CVE-2023-52700

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

tipc: fix kernel warning when sending SYN message

When sending a SYN message, this kernel stack trace is observed:

… [ 13.396352] RIP: 0010:_copy_from_iter+0xb4/0x550 … [ 13.398494] Call Trace: [ 13.398630] [ 13.398630] ? __alloc_skb+0xed/0x1a0 [ 13.398630] tipc_msg_build+0x12c/0x670 [tipc] [ 13.398630] ? shmem_add_to_page_cache.isra.71+0x151/0x290 [ 13.398630] __tipc_sendmsg+0x2d1/0x710 [tipc] [ 13.398630] ? tipc_connect+0x1d9/0x230 [tipc] [ 13.398630] ? __local_bh_enable_ip+0x37/0x80 [ 13.398630] tipc_connect+0x1d9/0x230 [tipc] [ 13.398630] ? __sys_connect+0x9f/0xd0 [ 13.398630] __sys_connect+0x9f/0xd0 [ 13.398630] ? preempt_count_add+0x4d/0xa0 [ 13.398630] ? fpregs_assert_state_consistent+0x22/0x50 [ 13.398630] __x64_sys_connect+0x16/0x20 [ 13.398630] do_syscall_64+0x42/0x90 [ 13.398630] entry_SYSCALL_64_after_hwframe+0x63/0xcd

It is because commit a41dad905e5a (iov_iter: saner checks for attempt to copy to/from iterator) has introduced sanity check for copying from/to iov iterator. Lacking of copy direction from the iterator viewpoint would lead to kernel stack trace like above.

This commit fixes this issue by initializing the iov iterator with the correct copy direction when sending SYN or ACK without data.

Weakness

The product exposes a resource to the wrong control sphere, providing unintended actors with inappropriate access to the resource.

Affected Software

Extended Description

Resources such as files and directories may be inadvertently exposed through mechanisms such as insecure permissions, or when a program accidentally operates on the wrong object. For example, a program may intend that private files can only be provided to a specific user. This effectively defines a control sphere that is intended to prevent attackers from accessing these private files. If the file permissions are insecure, then parties other than the user will be able to access those files. A separate control sphere might effectively require that the user can only access the private files, but not any other files on the system. If the program does not ensure that the user is only requesting private files, then the user might be able to access other files on the system. In either case, the end result is that a resource has been exposed to the wrong party.

References

• https://git.kernel.org/stable/c/11a4d6f67cf55883dc78e31c247d1903ed7feccc
• https://git.kernel.org/stable/c/54b6082aec178f16ad6d193b4ecdc9c4823d9a32
• https://git.kernel.org/stable/c/11a4d6f67cf55883dc78e31c247d1903ed7feccc
• https://git.kernel.org/stable/c/54b6082aec178f16ad6d193b4ecdc9c4823d9a32