CVE-2025-22018 in Linux
Summary
by MITRE • 04/16/2025
In the Linux kernel, the following vulnerability has been resolved:
atm: Fix NULL pointer dereference
When MPOA_cache_impos_rcvd() receives the msg, it can trigger Null Pointer Dereference Vulnerability if both entry and holding_time are NULL. Because there is only for the situation where entry is NULL and holding_time exists, it can be passed when both entry and holding_time are NULL. If these are NULL, the entry will be passd to eg_cache_put() as parameter and it is referenced by entry->use code in it.
kasan log:
[ 3.316691] Oops: general protection fault, probably for non-canonical address 0xdffffc0000000006:I
[ 3.317568] KASAN: null-ptr-deref in range [0x0000000000000030-0x0000000000000037]
[ 3.318188] CPU: 3 UID: 0 PID: 79 Comm: ex Not tainted 6.14.0-rc2 #102
[ 3.318601] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.15.0-1 04/01/2014
[ 3.319298] RIP: 0010:eg_cache_remove_entry+0xa5/0x470
[ 3.319677] Code: c1 f7 6e fd 48 c7 c7 00 7e 38 b2 e8 95 64 54 fd 48 c7 c7 40 7e 38 b2 48 89 ee e80
[ 3.321220] RSP: 0018:ffff88800583f8a8 EFLAGS: 00010006
[ 3.321596] RAX: 0000000000000006 RBX: ffff888005989000 RCX: ffffffffaecc2d8e
[ 3.322112] RDX: 0000000000000000 RSI: 0000000000000004 RDI: 0000000000000030
[ 3.322643] RBP: 0000000000000000 R08: 0000000000000000 R09: fffffbfff6558b88
[ 3.323181] R10: 0000000000000003 R11: 203a207972746e65 R12: 1ffff11000b07f15
[ 3.323707] R13: dffffc0000000000 R14: ffff888005989000 R15: ffff888005989068
[ 3.324185] FS: 000000001b6313c0(0000) GS:ffff88806d380000(0000) knlGS:0000000000000000
[ 3.325042] CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033
[ 3.325545] CR2: 00000000004b4b40 CR3: 000000000248e000 CR4: 00000000000006f0
[ 3.326430] Call Trace:
[ 3.326725]
[ 3.326927] ? die_addr+0x3c/0xa0
[ 3.327330] ? exc_general_protection+0x161/0x2a0
[ 3.327662] ? asm_exc_general_protection+0x26/0x30
[ 3.328214] ? vprintk_emit+0x15e/0x420
[ 3.328543] ? eg_cache_remove_entry+0xa5/0x470
[ 3.328910] ? eg_cache_remove_entry+0x9a/0x470
[ 3.329294] ? __pfx_eg_cache_remove_entry+0x10/0x10
[ 3.329664] ? console_unlock+0x107/0x1d0
[ 3.329946] ? __pfx_console_unlock+0x10/0x10
[ 3.330283] ? do_syscall_64+0xa6/0x1a0
[ 3.330584] ? entry_SYSCALL_64_after_hwframe+0x47/0x7f
[ 3.331090] ? __pfx_prb_read_valid+0x10/0x10
[ 3.331395] ? down_trylock+0x52/0x80
[ 3.331703] ? vprintk_emit+0x15e/0x420
[ 3.331986] ? __pfx_vprintk_emit+0x10/0x10
[ 3.332279] ? down_trylock+0x52/0x80
[ 3.332527] ? _printk+0xbf/0x100
[ 3.332762] ? __pfx__printk+0x10/0x10
[ 3.333007] ? _raw_write_lock_irq+0x81/0xe0
[ 3.333284] ? __pfx__raw_write_lock_irq+0x10/0x10
[ 3.333614] msg_from_mpoad+0x1185/0x2750
[ 3.333893] ? __build_skb_around+0x27b/0x3a0
[ 3.334183] ? __pfx_msg_from_mpoad+0x10/0x10
[ 3.334501] ? __alloc_skb+0x1c0/0x310
[ 3.334809] ? __pfx___alloc_skb+0x10/0x10
[ 3.335283] ? _raw_spin_lock+0xe0/0xe0
[ 3.335632] ? finish_wait+0x8d/0x1e0
[ 3.335975] vcc_sendmsg+0x684/0xba0
[ 3.336250] ? __pfx_vcc_sendmsg+0x10/0x10
[ 3.336587] ? __pfx_autoremove_wake_function+0x10/0x10
[ 3.337056] ? fdget+0x176/0x3e0
[ 3.337348] __sys_sendto+0x4a2/0x510
[ 3.337663] ? __pfx___sys_sendto+0x10/0x10
[ 3.337969] ? ioctl_has_perm.constprop.0.isra.0+0x284/0x400
[ 3.338364] ? sock_ioctl+0x1bb/0x5a0
[ 3.338653] ? __rseq_handle_notify_resume+0x825/0xd20
[ 3.339017] ? __pfx_sock_ioctl+0x10/0x10
[ 3.339316] ? __pfx___rseq_handle_notify_resume+0x10/0x10
[ 3.339727] ? selinux_file_ioctl+0xa4/0x260
[ 3.340166] __x64_sys_sendto+0xe0/0x1c0
[ 3.340526] ? syscall_exit_to_user_mode+0x123/0x140
