On 2022/11/10 16:53, Herbert Xu wrote: > On Thu, Nov 10, 2022 at 12:11:15PM +0800, liulongfang wrote: >> >> When using crypto's skcipher series interfaces for encryption and decryption >> services, User can use synchronous mode(by adjusting some skcipher interfaces, >> here is to remove skcipher_request_set_callback()) or asynchronous mode, >> but when using synchronous mode and the current asynchronous mode is loaded >> it will cause a calltrace. >> >> The current problem is that the interface of skcipher does not restrict users >> to call functions in this way for encryption services. >> >> If the current driver doesn't handle this, there is a possibility that some users >> deliberately create this kind of problem to cause the kernel to crash. > > It sounds like your code is misusing the skcipher API. By default > skcipher is always async. You must always set a callback. > > The only way to legally use skcipher without setting a callback > is by allocating it with crypto_alloc_sync_skcipher. In which case OK! I found in Documentation/crypto/architecture.rst the description that async mode must provide a callback function. However, what is confusing is that this document does not describe the synchronization mode so clearly. > unless your driver incorrectly declares itself as sync instead of > async, then it will never be used by such a user. > > Cheers, > Thanks, Longfang.
