{"dataType": "CVE_RECORD", "dataVersion": "5.1", "cveMetadata": {"cveId": "CVE-2023-53585", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-10-04T15:40:38.477Z", "datePublished": "2025-10-04T15:44:01.022Z", "dateUpdated": "2025-10-04T15:44:01.022Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2025-10-04T15:44:01.022Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: reject unhashed sockets in bpf_sk_assign\n\nThe semantics for bpf_sk_assign are as follows:\n\n sk = some_lookup_func()\n bpf_sk_assign(skb, sk)\n bpf_sk_release(sk)\n\nThat is, the sk is not consumed by bpf_sk_assign. The function\ntherefore needs to make sure that sk lives long enough to be\nconsumed from __inet_lookup_skb. The path through the stack for a\nTCPv4 packet is roughly:\n\n netif_receive_skb_core: takes RCU read lock\n __netif_receive_skb_core:\n sch_handle_ingress:\n tcf_classify:\n bpf_sk_assign()\n deliver_ptype_list_skb:\n deliver_skb:\n ip_packet_type->func == ip_rcv:\n ip_rcv_core:\n ip_rcv_finish_core:\n dst_input:\n ip_local_deliver:\n ip_local_deliver_finish:\n ip_protocol_deliver_rcu:\n tcp_v4_rcv:\n __inet_lookup_skb:\n skb_steal_sock\n\nThe existing helper takes advantage of the fact that everything\nhappens in the same RCU critical section: for sockets with\nSOCK_RCU_FREE set bpf_sk_assign never takes a reference.\nskb_steal_sock then checks SOCK_RCU_FREE again and does sock_put\nif necessary.\n\nThis approach assumes that SOCK_RCU_FREE is never set on a sk\nbetween bpf_sk_assign and skb_steal_sock, but this invariant is\nviolated by unhashed UDP sockets. A new UDP socket is created\nin TCP_CLOSE state but without SOCK_RCU_FREE set. That flag is only\nadded in udp_lib_get_port() which happens when a socket is bound.\n\nWhen bpf_sk_assign was added it wasn't possible to access unhashed\nUDP sockets from BPF, so this wasn't a problem. This changed\nin commit 0c48eefae712 (\"sock_map: Lift socket state restriction\nfor datagram sockets\"), but the helper wasn't adjusted accordingly.\nThe following sequence of events will therefore lead to a refcount\nleak:\n\n1. Add socket(AF_INET, SOCK_DGRAM) to a sockmap.\n2. Pull socket out of sockmap and bpf_sk_assign it. Since\n SOCK_RCU_FREE is not set we increment the refcount.\n3. bind() or connect() the socket, setting SOCK_RCU_FREE.\n4. skb_steal_sock will now set refcounted = false due to\n SOCK_RCU_FREE.\n5. tcp_v4_rcv() skips sock_put().\n\nFix the problem by rejecting unhashed sockets in bpf_sk_assign().\nThis matches the behaviour of __inet_lookup_skb which is ultimately\nthe goal of bpf_sk_assign()."}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["net/core/filter.c"], "versions": [{"version": "cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449", "lessThan": "791a12102e5191dcb6ce0b3a99d71b5a2802d12a", "status": "affected", "versionType": "git"}, {"version": "cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449", "lessThan": "7dcbc0bb0e5cc1823923744befce59ac353135e6", "status": "affected", "versionType": "git"}, {"version": "cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449", "lessThan": "c0ce0fb76610d5fad31f56f2ca8241a2a6717a1b", "status": "affected", "versionType": "git"}, {"version": "cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449", "lessThan": "8aa43cfbb68b25119d2ced14ec717173e2901fa2", "status": "affected", "versionType": "git"}, {"version": "cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449", "lessThan": "3d4522f59fb748a54446846522941a4f09da63e9", "status": "affected", "versionType": "git"}, {"version": "cf7fbe660f2dbd738ab58aea8e9b0ca6ad232449", "lessThan": "67312adc96b5a585970d03b62412847afe2c6b01", "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/core/filter.c"], "versions": [{"version": "5.7", "status": "affected"}, {"version": "0", "lessThan": "5.7", "status": "unaffected", "versionType": "semver"}, {"version": "5.10.195", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver"}, {"version": "5.15.132", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.53", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.4.16", "lessThanOrEqual": "6.4.