On 12/10/2015 10:49 AM, Fabrizio Demaria wrote: > Hello, > > I am investigating the current usage of kernel crypto-libraries in the > SCTP code, considering to adopt the same crypto framework for the > MPTCP implementation. > > In sm_make_chunk.c, the crypto function "crypto_hash_setkey" is called > in an atomic context, despite the fact that this function CAN invoke a > GFP_KERNEL (sleeping) memory allocation. Calling a sleeping function > from an atomic context can end up in deadlock. Has this factor been > considered when adding the crypto functions into the SCTP code or has > it been safely handled/verified in any way? That code has been in use since the very beginning and we've never seen any atomicity issues. I think the reason for this is that we are only using the sha1 hash code which doesn't seem to provide its own setkey function. What I think it's using is the hmac version of setkey (I could be wrong here...) and that doesn't actually allocate any memory. -vlad > > > Thanks, > Fabrizio > -- > To unsubscribe from this list: send the line "unsubscribe linux-sctp" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > -- To unsubscribe from this list: send the line "unsubscribe linux-sctp" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
