CVE-2022-49017 in Linux
Summary
by MITRE • 10/21/2024
In the Linux kernel, the following vulnerability has been resolved:
tipc: re-fetch skb cb after tipc_msg_validate
As the call trace shows, the original skb was freed in tipc_msg_validate(), and dereferencing the old skb cb would cause an use-after-free crash.
BUG: KASAN: use-after-free in tipc_crypto_rcv_complete+0x1835/0x2240 [tipc]
Call Trace: tipc_crypto_rcv_complete+0x1835/0x2240 [tipc]
tipc_crypto_rcv+0xd32/0x1ec0 [tipc]
tipc_rcv+0x744/0x1150 [tipc]
... Allocated by task 47078: kmem_cache_alloc_node+0x158/0x4d0 __alloc_skb+0x1c1/0x270 tipc_buf_acquire+0x1e/0xe0 [tipc]
tipc_msg_create+0x33/0x1c0 [tipc]
tipc_link_build_proto_msg+0x38a/0x2100 [tipc]
tipc_link_timeout+0x8b8/0xef0 [tipc]
tipc_node_timeout+0x2a1/0x960 [tipc]
call_timer_fn+0x2d/0x1c0 ... Freed by task 47078: tipc_msg_validate+0x7b/0x440 [tipc]
tipc_crypto_rcv_complete+0x4b5/0x2240 [tipc]
tipc_crypto_rcv+0xd32/0x1ec0 [tipc]
tipc_rcv+0x744/0x1150 [tipc]
This patch fixes it by re-fetching the skb cb from the new allocated skb after calling tipc_msg_validate().
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Analysis
by VulDB Data Team • 01/19/2026
The vulnerability identified as CVE-2022-49017 resides within the Linux kernel's TIPC (Transparent Inter-Process Communication) subsystem, representing a classic use-after-free condition that can lead to system instability and potential exploitation. This flaw manifests when the TIPC protocol stack processes incoming network messages, specifically during the validation and cryptographic reception phases. The issue stems from improper handling of socket buffer control blocks, which are essential metadata structures that accompany network packets in the kernel's networking stack. When tipc_msg_validate() function executes, it frees the original socket buffer, but subsequent code attempts to access control block data from the now-freed memory region, creating a dangerous scenario where memory corruption can occur.
The technical execution of this vulnerability follows a well-defined call trace that demonstrates the memory management failure. Initially, the kernel allocates a socket buffer through tipc_buf_acquire() and tipc_msg_create() functions, establishing the necessary infrastructure for message handling. However, during the validation process, tipc_msg_validate() frees this socket buffer, yet the control flow continues to reference the freed control block data in tipc_crypto_rcv_complete(). This sequence creates a use-after-free condition that the kernel's KASAN (Kernel Address Sanitizer) detects, generating the specific error message indicating the problematic function call chain. The allocation and deallocation patterns clearly show that the same task ID handles both operations, confirming the direct relationship between the memory allocation and subsequent freeing.
This vulnerability impacts the TIPC subsystem's ability to securely process network messages, potentially allowing attackers to trigger system crashes or, in more sophisticated scenarios, achieve privilege escalation through memory corruption. The operational impact extends beyond simple denial of service, as the use-after-free condition can be exploited to manipulate kernel memory structures, potentially leading to arbitrary code execution. The vulnerability affects systems running Linux kernels with TIPC support, particularly those implementing cryptographic message handling within the TIPC protocol stack. The flaw represents a critical security concern because it occurs during normal network message processing, meaning any system receiving TIPC messages could be vulnerable to exploitation.
The patch for this vulnerability implements a straightforward but critical fix by ensuring that socket buffer control block data is re-fetched from the newly allocated socket buffer after tipc_msg_validate() completes its execution. This approach prevents the use-after-free condition by eliminating references to freed memory before they can be accessed again. The solution aligns with standard kernel security practices for handling memory management operations and addresses the core issue identified in the call trace. This fix directly relates to CWE-416, which defines use-after-free vulnerabilities as a well-known weakness in software security where memory is accessed after it has been freed. From an ATT&CK perspective, this vulnerability could be leveraged for privilege escalation or denial of service, potentially mapping to techniques involving kernel memory corruption and system instability exploitation. The patch ensures proper memory lifecycle management within the TIPC subsystem, maintaining the integrity of kernel data structures during message processing operations.