{
    "dataType": "CVE_RECORD",
    "dataVersion": "5.2",
    "cveMetadata": {
        "cveId": "CVE-2025-38475",
        "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "state": "PUBLISHED",
        "assignerShortName": "Linux",
        "dateReserved": "2025-04-16T04:51:24.021Z",
        "datePublished": "2025-07-28T11:21:36.293Z",
        "dateUpdated": "2026-08-05T12:02:12.245Z"
    },
    "containers": {
        "cna": {
            "providerMetadata": {
                "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
                "shortName": "Linux",
                "dateUpdated": "2026-08-05T12:02:12.245Z"
            },
            "descriptions": [
                {
                    "lang": "en",
                    "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmc: Fix various oops due to inet_sock type confusion.\n\nsyzbot reported weird splats [0][1] in cipso_v4_sock_setattr() while\nfreeing inet_sk(sk)->inet_opt.\n\nThe address was freed multiple times even though it was read-only memory.\n\ncipso_v4_sock_setattr() did nothing wrong, and the root cause was type\nconfusion.\n\nThe cited commit made it possible to create smc_sock as an INET socket.\n\nThe issue is that struct smc_sock does not have struct inet_sock as the\nfirst member but hijacks AF_INET and AF_INET6 sk_family, which confuses\nvarious places.\n\nIn this case, inet_sock.inet_opt was actually smc_sock.clcsk_data_ready(),\nwhich is an address of a function in the text segment.\n\n  $ pahole -C inet_sock vmlinux\n  struct inet_sock {\n  ...\n          struct ip_options_rcu *    inet_opt;             /*   784     8 */\n\n  $ pahole -C smc_sock vmlinux\n  struct smc_sock {\n  ...\n          void                       (*clcsk_data_ready)(struct sock *); /*   784     8 */\n\nThe same issue for another field was reported before. [2][3]\n\nAt that time, an ugly hack was suggested [4], but it makes both INET\nand SMC code error-prone and hard to change.\n\nAlso, yet another variant was fixed by a hacky commit 98d4435efcbf3\n(\"net/smc: prevent NULL pointer dereference in txopt_get\").\n\nInstead of papering over the root cause by such hacks, we should not\nallow non-INET socket to reuse the INET infra.\n\nLet's add inet_sock as the first member of smc_sock.\n\n[0]:\nkvfree_call_rcu(): Double-freed call. rcu_head 000000006921da73\nWARNING: CPU: 0 PID: 6718 at mm/slab_common.c:1956 kvfree_call_rcu+0x94/0x3f0 mm/slab_common.c:1955\nModules linked in:\nCPU: 0 UID: 0 PID: 6718 Comm: syz.0.17 Tainted: G        W           6.16.0-rc4-syzkaller-g7482bb149b9f #0 PREEMPT\nTainted: [W]=WARN\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 05/07/2025\npstate: 60400005 (nZCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--)\npc : kvfree_call_rcu+0x94/0x3f0 mm/slab_common.c:1955\nlr : kvfree_call_rcu+0x94/0x3f0 mm/slab_common.c:1955\nsp : ffff8000a03a7730\nx29: ffff8000a03a7730 x28: 00000000fffffff5 x27: 1fffe000184823d3\nx26: dfff800000000000 x25: ffff0000c2411e9e x24: ffff0000dd88da00\nx23: ffff8000891ac9a0 x22: 00000000ffffffea x21: ffff8000891ac9a0\nx20: ffff8000891ac9a0 x19: ffff80008afc2480 x18: 00000000ffffffff\nx17: 0000000000000000 x16: ffff80008ae642c8 x15: ffff700011ede14c\nx14: 1ffff00011ede14c x13: 0000000000000004 x12: ffffffffffffffff\nx11: ffff700011ede14c x10: 0000000000ff0100 x9 : 5fa3c1ffaf0ff000\nx8 : 5fa3c1ffaf0ff000 x7 : 0000000000000001 x6 : 0000000000000001\nx5 : ffff8000a03a7078 x4 : ffff80008f766c20 x3 : ffff80008054d360\nx2 : 0000000000000000 x1 : 0000000000000201 x0 : 0000000000000000\nCall trace:\n kvfree_call_rcu+0x94/0x3f0 mm/slab_common.c:1955 (P)\n cipso_v4_sock_setattr+0x2f0/0x3f4 net/ipv4/cipso_ipv4.c:1914\n netlbl_sock_setattr+0x240/0x334 net/netlabel/netlabel_kapi.c:1000\n smack_netlbl_add+0xa8/0x158 security/smack/smack_lsm.c:2581\n smack_inode_setsecurity+0x378/0x430 security/smack/smack_lsm.c:2912\n security_inode_setsecurity+0x118/0x3c0 security/security.c:2706\n __vfs_setxattr_noperm+0x174/0x5c4 fs/xattr.c:251\n __vfs_setxattr_locked+0x1ec/0x218 fs/xattr.c:295\n vfs_setxattr+0x158/0x2ac fs/xattr.c:321\n do_setxattr fs/xattr.c:636 [inline]\n file_setxattr+0x1b8/0x294 fs/xattr.c:646\n path_setxattrat+0x2ac/0x320 fs/xattr.c:711\n __do_sys_fsetxattr fs/xattr.c:761 [inline]\n __se_sys_fsetxattr fs/xattr.c:758 [inline]\n __arm64_sys_fsetxattr+0xc0/0xdc fs/xattr.c:758\n __invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]\n invoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49\n el0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132\n do_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151\n el0_svc+0x58/0x180 arch/arm64/kernel/entry-common.c:879\n el0t_64_sync_handler+0x84/0x12c arch/arm64/kernel/entry-common.c:898\n el0t_64_sync+0x198/0x19c arch/arm64/kernel/entry.S:600\n\n[\n---truncated---"
                }
            ],
            "metrics": [
                {
                    "cvssV3_1": {
                        "version": "3.1",
                        "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
                        "baseScore": 7.8,
                        "baseSeverity": "HIGH"
                    },
                    "scenarios": [
                        {
                            "lang": "en",
