Vigie VulnDBEuropean-hosted Vulnerability DB
EN
Menu

ppp: Fix KMSAN uninit-value warning with bpf (Linux Linux)

CVE-2025-21922
MEDIUM 5.5

En bref

Source
NVD
EPSS
EPSS 0.23 % · centile 14 ()
État
PUBLISHED
Publiée
Mise à jour
Attribuée par
Linux
Statut NVD
Modified

Rechercher sur…

Description

In the Linux kernel, the following vulnerability has been resolved: ppp: Fix KMSAN uninit-value warning with bpf Syzbot caught an "KMSAN: uninit-value" warning [1], which is caused by the ppp driver not initializing a 2-byte header when using socket filter. The following code can generate a PPP filter BPF program: ''' struct bpf_program fp; pcap_t *handle; handle = pcap_open_dead(DLT_PPP_PPPD, 65535); pcap_compile(handle, &fp, "ip and outbound", 0, 0); bpf_dump(&fp, 1); ''' Its output is: ''' (000) ldh [2] (001) jeq #0x21 jt 2 jf 5 (002) ldb [0] (003) jeq #0x1 jt 4 jf 5 (004) ret #65535 (005) ret #0 ''' Wen can find similar code at the following link: https://github.com/ppp-project/ppp/blob/master/pppd/options.c#L1680 The maintainer of this code repository is also the original maintainer of the ppp driver. As you can see the BPF program skips 2 bytes of data and then reads the 'Protocol' field to determine if it's an IP packet. Then it read the first byte of the first 2 bytes to determine the direction. The issue is that only the first byte indicating direction is initialized in current ppp driver code while the second byte is not initialized. For normal BPF programs generated by libpcap, uninitialized data won't be used, so it's not a problem. However, for carefully crafted BPF programs, such as those generated by syzkaller [2], which start reading from offset 0, the uninitialized data will be used and caught by KMSAN. [1] https://syzkaller.appspot.com/bug?extid=853242d9c9917165d791 [2] https://syzkaller.appspot.com/text?tag=ReproC&x=11994913980000

Faiblesses (CWE)

  • CWE-908 — Utilisation d'une ressource non initialisée

Références

Scores

VersionScoreVecteurÉvalué par
CVSS 3.1MEDIUM 5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HCISA-ADP
CVSS 3.1MEDIUM 5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HNVD · nvd@nist.gov (Primary)
CVSS 3.1MEDIUM 5.5CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:HNVD · 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary)

Références européennes

Avis du CERT-FR

Configurations affectées (CPE NVD)

Produits affectés

ProduitVersions
Linux · Linuxaffected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < d685096c8129c9a92689975193e268945fd21dbf ; affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 2f591cb158807bdcf424f66f1fbfa6e4e50f3757 ; affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 4e2191b0fd0c064d37b0db67396216f2d4787e0f ; affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 3de809a768464528762757e433cd50de35bcb3c1 ; affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 1eacd47636a9de5bee25d9d5962dc538a82d9f0b ; affected 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 8aa8a40c766b3945b40565a70349d5581458ff63
Linux · Linuxaffected 2.6.12 ; unaffected 0 < 2.6.12 ; unaffected 5.4.291 ≤ 5.4.* ; unaffected 5.10.235 ≤ 5.10.* ; unaffected 5.15.179 ≤ 5.15.* ; unaffected 6.1.131 ≤ 6.1.*

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD