218 lines
13 KiB
JSON
218 lines
13 KiB
JSON
{
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"dataType": "CVE_RECORD",
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"dataVersion": "5.2",
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"cveMetadata": {
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"cveId": "CVE-2024-47702",
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"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"state": "PUBLISHED",
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"assignerShortName": "Linux",
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"dateReserved": "2024-09-30T16:00:12.945Z",
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"datePublished": "2024-10-21T11:53:37.958Z",
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"dateUpdated": "2026-10-03T10:55:18.539Z"
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},
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"containers": {
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"cna": {
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"providerMetadata": {
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"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
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"shortName": "Linux",
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"dateUpdated": "2026-10-03T10:55:18.539Z"
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},
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"descriptions": [
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{
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"lang": "en",
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Fail verification for sign-extension of packet data/data_end/data_meta\n\nsyzbot reported a kernel crash due to\n commit 1f1e864b6555 (\"bpf: Handle sign-extenstin ctx member accesses\").\nThe reason is due to sign-extension of 32-bit load for\npacket data/data_end/data_meta uapi field.\n\nThe original code looks like:\n r2 = *(s32 *)(r1 + 76) /* load __sk_buff->data */\n r3 = *(u32 *)(r1 + 80) /* load __sk_buff->data_end */\n r0 = r2\n r0 += 8\n if r3 > r0 goto +1\n ...\nNote that __sk_buff->data load has 32-bit sign extension.\n\nAfter verification and convert_ctx_accesses(), the final asm code looks like:\n r2 = *(u64 *)(r1 +208)\n r2 = (s32)r2\n r3 = *(u64 *)(r1 +80)\n r0 = r2\n r0 += 8\n if r3 > r0 goto pc+1\n ...\nNote that 'r2 = (s32)r2' may make the kernel __sk_buff->data address invalid\nwhich may cause runtime failure.\n\nCurrently, in C code, typically we have\n void *data = (void *)(long)skb->data;\n void *data_end = (void *)(long)skb->data_end;\n ...\nand it will generate\n r2 = *(u64 *)(r1 +208)\n r3 = *(u64 *)(r1 +80)\n r0 = r2\n r0 += 8\n if r3 > r0 goto pc+1\n\nIf we allow sign-extension,\n void *data = (void *)(long)(int)skb->data;\n void *data_end = (void *)(long)skb->data_end;\n ...\nthe generated code looks like\n r2 = *(u64 *)(r1 +208)\n r2 <<= 32\n r2 s>>= 32\n r3 = *(u64 *)(r1 +80)\n r0 = r2\n r0 += 8\n if r3 > r0 goto pc+1\nand this will cause verification failure since \"r2 <<= 32\" is not allowed\nas \"r2\" is a packet pointer.\n\nTo fix this issue for case\n r2 = *(s32 *)(r1 + 76) /* load __sk_buff->data */\nthis patch added additional checking in is_valid_access() callback\nfunction for packet data/data_end/data_meta access. If those accesses\nare with sign-extenstion, the verification will fail.\n\n [1] https://lore.kernel.org/bpf/000000000000c90eee061d236d37@google.com/"
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}
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],
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"metrics": [
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{
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"cvssV3_1": {
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"version": "3.1",
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"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
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"baseScore": 7.8,
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"baseSeverity": "HIGH"
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},
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"scenarios": [
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{
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"lang": "en",
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"value": "AV:L - The vulnerability is reached by loading a crafted eBPF program through the bpf(BPF_PROG_LOAD) syscall, which requires local access to the system; the attacker supplies the malicious LDSX instruction, not a remote peer.\nAC:L - The attacker authors the BPF bytecode directly, so the verifier bypass is accepted deterministically on every load, and the corrupted `(s32)skb->data` pointer is produced on every execution of the program with no race or unpredictable precondition; running the hook repeatedly over many skbs makes the out-of-bounds dereference a certainty.\nPR:L - Loading the affected program types requires CAP_BPF/CAP_NET_ADMIN, which BPF token delegation (`bpf_token_capable()` → `bpf_ns_capable(token->userns, cap)`, present in the affected 6.9–6.11 range) makes available to a host-unprivileged user inside a user namespace, and CAP_BPF is by design a reduced privilege whose security boundary is the verifier itself.\nUI:N - The attacker loads and attaches the program and then generates the traffic (or uses BPF_PROG_TEST_RUN) that executes it; no action from any other user is needed.\nS:U - The out-of-bounds access and resulting corruption occur within the kernel's own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - The verifier still tracks the truncated value as a valid PTR_TO_PACKET, so the program performs kernel-mode reads at `(s32)skb->data + K` far outside any packet buffer and can copy the results into a BPF map or the packet, giving an out-of-bounds kernel memory read primitive.\nI:H - `may_access_direct_pkt_data()` grants direct packet writes to SCHED_CLS, SCHED_ACT, XDP, LWT_XMIT and SK_SKB, so the same corrupted pointer yields kernel-mode stores at an attacker-influenced address — memory corruption exploitable for further escalation.\nA:H - syzbot reported this as a kernel crash; dereferencing the mangled address from softirq/NAPI context produces a page fault or general protection fault in kernel mode, oopsing or panicking the machine."
