Am Mittwoch, 29. November 2017, 00:02:40 CET schrieb Herbert Xu: Hi Herbert,
> > --- a/crypto/algif_aead.c > > +++ b/crypto/algif_aead.c > > @@ -110,6 +110,7 @@ static int _aead_recvmsg(struct socket *sock, struct > > msghdr *msg,> > > size_t outlen = 0; /* [out] RX bufs produced by kernel */ > > size_t usedpages = 0; /* [in] RX bufs to be used from user */ > > size_t processed = 0; /* [in] TX bufs to be consumed */ > > > > + bool enc = ctx->enc; /* prevent race if sock lock dropped */ > > This is wrong. You can't fetch ctx->enc before you wait. It has > to be done after the wait as otherwise ctx->enc may not even have > been initialised. All ctx variables are initialized in aead_accept_parent_nokey. Thus, if no sendmsg call is invoked by user space, at least a valid operation is performed. > > In fact the position of the wait call is just wrong. You should only > ever do at most one wait at the start of the recvmsg call. Once you > have enough data from that wait no further waits should be done for > that recvmsg call. The original commit had it right with just one > wait at the start of recvmsg (400c40cf78da). I am wondering about the wait call inside the while () in af_alg_get_rsgl: this has been taken from algif_skcipher. It would seem that moving the wait call to the beginning of the recvmsg call would be applicable to skcipher as well. I.e. the wait call should be removed from af_alg_get_rsgl entirely and placed at the beginning the recvmsg function in both, the aead and skcipher code paths. > > Fetching of ctx state should be performed after this wait. > > Cheers, Ciao Stephan
