ghsa-9x8c-4rx4-5mxv
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
bridge: switchdev: Fix memory leaks when changing VLAN protocol
The bridge driver can offload VLANs to the underlying hardware either via switchdev or the 8021q driver. When the former is used, the VLAN is marked in the bridge driver with the 'BR_VLFLAG_ADDED_BY_SWITCHDEV' private flag.
To avoid the memory leaks mentioned in the cited commit, the bridge driver will try to delete a VLAN via the 8021q driver if the VLAN is not marked with the previously mentioned flag.
When the VLAN protocol of the bridge changes, switchdev drivers are notified via the 'SWITCHDEV_ATTR_ID_BRIDGE_VLAN_PROTOCOL' attribute, but the 8021q driver is also called to add the existing VLANs with the new protocol and delete them with the old protocol.
In case the VLANs were offloaded via switchdev, the above behavior is both redundant and buggy. Redundant because the VLANs are already programmed in hardware and drivers that support VLAN protocol change (currently only mlx5) change the protocol upon the switchdev attribute notification. Buggy because the 8021q driver is called despite these VLANs being marked with 'BR_VLFLAG_ADDED_BY_SWITCHDEV'. This leads to memory leaks [1] when the VLANs are deleted.
Fix by not calling the 8021q driver for VLANs that were already programmed via switchdev.
[1] unreferenced object 0xffff8881f6771200 (size 256): comm "ip", pid 446855, jiffies 4298238841 (age 55.240s) hex dump (first 32 bytes): 00 00 7f 0e 83 88 ff ff 00 00 00 00 00 00 00 00 ................ 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................ backtrace: [<00000000012819ac>] vlan_vid_add+0x437/0x750 [<00000000f2281fad>] __br_vlan_set_proto+0x289/0x920 [<000000000632b56f>] br_changelink+0x3d6/0x13f0 [<0000000089d25f04>] __rtnl_newlink+0x8ae/0x14c0 [<00000000f6276baf>] rtnl_newlink+0x5f/0x90 [<00000000746dc902>] rtnetlink_rcv_msg+0x336/0xa00 [<000000001c2241c0>] netlink_rcv_skb+0x11d/0x340 [<0000000010588814>] netlink_unicast+0x438/0x710 [<00000000e1a4cd5c>] netlink_sendmsg+0x788/0xc40 [<00000000e8992d4e>] sock_sendmsg+0xb0/0xe0 [<00000000621b8f91>] _syssendmsg+0x4ff/0x6d0 [<000000000ea26996>] _sys_sendmsg+0x12e/0x1b0 [<00000000684f7e25>] __sys_sendmsg+0xab/0x130 [<000000004538b104>] do_syscall_64+0x3d/0x90 [<0000000091ed9678>] entry_SYSCALL_64_after_hwframe+0x46/0xb0
{
"affected": [],
"aliases": [
"CVE-2022-49812"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2025-05-01T15:16:04Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nbridge: switchdev: Fix memory leaks when changing VLAN protocol\n\nThe bridge driver can offload VLANs to the underlying hardware either\nvia switchdev or the 8021q driver. When the former is used, the VLAN is\nmarked in the bridge driver with the \u0027BR_VLFLAG_ADDED_BY_SWITCHDEV\u0027\nprivate flag.\n\nTo avoid the memory leaks mentioned in the cited commit, the bridge\ndriver will try to delete a VLAN via the 8021q driver if the VLAN is not\nmarked with the previously mentioned flag.\n\nWhen the VLAN protocol of the bridge changes, switchdev drivers are\nnotified via the \u0027SWITCHDEV_ATTR_ID_BRIDGE_VLAN_PROTOCOL\u0027 attribute, but\nthe 8021q driver is also called to add the existing VLANs with the new\nprotocol and delete them with the old protocol.\n\nIn case the VLANs were offloaded via switchdev, the above behavior is\nboth redundant and buggy. Redundant because the VLANs are already\nprogrammed in hardware and drivers that support VLAN protocol change\n(currently only mlx5) change the protocol upon the switchdev attribute\nnotification. Buggy because the 8021q driver is called despite these\nVLANs being marked with \u0027BR_VLFLAG_ADDED_BY_SWITCHDEV\u0027. This leads to\nmemory leaks [1] when the VLANs are deleted.\n\nFix by not calling the 8021q driver for VLANs that were already\nprogrammed via switchdev.\n\n[1]\nunreferenced object 0xffff8881f6771200 (size 256):\n comm \"ip\", pid 446855, jiffies 4298238841 (age 55.240s)\n hex dump (first 32 bytes):\n 00 00 7f 0e 83 88 ff ff 00 00 00 00 00 00 00 00 ................\n 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 ................\n backtrace:\n [\u003c00000000012819ac\u003e] vlan_vid_add+0x437/0x750\n [\u003c00000000f2281fad\u003e] __br_vlan_set_proto+0x289/0x920\n [\u003c000000000632b56f\u003e] br_changelink+0x3d6/0x13f0\n [\u003c0000000089d25f04\u003e] __rtnl_newlink+0x8ae/0x14c0\n [\u003c00000000f6276baf\u003e] rtnl_newlink+0x5f/0x90\n [\u003c00000000746dc902\u003e] rtnetlink_rcv_msg+0x336/0xa00\n [\u003c000000001c2241c0\u003e] netlink_rcv_skb+0x11d/0x340\n [\u003c0000000010588814\u003e] netlink_unicast+0x438/0x710\n [\u003c00000000e1a4cd5c\u003e] netlink_sendmsg+0x788/0xc40\n [\u003c00000000e8992d4e\u003e] sock_sendmsg+0xb0/0xe0\n [\u003c00000000621b8f91\u003e] ____sys_sendmsg+0x4ff/0x6d0\n [\u003c000000000ea26996\u003e] ___sys_sendmsg+0x12e/0x1b0\n [\u003c00000000684f7e25\u003e] __sys_sendmsg+0xab/0x130\n [\u003c000000004538b104\u003e] do_syscall_64+0x3d/0x90\n [\u003c0000000091ed9678\u003e] entry_SYSCALL_64_after_hwframe+0x46/0xb0",
"id": "GHSA-9x8c-4rx4-5mxv",
"modified": "2025-05-01T15:31:48Z",
"published": "2025-05-01T15:31:48Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2022-49812"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/347f1793b573466424c550f2748ed837b6690fe7"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/9d45921ee4cb364910097e7d1b7558559c2f9fd2"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f8926e2d2225eb7b7e11cd3fa266aaad9075b767"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/fc16a2c81a3eb1cbba8775f5bdc67856df903a7c"
}
],
"schema_version": "1.4.0",
"severity": []
}
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- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
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- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.