29a8e5c4a74b8388b960, <=5.16.*, 5.10.220) est présent sur votre parc.
• Appliquez le correctif ou la version corrigée indiqués dans les références de l'éditeur.
• À défaut de correctif, limitez l'exposition (filtrage réseau, désactivation du composant).
• Automatisez la détection : les agents CVE Heimdall (gratuits, open source) corrèlent l'inventaire de vos serveurs avec la base CVE.

Références

• https://git.kernel.org/stable/c/1726a39b0879acfb490b22dca643f26f4f907da9
• https://git.kernel.org/stable/c/c6eff5c4277146a78b4fb8c9b668dd64542c41b0
• https://git.kernel.org/stable/c/44502aca8e02ab32d6b0eb52e006a5ec9402719b
• https://git.kernel.org/stable/c/0cb4d23ae08c48f6bf3c29a8e5c4a74b8388b960