{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2022-49979", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-06-18T10:57:27.385Z", "datePublished": "2025-06-18T11:00:41.513Z", "dateUpdated": "2026-08-05T08:57:00.093Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T08:57:00.093Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: fix refcount bug in sk_psock_get (2)\n\nSyzkaller reports refcount bug as follows:\n------------[ cut here ]------------\nrefcount_t: saturated; leaking memory.\nWARNING: CPU: 1 PID: 3605 at lib/refcount.c:19 refcount_warn_saturate+0xf4/0x1e0 lib/refcount.c:19\nModules linked in:\nCPU: 1 PID: 3605 Comm: syz-executor208 Not tainted 5.18.0-syzkaller-03023-g7e062cda7d90 #0\n \n __refcount_add_not_zero include/linux/refcount.h:163 [inline]\n __refcount_inc_not_zero include/linux/refcount.h:227 [inline]\n refcount_inc_not_zero include/linux/refcount.h:245 [inline]\n sk_psock_get+0x3bc/0x410 include/linux/skmsg.h:439\n tls_data_ready+0x6d/0x1b0 net/tls/tls_sw.c:2091\n tcp_data_ready+0x106/0x520 net/ipv4/tcp_input.c:4983\n tcp_data_queue+0x25f2/0x4c90 net/ipv4/tcp_input.c:5057\n tcp_rcv_state_process+0x1774/0x4e80 net/ipv4/tcp_input.c:6659\n tcp_v4_do_rcv+0x339/0x980 net/ipv4/tcp_ipv4.c:1682\n sk_backlog_rcv include/net/sock.h:1061 [inline]\n __release_sock+0x134/0x3b0 net/core/sock.c:2849\n release_sock+0x54/0x1b0 net/core/sock.c:3404\n inet_shutdown+0x1e0/0x430 net/ipv4/af_inet.c:909\n __sys_shutdown_sock net/socket.c:2331 [inline]\n __sys_shutdown_sock net/socket.c:2325 [inline]\n __sys_shutdown+0xf1/0x1b0 net/socket.c:2343\n __do_sys_shutdown net/socket.c:2351 [inline]\n __se_sys_shutdown net/socket.c:2349 [inline]\n __x64_sys_shutdown+0x50/0x70 net/socket.c:2349\n do_syscall_x64 arch/x86/entry/common.c:50 [inline]\n do_syscall_64+0x35/0xb0 arch/x86/entry/common.c:80\n entry_SYSCALL_64_after_hwframe+0x46/0xb0\n \n\nDuring SMC fallback process in connect syscall, kernel will\nreplaces TCP with SMC. In order to forward wakeup\nsmc socket waitqueue after fallback, kernel will sets\nclcsk->sk_user_data to origin smc socket in\nsmc_fback_replace_callbacks().\n\nLater, in shutdown syscall, kernel will calls\nsk_psock_get(), which treats the clcsk->sk_user_data\nas psock type, triggering the refcnt warning.\n\nSo, the root cause is that smc and psock, both will use\nsk_user_data field. So they will mismatch this field\neasily.\n\nThis patch solves it by using another bit(defined as\nSK_USER_DATA_PSOCK) in PTRMASK, to mark whether\nsk_user_data points to a psock object or not.\nThis patch depends on a PTRMASK introduced in commit f1ff5ce2cd5e\n(\"net, sk_msg: Clear sk_user_data pointer on clone if tagged\").\n\nFor there will possibly be more flags in the sk_user_data field,\nthis patch also refactor sk_user_data flags code to be more generic\nto improve its maintainability." } ], "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 - Exploitation requires local syscalls: create an AF_SMC socket, connect to trigger fallback (storing smc_sock in sk_user_data), enable kTLS via setsockopt, then shutdown/recv. Remote packets alone cannot establish this confused socket state.\nAC:L - The attacker fully controls the setup sequence (SMC connect fallback, TCP_ULP/TLS_RX, shutdown); no race or external timing is required. SMC is autoloadable via socket(AF_SMC) and kTLS is commonly available as a loaded/built-in module.\nPR:L - An unprivileged local user can create AF_SMC sockets, trigger fallback to a normal TCP peer, and set TCP_ULP/\"tls\" plus TLS_RX on their own socket with no capabilities required once the TLS module is present.\nUI:N - The attacker performs connect, setsockopt, and shutdown on their own sockets; no victim interaction is needed.\nS:U - Impact is confined to the local kernel's network stack authority (corruption/UAF of kernel socket objects); this is standard privilege escalation scope, not a VM/host boundary crossing.\nC:H - Type confusion treats a live smc_sock as sk_psock, reading sock fields as list heads and enabling a path to sk_psock_drop/kfree of the wrong object—UAF-class memory corruption that can be leveraged for arbitrary kernel read primitives.\nI:H - sk_psock_get performs refcount_inc_not_zero at a fixed offset into the smc_sock's embedded struct sock, and a successful get/put path can invoke sk_psock_drop (function-pointer misuse and kfree of the SMC object), yielding write/UAF primitives and potential control-flow hijack.\nA:H - The bug triggers refcount saturation WARNINGs and can oops/panic via bad pointer interpretation or UAF when the misaligned field permits sk_psock_drop, reliably impacting kernel availability." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/linux/skmsg.h", "include/net/sock.h", "net/core/skmsg.c" ], "versions": [ { "version": "0ef6049f664941bc0f75828b3a61877635048b27", "lessThan": "a5d1cb908131e939bd8b63b8e5e23365bbc2edaf", "status": "affected", "versionType": "git" }, { "version": "341adeec9adad0874f29a0a1af35638207352a39", "lessThan": "86026be8535c16fcc5e4f960286faf04d7f77815", "status": "affected", "versionType": "git" }, { "version": "341adeec9adad0874f29a0a1af35638207352a39", "lessThan": "2a0133723f9ebeb751cfce19f74ec07e108bef1f", "status": "affected", "versionType": "git" }, { "version": "504078fbe9dd570d685361b57784a6050bc40aaa", "status": "affected", "versionType": "git" }, { "version": "5.15.22", "lessThan": "5.15.65", "status": "affected", "versionType": "semver" }, { "version": "5.16.8", "lessThan": "5.17", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "include/linux/skmsg.h", "include/net/sock.h", "net/core/skmsg.c" ], "versions": [ { "version": "5.17", "status": "affected" }, { "version": "0", "lessThan": "5.17", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.65", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.19.7", "lessThanOrEqual": "5.19.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.0", "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": "5.15.22", "versionEndExcluding": "5.15.65" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.17", "versionEndExcluding": "5.19.7" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.17", "versionEndExcluding": "6.0" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.16.8" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/a5d1cb908131e939bd8b63b8e5e23365bbc2edaf" }, { "url": "https://git.kernel.org/stable/c/86026be8535c16fcc5e4f960286faf04d7f77815" }, { "url": "https://git.kernel.org/stable/c/2a0133723f9ebeb751cfce19f74ec07e108bef1f" } ], "title": "net: fix refcount bug in sk_psock_get (2)", "x_generator": { "engine": "bippy-1.2.0" } } } }