ghsa-692g-7998-j2vj
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
tls: fix missing memory barrier in tls_init
In tls_init(), a write memory barrier is missing, and store-store reordering may cause NULL dereference in tls_{setsockopt,getsockopt}.
CPU0 CPU1 ----- ----- // In tls_init() // In tls_ctx_create() ctx = kzalloc() ctx->sk_proto = READ_ONCE(sk->sk_prot) -(1)
// In update_sk_prot() WRITE_ONCE(sk->sk_prot, tls_prots) -(2)
// In sock_common_setsockopt()
READ_ONCE(sk->sk_prot)->setsockopt()
// In tls_{setsockopt,getsockopt}()
ctx->sk_proto->setsockopt() -(3)
In the above scenario, when (1) and (2) are reordered, (3) can observe the NULL value of ctx->sk_proto, causing NULL dereference.
To fix it, we rely on rcu_assign_pointer() which implies the release barrier semantic. By moving rcu_assign_pointer() after ctx->sk_proto is initialized, we can ensure that ctx->sk_proto are visible when changing sk->sk_prot.
{ "affected": [], "aliases": [ "CVE-2024-36489" ], "database_specific": { "cwe_ids": [ "CWE-476" ], "github_reviewed": false, "github_reviewed_at": null, "nvd_published_at": "2024-06-21T11:15:10Z", "severity": "MODERATE" }, "details": "In the Linux kernel, the following vulnerability has been resolved:\n\ntls: fix missing memory barrier in tls_init\n\nIn tls_init(), a write memory barrier is missing, and store-store\nreordering may cause NULL dereference in tls_{setsockopt,getsockopt}.\n\nCPU0 CPU1\n----- -----\n// In tls_init()\n// In tls_ctx_create()\nctx = kzalloc()\nctx-\u003esk_proto = READ_ONCE(sk-\u003esk_prot) -(1)\n\n// In update_sk_prot()\nWRITE_ONCE(sk-\u003esk_prot, tls_prots) -(2)\n\n // In sock_common_setsockopt()\n READ_ONCE(sk-\u003esk_prot)-\u003esetsockopt()\n\n // In tls_{setsockopt,getsockopt}()\n ctx-\u003esk_proto-\u003esetsockopt() -(3)\n\nIn the above scenario, when (1) and (2) are reordered, (3) can observe\nthe NULL value of ctx-\u003esk_proto, causing NULL dereference.\n\nTo fix it, we rely on rcu_assign_pointer() which implies the release\nbarrier semantic. By moving rcu_assign_pointer() after ctx-\u003esk_proto is\ninitialized, we can ensure that ctx-\u003esk_proto are visible when\nchanging sk-\u003esk_prot.", "id": "GHSA-692g-7998-j2vj", "modified": "2024-09-09T15:30:37Z", "published": "2024-06-21T12:31:20Z", "references": [ { "type": "ADVISORY", "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-36489" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/2c260a24cf1c4d30ea3646124f766ee46169280b" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/335c8f1566d8e44c384d16b450a18554896d4e8b" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/91e61dd7a0af660408e87372d8330ceb218be302" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/ab67c2fd3d070a21914d0c31319d3858ab4e199c" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/d72e126e9a36d3d33889829df8fc90100bb0e071" }, { "type": "WEB", "url": "https://git.kernel.org/stable/c/ef21007a7b581c7fe64d5a10c320880a033c837b" } ], "schema_version": "1.4.0", "severity": [ { "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "type": "CVSS_V3" } ] }
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