CVE-2025-71304smack: /smack/doi: accept previously used values

Official description

In the Linux kernel, the following vulnerability has been resolved: smack: /smack/doi: accept previously used values Writing to /smack/doi a value that has ever been written there in the past disables networking for non-ambient labels. E.g. # cat /smack/doi 3 # netlabelctl -p cipso list Configured CIPSO mappings (1) DOI value : 3 mapping type : PASS_THROUGH # netlabelctl -p map list Configured NetLabel domain mappings (3) domain: "_" (IPv4) protocol: UNLABELED domain: DEFAULT (IPv4) protocol: CIPSO, DOI = 3 domain: DEFAULT (IPv6) protocol: UNLABELED # cat /smack/ambient _ # cat /proc/$$/attr/smack/current _ # ping -c1 10.1.95.12 64 bytes from 10.1.95.12: icmp_seq=1 ttl=64 time=0.964 ms # echo foo >/proc/$$/attr/smack/current # ping -c1 10.1.95.12 64 bytes from 10.1.95.12: icmp_seq=1 ttl=64 time=0.956 ms unknown option 86 # echo 4 >/smack/doi # echo 3 >/smack/doi !> [ 214.050395] smk_cipso_doi:691 cipso add rc = -17 # echo 3 >/smack/doi !> [ 249.402261] smk_cipso_doi:678 remove rc = -2 !> [ 249.402261] smk_cipso_doi:691 cipso add rc = -17 # ping -c1 10.1.95.12 !!> ping: 10.1.95.12: Address family for hostname not supported # echo _ >/proc/$$/attr/smack/current # ping -c1 10.1.95.12 64 bytes from 10.1.95.12: icmp_seq=1 ttl=64 time=0.617 ms This happens because Smack keeps decommissioned DOIs, fails to re-add them, and consequently refuses to add the “default” domain map: # netlabelctl -p cipso list Configured CIPSO mappings (2) DOI value : 3 mapping type : PASS_THROUGH DOI value : 4 mapping type : PASS_THROUGH # netlabelctl -p map list Configured NetLabel domain mappings (2) domain: "_" (IPv4) protocol: UNLABELED !> (no ipv4 map for default domain here) domain: DEFAULT (IPv6) protocol: UNLABELED Fix by clearing decommissioned DOI definitions and serializing concurrent DOI updates with a new lock. Also: - allow /smack/doi to live unconfigured, since adding a map (netlbl_cfg_cipsov4_map_add) may fail. CIPSO_V4_DOI_UNKNOWN(0) indicates the unconfigured DOI - add new DOI before removing the old default map, so the old map remains if the add fails (2008-02-04, Casey Schaufler)

Affected packages & fixed versions

Affected products (as reported)

References

• https://git.kernel.org/stable/c/eb718a3c8181ada679340db34cd61bce48e44749
• https://git.kernel.org/stable/c/6ec091c5c7eeabd249a7c46813cad1e9f555f859
• https://git.kernel.org/stable/c/199452f22d2f74b897fe826f81ec402b0a8461a0
• https://git.kernel.org/stable/c/1c7ee23dfcd18d80770d8f90f2ab5bb1b2bfd8a3
• https://git.kernel.org/stable/c/f8071500177f38cff38892bd85ac631cc6e010b2
• https://git.kernel.org/stable/c/5a247a84de0ba44edbbd6be851c8a6b2aa60ff85
• https://git.kernel.org/stable/c/8beebb8ad9a003f978e53b06237986588223e15e
• https://git.kernel.org/stable/c/33d589ed60ae433b483761987b85e0d24e54584e