GHSA-GQP6-8CCJ-768W
Vulnerability from github – Published: 2024-08-17 09:30 – Updated: 2025-11-04 00:31In the Linux kernel, the following vulnerability has been resolved:
net/iucv: fix use after free in iucv_sock_close()
iucv_sever_path() is called from process context and from bh context. iucv->path is used as indicator whether somebody else is taking care of severing the path (or it is already removed / never existed). This needs to be done with atomic compare and swap, otherwise there is a small window where iucv_sock_close() will try to work with a path that has already been severed and freed by iucv_callback_connrej() called by iucv_tasklet_fn().
Example: [452744.123844] Call Trace: [452744.123845] ([<0000001e87f03880>] 0x1e87f03880) [452744.123966] [<00000000d593001e>] iucv_path_sever+0x96/0x138 [452744.124330] [<000003ff801ddbca>] iucv_sever_path+0xc2/0xd0 [af_iucv] [452744.124336] [<000003ff801e01b6>] iucv_sock_close+0xa6/0x310 [af_iucv] [452744.124341] [<000003ff801e08cc>] iucv_sock_release+0x3c/0xd0 [af_iucv] [452744.124345] [<00000000d574794e>] __sock_release+0x5e/0xe8 [452744.124815] [<00000000d5747a0c>] sock_close+0x34/0x48 [452744.124820] [<00000000d5421642>] __fput+0xba/0x268 [452744.124826] [<00000000d51b382c>] task_work_run+0xbc/0xf0 [452744.124832] [<00000000d5145710>] do_notify_resume+0x88/0x90 [452744.124841] [<00000000d5978096>] system_call+0xe2/0x2c8 [452744.125319] Last Breaking-Event-Address: [452744.125321] [<00000000d5930018>] iucv_path_sever+0x90/0x138 [452744.125324] [452744.125325] Kernel panic - not syncing: Fatal exception in interrupt
Note that bh_lock_sock() is not serializing the tasklet context against process context, because the check for sock_owned_by_user() and corresponding handling is missing.
Ideas for a future clean-up patch: A) Correct usage of bh_lock_sock() in tasklet context, as described in Re-enqueue, if needed. This may require adding return values to the tasklet functions and thus changes to all users of iucv.
B) Change iucv tasklet into worker and use only lock_sock() in af_iucv.
{
"affected": [],
"aliases": [
"CVE-2024-42271"
],
"database_specific": {
"cwe_ids": [
"CWE-416"
],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-08-17T09:15:08Z",
"severity": "HIGH"
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet/iucv: fix use after free in iucv_sock_close()\n\niucv_sever_path() is called from process context and from bh context.\niucv-\u003epath is used as indicator whether somebody else is taking care of\nsevering the path (or it is already removed / never existed).\nThis needs to be done with atomic compare and swap, otherwise there is a\nsmall window where iucv_sock_close() will try to work with a path that has\nalready been severed and freed by iucv_callback_connrej() called by\niucv_tasklet_fn().\n\nExample:\n[452744.123844] Call Trace:\n[452744.123845] ([\u003c0000001e87f03880\u003e] 0x1e87f03880)\n[452744.123966] [\u003c00000000d593001e\u003e] iucv_path_sever+0x96/0x138\n[452744.124330] [\u003c000003ff801ddbca\u003e] iucv_sever_path+0xc2/0xd0 [af_iucv]\n[452744.124336] [\u003c000003ff801e01b6\u003e] iucv_sock_close+0xa6/0x310 [af_iucv]\n[452744.124341] [\u003c000003ff801e08cc\u003e] iucv_sock_release+0x3c/0xd0 [af_iucv]\n[452744.124345] [\u003c00000000d574794e\u003e] __sock_release+0x5e/0xe8\n[452744.124815] [\u003c00000000d5747a0c\u003e] sock_close+0x34/0x48\n[452744.124820] [\u003c00000000d5421642\u003e] __fput+0xba/0x268\n[452744.124826] [\u003c00000000d51b382c\u003e] task_work_run+0xbc/0xf0\n[452744.124832] [\u003c00000000d5145710\u003e] do_notify_resume+0x88/0x90\n[452744.124841] [\u003c00000000d5978096\u003e] system_call+0xe2/0x2c8\n[452744.125319] Last Breaking-Event-Address:\n[452744.125321] [\u003c00000000d5930018\u003e] iucv_path_sever+0x90/0x138\n[452744.125324]\n[452744.125325] Kernel panic - not syncing: Fatal exception in interrupt\n\nNote that bh_lock_sock() is not serializing the tasklet context against\nprocess context, because the check for sock_owned_by_user() and\ncorresponding handling is missing.\n\nIdeas for a future clean-up patch:\nA) Correct usage of bh_lock_sock() in tasklet context, as described in\nRe-enqueue, if needed. This may require adding return values to the\ntasklet functions and thus changes to all users of iucv.\n\nB) Change iucv tasklet into worker and use only lock_sock() in af_iucv.",
"id": "GHSA-gqp6-8ccj-768w",
"modified": "2025-11-04T00:31:12Z",
"published": "2024-08-17T09:30:24Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-42271"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/01437282fd3904810603f3dc98d2cac6b8b6fc84"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/37652fbef9809411cea55ea5fa1a170e299efcd0"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/69620522c48ce8215e5eb55ffbab8cafee8f407d"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/84f40b46787ecb67c7ad08a5bb1376141fa10c01"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/8b424c9e44111c5a76f41c6b741f8d4c4179d876"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/ac758e1f663fe9bc64f6b47212a2aa18697524f5"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/c65f72eec60a34ace031426e04e9aff8e5f04895"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/f558120cd709682b739207b48cf7479fd9568431"
},
{
"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:H/I:H/A:H",
"type": "CVSS_V3"
}
]
}
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