{
  "threat_severity" : "Moderate",
  "public_date" : "2024-12-27T00:00:00Z",
  "bugzilla" : {
    "description" : "kernel: tcp_bpf: Fix the sk_mem_uncharge logic in tcp_bpf_sendmsg",
    "id" : "2334549",
    "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2334549"
  },
  "cvss3" : {
    "cvss3_base_score" : "5.5",
    "cvss3_scoring_vector" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H",
    "status" : "verified"
  },
  "cwe" : "CWE-99",
  "details" : [ "In the Linux kernel, the following vulnerability has been resolved:\ntcp_bpf: Fix the sk_mem_uncharge logic in tcp_bpf_sendmsg\nThe current sk memory accounting logic in __SK_REDIRECT is pre-uncharging\ntosend bytes, which is either msg->sg.size or a smaller value apply_bytes.\nPotential problems with this strategy are as follows:\n- If the actual sent bytes are smaller than tosend, we need to charge some\nbytes back, as in line 487, which is okay but seems not clean.\n- When tosend is set to apply_bytes, as in line 417, and (ret < 0), we may\nmiss uncharging (msg->sg.size - apply_bytes) bytes.\n[...]\n415 tosend = msg->sg.size;\n416 if (psock->apply_bytes && psock->apply_bytes < tosend)\n417   tosend = psock->apply_bytes;\n[...]\n443 sk_msg_return(sk, msg, tosend);\n444 release_sock(sk);\n446 origsize = msg->sg.size;\n447 ret = tcp_bpf_sendmsg_redir(sk_redir, redir_ingress,\n448                             msg, tosend, flags);\n449 sent = origsize - msg->sg.size;\n[...]\n454 lock_sock(sk);\n455 if (unlikely(ret < 0)) {\n456   int free = sk_msg_free_nocharge(sk, msg);\n458   if (!cork)\n459     *copied -= free;\n460 }\n[...]\n487 if (eval == __SK_REDIRECT)\n488   sk_mem_charge(sk, tosend - sent);\n[...]\nWhen running the selftest test_txmsg_redir_wait_sndmem with txmsg_apply,\nthe following warning will be reported:\n------------[ cut here ]------------\nWARNING: CPU: 6 PID: 57 at net/ipv4/af_inet.c:156 inet_sock_destruct+0x190/0x1a0\nModules linked in:\nCPU: 6 UID: 0 PID: 57 Comm: kworker/6:0 Not tainted 6.12.0-rc1.bm.1-amd64+ #43\nHardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.12.0-1 04/01/2014\nWorkqueue: events sk_psock_destroy\nRIP: 0010:inet_sock_destruct+0x190/0x1a0\nRSP: 0018:ffffad0a8021fe08 EFLAGS: 00010206\nRAX: 0000000000000011 RBX: ffff9aab4475b900 RCX: ffff9aab481a0800\nRDX: 0000000000000303 RSI: 0000000000000011 RDI: ffff9aab4475b900\nRBP: ffff9aab4475b990 R08: 0000000000000000 R09: ffff9aab40050ec0\nR10: 0000000000000000 R11: ffff9aae6fdb1d01 R12: ffff9aab49c60400\nR13: ffff9aab49c60598 R14: ffff9aab49c60598 R15: dead000000000100\nFS:  0000000000000000(0000) GS:ffff9aae6fd80000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 00007ffec7e47bd8 CR3: 00000001a1a1c004 CR4: 0000000000770ef0\nDR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\nDR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\nPKRU: 55555554\nCall Trace:\n<TASK>\n? __warn+0x89/0x130\n? inet_sock_destruct+0x190/0x1a0\n? report_bug+0xfc/0x1e0\n? handle_bug+0x5c/0xa0\n? exc_invalid_op+0x17/0x70\n? asm_exc_invalid_op+0x1a/0x20\n? inet_sock_destruct+0x190/0x1a0\n__sk_destruct+0x25/0x220\nsk_psock_destroy+0x2b2/0x310\nprocess_scheduled_works+0xa3/0x3e0\nworker_thread+0x117/0x240\n? __pfx_worker_thread+0x10/0x10\nkthread+0xcf/0x100\n? __pfx_kthread+0x10/0x10\nret_from_fork+0x31/0x40\n? __pfx_kthread+0x10/0x10\nret_from_fork_asm+0x1a/0x30\n</TASK>\n---[ end trace 0000000000000000 ]---\nIn __SK_REDIRECT, a more concise way is delaying the uncharging after sent\nbytes are finalized, and uncharge this value. When (ret < 0), we shall\ninvoke sk_msg_free.\nSame thing happens in case __SK_DROP, when tosend is set to apply_bytes,\nwe may miss uncharging (msg->sg.size - apply_bytes) bytes. The same\nwarning will be reported in selftest.\n[...]\n468 case __SK_DROP:\n469 default:\n470 sk_msg_free_partial(sk, msg, tosend);\n471 sk_msg_apply_bytes(psock, tosend);\n472 *copied -= (tosend + delta);\n473 return -EACCES;\n[...]\nSo instead of sk_msg_free_partial we can do sk_msg_free here." ],
  "affected_release" : [ {
    "product_name" : "Red Hat Enterprise Linux 10",
    "release_date" : "2026-05-19T00:00:00Z",
    "advisory" : "RHSA-2026:18134",
    "cpe" : "cpe:/o:redhat:enterprise_linux:10.2",
    "package" : "kernel-0:6.12.0-211.7.1.el10_2"
  } ],
  "package_state" : [ {
    "product_name" : "Red Hat Enterprise Linux 6",
    "fix_state" : "Not affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:6"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Not affected",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 7",
    "fix_state" : "Not affected",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:7"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Out of support scope",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 8",
    "fix_state" : "Out of support scope",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:8"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Will not fix",
    "package_name" : "kernel",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  }, {
    "product_name" : "Red Hat Enterprise Linux 9",
    "fix_state" : "Will not fix",
    "package_name" : "kernel-rt",
    "cpe" : "cpe:/o:redhat:enterprise_linux:9"
  } ],
  "references" : [ "https://www.cve.org/CVERecord?id=CVE-2024-56633\nhttps://nvd.nist.gov/vuln/detail/CVE-2024-56633\nhttps://lore.kernel.org/linux-cve-announce/2024122734-CVE-2024-56633-ac1d@gregkh/T" ],
  "name" : "CVE-2024-56633",
  "csaw" : false
}