GHSA-QRRH-7FHH-G486

Vulnerability from github – Published: 2024-09-18 09:30 – Updated: 2025-11-04 00:31
VLAI
Details

In the Linux kernel, the following vulnerability has been resolved:

fou: Fix null-ptr-deref in GRO.

We observed a null-ptr-deref in fou_gro_receive() while shutting down a host. [0]

The NULL pointer is sk->sk_user_data, and the offset 8 is of protocol in struct fou.

When fou_release() is called due to netns dismantle or explicit tunnel teardown, udp_tunnel_sock_release() sets NULL to sk->sk_user_data. Then, the tunnel socket is destroyed after a single RCU grace period.

So, in-flight udp4_gro_receive() could find the socket and execute the FOU GRO handler, where sk->sk_user_data could be NULL.

Let's use rcu_dereference_sk_user_data() in fou_from_sock() and add NULL checks in FOU GRO handlers.

[0]: BUG: kernel NULL pointer dereference, address: 0000000000000008 PF: supervisor read access in kernel mode PF: error_code(0x0000) - not-present page PGD 80000001032f4067 P4D 80000001032f4067 PUD 103240067 PMD 0 SMP PTI CPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.10.216-204.855.amzn2.x86_64 #1 Hardware name: Amazon EC2 c5.large/, BIOS 1.0 10/16/2017 RIP: 0010:fou_gro_receive (net/ipv4/fou.c:233) [fou] Code: 41 5f c3 cc cc cc cc e8 e7 2e 69 f4 0f 1f 80 00 00 00 00 0f 1f 44 00 00 49 89 f8 41 54 48 89 f7 48 89 d6 49 8b 80 88 02 00 00 <0f> b6 48 08 0f b7 42 4a 66 25 fd fd 80 cc 02 66 89 42 4a 0f b6 42 RSP: 0018:ffffa330c0003d08 EFLAGS: 00010297 RAX: 0000000000000000 RBX: ffff93d9e3a6b900 RCX: 0000000000000010 RDX: ffff93d9e3a6b900 RSI: ffff93d9e3a6b900 RDI: ffff93dac2e24d08 RBP: ffff93d9e3a6b900 R08: ffff93dacbce6400 R09: 0000000000000002 R10: 0000000000000000 R11: ffffffffb5f369b0 R12: ffff93dacbce6400 R13: ffff93dac2e24d08 R14: 0000000000000000 R15: ffffffffb4edd1c0 FS: 0000000000000000(0000) GS:ffff93daee800000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 0000000000000008 CR3: 0000000102140001 CR4: 00000000007706f0 DR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000 DR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400 PKRU: 55555554 Call Trace: ? show_trace_log_lvl (arch/x86/kernel/dumpstack.c:259) ? __die_body.cold (arch/x86/kernel/dumpstack.c:478 arch/x86/kernel/dumpstack.c:420) ? no_context (arch/x86/mm/fault.c:752) ? exc_page_fault (arch/x86/include/asm/irqflags.h:49 arch/x86/include/asm/irqflags.h:89 arch/x86/mm/fault.c:1435 arch/x86/mm/fault.c:1483) ? asm_exc_page_fault (arch/x86/include/asm/idtentry.h:571) ? fou_gro_receive (net/ipv4/fou.c:233) [fou] udp_gro_receive (include/linux/netdevice.h:2552 net/ipv4/udp_offload.c:559) udp4_gro_receive (net/ipv4/udp_offload.c:604) inet_gro_receive (net/ipv4/af_inet.c:1549 (discriminator 7)) dev_gro_receive (net/core/dev.c:6035 (discriminator 4)) napi_gro_receive (net/core/dev.c:6170) ena_clean_rx_irq (drivers/amazon/net/ena/ena_netdev.c:1558) [ena] ena_io_poll (drivers/amazon/net/ena/ena_netdev.c:1742) [ena] napi_poll (net/core/dev.c:6847) net_rx_action (net/core/dev.c:6917) __do_softirq (arch/x86/include/asm/jump_label.h:25 include/linux/jump_label.h:200 include/trace/events/irq.h:142 kernel/softirq.c:299) asm_call_irq_on_stack (arch/x86/entry/entry_64.S:809) do_softirq_own_stack (arch/x86/include/asm/irq_stack.h:27 arch/x86/include/asm/irq_stack.h:77 arch/x86/kernel/irq_64.c:77) irq_exit_rcu (kernel/softirq.c:393 kernel/softirq.c:423 kernel/softirq.c:435) common_interrupt (arch/x86/kernel/irq.c:239) asm_common_interrupt (arch/x86/include/asm/idtentry.h:626) RIP: 0010:acpi_idle_do_entry (arch/x86/include/asm/irqflags.h:49 arch/x86/include/asm/irqflags.h:89 drivers/acpi/processor_idle.c:114 drivers/acpi/processor_idle.c:575) Code: 8b 15 d1 3c c4 02 ed c3 cc cc cc cc 65 48 8b 04 25 40 ef 01 00 48 8b 00 a8 08 75 eb 0f 1f 44 00 00 0f 00 2d d5 09 55 00 fb f4 c3 cc cc cc cc e9 be fc ff ff 66 66 2e 0f 1f 84 00 00 00 00 00 RSP: 0018:ffffffffb5603e58 EFLAGS: 00000246 RAX: 0000000000004000 RBX: ffff93dac0929c00 RCX: ffff93daee833900 RDX: ffff93daee800000 RSI: ffff93d ---truncated---

