CVE-2025-21852 DetailDescriptionIn the Linux kernel, the following vulnerability has been resolved: net: Add rx_skb of kfree_skb to raw_tp_null_args[]. Yan Zhai reported a BPF prog could trigger a null-ptr-deref [0] in trace_kfree_skb if the prog does not check if rx_sk is NULL. Commit c53795d48ee8 ("net: add rx_sk to trace_kfree_skb") added rx_sk to trace_kfree_skb, but rx_sk is optional and could be NULL. Let's add kfree_skb to raw_tp_null_args[] to let the BPF verifier validate such a prog and prevent the issue. Now we fail to load such a prog: libbpf: prog 'drop': -- BEGIN PROG LOAD LOG -- 0: R1=ctx() R10=fp0 ; int BPF_PROG(drop, struct sk_buff *skb, void *location, @ kfree_skb_sk_null.bpf.c:21 0: (79) r3 = *(u64 *)(r1 +24) func 'kfree_skb' arg3 has btf_id 5253 type STRUCT 'sock' 1: R1=ctx() R3_w=trusted_ptr_or_null_sock(id=1) ; bpf_printk("sk: %d, %d\n", sk, sk->__sk_common.skc_family); @ kfree_skb_sk_null.bpf.c:24 1: (69) r4 = *(u16 *)(r3 +16) R3 invalid mem access 'trusted_ptr_or_null_' processed 2 insns (limit 1000000) max_states_per_insn 0 total_states 0 peak_states 0 mark_read 0 -- END PROG LOAD LOG -- Note this fix requires commit 838a10bd2ebf ("bpf: Augment raw_tp arguments with PTR_MAYBE_NULL"). [0]: BUG: kernel NULL pointer dereference, address: 0000000000000010 PF: supervisor read access in kernel mode PF: error_code(0x0000) - not-present page PGD 0 P4D 0 PREEMPT SMP RIP: 0010:bpf_prog_5e21a6db8fcff1aa_drop+0x10/0x2d Call Trace: <TASK> ? __die+0x1f/0x60 ? page_fault_oops+0x148/0x420 ? search_bpf_extables+0x5b/0x70 ? fixup_exception+0x27/0x2c0 ? exc_page_fault+0x75/0x170 ? asm_exc_page_fault+0x22/0x30 ? bpf_prog_5e21a6db8fcff1aa_drop+0x10/0x2d bpf_trace_run4+0x68/0xd0 ? unix_stream_connect+0x1f4/0x6f0 sk_skb_reason_drop+0x90/0x120 unix_stream_connect+0x1f4/0x6f0 __sys_connect+0x7f/0xb0 __x64_sys_connect+0x14/0x20 do_syscall_64+0x47/0xc30 entry_SYSCALL_64_after_hwframe+0x4b/0x53 Metrics
NVD enrichment efforts reference publicly available information to associate
vector strings. CVSS information contributed by other sources is also
displayed.
CVSS 4.0 Severity and Vector Strings:
References to Advisories, Solutions, and ToolsBy selecting these links, you will be leaving NIST webspace. We have provided these links to other web sites because they may have information that would be of interest to you. No inferences should be drawn on account of other sites being referenced, or not, from this page. There may be other web sites that are more appropriate for your purpose. NIST does not necessarily endorse the views expressed, or concur with the facts presented on these sites. Further, NIST does not endorse any commercial products that may be mentioned on these sites. Please address comments about this page to [email protected]. Weakness Enumeration
Known Affected Software Configurations Switch to CPE 2.2CPEs loading, please wait.
Denotes Vulnerable Software Quick InfoCVE Dictionary Entry:CVE-2025-21852 NVD Published Date: 03/12/2025 NVD Last Modified: 03/13/2025 Source: kernel.org |
|||||||
Official websites use .gov
A .gov website belongs to an official government organization in the United States.
Secure .gov websites use HTTPS
A lock (
) or https:// means you've safely connected to the .gov website. Share sensitive information only on official, secure websites.
Information Technology Laboratory
National Vulnerability Database
National Vulnerability Database
NVD
