From: Alexander Sverdlin Subject: Re: [PATCH 2/4] crypto: af_alg - Allow arbitrarily long algorithm names Date: Thu, 6 Apr 2017 14:32:27 +0200 Message-ID: <32d123fa-5c5f-4db6-d333-24b71639b738@nokia.com> References: <20170406081509.GB30557@gondor.apana.org.au> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit To: Herbert Xu , "David S. Miller" , , Return-path: In-Reply-To: Sender: netdev-owner@vger.kernel.org List-Id: linux-crypto.vger.kernel.org Hi! On 06/04/17 10:16, Herbert Xu wrote: > This patch removes the hard-coded 64-byte limit on the length > of the algorithm name through bind(2). The address length can > now exceed that. The user-space structure remains unchanged. > In order to use a longer name simply extend the salg_name array > beyond its defined 64 bytes length. > > Signed-off-by: Herbert Xu > --- > > crypto/af_alg.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/crypto/af_alg.c b/crypto/af_alg.c > index 690deca..3556d8e 100644 > --- a/crypto/af_alg.c > +++ b/crypto/af_alg.c > @@ -160,11 +160,11 @@ static int alg_bind(struct socket *sock, struct sockaddr *uaddr, int addr_len) > if (sock->state == SS_CONNECTED) > return -EINVAL; > > - if (addr_len != sizeof(*sa)) > + if (addr_len < sizeof(*sa)) > return -EINVAL; > > sa->salg_type[sizeof(sa->salg_type) - 1] = 0; > - sa->salg_name[sizeof(sa->salg_name) - 1] = 0; > + sa->salg_name[sizeof(sa->salg_name) + addr_len - sizeof(*sa) - 1] = 0; > > type = alg_get_type(sa->salg_type); > if (IS_ERR(type) && PTR_ERR(type) == -ENOENT) { Why should userspace ever extend the structure if salg_name is hardcoded to 64 in if_alg.h? This patch doesn't change the behavior at all, or am I missing something? -- Best regards, Alexander Sverdlin.