{ "data_version": "4.0", "data_type": "CVE", "data_format": "MITRE", "CVE_data_meta": { "ID": "CVE-2024-49949", "ASSIGNER": "cve@kernel.org", "STATE": "PUBLIC" }, "description": { "description_data": [ { "lang": "eng", "value": "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---" } ] }, "problemtype": { "problemtype_data": [ { "description": [ { "lang": "eng", "value": "n/a" } ] } ] }, "affects": { "vendor": { "vendor_data": [ { "vendor_name": "Linux", "product": { "product_data": [ { "product_name": "Linux", "version": { "version_data": [ { "version_affected": "<", "version_name": "8e6bae950da9", "version_value": "ba26060a29d3" }, { "version_affected": "<", "version_name": "0f810d06b507", "version_value": "939c88cbdc66" }, { "version_affected": "<", "version_name": "cf9acc90c80e", "version_value": "d6114993e0a8" }, { "version_value": "not down converted", "x_cve_json_5_version_data": { "versions": [ { "version": "5.16", "status": "affected" }, { "version": "0", "lessThan": "5.16", "status": "unaffected", "versionType": "custom" }, { "version": "5.10.227", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "custom" }, { "version": "5.15.168", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "custom" }, { "version": "6.1.113", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "custom" }, { "version": "6.6.55", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "custom" }, { "version": "6.10.14", "lessThanOrEqual": "6.10.*", "status": "unaffected", "versionType": "custom" }, { "version": "6.11.3", "lessThanOrEqual": "6.11.*", "status": "unaffected", "versionType": "custom" }, { "version": "6.12-rc2", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ], "defaultStatus": "affected" } } ] } } ] } } ] } }, "references": { "reference_data": [ { "url": "https://git.kernel.org/stable/c/ba26060a29d3ca1bfc737aa79f7125128f35147c", "refsource": "MISC", "name": "https://git.kernel.org/stable/c/ba26060a29d3ca1bfc737aa79f7125128f35147c" }, { "url": "https://git.kernel.org/stable/c/939c88cbdc668dadd8cfa7a35d9066331239041c", "refsource": "MISC", "name": "https://git.kernel.org/stable/c/939c88cbdc668dadd8cfa7a35d9066331239041c" }, { "url": "https://git.kernel.org/stable/c/d6114993e0a89fde84a60a60a8329a571580b174", "refsource": "MISC", "name": "https://git.kernel.org/stable/c/d6114993e0a89fde84a60a60a8329a571580b174" }, { "url": "https://git.kernel.org/stable/c/25ab0b87dbd89cecef8a9c60a02bb97832e471d1", "refsource": "MISC", "name": "https://git.kernel.org/stable/c/25ab0b87dbd89cecef8a9c60a02bb97832e471d1" }, { "url": "https://git.kernel.org/stable/c/f959cce8a2a04ce776aa8b78e83ce339e0d7fbac", "refsource": "MISC", "name": "https://git.kernel.org/stable/c/f959cce8a2a04ce776aa8b78e83ce339e0d7fbac" }, { "url": "https://git.kernel.org/stable/c/81fd007dcd47c34471766249853e4d4bce8eea4b", "refsource": "MISC", "name": "https://git.kernel.org/stable/c/81fd007dcd47c34471766249853e4d4bce8eea4b" }, { "url": "https://git.kernel.org/stable/c/c20029db28399ecc50e556964eaba75c43b1e2f1", "refsource": "MISC", "name": "https://git.kernel.org/stable/c/c20029db28399ecc50e556964eaba75c43b1e2f1" } ] }, "generator": { "engine": "bippy-c9c4e1df01b2" } }