{"id":"CVE-2024-49949","revision":"5cba571540c549d8b9fc511faf6c3335","records":[{"revision":"5cba571540c549d8b9fc511faf6c3335","observedAt":"2026-10-23T15:48:27.903+00:00","statement":{"source":"cve-program","id":"CVE-2024-49949","aliases":[],"title":"net: avoid potential underflow in qdisc_pkt_len_init() with UFO","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nnet: avoid potential underflow in qdisc_pkt_len_init() with UFO\n\nAfter commit 7c6d2ecbda83 (\"net: be more gentle about silly gso\nrequests coming from user\") virtio_net_hdr_to_skb() had sanity check\nto detect malicious attempts from user space to cook a bad GSO packet.\n\nThen commit cf9acc90c80ec (\"net: virtio_net_hdr_to_skb: count\ntransport header in UFO\") while fixing one issue, allowed user space\nto cook a GSO packet with the following characteristic :\n\nIPv4 SKB_GSO_UDP, gso_size=3, skb->len = 28.\n\nWhen this packet arrives in qdisc_pkt_len_init(), we end up\nwith hdr_len = 28 (IPv4 header + UDP header), matching skb->len\n\nThen the following sets gso_segs to 0 :\n\ngso_segs = DIV_ROUND_UP(skb->len - hdr_len,\n shinfo->gso_size);\n\nThen later we set qdisc_skb_cb(skb)->pkt_len to back to zero :/\n\nqdisc_skb_cb(skb)->pkt_len += (gso_segs - 1) * hdr_len;\n\nThis leads to the following crash in fq_codel [1]\n\nqdisc_pkt_len_init() is best effort, we only want an estimation\nof the bytes sent on the wire, not crashing the kernel.\n\nThis patch is fixing this particular issue, a following one\nadds more sanity checks for another potential bug.\n\n[1]\n[ 70.724101] BUG: kernel NULL pointer dereference, address: 0000000000000000\n[ 70.724561] #PF: supervisor read access in kernel mode\n[ 70.724561] #PF: error_code(0x0000) - not-present page\n[ 70.724561] PGD 10ac61067 P4D 10ac61067 PUD 107ee2067 PMD 0\n[ 70.724561] Oops: Oops: 0000 [#1] SMP NOPTI\n[ 70.724561] CPU: 11 UID: 0 PID: 2163 Comm: b358537762 Not tainted 6.11.0-virtme #991\n[ 70.724561] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-debian-1.16.3-2 04/01/2014\n[ 70.724561] RIP: 0010:fq_codel_enqueue (net/sched/sch_fq_codel.c:120 net/sched/sch_fq_codel.c:168 net/sched/sch_fq_codel.c:230) sch_fq_codel\n[ 70.724561] Code: 24 08 49 c1 e1 06 44 89 7c 24 18 45 31 ed 45 31 c0 31 ff 89 44 24 14 4c 03 8b 90 01 00 00 eb 04 39 ca 73 37 4d 8b 39 83 c7 01 <49> 8b 17 49 89 11 41 8b 57 28 45 8b 5f 34 49 c7 07 00 00 00 00 49\nAll code\n========\n 0:\t24 08 \tand $0x8,%al\n 2:\t49 c1 e1 06 \tshl $0x6,%r9\n 6:\t44 89 7c 24 18 \tmov %r15d,0x18(%rsp)\n b:\t45 31 ed \txor %r13d,%r13d\n e:\t45 31 c0 \txor %r8d,%r8d\n 11:\t31 ff \txor %edi,%edi\n 13:\t89 44 24 14 \tmov %eax,0x14(%rsp)\n 17:\t4c 03 8b 90 01 00 00 \tadd 0x190(%rbx),%r9\n 1e:\teb 04 \tjmp 0x24\n 20:\t39 ca \tcmp %ecx,%edx\n 22:\t73 37 \tjae 0x5b\n 24:\t4d 8b 39 \tmov (%r9),%r15\n 27:\t83 c7 01 \tadd $0x1,%edi\n 2a:*\t49 8b 17 \tmov (%r15),%rdx\t\t<-- trapping instruction\n 2d:\t49 89 11 \tmov %rdx,(%r9)\n 30:\t41 8b 57 28 \tmov 0x28(%r15),%edx\n 34:\t45 8b 5f 34 \tmov 0x34(%r15),%r11d\n 38:\t49 c7 07 00 00 00 00 \tmovq $0x0,(%r15)\n 3f:\t49 \trex.WB\n\nCode starting with the faulting instruction\n===========================================\n 0:\t49 8b 17 \tmov (%r15),%rdx\n 3:\t49 89 11 \tmov %rdx,(%r9)\n 6:\t41 8b 57 28 \tmov 0x28(%r15),%edx\n a:\t45 8b 5f 34 \tmov 0x34(%r15),%r11d\n e:\t49 c7 07 00 00 00 00 \tmovq $0x0,(%r15)\n 15:\t49 \trex.WB\n[ 70.724561] RSP: 0018:ffff95ae85e6fb90 EFLAGS: 00000202\n[ 70.724561] RAX: 0000000002000000 RBX: ffff95ae841de000 RCX: 0000000000000000\n[ 70.724561] RDX: 0000000000000000 RSI: 0000000000000001 RDI: 0000000000000001\n[ 70.724561] RBP: ffff95ae85e6fbf8 R08: 0000000000000000 R09: ffff95b710a30000\n[ 70.724561] R10: 0000000000000000 R11: bdf289445ce31881 R12: ffff95ae85e6fc58\n[ 70.724561] R13: 0000000000000000 R14: 0000000000000040 R15: 0000000000000000\n[ 70.724561] FS: 000000002c5c1380(0000) GS:ffff95bd7fcc0000(0000) knlGS:0000000000000000\n[ 70.724561] CS: 0010 DS: 0000 ES: 0000 C\n---truncated---","state":0,"publishedAt":"2024-10-21T18:02:05.756+00:00","modifiedAt":"2026-10-15T00:54:55.533+00:00","affected":[{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"unaffected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"net/core/dev.c\"\n ],\n \"versions\": [\n {\n \"version\": \"960b360ca7463921c1a6b72e7066a706d6406223\",\n \"lessThan\": \"d70ca7598943572d5e384227bd268acb5109bf72\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"fb2dbc124a7f800cd0e4f901a1bbb769a017104c\",\n \"lessThan\": \"1598d70ad9c7d0a4d9d54b82094e9f45908fda6d\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"8e6bae950da9dc2d2c6c18b1c6b206dc00dc8772\",\n \"lessThan\": \"ba26060a29d3ca1bfc737aa79f7125128f35147c\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"0f810d06b507aa40fef8d1ac0a88e6d0590dbfc3\",\n \"lessThan\": \"939c88cbdc668dadd8cfa7a35d9066331239041c\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"cf9acc90c80ecbee00334aa85d92f4e74014bcff\",\n \"lessThan\": \"d6114993e0a89fde84a60a60a8329a571580b174\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"cf9acc90c80ecbee00334aa85d92f4e74014bcff\",\n \"lessThan\": \"25ab0b87dbd89cecef8a9c60a02bb97832e471d1\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"cf9acc90c80ecbee00334aa85d92f4e74014bcff\",\n \"lessThan\": \"f959cce8a2a04ce776aa8b78e83ce339e0d7fbac\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"cf9acc90c80ecbee00334aa85d92f4e74014bcff\",\n \"lessThan\": \"81fd007dcd47c34471766249853e4d4bce8eea4b\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"cf9acc90c80ecbee00334aa85d92f4e74014bcff\",\n \"lessThan\": \"c20029db28399ecc50e556964eaba75c43b1e2f1\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"2128303bff700c857739a0af8cc39c1a41840650\",\n \"status\": \"affected\",\n \"versionType\": \"git\"\n },\n {\n \"version\": \"4.19.218\",\n \"lessThan\": \"4.19.323\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.4.162\",\n \"lessThan\": \"5.4.285\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.10.82\",\n \"lessThan\": \"5.10.227\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.15.5\",\n \"lessThan\": \"5.15.168\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"4.14.256\",\n \"lessThan\": \"4.15\",\n \"status\": \"affected\",\n \"versionType\": \"semver\"\n }\n ]\n }"},{"ecosystem":"Vendor product","name":"Linux","ranges":[],"versions":[],"rawVersionEvidence":"{\n \"product\": \"Linux\",\n \"vendor\": \"Linux\",\n \"defaultStatus\": \"affected\",\n \"repo\": \"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\n \"programFiles\": [\n \"net/core/dev.c\"\n ],\n \"versions\": [\n {\n \"version\": \"5.16\",\n \"status\": \"affected\"\n },\n {\n \"version\": \"0\",\n \"lessThan\": \"5.16\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"4.19.323\",\n \"lessThanOrEqual\": \"4.19.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.4.285\",\n \"lessThanOrEqual\": \"5.4.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.10.227\",\n \"lessThanOrEqual\": \"5.10.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"5.15.168\",\n \"lessThanOrEqual\": \"5.15.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.1.113\",\n \"lessThanOrEqual\": \"6.1.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.6.55\",\n \"lessThanOrEqual\": \"6.6.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.10.14\",\n \"lessThanOrEqual\": \"6.10.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.11.3\",\n \"lessThanOrEqual\": \"6.11.*\",\n \"status\": \"unaffected\",\n \"versionType\": \"semver\"\n },\n {\n \"version\": \"6.12\",\n \"lessThanOrEqual\": \"*\",\n \"status\": \"unaffected\",\n \"versionType\": \"original_commit_for_fix\"\n }\n ]\n }"}],"metrics":[],"references":["https://git.kernel.org/stable/c/d70ca7598943572d5e384227bd268acb5109bf72","https://git.kernel.org/stable/c/1598d70ad9c7d0a4d9d54b82094e9f45908fda6d","https://git.kernel.org/stable/c/ba26060a29d3ca1bfc737aa79f7125128f35147c","https://git.kernel.org/stable/c/939c88cbdc668dadd8cfa7a35d9066331239041c","https://git.kernel.org/stable/c/d6114993e0a89fde84a60a60a8329a571580b174","https://git.kernel.org/stable/c/25ab0b87dbd89cecef8a9c60a02bb97832e471d1","https://git.kernel.org/stable/c/f959cce8a2a04ce776aa8b78e83ce339e0d7fbac","https://git.kernel.org/stable/c/81fd007dcd47c34471766249853e4d4bce8eea4b","https://git.kernel.org/stable/c/c20029db28399ecc50e556964eaba75c43b1e2f1"],"sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2024-49949","license":"CVE Program Terms of Use","key":"cve-program:CVE-2024-49949","identifiers":["CVE-2024-49949"]},"retained":false,"historicalAffected":[]}],"coverage":[]}