                            "value": "AV:L - The type confusion is created and triggered locally via the `socket(AF_INET, SOCK_STREAM, IPPROTO_SMC)` / `fsetxattr` / `listen` syscall sequence; although the hijacked `clcsk_data_ready` pointer is finally dereferenced when a remote peer connects, an attacker with local socket access is required to establish the corruption.\nAC:L - Deterministic and race-free — a single unprivileged `socket()` call on a NetLabel/CIPSO-labeling system (Smack labels every PF_INET socket at creation by default) immediately overwrites the aliased field, and the syzbot reproducers are reliable and were confirmed by the Tested-by tag.\nPR:L - No capability check exists anywhere on the SMC INET create path, and `MODULE_ALIAS_NET_PF_PROTO_TYPE(PF_INET, 256, 1)` lets any unprivileged user autoload the module; the LSM netlabel hook then runs on the attacker's own socket with no privileges needed.\nUI:N - The attacker performs the entire sequence — socket creation, optional xattr set, listen — with no action from any other user or administrator.\nS:U - The corruption is confined to kernel memory managed by the same kernel security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - Type confusion between `inet_sock` and `smc_sock` makes the kernel read through and dereference a field it misinterprets (`old->opt.optlen` read from a `.text` address), and the resulting function-pointer control gives an attacker the leverage to build arbitrary kernel-memory read primitives.\nI:H - `rcu_assign_pointer(sk_inet->inet_opt, opt)` plants an attacker-influenced heap pointer into the `clcsk_data_ready` function-pointer slot that `smc_clcsock_data_ready()` later calls indirectly, and `kfree_rcu()` is invoked on a read-only `.text` address — a type-confusion write and control-flow hijack primitive.\nA:H - syzbot captured a `WARNING` in `kvfree_call_rcu()` (double free) and a fatal \"Unable to handle kernel write to read-only memory\" Oops, both of which panic or kill the kernel and are trivially repeatable."
                        }
                    ]
                }
            ],
            "affected": [
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "net/smc/af_smc.c",
                        "net/smc/smc.h"
                    ],
                    "versions": [
                        {
                            "version": "d25a92ccae6bed02327b63d138e12e7806830f78",
                            "lessThan": "5b02e397929e5b13b969ef1f8e43c7951e2864f5",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "d25a92ccae6bed02327b63d138e12e7806830f78",
                            "lessThan": "67a167a6b8b45607bc34aa541d1c75097d18d460",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "d25a92ccae6bed02327b63d138e12e7806830f78",
                            "lessThan": "60ada4fe644edaa6c2da97364184b0425e8aeaf5",
                            "status": "affected",
                            "versionType": "git"
                        }
                    ]
                },
                {
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "net/smc/af_smc.c",
                        "net/smc/smc.h"
                    ],
                    "versions": [
                        {
                            "version": "6.11",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "6.11",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.12.40",
                            "lessThanOrEqual": "6.12.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.15.8",
                            "lessThanOrEqual": "6.15.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.16",
                            "lessThanOrEqual": "*",
                            "status": "unaffected",
                            "versionType": "original_commit_for_fix"
                        }
                    ]
                }
            ],
            "cpeApplicability": [
                {
                    "nodes": [
                        {
                            "operator": "OR",
                            "negate": false,
                            "cpeMatch": [
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "6.11",
                                    "versionEndExcluding": "6.12.40"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "6.11",
                                    "versionEndExcluding": "6.15.8"
                                },
                                {
                                    "vulnerable": true,
                                    "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
                                    "versionStartIncluding": "6.11",
                                    "versionEndExcluding": "6.16"
                                }
                            ]
                        }
                    ]
                }
            ],
            "references": [
                {
                    "url": "https://git.kernel.org/stable/c/5b02e397929e5b13b969ef1f8e43c7951e2864f5"
                },
                {
                    "url": "https://git.kernel.org/stable/c/67a167a6b8b45607bc34aa541d1c75097d18d460"
                },
                {
                    "url": "https://git.kernel.org/stable/c/60ada4fe644edaa6c2da97364184b0425e8aeaf5"
                }
            ],
            "title": "smc: Fix various oops due to inet_sock type confusion.",
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                "engine": "bippy-1.2.0"
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}