ghsa-jgpw-6hf2-c2m5
Vulnerability from github
In the Linux kernel, the following vulnerability has been resolved:
dpll: fix possible deadlock during netlink dump operation
Recently, I've been hitting following deadlock warning during dpll pin dump:
[52804.637962] ====================================================== [52804.638536] WARNING: possible circular locking dependency detected [52804.639111] 6.8.0-rc2jiri+ #1 Not tainted [52804.639529] ------------------------------------------------------ [52804.640104] python3/2984 is trying to acquire lock: [52804.640581] ffff88810e642678 (nlk_cb_mutex-GENERIC){+.+.}-{3:3}, at: netlink_dump+0xb3/0x780 [52804.641417] but task is already holding lock: [52804.642010] ffffffff83bde4c8 (dpll_lock){+.+.}-{3:3}, at: dpll_lock_dumpit+0x13/0x20 [52804.642747] which lock already depends on the new lock.
[52804.643551] the existing dependency chain (in reverse order) is: [52804.644259] -> #1 (dpll_lock){+.+.}-{3:3}: [52804.644836] lock_acquire+0x174/0x3e0 [52804.645271] __mutex_lock+0x119/0x1150 [52804.645723] dpll_lock_dumpit+0x13/0x20 [52804.646169] genl_start+0x266/0x320 [52804.646578] __netlink_dump_start+0x321/0x450 [52804.647056] genl_family_rcv_msg_dumpit+0x155/0x1e0 [52804.647575] genl_rcv_msg+0x1ed/0x3b0 [52804.648001] netlink_rcv_skb+0xdc/0x210 [52804.648440] genl_rcv+0x24/0x40 [52804.648831] netlink_unicast+0x2f1/0x490 [52804.649290] netlink_sendmsg+0x36d/0x660 [52804.649742] __sock_sendmsg+0x73/0xc0 [52804.650165] __sys_sendto+0x184/0x210 [52804.650597] __x64_sys_sendto+0x72/0x80 [52804.651045] do_syscall_64+0x6f/0x140 [52804.651474] entry_SYSCALL_64_after_hwframe+0x46/0x4e [52804.652001] -> #0 (nlk_cb_mutex-GENERIC){+.+.}-{3:3}: [52804.652650] check_prev_add+0x1ae/0x1280 [52804.653107] __lock_acquire+0x1ed3/0x29a0 [52804.653559] lock_acquire+0x174/0x3e0 [52804.653984] __mutex_lock+0x119/0x1150 [52804.654423] netlink_dump+0xb3/0x780 [52804.654845] __netlink_dump_start+0x389/0x450 [52804.655321] genl_family_rcv_msg_dumpit+0x155/0x1e0 [52804.655842] genl_rcv_msg+0x1ed/0x3b0 [52804.656272] netlink_rcv_skb+0xdc/0x210 [52804.656721] genl_rcv+0x24/0x40 [52804.657119] netlink_unicast+0x2f1/0x490 [52804.657570] netlink_sendmsg+0x36d/0x660 [52804.658022] __sock_sendmsg+0x73/0xc0 [52804.658450] __sys_sendto+0x184/0x210 [52804.658877] __x64_sys_sendto+0x72/0x80 [52804.659322] do_syscall_64+0x6f/0x140 [52804.659752] entry_SYSCALL_64_after_hwframe+0x46/0x4e [52804.660281] other info that might help us debug this:
[52804.661077] Possible unsafe locking scenario:
[52804.661671] CPU0 CPU1 [52804.662129] ---- ---- [52804.662577] lock(dpll_lock); [52804.662924] lock(nlk_cb_mutex-GENERIC); [52804.663538] lock(dpll_lock); [52804.664073] lock(nlk_cb_mutex-GENERIC); [52804.664490]
The issue as follows: __netlink_dump_start() calls control->start(cb) with nlk->cb_mutex held. In control->start(cb) the dpll_lock is taken. Then nlk->cb_mutex is released and taken again in netlink_dump(), while dpll_lock still being held. That leads to ABBA deadlock when another CPU races with the same operation.
Fix this by moving dpll_lock taking into dumpit() callback which ensures correct lock taking order.
