CVE-2024-0641 (published 2024-01-17T16:15Z)

A denial of service vulnerability was found in tipc_crypto_key_revoke in net/tipc/crypto.c in the Linux kernel’s TIPC subsystem. This flaw allows guests with local user privileges to trigger a deadlock and potentially crash the system.

CVSS v3 base score: 5.5, MEDIUM (CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H)

Weakness information:
cwe_id: CWE-667
cwe_name: Improper Locking
description: The product does not properly acquire or release a lock on a resource, leading to unexpected resource state changes and behaviors.
extended_description: 
	   Locking is a type of synchronization behavior that ensures that multiple independently-operating processes or threads do not interfere with each other when accessing the same resource. All processes/threads are expected to follow the same steps for locking. If these steps are not followed precisely - or if no locking is done at all - then another process/thread could modify the shared resource in a way that is not visible or predictable to the original process.  This can lead to data or memory corruption, denial of service, etc.
         

Fix information:
repo_url: https://github.com/torvalds/linux
commit_details: repo_url: https://github.com/torvalds/linux
author: Chengfeng Ye
author_date: 2023-09-27 18:14:14+00:00
msg: tipc: fix a potential deadlock on &tx->lock

It seems that tipc_crypto_key_revoke() could be be invoked by
wokequeue tipc_crypto_work_rx() under process context and
timer/rx callback under softirq context, thus the lock acquisition
on &tx->lock seems better use spin_lock_bh() to prevent possible
deadlock.

This flaw was found by an experimental static analysis tool I am
developing for irq-related deadlock.

tipc_crypto_work_rx() <workqueue>
--> tipc_crypto_key_distr()
--> tipc_bcast_xmit()
--> tipc_bcbase_xmit()
--> tipc_bearer_bc_xmit()
--> tipc_crypto_xmit()
--> tipc_ehdr_build()
--> tipc_crypto_key_revoke()
--> spin_lock(&tx->lock)
<timer interrupt>
   --> tipc_disc_timeout()
   --> tipc_bearer_xmit_skb()
   --> tipc_crypto_xmit()
   --> tipc_ehdr_build()
   --> tipc_crypto_key_revoke()
   --> spin_lock(&tx->lock) <deadlock here>

Signed-off-by: Chengfeng Ye <dg573847474@gmail.com>
Reviewed-by: Jacob Keller <jacob.e.keller@intel.com>
Acked-by: Jon Maloy <jmaloy@redhat.com>
Fixes: fc1b6d6de220 ("tipc: introduce TIPC encryption & authentication")
Link: https://lore.kernel.org/r/20230927181414.59928-1-dg573847474@gmail.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
repository: repo_url: https://github.com/torvalds/linux
repo_name: torvalds/linux
description: Linux kernel source tree
repo_language: C
owner: torvalds
file_changes: filename: crypto.c
change_type: ModificationType.MODIFY
diff: @@ -1441,14 +1441,14 @@ static int tipc_crypto_key_revoke(struct net *net, u8 tx_key)
 	struct tipc_crypto *tx = tipc_net(net)->crypto_tx;
 	struct tipc_key key;
 
-	spin_lock(&tx->lock);
+	spin_lock_bh(&tx->lock);
 	key = tx->key;
 	WARN_ON(!key.active || tx_key != key.active);
 
 	/* Free the active key */
 	tipc_crypto_key_set_state(tx, key.passive, 0, key.pending);
 	tipc_crypto_key_detach(tx->aead[key.active], &tx->lock);
-	spin_unlock(&tx->lock);
+	spin_unlock_bh(&tx->lock);
 
 	pr_warn("%s: key is revoked\n", tx->name);
 	return -EKEYREVOKED;

programming_language: C