{"id":"CVE-2022-49771","title":"dm ioctl: fix misbehavior if list_versions races with module loading","summary":"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_g…","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 0c8d4112df329bf3dfbf27693f918c3b08676538","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 6a818db0d5aecf80d4ba9e10ac153f60adc629ca","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 3a1c35d72dc0b34d1e746ed705790c0f630aa427","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < b545c0e1e4094d4de2bdfe9a3823f9154b0c0005","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < f59f5a269ca5e43c567aca7f1f52500a0186e9b7","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 6ffce7a92ef5c68f7e5d6f4d722c2f96280c064b","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 5398b8e275bf81a2517b327d216c0f37ac9ac5ae","Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 4fe1ec995483737f3d2a14c3fe1d8fe634972979","Linux 2.6.12"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-11-05T19:47:10.840760Z"},"published":"2025-05-01","updated":"2026-11-05","sourceUpdated":"2026-11-05T19:49:42.811Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2022-49771","references":[{"url":"https://git.kernel.org/stable/c/0c8d4112df329bf3dfbf27693f918c3b08676538"},{"url":"https://git.kernel.org/stable/c/6a818db0d5aecf80d4ba9e10ac153f60adc629ca"},{"url":"https://git.kernel.org/stable/c/3a1c35d72dc0b34d1e746ed705790c0f630aa427"},{"url":"https://git.kernel.org/stable/c/b545c0e1e4094d4de2bdfe9a3823f9154b0c0005"},{"url":"https://git.kernel.org/stable/c/f59f5a269ca5e43c567aca7f1f52500a0186e9b7"},{"url":"https://git.kernel.org/stable/c/6ffce7a92ef5c68f7e5d6f4d722c2f96280c064b"},{"url":"https://git.kernel.org/stable/c/5398b8e275bf81a2517b327d216c0f37ac9ac5ae"},{"url":"https://git.kernel.org/stable/c/4fe1ec995483737f3d2a14c3fe1d8fe634972979"}],"tags":["cve.org"],"epss":0.00159,"epssPercentile":0.0507,"ingestedAt":"2026-11-05T22:38:31.586Z","slug":"CVE-2022-49771","body":"## Overview\n\nIn 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->data_size = param->data_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->data_size is set to\n\"needed\", so it may write data past the param->data_size value. The ioctl\ninterface copies only up to param->data_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->name) + 1\" to the needed size, not \"strlen(tt->name)\".\n\n## Affected\n\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 0c8d4112df329bf3dfbf27693f918c3b08676538`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 6a818db0d5aecf80d4ba9e10ac153f60adc629ca`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 3a1c35d72dc0b34d1e746ed705790c0f630aa427`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < b545c0e1e4094d4de2bdfe9a3823f9154b0c0005`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < f59f5a269ca5e43c567aca7f1f52500a0186e9b7`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 6ffce7a92ef5c68f7e5d6f4d722c2f96280c064b`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 5398b8e275bf81a2517b327d216c0f37ac9ac5ae`\n- `Linux >= 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 < 4fe1ec995483737f3d2a14c3fe1d8fe634972979`\n- `Linux 2.6.12`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}