crypto: gcm - fix assumption that assoc has one segment

rfc4543(gcm(*)) code for GMAC assumes that assoc scatterlist always contains only one segment and only makes use of this first segment. However ipsec passes assoc with three segments when using 'extended sequence number' thus in this case rfc4543(gcm(*)) fails to function correctly. Patch fixes this issue. Reported-by: Chaoxing Lin <[email protected]> Tested-by: Chaoxing Lin <[email protected]> Cc: [email protected] Signed-off-by: Jussi Kivilinna <[email protected]> Signed-off-by: Herbert Xu <[email protected]>
sfionov · Apr 2, 2013 · d3dde52 · d3dde52
1 parent 246bbed
commit d3dde52
Showing 1 changed file with 14 additions and 3 deletions.
diff --git a/crypto/gcm.c b/crypto/gcm.c
@@ -44,6 +44,7 @@ struct crypto_rfc4543_ctx {
 
 struct crypto_rfc4543_req_ctx {
 	u8 auth_tag[16];
+	u8 assocbuf[32];
 	struct scatterlist cipher[1];
 	struct scatterlist payload[2];
 	struct scatterlist assoc[2];
@@ -1133,9 +1134,19 @@ static struct aead_request *crypto_rfc4543_crypt(struct aead_request *req,
 	scatterwalk_crypto_chain(payload, dst, vdst == req->iv + 8, 2);
 	assoclen += 8 + req->cryptlen - (enc ? 0 : authsize);
 
-	sg_init_table(assoc, 2);
-	sg_set_page(assoc, sg_page(req->assoc), req->assoc->length,
-		    req->assoc->offset);
+	if (req->assoc->length == req->assoclen) {
+		sg_init_table(assoc, 2);
+		sg_set_page(assoc, sg_page(req->assoc), req->assoc->length,
+			    req->assoc->offset);
+	} else {
+		BUG_ON(req->assoclen > sizeof(rctx->assocbuf));
+
+		scatterwalk_map_and_copy(rctx->assocbuf, req->assoc, 0,
+					 req->assoclen, 0);
+
+		sg_init_table(assoc, 2);
+		sg_set_buf(assoc, rctx->assocbuf, req->assoclen);
+	}
 	scatterwalk_crypto_chain(assoc, payload, 0, 2);
 
 	aead_request_set_tfm(subreq, ctx->child);