CVE-2023-53083

Description

In the Linux kernel, the following vulnerability has been resolved: nfsd: don't replace page in rq_pages if it's a continuation of last page The splice read calls nfsd_splice_actor to put the pages containing file data into the svc_rqst->rq_pages array. It's possible however to get a splice result that only has a partial page at the end, if (e.g.) the filesystem hands back a short read that doesn't cover the whole page. nfsd_splice_actor will plop the partial page into its rq_pages array and return. Then later, when nfsd_splice_actor is called again, the remainder of the page may end up being filled out. At this point, nfsd_splice_actor will put the page into the array _again_ corrupting the reply. If this is done enough times, rq_next_page will overrun the array and corrupt the trailing fields -- the rq_respages and rq_next_page pointers themselves. If we've already added the page to the array in the last pass, don't add it to the array a second time when dealing with a splice continuation. This was originally handled properly in nfsd_splice_actor, but commit 91e23b1c3982 ("NFSD: Clean up nfsd_splice_actor()") removed the check for it.

Gravité et risque d'exploitation

CVE-2023-53083 obtient un score CVSS de 9.8/10, soit une gravité critique. Selon le modèle EPSS, la probabilité qu'elle soit exploitée dans les 30 prochains jours est de 0.50 %, ce qui la place devant 41.7 % des CVE référencées.

Que faire ?

• Vérifiez si Linux (versions <=6.1.*, <=*, 91e23b1c39820bfed642119ff6b6ef9f43cf09ce, <8235cd619db6e67f1d7d26c55f1f3e4e575c947d, 6.2.9, 56bc7e3821e847a6cc8027ddaba32e9a440225a5, <51ddb84baff6f09ad62b5999ece3ec172e4e3568, <=6.2.*, <0101067f376eb7b9afd00279270f25d5111a091d, 0, 6.3, <12eca509234acb6b666802edf77408bb70d7bfca, 6.1.22, <27c934dd8832dd40fd34776f916dc201e18b319b, <5.19, 5.19, bf1cbe2f3650b4f4a8add6af933c6d7f6af1f361) 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/8235cd619db6e67f1d7d26c55f1f3e4e575c947d
• https://git.kernel.org/stable/c/12eca509234acb6b666802edf77408bb70d7bfca
• https://git.kernel.org/stable/c/51ddb84baff6f09ad62b5999ece3ec172e4e3568
• https://git.kernel.org/stable/c/0101067f376eb7b9afd00279270f25d5111a091d
• https://git.kernel.org/stable/c/27c934dd8832dd40fd34776f916dc201e18b319b