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CVE-2025-38165

Description

In the Linux kernel, the following vulnerability has been resolved:bpf, sockmap: Fix panic when calling skb_linearizeThe panic can be reproduced by executing the command:./bench sockmap -c 2 -p 1 -a --rx-verdict-ingress --rx-strp 100000Then a kernel panic was captured:'''[ 657.460555] kernel BUG at net/core/skbuff.c:2178![ 657.462680] Tainted: [W]=WARN[ 657.463287] Workqueue: events sk_psock_backlog...[ 657.469610] [ 657.469738] ? die+0x36/0x90[ 657.469916] ? do_trap+0x1d0/0x270[ 657.470118] ? pskb_expand_head+0x612/0xf40[ 657.470376] ? pskb_expand_head+0x612/0xf40[ 657.470620] ? do_error_trap+0xa3/0x170[ 657.470846] ? pskb_expand_head+0x612/0xf40[ 657.471092] ? handle_invalid_op+0x2c/0x40[ 657.471335] ? pskb_expand_head+0x612/0xf40[ 657.471579] ? exc_invalid_op+0x2d/0x40[ 657.471805] ? asm_exc_invalid_op+0x1a/0x20[ 657.472052] ? pskb_expand_head+0xd1/0xf40[ 657.472292] ? pskb_expand_head+0x612/0xf40[ 657.472540] ? lock_acquire+0x18f/0x4e0[ 657.472766] ? find_held_lock+0x2d/0x110[ 657.472999] ? __pfx_pskb_expand_head+0x10/0x10[ 657.473263] ? __kmalloc_cache_noprof+0x5b/0x470[ 657.473537] ? __pfx___lock_release.isra.0+0x10/0x10[ 657.473826] __pskb_pull_tail+0xfd/0x1d20[ 657.474062] ? __kasan_slab_alloc+0x4e/0x90[ 657.474707] sk_psock_skb_ingress_enqueue+0x3bf/0x510[ 657.475392] ? __kasan_kmalloc+0xaa/0xb0[ 657.476010] sk_psock_backlog+0x5cf/0xd70[ 657.476637] process_one_work+0x858/0x1a20'''The panic originates from the assertion BUG_ON(skb_shared(skb)) inskb_linearize(). A previous commit(see Fixes tag) introduced skb_get()to avoid race conditions between skb operations in the backlog and skbrelease in the recvmsg path. However, this caused the panic to alwaysoccur when skb_linearize is executed.The "--rx-strp 100000" parameter forces the RX path to use the strparsermodule which aggregates data until it reaches 100KB before calling sockmaplogic. The 100KB payload exceeds MAX_MSG_FRAGS, triggering skb_linearize.To fix this issue, just move skb_get into sk_psock_skb_ingress_enqueue.'''sk_psock_backlog: sk_psock_handle_skb skb_get(skb) <== we move it into 'sk_psock_skb_ingress_enqueue' sk_psock_skb_ingress____________ ↓ | | → sk_psock_skb_ingress_self | sk_psock_skb_ingress_enqueuesk_psock_verdict_apply_________________↑ skb_linearize'''Note that for verdict_apply path, the skb_get operation is unnecessary sowe add 'take_ref' param to control it's behavior.

POC

Reference

No PoCs from references.

Github

- https://github.com/w4zu/Debian_security