{"id":"CVE-2023-53798","summary":"ethtool: Fix uninitialized number of lanes","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nethtool: Fix uninitialized number of lanes\n\nIt is not possible to set the number of lanes when setting link modes\nusing the legacy IOCTL ethtool interface. Since 'struct\nethtool_link_ksettings' is not initialized in this path, drivers receive\nan uninitialized number of lanes in 'struct\nethtool_link_ksettings::lanes'.\n\nWhen this information is later queried from drivers, it results in the\nethtool code making decisions based on uninitialized memory, leading to\nthe following KMSAN splat [1]. In practice, this most likely only\nhappens with the tun driver that simply returns whatever it got in the\nset operation.\n\nAs far as I can tell, this uninitialized memory is not leaked to user\nspace thanks to the 'ethtool_ops-\u003ecap_link_lanes_supported' check in\nlinkmodes_prepare_data().\n\nFix by initializing the structure in the IOCTL path. Did not find any\nmore call sites that pass an uninitialized structure when calling\n'ethtool_ops::set_link_ksettings()'.\n\n[1]\nBUG: KMSAN: uninit-value in ethnl_update_linkmodes net/ethtool/linkmodes.c:273 [inline]\nBUG: KMSAN: uninit-value in ethnl_set_linkmodes+0x190b/0x19d0 net/ethtool/linkmodes.c:333\n ethnl_update_linkmodes net/ethtool/linkmodes.c:273 [inline]\n ethnl_set_linkmodes+0x190b/0x19d0 net/ethtool/linkmodes.c:333\n ethnl_default_set_doit+0x88d/0xde0 net/ethtool/netlink.c:640\n genl_family_rcv_msg_doit net/netlink/genetlink.c:968 [inline]\n genl_family_rcv_msg net/netlink/genetlink.c:1048 [inline]\n genl_rcv_msg+0x141a/0x14c0 net/netlink/genetlink.c:1065\n netlink_rcv_skb+0x3f8/0x750 net/netlink/af_netlink.c:2577\n genl_rcv+0x40/0x60 net/netlink/genetlink.c:1076\n netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]\n netlink_unicast+0xf41/0x1270 net/netlink/af_netlink.c:1365\n netlink_sendmsg+0x127d/0x1430 net/netlink/af_netlink.c:1942\n sock_sendmsg_nosec net/socket.c:724 [inline]\n sock_sendmsg net/socket.c:747 [inline]\n ____sys_sendmsg+0xa24/0xe40 net/socket.c:2501\n ___sys_sendmsg+0x2a1/0x3f0 net/socket.c:2555\n __sys_sendmsg net/socket.c:2584 [inline]\n __do_sys_sendmsg net/socket.c:2593 [inline]\n __se_sys_sendmsg net/socket.c:2591 [inline]\n __x64_sys_sendmsg+0x36b/0x540 net/socket.c:2591\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80\n entry_SYSCALL_64_after_hwframe+0x63/0xcd\n\nUninit was stored to memory at:\n tun_get_link_ksettings+0x37/0x60 drivers/net/tun.c:3544\n __ethtool_get_link_ksettings+0x17b/0x260 net/ethtool/ioctl.c:441\n ethnl_set_linkmodes+0xee/0x19d0 net/ethtool/linkmodes.c:327\n ethnl_default_set_doit+0x88d/0xde0 net/ethtool/netlink.c:640\n genl_family_rcv_msg_doit net/netlink/genetlink.c:968 [inline]\n genl_family_rcv_msg net/netlink/genetlink.c:1048 [inline]\n genl_rcv_msg+0x141a/0x14c0 net/netlink/genetlink.c:1065\n netlink_rcv_skb+0x3f8/0x750 net/netlink/af_netlink.c:2577\n genl_rcv+0x40/0x60 net/netlink/genetlink.c:1076\n netlink_unicast_kernel net/netlink/af_netlink.c:1339 [inline]\n netlink_unicast+0xf41/0x1270 net/netlink/af_netlink.c:1365\n netlink_sendmsg+0x127d/0x1430 net/netlink/af_netlink.c:1942\n sock_sendmsg_nosec net/socket.c:724 [inline]\n sock_sendmsg net/socket.c:747 [inline]\n ____sys_sendmsg+0xa24/0xe40 net/socket.c:2501\n ___sys_sendmsg+0x2a1/0x3f0 net/socket.c:2555\n __sys_sendmsg net/socket.c:2584 [inline]\n __do_sys_sendmsg net/socket.c:2593 [inline]\n __se_sys_sendmsg net/socket.c:2591 [inline]\n __x64_sys_sendmsg+0x36b/0x540 net/socket.c:2591\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n do_syscall_64+0x41/0xc0 arch/x86/entry/common.c:80\n entry_SYSCALL_64_after_hwframe+0x63/0xcd\n\nUninit was stored to memory at:\n tun_set_link_ksettings+0x37/0x60 drivers/net/tun.c:3553\n ethtool_set_link_ksettings+0x600/0x690 net/ethtool/ioctl.c:609\n __dev_ethtool net/ethtool/ioctl.c:3024 [inline]\n dev_ethtool+0x1db9/0x2a70 net/ethtool/ioctl.c:3078\n dev_ioctl+0xb07/0x1270 net/core/dev_ioctl.c:524\n sock_do_ioctl+0x295/0x540 net/socket.c:1213\n sock_i\n---truncated---","modified":"2026-03-20T12:33:20.900866Z","published":"2025-12-09T00:00:54.769Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/53xxx/CVE-2023-53798.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/6456d80045d6de47734b1a3879c91f72af186529"},{"type":"WEB","url":"https://git.kernel.org/stable/c/72808c4ab5fd01bf1214195005e15b434bf55cef"},{"type":"WEB","url":"https://git.kernel.org/stable/c/942a2a0184f7bb1c1ae4bbc556559c86c054b0d2"},{"type":"WEB","url":"https://git.kernel.org/stable/c/9ad685dbfe7e856bbf17a7177b64676d324d6ed7"},{"type":"WEB","url":"https://git.kernel.org/stable/c/da81af0ef8092ecacd87fac3229c29e2e0ce39fd"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2023/53xxx/CVE-2023-53798.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2023-53798"},{"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":"012ce4dd3102a0f4d80167de343e9d44b257c1b8"},{"fixed":"da81af0ef8092ecacd87fac3229c29e2e0ce39fd"},{"fixed":"942a2a0184f7bb1c1ae4bbc556559c86c054b0d2"},{"fixed":"6456d80045d6de47734b1a3879c91f72af186529"},{"fixed":"72808c4ab5fd01bf1214195005e15b434bf55cef"},{"fixed":"9ad685dbfe7e856bbf17a7177b64676d324d6ed7"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2023-53798.json"}},{"package":{"name":"Kernel","ecosystem":"Linux"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"5.12.0"},{"fixed":"5.15.112"}]},{"type":"ECOSYSTEM","events":[{"introduced":"5.16.0"},{"fixed":"6.1.29"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.2.0"},{"fixed":"6.2.16"}]},{"type":"ECOSYSTEM","events":[{"introduced":"6.3.0"},{"fixed":"6.3.3"}]}],"database_specific":{"source":"https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2023-53798.json"}}],"schema_version":"1.7.5"}