{
"affected": [],
"aliases": [
"CVE-2024-26725"
],
"database_specific": {
"cwe_ids": [],
"github_reviewed": false,
"github_reviewed_at": null,
"nvd_published_at": "2024-04-03T15:15:54Z",
"severity": null
},
"details": "In the Linux kernel, the following vulnerability has been resolved:\n\ndpll: fix possible deadlock during netlink dump operation\n\nRecently, I\u0027ve been hitting following deadlock warning during dpll pin\ndump:\n\n[52804.637962] ======================================================\n[52804.638536] WARNING: possible circular locking dependency detected\n[52804.639111] 6.8.0-rc2jiri+ #1 Not tainted\n[52804.639529] ------------------------------------------------------\n[52804.640104] python3/2984 is trying to acquire lock:\n[52804.640581] ffff88810e642678 (nlk_cb_mutex-GENERIC){+.+.}-{3:3}, at: netlink_dump+0xb3/0x780\n[52804.641417]\n but task is already holding lock:\n[52804.642010] ffffffff83bde4c8 (dpll_lock){+.+.}-{3:3}, at: dpll_lock_dumpit+0x13/0x20\n[52804.642747]\n which lock already depends on the new lock.\n\n[52804.643551]\n the existing dependency chain (in reverse order) is:\n[52804.644259]\n -\u003e #1 (dpll_lock){+.+.}-{3:3}:\n[52804.644836] lock_acquire+0x174/0x3e0\n[52804.645271] __mutex_lock+0x119/0x1150\n[52804.645723] dpll_lock_dumpit+0x13/0x20\n[52804.646169] genl_start+0x266/0x320\n[52804.646578] __netlink_dump_start+0x321/0x450\n[52804.647056] genl_family_rcv_msg_dumpit+0x155/0x1e0\n[52804.647575] genl_rcv_msg+0x1ed/0x3b0\n[52804.648001] netlink_rcv_skb+0xdc/0x210\n[52804.648440] genl_rcv+0x24/0x40\n[52804.648831] netlink_unicast+0x2f1/0x490\n[52804.649290] netlink_sendmsg+0x36d/0x660\n[52804.649742] __sock_sendmsg+0x73/0xc0\n[52804.650165] __sys_sendto+0x184/0x210\n[52804.650597] __x64_sys_sendto+0x72/0x80\n[52804.651045] do_syscall_64+0x6f/0x140\n[52804.651474] entry_SYSCALL_64_after_hwframe+0x46/0x4e\n[52804.652001]\n -\u003e #0 (nlk_cb_mutex-GENERIC){+.+.}-{3:3}:\n[52804.652650] check_prev_add+0x1ae/0x1280\n[52804.653107] __lock_acquire+0x1ed3/0x29a0\n[52804.653559] lock_acquire+0x174/0x3e0\n[52804.653984] __mutex_lock+0x119/0x1150\n[52804.654423] netlink_dump+0xb3/0x780\n[52804.654845] __netlink_dump_start+0x389/0x450\n[52804.655321] genl_family_rcv_msg_dumpit+0x155/0x1e0\n[52804.655842] genl_rcv_msg+0x1ed/0x3b0\n[52804.656272] netlink_rcv_skb+0xdc/0x210\n[52804.656721] genl_rcv+0x24/0x40\n[52804.657119] netlink_unicast+0x2f1/0x490\n[52804.657570] netlink_sendmsg+0x36d/0x660\n[52804.658022] __sock_sendmsg+0x73/0xc0\n[52804.658450] __sys_sendto+0x184/0x210\n[52804.658877] __x64_sys_sendto+0x72/0x80\n[52804.659322] do_syscall_64+0x6f/0x140\n[52804.659752] entry_SYSCALL_64_after_hwframe+0x46/0x4e\n[52804.660281]\n other info that might help us debug this:\n\n[52804.661077] Possible unsafe locking scenario:\n\n[52804.661671] CPU0 CPU1\n[52804.662129] ---- ----\n[52804.662577] lock(dpll_lock);\n[52804.662924] lock(nlk_cb_mutex-GENERIC);\n[52804.663538] lock(dpll_lock);\n[52804.664073] lock(nlk_cb_mutex-GENERIC);\n[52804.664490]\n\nThe issue as follows: __netlink_dump_start() calls control-\u003estart(cb)\nwith nlk-\u003ecb_mutex held. In control-\u003estart(cb) the dpll_lock is taken.\nThen nlk-\u003ecb_mutex is released and taken again in netlink_dump(), while\ndpll_lock still being held. That leads to ABBA deadlock when another\nCPU races with the same operation.\n\nFix this by moving dpll_lock taking into dumpit() callback which ensures\ncorrect lock taking order.",
"id": "GHSA-jgpw-6hf2-c2m5",
"modified": "2024-04-03T15:30:43Z",
"published": "2024-04-03T15:30:43Z",
"references": [
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2024-26725"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/087739cbd0d0b87b6cec2c0799436ac66e24acc8"
},
{
"type": "WEB",
"url": "https://git.kernel.org/stable/c/53c0441dd2c44ee93fddb5473885fd41e4bc2361"
}
],
"schema_version": "1.4.0",
"severity": []
}