{"id":"CVE-2022-49771","summary":"dm ioctl: fix misbehavior if list_versions races with module loading","details":"In the Linux kernel, the following vulnerability has been resolved:\n\ndm ioctl: fix misbehavior if list_versions races with module loading\n\n__list_versions will first estimate the required space using the\n\"dm_target_iterate(list_version_get_needed, &needed)\" call and then will\nfill the space using the \"dm_target_iterate(list_version_get_info,\n&iter_info)\" call. Each of these calls locks the targets using the\n\"down_read(&_lock)\" and \"up_read(&_lock)\" calls, however between the first\nand second \"dm_target_iterate\" there is no lock held and the target\nmodules can be loaded at this point, so the second \"dm_target_iterate\"\ncall may need more space than what was the first \"dm_target_iterate\"\nreturned.\n\nThe code tries to handle this overflow (see the beginning of\nlist_version_get_info), however this handling is incorrect.\n\nThe code sets \"param-\u003edata_size = param-\u003edata_start + needed\" and\n\"iter_info.end = (char *)vers+len\" - \"needed\" is the size returned by the\nfirst dm_target_iterate call; \"len\" is the size of the buffer allocated by\nuserspace.\n\n\"len\" may be greater than \"needed\"; in this case, the code will write up\nto \"len\" bytes into the buffer, however param-\u003edata_size is set to\n\"needed\", so it may write data past the param-\u003edata_size value. The ioctl\ninterface copies only up to param-\u003edata_size into userspace, thus part of\nthe result will be truncated.\n\nFix this bug by setting \"iter_info.end = (char *)vers + needed;\" - this\nguarantees that the second \"dm_target_iterate\" call will write only up to\nthe \"needed\" buffer and it will exit with \"DM_BUFFER_FULL_FLAG\" if it\noverflows the \"needed\" space - in this case, userspace will allocate a\nlarger buffer and retry.\n\nNote that there is also a bug in list_version_get_needed - we need to add\n\"strlen(tt-\u003ename) + 1\" to the needed size, not \"strlen(tt-\u003ename)\".","modified":"2026-04-11T12:44:30.488191Z","published":"2025-05-01T14:09:08.813Z","related":["SUSE-SU-2025:01918-1","SUSE-SU-2025:01966-1","SUSE-SU-2025:01982-1","SUSE-SU-2025:01983-1","SUSE-SU-2025:01995-1","SUSE-SU-2025:02173-1","SUSE-SU-2025:02262-1"],"database_specific":{"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/49xxx/CVE-2022-49771.json","cna_assigner":"Linux"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/0c8d4112df329bf3dfbf27693f918c3b08676538"},{"type":"WEB","url":"https://git.kernel.org/stable/c/3a1c35d72dc0b34d1e746ed705790c0f630aa427"},{"type":"WEB","url":"https://git.kernel.org/stable/c/4fe1ec995483737f3d2a14c3fe1d8fe634972979"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5398b8e275bf81a2517b327d216c0f37ac9ac5ae"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6a818db0d5aecf80d4ba9e10ac153f60adc629ca"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6ffce7a92ef5c68f7e5d6f4d722c2f96280c064b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b545c0e1e4094d4de2bdfe9a3823f9154b0c0005"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f59f5a269ca5e43c567aca7f1f52500a0186e9b7"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2022/49xxx/CVE-2022-49771.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2022-49771"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"1da177e4c3f41524e886b7f1b8a0c1fc7321cac2"},{"fixed":"0c8d4112df329bf3dfbf27693f918c3b08676538"},{"fixed":"6a818db0d5aecf80d4ba9e10ac153f60adc629ca"},{"fixed":"3a1c35d72dc0b34d1e746ed705790c0f630aa427"},{"fixed":"b545c0e1e4094d4de2bdfe9a3823f9154b0c0005"},{"fixed":"f59f5a269ca5e43c567aca7f1f52500a0186e9b7"},{"fixed":"6ffce7a92ef5c68f7e5d6f4d722c2f96280c064b"},{"fixed":"5398b8e275bf81a2517b327d216c0f37ac9ac5ae"},{"fixed":"4fe1ec995483737f3d2a14c3fe1d8fe634972979"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2022-49771.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"2.6.12"},{"fixed":"4.9.334"}]},{"type":"ECOSYSTEM","events":[{"introduced":"4.10.0"},{"fixed":"4.14.300"}]},{"type":"ECOSYSTEM","events":[{"introduced":"4.15.0"},{"fixed":"4.19.267"}]},{"type":"ECOSYSTEM","events":[{"introduced":"4.20.0"},{"fixed":"5.4.225"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.5.0"},{"fixed":"5.10.156"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.11.0"},{"fixed":"5.15.80"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.0.10"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2022-49771.json"}}],"schema_version":"1.7.5"}