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.5.3", "lessThanOrEqual": "6.5.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6", "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": "5.7", "versionEndExcluding": "5.10.195"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "5.15.132"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.1.53"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.4.16"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.5.3"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.7", "versionEndExcluding": "6.6"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/791a12102e5191dcb6ce0b3a99d71b5a2802d12a"}, {"url": "https://git.kernel.org/stable/c/7dcbc0bb0e5cc1823923744befce59ac353135e6"}, {"url": "https://git.kernel.org/stable/c/c0ce0fb76610d5fad31f56f2ca8241a2a6717a1b"}, {"url": "https://git.kernel.org/stable/c/8aa43cfbb68b25119d2ced14ec717173e2901fa2"}, {"url": "https://git.kernel.org/stable/c/3d4522f59fb748a54446846522941a4f09da63e9"}, {"url": "https://git.kernel.org/stable/c/67312adc96b5a585970d03b62412847afe2c6b01"}], "title": "bpf: reject unhashed sockets in bpf_sk_assign", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: reject unhashed sockets in bpf_sk_assign\n\nThe semantics for bpf_sk_assign are as follows:\n\n sk = some_lookup_func()\n bpf_sk_assign(skb, sk)\n bpf_sk_release(sk)\n\nThat is, the sk is not consumed by bpf_sk_assign. The function\ntherefore needs to make sure that sk lives long enough to be\nconsumed from __inet_lookup_skb. The path through the stack for a\nTCPv4 packet is roughly:\n\n netif_receive_skb_core: takes RCU read lock\n __netif_receive_skb_core:\n sch_handle_ingress:\n tcf_classify:\n bpf_sk_assign()\n deliver_ptype_list_skb:\n deliver_skb:\n ip_packet_type->func == ip_rcv:\n ip_rcv_core:\n ip_rcv_finish_core:\n dst_input:\n ip_local_deliver:\n ip_local_deliver_finish:\n ip_protocol_deliver_rcu:\n tcp_v4_rcv:\n __inet_lookup_skb:\n skb_steal_sock\n\nThe existing helper takes advantage of the fact that everything\nhappens in the same RCU critical section: for sockets with\nSOCK_RCU_FREE set bpf_sk_assign never takes a reference.\nskb_steal_sock then checks SOCK_RCU_FREE again and does sock_put\nif necessary.\n\nThis approach assumes that SOCK_RCU_FREE is never set on a sk\nbetween bpf_sk_assign and skb_steal_sock, but this invariant is\nviolated by unhashed UDP sockets. A new UDP socket is created\nin TCP_CLOSE state but without SOCK_RCU_FREE set. That flag is only\nadded in udp_lib_get_port() which happens when a socket is bound.\n\nWhen bpf_sk_assign was added it wasn't possible to access unhashed\nUDP sockets from BPF, so this wasn't a problem. This changed\nin commit 0c48eefae712 (\"sock_map: Lift socket state restriction\nfor datagram sockets\"), but the helper wasn't adjusted accordingly.\nThe following sequence of events will therefore lead to a refcount\nleak:\n\n1. Add socket(AF_INET, SOCK_DGRAM) to a sockmap.\n2. Pull socket out of sockmap and bpf_sk_assign it. Since\n SOCK_RCU_FREE is not set we increment the refcount.\n3. bind() or connect() the socket, setting SOCK_RCU_FREE.\n4. skb_steal_sock will now set refcounted = false due to\n SOCK_RCU_FREE.\n5. tcp_v4_rcv() skips sock_put().\n\nFix the problem by rejecting unhashed sockets in bpf_sk_assign().\nThis matches the behaviour of __inet_lookup_skb which is ultimately\nthe goal of bpf_sk_assign()."}], "id": "CVE-2023-53585", "lastModified": "2025-10-04T16:15:54.703", "metrics": {}, "published": "2025-10-04T16:15:54.703", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/3d4522f59fb748a54446846522941a4f09da63e9"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/67312adc96b5a585970d03b62412847afe2c6b01"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/791a12102e5191dcb6ce0b3a99d71b5a2802d12a"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/7dcbc0bb0e5cc1823923744befce59ac353135e6"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/8aa43cfbb68b25119d2ced14ec717173e2901fa2"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/c0ce0fb76610d5fad31f56f2ca8241a2a6717a1b"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{}

{}