CVE-2024-57841

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

net: fix memory leak in tcp_conn_request()

If inet_csk_reqsk_queue_hash_add() return false, tcp_conn_request() will return without free the dst memory, which allocated in af_ops->route_req.

Here is the kmemleak stack:

unreferenced object 0xffff8881198631c0 (size 240): comm softirq, pid 0, jiffies 4299266571 (age 1802.392s) hex dump (first 32 bytes): 00 10 9b 03 81 88 ff ff 80 98 da bc ff ff ff ff ……………. 81 55 18 bb ff ff ff ff 00 00 00 00 00 00 00 00 .U………….. backtrace: [] kmem_cache_alloc+0x60c/0xa80 [] dst_alloc+0x55/0x250 [] rt_dst_alloc+0x46/0x1d0 [] __mkroute_output+0x29a/0xa50 [] ip_route_output_key_hash+0x10b/0x240 [] ip_route_output_flow+0x1d/0x90 [] inet_csk_route_req+0x2c5/0x500 [] tcp_conn_request+0x691/0x12c0 [] tcp_rcv_state_process+0x3c8/0x11b0 [] tcp_v4_do_rcv+0x156/0x3b0 [] tcp_v4_rcv+0x1cf8/0x1d80 [] ip_protocol_deliver_rcu+0xf6/0x360 [] ip_local_deliver_finish+0xe6/0x1e0 [] ip_local_deliver+0xee/0x360 [] ip_rcv+0xad/0x2f0 [] __netif_receive_skb_one_core+0x123/0x140

Call dst_release() to free the dst memory when inet_csk_reqsk_queue_hash_add() return false in tcp_conn_request().

Weakness

The product does not sufficiently track and release allocated memory after it has been used, which slowly consumes remaining memory.

Affected Software

Potential Mitigations

• Choose a language or tool that provides automatic memory management, or makes manual memory management less error-prone.
• For example, glibc in Linux provides protection against free of invalid pointers.
• When using Xcode to target OS X or iOS, enable automatic reference counting (ARC) [REF-391].
• To help correctly and consistently manage memory when programming in C++, consider using a smart pointer class such as std::auto_ptr (defined by ISO/IEC ISO/IEC 14882:2003), std::shared_ptr and std::unique_ptr (specified by an upcoming revision of the C++ standard, informally referred to as C++ 1x), or equivalent solutions such as Boost.

References

• https://git.kernel.org/stable/c/2af69905180b3fea12f9c1db374b153a06977021
• https://git.kernel.org/stable/c/4f4aa4aa28142d53f8b06585c478476cfe325cfc
• https://git.kernel.org/stable/c/9d38959677291552d1b0ed2689a540af279b5bf8
• https://git.kernel.org/stable/c/b0b190218c78d8aeecfba36ea3a90063b3ede52d
• https://git.kernel.org/stable/c/de3f999bf8aee16e9da1c1224191abdc69e97c9d