CVE-2024-41041 — udp: Set SOCK_RCU_FREE earlier in udp_lib_get_port().

Affected: Linux

In the Linux kernel, the following vulnerability has been resolved:

udp: Set SOCK_RCU_FREE earlier in udp_lib_get_port().

syzkaller triggered the warning [0] in udp_v4_early_demux().

In udp_v[46]_early_demux() and sk_lookup(), we do not touch the refcount of the looked-up sk and use sock_pfree() as skb->destructor, so we check SOCK_RCU_FREE to ensure that the sk is safe to access during the RCU grace period.

Currently, SOCK_RCU_FREE is flagged for a bound socket after being put into the hash table. Moreover, the SOCK_RCU_FREE check is done too early in udp_v[46]_early_demux() and sk_lookup(), so there could be a small race window:

CPU1 CPU2 ---- ---- udp_v4_early_demux() udp_lib_get_port() | |- hlist_add_head_rcu() |- sk = __udp4_lib_demux_lookup() | |- DEBUG_NET_WARN_ON_ONCE(sk_is_refcounted(sk)); `- sock_set_flag(sk, SOCK_RCU_FREE)

We had the same bug in TCP and fixed it in commit 871019b22d1b ("net: set SOCK_RCU_FREE before inserting socket into hashtable").

Let's apply the same fix for UDP.

[0]: WARNING: CPU: 0 PID: 11198 at net/ipv4/udp.c:2599 udp_v4_early_demux+0x481/0xb70 net/ipv4/udp.c:2599 Modules linked in: CPU: 0 PID: 11198 Comm: syz-executor.1 Not tainted 6.9.0-g93bda33046e7 #13 Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.0-0-gd239552ce722-prebuilt.qemu.org 04/01/…

USN-7003-1 — linux, linux-aws, linux-azure, linux-bluefield, linux-gcp, linux-gkeop, linux-ibm, linux-kvm, linux-oracle vulnerabilit…

Affected: Ubuntu:20.04:LTS: linux, Ubuntu:20.04:LTS: linux-aws, Ubuntu:20.04:LTS: linux-azure, Ubuntu:20.04:LTS: linux-bluefield, Ubuntu:20.04:LTS: linux-gcp, Ubuntu:20.04:LTS: linux-gkeop, Ubuntu:20.04:LTS: linux-ibm, Ubuntu:20.04:LTS: linux-kvm, Ubuntu:20.04:LTS: linux-oracle

It was discovered that the JFS file system contained an out-of-bounds read vulnerability when printing xattr debug information. A local attacker could use this to cause a denial of service (system crash). (CVE-2024-40902)

Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems: - MIPS architecture; - PowerPC architecture; - x86 architecture; - ACPI drivers; - Serial ATA and Parallel ATA drivers; - Drivers core; - GPIO subsystem; - GPU drivers; - Greybus drivers; - HID subsystem; - I2C subsystem; - IIO subsystem; - InfiniBand drivers; - Media drivers; - VMware VMCI Driver; - Network drivers; - Pin controllers subsystem; - S/390 drivers; - SCSI drivers; - USB subsystem; - JFFS2 file system; - JFS file system; - File systems infrastructure; - NILFS2 file system; - IOMMU subsystem; - Sun RPC protocol; - Netfilter; - Memory management; - B.A.T.M.A.N. meshing protocol; - CAN network layer; - Ceph Core library; - Networking core; - IPv4 networking; - IPv6 networking; - IUCV driver; - MAC80211 subsystem; - NET/ROM layer; - Network traffic control; - SoC Audio for Freescale CPUs drivers; (CVE-2024-40905, CVE-2024-41095, CVE-2024-41035, CVE-2024-36974, CVE-2024-40959, CVE-2024-40978, CVE-2024-42236, CVE-2024-40963, CVE-2024-40916, CVE-2024-41006, CVE-2024-39495, CVE-2023-52803, CVE-2024…

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CVE-2024-41041 — udp: Set SOCK_RCU_FREE earlier in udp_lib_get_port().

USN-7003-1 — linux, linux-aws, linux-azure, linux-bluefield, linux-gcp, linux-gkeop, linux-ibm, linux-kvm, linux-oracle vulnerabilit…