From 95ec01ba1ef01ffe3cfa755d3d61e24c863ed9b2 Mon Sep 17 00:00:00 2001 From: James Bottomley Date: Thu, 1 Mar 2018 14:37:42 -0800 Subject: [PATCH] crypto: ecdh - fix to allow multi segment scatterlists Apparently the ecdh use case was in bluetooth which always has single element scatterlists, so the ecdh module was hard coded to expect them. Now we're using this in TPM, we need multi-element scatterlists, so remove this limitation. Signed-off-by: James Bottomley Signed-off-by: Herbert Xu --- crypto/ecdh.c | 23 +++++++++++++++++------ 1 file changed, 17 insertions(+), 6 deletions(-) diff --git a/crypto/ecdh.c b/crypto/ecdh.c index 3aca0933ec44..d2ec33f0e098 100644 --- a/crypto/ecdh.c +++ b/crypto/ecdh.c @@ -89,12 +89,19 @@ static int ecdh_compute_value(struct kpp_request *req) if (!shared_secret) goto free_pubkey; - copied = sg_copy_to_buffer(req->src, 1, public_key, - public_key_sz); - if (copied != public_key_sz) { - ret = -EINVAL; + /* from here on it's invalid parameters */ + ret = -EINVAL; + + /* must have exactly two points to be on the curve */ + if (public_key_sz != req->src_len) + goto free_all; + + copied = sg_copy_to_buffer(req->src, + sg_nents_for_len(req->src, + public_key_sz), + public_key, public_key_sz); + if (copied != public_key_sz) goto free_all; - } ret = crypto_ecdh_shared_secret(ctx->curve_id, ctx->ndigits, ctx->private_key, public_key, @@ -111,7 +118,11 @@ static int ecdh_compute_value(struct kpp_request *req) if (ret < 0) goto free_all; - copied = sg_copy_from_buffer(req->dst, 1, buf, nbytes); + /* might want less than we've got */ + nbytes = min_t(size_t, nbytes, req->dst_len); + copied = sg_copy_from_buffer(req->dst, sg_nents_for_len(req->dst, + nbytes), + buf, nbytes); if (copied != nbytes) ret = -EINVAL;