{"id":"CVE-2025-68299","state":"PUBLISHED","title":"afs: Fix delayed allocation of a cell's anonymous key","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nafs: Fix delayed allocation of a cell's anonymous key\n\nThe allocation of a cell's anonymous key is done in a background thread\nalong with other cell setup such as doing a DNS upcall.  In the reported\nbug, this is triggered by afs_parse_source() parsing the device name given\nto mount() and calling afs_lookup_cell() with the name of the cell.\n\nThe normal key lookup then tries to use the key description on the\nanonymous authentication key as the reference for request_key() - but it\nmay not yet be set and so an oops can happen.\n\nThis has been made more likely to happen by the fix for dynamic lookup\nfailure.\n\nFix this by firstly allocating a reference name and attaching it to the\nafs_cell record when the record is created.  It can share the memory\nallocation with the cell name (unfortunately it can't just overlap the cell\nname by prepending it with \"afs@\" as the cell name already has a '.'\nprepended for other purposes).  This reference name is then passed to\nrequest_key().\n\nSecondly, the anon key is now allocated on demand at the point a key is\nrequested in afs_request_key() if it is not already allocated.  A mutex is\nused to prevent multiple allocation for a cell.\n\nThirdly, make afs_request_key_rcu() return NULL if the anonymous key isn't\nyet allocated (if we need it) and then the caller can return -ECHILD to\ndrop out of RCU-mode and afs_request_key() can be called.\n\nNote that the anonymous key is kind of necessary to make the key lookup\ncache work as that doesn't currently cache a negative lookup, but it's\nprobably worth some investigation to see if NULL can be used instead.","publishedAt":"2025-12-16T15:06:18.246Z","updatedAt":"2026-08-03T09:32:28.315Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"fa4ccdccf1489a6dac4369a8c69f11b455b3355c","status":"affected","lessThan":"bd18d2cbc9377c6b270c0b7ea44b0e6ed1d99c07","versionType":"git"},{"version":"7e33b15d5a6578a99ebf189cea34983270ae92dd","status":"affected","lessThan":"5613bde937dfac6725e9c3fc766b9d6b8481e55b","versionType":"git"},{"version":"330e2c514823008b22e6afd2055715bc46dd8d55","status":"affected","lessThan":"d27c71257825dced46104eefe42e4d9964bd032e","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/afs/cell.c","fs/afs/internal.h","fs/afs/security.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"6.17.9","status":"affected","lessThan":"6.17.11","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/afs/cell.c","fs/afs/internal.h","fs/afs/security.c"]}],"references":["https://git.kernel.org/stable/c/bd18d2cbc9377c6b270c0b7ea44b0e6ed1d99c07","https://git.kernel.org/stable/c/5613bde937dfac6725e9c3fc766b9d6b8481e55b","https://git.kernel.org/stable/c/d27c71257825dced46104eefe42e4d9964bd032e"],"weaknesses":[],"ingestedAt":"2026-10-29T20:09:56.034Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/68xxx/CVE-2025-68299.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-68299","state":"PUBLISHED","datePublished":"2025-12-16T15:06:18.246Z","dateUpdated":"2026-08-03T09:32:28.315Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-12-16T14:48:05.293Z"},"containers":{"cna":{"title":"afs: Fix delayed allocation of a cell's anonymous key","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nafs: Fix delayed allocation of a cell's anonymous key\n\nThe allocation of a cell's anonymous key is done in a background thread\nalong with other cell setup such as doing a DNS upcall.  In the reported\nbug, this is triggered by afs_parse_source() parsing the device name given\nto mount() and calling afs_lookup_cell() with the name of the cell.\n\nThe normal key lookup then tries to use the key description on the\nanonymous authentication key as the reference for request_key() - but it\nmay not yet be set and so an oops can happen.\n\nThis has been made more likely to happen by the fix for dynamic lookup\nfailure.\n\nFix this by firstly allocating a reference name and attaching it to the\nafs_cell record when the record is created.  It can share the memory\nallocation with the cell name (unfortunately it can't just overlap the cell\nname by prepending it with \"afs@\" as the cell name already has a '.'\nprepended for other purposes).  This reference name is then passed to\nrequest_key().\n\nSecondly, the anon key is now allocated on demand at the point a key is\nrequested in afs_request_key() if it is not already allocated.  A mutex is\nused to prevent multiple allocation for a cell.\n\nThirdly, make afs_request_key_rcu() return NULL if the anonymous key isn't\nyet allocated (if we need it) and then the caller can return -ECHILD to\ndrop out of RCU-mode and afs_request_key() can be called.\n\nNote that the anonymous key is kind of necessary to make the key lookup\ncache work as that doesn't currently cache a negative lookup, but it's\nprobably worth some investigation to see if NULL can be used instead."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"fa4ccdccf1489a6dac4369a8c69f11b455b3355c","status":"affected","lessThan":"bd18d2cbc9377c6b270c0b7ea44b0e6ed1d99c07","versionType":"git"},{"version":"7e33b15d5a6578a99ebf189cea34983270ae92dd","status":"affected","lessThan":"5613bde937dfac6725e9c3fc766b9d6b8481e55b","versionType":"git"},{"version":"330e2c514823008b22e6afd2055715bc46dd8d55","status":"affected","lessThan":"d27c71257825dced46104eefe42e4d9964bd032e","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/afs/cell.c","fs/afs/internal.h","fs/afs/security.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"6.17.9","status":"affected","lessThan":"6.17.11","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/afs/cell.c","fs/afs/internal.h","fs/afs/security.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/bd18d2cbc9377c6b270c0b7ea44b0e6ed1d99c07"},{"url":"https://git.kernel.org/stable/c/5613bde937dfac6725e9c3fc766b9d6b8481e55b"},{"url":"https://git.kernel.org/stable/c/d27c71257825dced46104eefe42e4d9964bd032e"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-08-03T09:32:28.315Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.17.9","versionEndExcluding":"6.17.11"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}