Severity
5.5 (Medium)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
Show details on source website
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{
  "affected": [],
  "aliases": [
    "CVE-2024-46763"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-476"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2024-09-18T08:15:04Z",
    "severity": "MODERATE"
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfou: Fix null-ptr-deref in GRO.\n\nWe observed a null-ptr-deref in fou_gro_receive() while shutting down\na host.  [0]\n\nThe NULL pointer is sk-\u003esk_user_data, and the offset 8 is of protocol\nin struct fou.\n\nWhen fou_release() is called due to netns dismantle or explicit tunnel\nteardown, udp_tunnel_sock_release() sets NULL to sk-\u003esk_user_data.\nThen, the tunnel socket is destroyed after a single RCU grace period.\n\nSo, in-flight udp4_gro_receive() could find the socket and execute the\nFOU GRO handler, where sk-\u003esk_user_data could be NULL.\n\nLet\u0027s use rcu_dereference_sk_user_data() in fou_from_sock() and add NULL\nchecks in FOU GRO handlers.\n\n[0]:\nBUG: kernel NULL pointer dereference, address: 0000000000000008\n PF: supervisor read access in kernel mode\n PF: error_code(0x0000) - not-present page\nPGD 80000001032f4067 P4D 80000001032f4067 PUD 103240067 PMD 0\nSMP PTI\nCPU: 0 PID: 0 Comm: swapper/0 Not tainted 5.10.216-204.855.amzn2.x86_64 #1\nHardware name: Amazon EC2 c5.large/, BIOS 1.0 10/16/2017\nRIP: 0010:fou_gro_receive (net/ipv4/fou.c:233) [fou]\nCode: 41 5f c3 cc cc cc cc e8 e7 2e 69 f4 0f 1f 80 00 00 00 00 0f 1f 44 00 00 49 89 f8 41 54 48 89 f7 48 89 d6 49 8b 80 88 02 00 00 \u003c0f\u003e b6 48 08 0f b7 42 4a 66 25 fd fd 80 cc 02 66 89 42 4a 0f b6 42\nRSP: 0018:ffffa330c0003d08 EFLAGS: 00010297\nRAX: 0000000000000000 RBX: ffff93d9e3a6b900 RCX: 0000000000000010\nRDX: ffff93d9e3a6b900 RSI: ffff93d9e3a6b900 RDI: ffff93dac2e24d08\nRBP: ffff93d9e3a6b900 R08: ffff93dacbce6400 R09: 0000000000000002\nR10: 0000000000000000 R11: ffffffffb5f369b0 R12: ffff93dacbce6400\nR13: ffff93dac2e24d08 R14: 0000000000000000 R15: ffffffffb4edd1c0\nFS:  0000000000000000(0000) GS:ffff93daee800000(0000) knlGS:0000000000000000\nCS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033\nCR2: 0000000000000008 CR3: 0000000102140001 CR4: 00000000007706f0\nDR0: 0000000000000000 DR1: 0000000000000000 DR2: 0000000000000000\nDR3: 0000000000000000 DR6: 00000000fffe0ff0 DR7: 0000000000000400\nPKRU: 55555554\nCall Trace:\n \u003cIRQ\u003e\n ? show_trace_log_lvl (arch/x86/kernel/dumpstack.c:259)\n ? __die_body.cold (arch/x86/kernel/dumpstack.c:478 arch/x86/kernel/dumpstack.c:420)\n ? no_context (arch/x86/mm/fault.c:752)\n ? exc_page_fault (arch/x86/include/asm/irqflags.h:49 arch/x86/include/asm/irqflags.h:89 