On Tue, Apr 09, 2024 at 10:51:30AM +0100, David Howells wrote: > Hi Herbert, > > Is the following code in crypto_alloc_sync_skcipher() wrong: > > /* Only sync algorithms allowed. */ > mask |= CRYPTO_ALG_ASYNC | CRYPTO_ALG_SKCIPHER_REQSIZE_LARGE; > > in its specification of CRYPTO_ALG_ASYNC? Given what the docs say: > > The mask flag restricts the type of cipher. The only allowed flag is > CRYPTO_ALG_ASYNC to restrict the cipher lookup function to > asynchronous ciphers. Usually, a caller provides a 0 for the mask flag. > ^^^^^^^^^^^^ > > or are the docs wrong? The mask is used together with the type bitfield. You need to set CRYPTO_ALG_ASYNC in both bitfields if you want to guarantee getting an async cipher. If you set CRYPTO_ALG_ASYNC in the mask but leave it unset in the type bitfield then you are guaranteed to get an algorithm with this bit turned off, in other words a synchronous cipher. Cheers, -- Email: Herbert Xu <herbert@xxxxxxxxxxxxxxxxxxx> Home Page: http://gondor.apana.org.au/~herbert/ PGP Key: http://gondor.apana.org.au/~herbert/pubkey.txt