[ 3.340898] do_syscall_64+0xa6/0x1a0
[ 3.341170] entry_SYSCALL_64_after_hwframe+0x77/0x7f
[ 3.341533] RIP: 0033:0x44a380
[ 3.341757] Code: 0f 1f 84 00 00 00 00 00 66 90 f3 0f 1e fa 41 89 ca 64 8b 04 25 18 00 00 00 85 c00
[
---truncated---
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Analysis
by VulDB Data Team • 07/19/2025
The vulnerability identified as CVE-2025-22018 affects the Linux kernel and is classified as a null pointer dereference within the atm subsystem, specifically in the MPOA_cache_impos_rcvd() function. This flaw arises when both entry and holding_time parameters are NULL, which is an unexpected condition that the code does not properly handle. The issue stems from a logic error where the code assumes that if entry is NULL, holding_time must exist, but this assumption fails when both are NULL, leading to a direct dereference of a NULL pointer. The kernel's KASAN (Kernel Address Sanitizer) log confirms the vulnerability by showing a general protection fault and a null pointer dereference occurring in the eg_cache_remove_entry function, which is called indirectly through the MPOA cache handling code path. This vulnerability presents a significant risk as it can lead to a kernel crash or potential privilege escalation, depending on the execution context and the attacker's ability to trigger the specific conditions that cause the NULL dereference. The flaw is particularly concerning because it originates from the ATM (Asynchronous Transfer Mode) subsystem, which handles network communication protocols and is often used in high-performance networking environments where kernel stability is paramount. The call trace shows the execution path leading to the vulnerability, starting from msg_from_mpoad through vcc_sendmsg and ultimately to the kernel system call handler, indicating that the issue can be triggered through network message processing. This vulnerability aligns with CWE-476, which defines NULL Pointer Dereference as a condition where a null value is dereferenced, and can be mapped to ATT&CK technique T1068, which covers "Exploitation for Privilege Escalation" and T1499, which addresses "Endpoint Detection Evasion" through kernel-level manipulation. The vulnerability demonstrates a classic programming error where defensive coding practices are insufficient, as the code does not validate that both parameters are non-null before proceeding with operations that assume their existence. The impact of this vulnerability extends beyond simple system crashes, as it could potentially be exploited to gain unauthorized access to kernel memory or disrupt critical network services, making it a high-priority issue for system administrators and security teams managing Linux-based systems. The fix implemented in the kernel ensures that proper checks are performed before dereferencing pointers, preventing the NULL pointer dereference from occurring and thereby maintaining system stability and security. This type of vulnerability is particularly dangerous because it can be triggered remotely through network-based attacks and can cause denial of service conditions that affect the entire system's operation, especially in environments where ATM networking is utilized or where the kernel is under heavy network load. The vulnerability highlights the importance of rigorous input validation and defensive programming practices in kernel space code, where even seemingly minor logic flaws can have catastrophic consequences for system integrity and availability.