{ "threat_severity" : "Moderate", "public_date" : "2024-10-21T00:00:00Z", "bugzilla" : { "description" : "kernel: ppp: do not assume bh is held in ppp_channel_bridge_input()", "id" : "2320471", "url" : "https://bugzilla.redhat.com/show_bug.cgi?id=2320471" }, "cvss3" : { "cvss3_base_score" : "5.5", "cvss3_scoring_vector" : "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H", "status" : "verified" }, "cwe" : "CWE-667", "details" : [ "In the Linux kernel, the following vulnerability has been resolved:\nppp: do not assume bh is held in ppp_channel_bridge_input()\nNetworking receive path is usually handled from BH handler.\nHowever, some protocols need to acquire the socket lock, and\npackets might be stored in the socket backlog is the socket was\nowned by a user process.\nIn this case, release_sock(), __release_sock(), and sk_backlog_rcv()\nmight call the sk->sk_backlog_rcv() handler in process context.\nsybot caught ppp was not considering this case in\nppp_channel_bridge_input() :\nWARNING: inconsistent lock state\n6.11.0-rc7-syzkaller-g5f5673607153 #0 Not tainted\n--------------------------------\ninconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage.\nksoftirqd/1/24 [HC0[0]:SC1[1]:HE1:SE0] takes:\nffff0000db7f11e0 (&pch->downl){+.?.}-{2:2}, at: spin_lock include/linux/spinlock.h:351 [inline]\nffff0000db7f11e0 (&pch->downl){+.?.}-{2:2}, at: ppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2272 [inline]\nffff0000db7f11e0 (&pch->downl){+.?.}-{2:2}, at: ppp_input+0x16c/0x854 drivers/net/ppp/ppp_generic.c:2304\n{SOFTIRQ-ON-W} state was registered at:\nlock_acquire+0x240/0x728 kernel/locking/lockdep.c:5759\n__raw_spin_lock include/linux/spinlock_api_smp.h:133 [inline]\n_raw_spin_lock+0x48/0x60 kernel/locking/spinlock.c:154\nspin_lock include/linux/spinlock.h:351 [inline]\nppp_channel_bridge_input drivers/net/ppp/ppp_generic.c:2272 [inline]\nppp_input+0x16c/0x854 drivers/net/ppp/ppp_generic.c:2304\npppoe_rcv_core+0xfc/0x314 drivers/net/ppp/pppoe.c:379\nsk_backlog_rcv include/net/sock.h:1111 [inline]\n__release_sock+0x1a8/0x3d8 net/core/sock.c:3004\nrelease_sock+0x68/0x1b8 net/core/sock.c:3558\npppoe_sendmsg+0xc8/0x5d8 drivers/net/ppp/pppoe.c:903\nsock_sendmsg_nosec net/socket.c:730 [inline]\n__sock_sendmsg net/socket.c:745 [inline]\n__sys_sendto+0x374/0x4f4 net/socket.c:2204\n__do_sys_sendto net/socket.c:2216 [inline]\n__se_sys_sendto net/socket.c:2212 [inline]\n__arm64_sys_sendto+0xd8/0xf8 net/socket.c:2212\n__invoke_syscall arch/arm64/kernel/syscall.c:35 [inline]\ninvoke_syscall+0x98/0x2b8 arch/arm64/kernel/syscall.c:49\nel0_svc_common+0x130/0x23c arch/arm64/kernel/syscall.c:132\ndo_el0_svc+0x48/0x58 arch/arm64/kernel/syscall.c:151\nel0_svc+0x54/0x168 arch/arm64/kernel/entry-common.c:712\nel0t_64_sync_handler+0x84/0xfc arch/arm64/kernel/entry-common.c:730\nel0t_64_sync+0x190/0x194 arch/arm64/kernel/entry.S:598\nirq event stamp: 282914\nhardirqs last enabled at (282914): [] __raw_spin_unlock_irqrestore include/linux/spinlock_api_smp.h:151 [inline]\nhardirqs last enabled at (282914): [] _raw_spin_unlock_irqrestore+0x38/0x98 kernel/locking/spinlock.c:194\nhardirqs last disabled at (282913): [] __raw_spin_lock_irqsave include/linux/spinlock_api_smp.h:108 [inline]\nhardirqs last disabled at (282913): [] _raw_spin_lock_irqsave+0x2c/0x7c kernel/locking/spinlock.c:162\nsoftirqs last enabled at (282904): [] softirq_handle_end kernel/softirq.c:400 [inline]\nsoftirqs last enabled at (282904): [] handle_softirqs+0xa3c/0xbfc kernel/softirq.c:582\nsoftirqs last disabled at (282909): [] run_ksoftirqd+0x70/0x158 kernel/softirq.c:928\nother info that might help us debug this:\nPossible unsafe locking scenario:\nCPU0\n----\nlock(&pch->downl);\n\nlock(&pch->downl);\n*** DEADLOCK ***\n1 lock held by ksoftirqd/1/24:\n#0: ffff80008f74dfa0 (rcu_read_lock){....}-{1:2}, at: rcu_lock_acquire+0x10/0x4c include/linux/rcupdate.h:325\nstack backtrace:\nCPU: 1 UID: 0 PID: 24 Comm: ksoftirqd/1 Not tainted 6.11.0-rc7-syzkaller-g5f5673607153 #0\nHardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 08/06/2024\nCall trace:\ndump_backtrace+0x1b8/0x1e4 arch/arm64/kernel/stacktrace.c:319\nshow_stack+0x2c/0x3c arch/arm64/kernel/stacktrace.c:326\n__dump_sta\n---truncated---" ], "affected_release" : [ { "product_name" : "Red Hat Enterprise Linux 9", "release_date" : "2025-05-13T00:00:00Z", "advisory" : "RHSA-2025:6966", "cpe" : "cpe:/a:redhat:enterprise_linux:9", "package" : "kernel-0:5.14.0-570.12.1.el9_6" }, { "product_name" : "Red Hat Enterprise Linux 9", "release_date" : "2025-05-13T00:00:00Z", "advisory" : "RHSA-2025:6966", "cpe" : "cpe:/o:redhat:enterprise_linux:9", "package" : "kernel-0:5.14.0-570.12.1.el9_6" } ], "package_state" : [ { "product_name" : "Red Hat Enterprise Linux 6", "fix_state" : "Not affected", "package_name" : "kernel", "cpe" : "cpe:/o:redhat:enterprise_linux:6" }, { "product_name" : "Red Hat Enterprise Linux 7", "fix_state" : "Out of support scope", "package_name" : "kernel", "cpe" : "cpe:/o:redhat:enterprise_linux:7" }, { "product_name" : "Red Hat Enterprise Linux 7", "fix_state" : "Out of support scope", "package_name" : "kernel-rt", "cpe" : "cpe:/o:redhat:enterprise_linux:7" }, { "product_name" : "Red Hat Enterprise Linux 8", "fix_state" : "Not affected", "package_name" : "kernel", "cpe" : "cpe:/o:redhat:enterprise_linux:8" }, { "product_name" : "Red Hat Enterprise Linux 8", "fix_state" : "Not affected", "package_name" : "kernel-rt", "cpe" : "cpe:/o:redhat:enterprise_linux:8" }, { "product_name" : "Red Hat Enterprise Linux 9", "fix_state" : "Will not fix", "package_name" : "kernel-rt", "cpe" : "cpe:/o:redhat:enterprise_linux:9" } ], "references" : [ "https://www.cve.org/CVERecord?id=CVE-2024-49946\nhttps://nvd.nist.gov/vuln/detail/CVE-2024-49946\nhttps://lore.kernel.org/linux-cve-announce/2024102129-CVE-2024-49946-762f@gregkh/T" ], "name" : "CVE-2024-49946", "csaw" : false }