phonet/pep: disable BH around forwarded sk_receive_skb()
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
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| Linux | Linux | unaffected |
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| Linux | Linux | affected |
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Configuration 1 [-]
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No data.
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| Linux | Linux Kernel |
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| Source | ID | Title |
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Ubuntu USN |
USN-8575-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8576-1 | Linux kernel (NVIDIA Tegra) vulnerabilities |
Ubuntu USN |
USN-8593-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8575-2 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8576-2 | Linux kernel (NVIDIA Tegra) vulnerabilities |
Ubuntu USN |
USN-8575-3 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8603-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8610-1 | Linux kernel (Azure CVM) vulnerabilities |
Ubuntu USN |
USN-8618-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8620-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8620-2 | Linux kernel (Azure FIPS) vulnerabilities |
Ubuntu USN |
USN-8620-3 | Linux kernel (Intel IoTG) vulnerabilities |
Ubuntu USN |
USN-8620-4 | Linux kernel (Intel IoTG) vulnerabilities |
Ubuntu USN |
USN-8663-1 | Linux kernel (NVIDIA) vulnerabilities |
Ubuntu USN |
USN-8664-1 | Linux kernel (NVIDIA BaseOS) vulnerabilities |
Ubuntu USN |
USN-8668-1 | Linux kernel (GCP) vulnerabilities |
Ubuntu USN |
USN-8728-1 | Linux kernel (GCP) vulnerabilities |
Ubuntu USN |
USN-8729-1 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8761-1 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8729-2 | Linux kernel (Raspberry Pi Real-time) vulnerabilities |
Ubuntu USN |
USN-8761-2 | Linux kernel (Azure FIPS) vulnerabilities |
Ubuntu USN |
USN-8781-1 | Linux kernel (NVIDIA Tegra) vulnerabilities |
Ubuntu USN |
USN-8668-2 | Linux kernel (Raspberry Pi) vulnerabilities |
Ubuntu USN |
USN-8729-3 | Linux kernel vulnerabilities |
Ubuntu USN |
USN-8802-1 | Linux kernel (Oracle) vulnerabilities |
Ubuntu USN |
USN-8728-2 | Linux kernel (Azure) vulnerabilities |
Ubuntu USN |
USN-8729-4 | Linux kernel (Low Latency) vulnerabilities |
Ubuntu USN |
USN-8729-5 | Linux kernel (AWS FIPS) vulnerabilities |
Ubuntu USN |
USN-8728-3 | Linux kernel (Oracle) vulnerabilities |
Ubuntu USN |
USN-8729-6 | Linux kernel (AWS) vulnerabilities |
Ubuntu USN |
USN-8906-1 | Linux kernel (IBM) vulnerabilities |
Ubuntu USN |
USN-9066-1 | Linux kernel (HWE) vulnerabilities |
No CVSS v4.0
No CVSS v3.0
No CVSS v2
This CVE is not in the KEV list.
Exploit prediction score: < 1% (0.114% probability within 30 days)
Key SSVC decision points have not yet been added.
| Type | Values Removed | Values Added |
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| Weaknesses | NVD-CWE-noinfo | |
| CPEs | cpe:2.3:o:linux:linux_kernel:7.1:rc1:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.1:rc2:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.1:rc3:*:*:*:*:*:* cpe:2.3:o:linux:linux_kernel:7.1:rc4:*:*:*:*:*:* |
| Type | Values Removed | Values Added |
|---|---|---|
| Weaknesses | CWE-833 | |
| References |
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| Metrics |
threat_severity
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cvssV3_1
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| Type | Values Removed | Values Added |
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| Description | In the Linux kernel, the following vulnerability has been resolved: phonet/pep: disable BH around forwarded sk_receive_skb() The networking receive path is usually run from softirq context, but protocols that take the socket lock may have packets stored in the backlog and processed later from process context. In that case release_sock() -> __release_sock() drops the slock with spin_unlock_bh() and then calls sk->sk_backlog_rcv() with bottom halves enabled. Typical sk_backlog_rcv handlers process the socket whose backlog is being drained, so the BH state at entry is irrelevant for the slocks they touch. pep_do_rcv() is different: when the inbound skb targets an existing PEP pipe, it forwards the skb to a different *child* socket via sk_receive_skb(). That helper takes the child slock with bh_lock_sock_nested(), which is just spin_lock_nested() and assumes BH is already off. The same child slock therefore ends up acquired with BH on (process path) and with BH off (softirq path): process context softirq context --------------- --------------- release_sock(listener) __netif_receive_skb() __release_sock() phonet_rcv() spin_unlock_bh() __sk_receive_skb(listener) [BH now ENABLED] [BH already disabled] sk_backlog_rcv: sk_backlog_rcv: pep_do_rcv() pep_do_rcv() sk_receive_skb(child) sk_receive_skb(child) bh_lock_sock_nested(child) bh_lock_sock_nested(child) => SOFTIRQ-ON-W => IN-SOFTIRQ-W Lockdep flags this as inconsistent lock state, and it can become a real self-deadlock if a softirq on the same CPU tries to receive to the same child socket while its slock is held in the BH-enabled path: WARNING: inconsistent lock state inconsistent {SOFTIRQ-ON-W} -> {IN-SOFTIRQ-W} usage. (slock-AF_PHONET/1){+.?.}-{3:3}, at: __sk_receive_skb+0x1cf/0x900 __sk_receive_skb net/core/sock.c:563 sk_receive_skb include/net/sock.h:2022 [inline] pep_do_rcv net/phonet/pep.c:675 sk_backlog_rcv include/net/sock.h:1190 __release_sock net/core/sock.c:3216 release_sock net/core/sock.c:3815 pep_sock_accept net/phonet/pep.c:879 Wrap the forwarded sk_receive_skb() in local_bh_disable() / local_bh_enable() so the child slock is always acquired with BH off. local_bh_disable() nests safely on the softirq path. Discovered via in-house syzkaller fuzzing; the same root cause also on the linux-6.1.y syzbot dashboard as extid 44f0626dd6284f02663c. Reproduced under KASAN + LOCKDEP + PROVE_LOCKING, reproducer: https://pastebin.com/A3t8xzCR | |
| Title | phonet/pep: disable BH around forwarded sk_receive_skb() | |
| First Time appeared |
Linux
Linux linux Kernel |
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| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
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| References |
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