{"id":"CVE-2024-41048","summary":"skmsg: Skip zero length skb in sk_msg_recvmsg","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nskmsg: Skip zero length skb in sk_msg_recvmsg\n\nWhen running BPF selftests (./test_progs -t sockmap_basic) on a Loongarch\nplatform, the following kernel panic occurs:\n\n  [...]\n  Oops[#1]:\n  CPU: 22 PID: 2824 Comm: test_progs Tainted: G           OE  6.10.0-rc2+ #18\n  Hardware name: LOONGSON Dabieshan/Loongson-TC542F0, BIOS Loongson-UDK2018\n     ... ...\n     ra: 90000000048bf6c0 sk_msg_recvmsg+0x120/0x560\n    ERA: 9000000004162774 copy_page_to_iter+0x74/0x1c0\n   CRMD: 000000b0 (PLV0 -IE -DA +PG DACF=CC DACM=CC -WE)\n   PRMD: 0000000c (PPLV0 +PIE +PWE)\n   EUEN: 00000007 (+FPE +SXE +ASXE -BTE)\n   ECFG: 00071c1d (LIE=0,2-4,10-12 VS=7)\n  ESTAT: 00010000 [PIL] (IS= ECode=1 EsubCode=0)\n   BADV: 0000000000000040\n   PRID: 0014c011 (Loongson-64bit, Loongson-3C5000)\n  Modules linked in: bpf_testmod(OE) xt_CHECKSUM xt_MASQUERADE xt_conntrack\n  Process test_progs (pid: 2824, threadinfo=0000000000863a31, task=...)\n  Stack : ...\n  Call Trace:\n  [\u003c9000000004162774\u003e] copy_page_to_iter+0x74/0x1c0\n  [\u003c90000000048bf6c0\u003e] sk_msg_recvmsg+0x120/0x560\n  [\u003c90000000049f2b90\u003e] tcp_bpf_recvmsg_parser+0x170/0x4e0\n  [\u003c90000000049aae34\u003e] inet_recvmsg+0x54/0x100\n  [\u003c900000000481ad5c\u003e] sock_recvmsg+0x7c/0xe0\n  [\u003c900000000481e1a8\u003e] __sys_recvfrom+0x108/0x1c0\n  [\u003c900000000481e27c\u003e] sys_recvfrom+0x1c/0x40\n  [\u003c9000000004c076ec\u003e] do_syscall+0x8c/0xc0\n  [\u003c9000000003731da4\u003e] handle_syscall+0xc4/0x160\n  Code: ...\n  ---[ end trace 0000000000000000 ]---\n  Kernel panic - not syncing: Fatal exception\n  Kernel relocated by 0x3510000\n   .text @ 0x9000000003710000\n   .data @ 0x9000000004d70000\n   .bss  @ 0x9000000006469400\n  ---[ end Kernel panic - not syncing: Fatal exception ]---\n  [...]\n\nThis crash happens every time when running sockmap_skb_verdict_shutdown\nsubtest in sockmap_basic.\n\nThis crash is because a NULL pointer is passed to page_address() in the\nsk_msg_recvmsg(). Due to the different implementations depending on the\narchitecture, page_address(NULL) will trigger a panic on Loongarch\nplatform but not on x86 platform. So this bug was hidden on x86 platform\nfor a while, but now it is exposed on Loongarch platform. The root cause\nis that a zero length skb (skb-\u003elen == 0) was put on the queue.\n\nThis zero length skb is a TCP FIN packet, which was sent by shutdown(),\ninvoked in test_sockmap_skb_verdict_shutdown():\n\n\tshutdown(p1, SHUT_WR);\n\nIn this case, in sk_psock_skb_ingress_enqueue(), num_sge is zero, and no\npage is put to this sge (see sg_set_page in sg_set_page), but this empty\nsge is queued into ingress_msg list.\n\nAnd in sk_msg_recvmsg(), this empty sge is used, and a NULL page is got by\nsg_page(sge). Pass this NULL page to copy_page_to_iter(), which passes it\nto kmap_local_page() and to page_address(), then kernel panics.\n\nTo solve this, we should skip this zero length skb. So in sk_msg_recvmsg(),\nif copy is zero, that means it's a zero length skb, skip invoking\ncopy_page_to_iter(). We are using the EFAULT return triggered by\ncopy_page_to_iter to check for is_fin in tcp_bpf.c.","modified":"2026-04-16T04:32:59.327235590Z","published":"2024-07-29T14:32:05.224Z","related":["SUSE-SU-2024:2892-1","SUSE-SU-2024:2894-1","SUSE-SU-2024:2901-1","SUSE-SU-2024:2939-1","SUSE-SU-2024:2940-1","SUSE-SU-2024:2947-1","SUSE-SU-2024:3194-1","SUSE-SU-2024:3195-1","SUSE-SU-2024:3383-1","SUSE-SU-2025:20044-1","SUSE-SU-2025:20047-1"],"database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/41xxx/CVE-2024-41048.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/195b7bcdfc5adc5b2468f279dd9eb7eebd2e7632"},{"type":"WEB","url":"https://git.kernel.org/stable/c/b180739b45a38b4caa88fe16bb5273072e6613dc"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f0c18025693707ec344a70b6887f7450bf4c826b"},{"type":"WEB","url":"https://git.kernel.org/stable/c/f8bd689f37f4198a4c61c4684f591ba639595b97"},{"type":"WEB","url":"https://git.kernel.org/stable/c/fb61d7b9fb6ef0032de469499a54dab4c7260d0d"},{"type":"WEB","url":"https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2024/41xxx/CVE-2024-41048.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2024-41048"},{"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":"604326b41a6fb9b4a78b6179335decee0365cd8c"},{"fixed":"195b7bcdfc5adc5b2468f279dd9eb7eebd2e7632"},{"fixed":"fb61d7b9fb6ef0032de469499a54dab4c7260d0d"},{"fixed":"b180739b45a38b4caa88fe16bb5273072e6613dc"},{"fixed":"f8bd689f37f4198a4c61c4684f591ba639595b97"},{"fixed":"f0c18025693707ec344a70b6887f7450bf4c826b"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2024-41048.json"}}],"schema_version":"1.7.5"}