diff options
| -rw-r--r-- | crypto/algif_aead.c | 57 |
1 files changed, 36 insertions, 21 deletions
diff --git a/crypto/algif_aead.c b/crypto/algif_aead.c index 80a0f1a78551..2fbf239bb1f2 100644 --- a/crypto/algif_aead.c +++ b/crypto/algif_aead.c @@ -81,7 +81,11 @@ static inline bool aead_sufficient_data(struct aead_ctx *ctx) { unsigned as = crypto_aead_authsize(crypto_aead_reqtfm(&ctx->aead_req)); - return ctx->used >= ctx->aead_assoclen + as; + /* + * The minimum amount of memory needed for an AEAD cipher is + * the AAD and in case of decryption the tag. + */ + return ctx->used >= ctx->aead_assoclen + (ctx->enc ? 0 : as); } static void aead_reset_ctx(struct aead_ctx *ctx) @@ -426,12 +430,15 @@ static int aead_recvmsg_async(struct socket *sock, struct msghdr *msg, goto unlock; } - used = ctx->used; - outlen = used; - if (!aead_sufficient_data(ctx)) goto unlock; + used = ctx->used; + if (ctx->enc) + outlen = used + as; + else + outlen = used - as; + req = sock_kmalloc(sk, reqlen, GFP_KERNEL); if (unlikely(!req)) goto unlock; @@ -445,7 +452,7 @@ static int aead_recvmsg_async(struct socket *sock, struct msghdr *msg, aead_request_set_ad(req, ctx->aead_assoclen); aead_request_set_callback(req, CRYPTO_TFM_REQ_MAY_BACKLOG, aead_async_cb, sk); - used -= ctx->aead_assoclen + (ctx->enc ? as : 0); + used -= ctx->aead_assoclen; /* take over all tx sgls from ctx */ areq->tsgl = sock_kmalloc(sk, sizeof(*areq->tsgl) * sgl->cur, @@ -461,7 +468,7 @@ static int aead_recvmsg_async(struct socket *sock, struct msghdr *msg, areq->tsgls = sgl->cur; /* create rx sgls */ - while (iov_iter_count(&msg->msg_iter)) { + while (outlen > usedpages && iov_iter_count(&msg->msg_iter)) { size_t seglen = min_t(size_t, iov_iter_count(&msg->msg_iter), (outlen - usedpages)); @@ -491,16 +498,14 @@ static int aead_recvmsg_async(struct socket *sock, struct msghdr *msg, last_rsgl = rsgl; - /* we do not need more iovecs as we have sufficient memory */ - if (outlen <= usedpages) - break; - iov_iter_advance(&msg->msg_iter, err); } - err = -EINVAL; + /* ensure output buffer is sufficiently large */ - if (usedpages < outlen) - goto free; + if (usedpages < outlen) { + err = -EINVAL; + goto unlock; + } aead_request_set_crypt(req, areq->tsgl, areq->first_rsgl.sgl.sg, used, areq->iv); @@ -571,6 +576,7 @@ static int aead_recvmsg_sync(struct socket *sock, struct msghdr *msg, int flags) goto unlock; } + /* data length provided by caller via sendmsg/sendpage */ used = ctx->used; /* @@ -585,16 +591,27 @@ static int aead_recvmsg_sync(struct socket *sock, struct msghdr *msg, int flags) if (!aead_sufficient_data(ctx)) goto unlock; - outlen = used; + /* + * Calculate the minimum output buffer size holding the result of the + * cipher operation. When encrypting data, the receiving buffer is + * larger by the tag length compared to the input buffer as the + * encryption operation generates the tag. For decryption, the input + * buffer provides the tag which is consumed resulting in only the + * plaintext without a buffer for the tag returned to the caller. + */ + if (ctx->enc) + outlen = used + as; + else + outlen = used - as; /* * The cipher operation input data is reduced by the associated data * length as this data is processed separately later on. */ - used -= ctx->aead_assoclen + (ctx->enc ? as : 0); + used -= ctx->aead_assoclen; /* convert iovecs of output buffers into scatterlists */ - while (iov_iter_count(&msg->msg_iter)) { + while (outlen > usedpages && iov_iter_count(&msg->msg_iter)) { size_t seglen = min_t(size_t, iov_iter_count(&msg->msg_iter), (outlen - usedpages)); @@ -621,16 +638,14 @@ static int aead_recvmsg_sync(struct socket *sock, struct msghdr *msg, int flags) last_rsgl = rsgl; - /* we do not need more iovecs as we have sufficient memory */ - if (outlen <= usedpages) - break; iov_iter_advance(&msg->msg_iter, err); } - err = -EINVAL; /* ensure output buffer is sufficiently large */ - if (usedpages < outlen) + if (usedpages < outlen) { + err = -EINVAL; goto unlock; + } sg_mark_end(sgl->sg + sgl->cur - 1); aead_request_set_crypt(&ctx->aead_req, sgl->sg, ctx->first_rsgl.sgl.sg, |