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}
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]
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}
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],
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"affected": [
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{
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"product": "Linux",
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"vendor": "Linux",
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"defaultStatus": "unaffected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"include/linux/bpf.h",
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"kernel/bpf/verifier.c",
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"net/core/filter.c"
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],
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"versions": [
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"version": "1f1e864b65554e33fe74e3377e58b12f4302f2eb",
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"lessThan": "4b48228eebce2ab1b01e3133da822164472b7e46",
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"status": "affected",
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"version": "1f1e864b65554e33fe74e3377e58b12f4302f2eb",
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"lessThan": "f1620c93a1ec950d87ef327a565d3907736d3340",
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"status": "affected",
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}
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]
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},
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{
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"product": "Linux",
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"vendor": "Linux",
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"defaultStatus": "affected",
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
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"programFiles": [
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"include/linux/bpf.h",
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"kernel/bpf/verifier.c",
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"net/core/filter.c"
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],
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"versions": [
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{
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"version": "6.6",
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"status": "affected"
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},
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{
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"version": "0",
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"lessThan": "6.6",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.6.158",
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"lessThanOrEqual": "6.6.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.10.13",
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"lessThanOrEqual": "6.10.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.11.2",
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"lessThanOrEqual": "6.11.*",
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"status": "unaffected",
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"versionType": "semver"
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},
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{
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"version": "6.12",
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"lessThanOrEqual": "*",
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"status": "unaffected",
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"versionType": "original_commit_for_fix"
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}
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]
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}
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"cpeApplicability": [
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"versionStartIncluding": "6.6",
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]
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],
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"references": [
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{
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"url": "https://git.kernel.org/stable/c/4b48228eebce2ab1b01e3133da822164472b7e46"
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},
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{
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"url": "https://git.kernel.org/stable/c/f1620c93a1ec950d87ef327a565d3907736d3340"
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"url": "https://git.kernel.org/stable/c/f09757fe97a225ae505886eac572e4cbfba96537"
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},
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{
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"url": "https://git.kernel.org/stable/c/92de36080c93296ef9005690705cba260b9bd68a"
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}
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],
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"title": "bpf: Fail verification for sign-extension of packet data/data_end/data_meta",
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"engine": "bippy-1.2.0"
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{
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"metrics": [
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{
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"other": {
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"type": "ssvc",
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"content": {
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"id": "CVE-2024-47702",
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"role": "CISA Coordinator",
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"options": [
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{
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"Exploitation": "none"
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},
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{
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"Automatable": "no"
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},
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{
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"Technical Impact": "partial"
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}
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],
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"version": "2.0.3",
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"timestamp": "2024-10-21T13:04:24.861686Z"
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}
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}
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}
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],
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"title": "CISA ADP Vulnrichment",
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"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
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"shortName": "CISA-ADP",
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"dateUpdated": "2024-10-21T13:14:13.443Z"
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}
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}
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} |