arch/x86/mm/fault.c:1435 arch/x86/mm/fault.c:1483)\n ? asm_exc_page_fault (arch/x86/include/asm/idtentry.h:571)\n ? fou_gro_receive (net/ipv4/fou.c:233) [fou]\n udp_gro_receive (include/linux/netdevice.h:2552 net/ipv4/udp_offload.c:559)\n udp4_gro_receive (net/ipv4/udp_offload.c:604)\n inet_gro_receive (net/ipv4/af_inet.c:1549 (discriminator 7))\n dev_gro_receive (net/core/dev.c:6035 (discriminator 4))\n napi_gro_receive (net/core/dev.c:6170)\n ena_clean_rx_irq (drivers/amazon/net/ena/ena_netdev.c:1558) [ena]\n ena_io_poll (drivers/amazon/net/ena/ena_netdev.c:1742) [ena]\n napi_poll (net/core/dev.c:6847)\n net_rx_action (net/core/dev.c:6917)\n __do_softirq (arch/x86/include/asm/jump_label.h:25 include/linux/jump_label.h:200 include/trace/events/irq.h:142 kernel/softirq.c:299)\n asm_call_irq_on_stack (arch/x86/entry/entry_64.S:809)\n\u003c/IRQ\u003e\n do_softirq_own_stack (arch/x86/include/asm/irq_stack.h:27 arch/x86/include/asm/irq_stack.h:77 arch/x86/kernel/irq_64.c:77)\n irq_exit_rcu (kernel/softirq.c:393 kernel/softirq.c:423 kernel/softirq.c:435)\n common_interrupt (arch/x86/kernel/irq.c:239)\n asm_common_interrupt (arch/x86/include/asm/idtentry.h:626)\nRIP: 0010:acpi_idle_do_entry (arch/x86/include/asm/irqflags.h:49 arch/x86/include/asm/irqflags.h:89 drivers/acpi/processor_idle.c:114 drivers/acpi/processor_idle.c:575)\nCode: 8b 15 d1 3c c4 02 ed c3 cc cc cc cc 65 48 8b 04 25 40 ef 01 00 48 8b 00 a8 08 75 eb 0f 1f 44 00 00 0f 00 2d d5 09 55 00 fb f4 \u003cfa\u003e c3 cc cc cc cc e9 be fc ff ff 66 66 2e 0f 1f 84 00 00 00 00 00\nRSP: 0018:ffffffffb5603e58 EFLAGS: 00000246\nRAX: 0000000000004000 RBX: ffff93dac0929c00 RCX: ffff93daee833900\nRDX: ffff93daee800000 RSI: ffff93d\n---truncated---",
  "id": "GHSA-qrrh-7fhh-g486",
  "modified": "2025-11-04T00:31:29Z",
  "published": "2024-09-18T09:30:37Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2024-46763"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/1df42be305fe478ded1ee0c1d775f4ece713483b"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/231c235d2f7a66f018f172e26ffd47c363f244ef"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/4494bccb52ffda22ce5a1163a776d970e6229e08"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/7e4196935069947d8b70b09c1660b67b067e75cb"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/c46cd6aaca81040deaea3500ba75126963294bd9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/d7567f098f54cb53ee3cee1c82e3d0ed9698b6b3"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2024/10/msg00003.html"
    },
    {
      "type": "WEB",
      "url": "https://lists.debian.org/debian-lts-announce/2025/01/msg00001.html"
    }
  ],
  "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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