From e049ff5af04b18bfb4105787be198d58c841fc99 Mon Sep 17 00:00:00 2001
From: Ryder Lee <ryder.lee@mediatek.com>
Date: Wed, 28 Aug 2019 14:37:13 +0800
Subject: [PATCH] crypto: mediatek - fix uninitialized value of gctx->textlen
Git-commit: e049ff5af04b18bfb4105787be198d58c841fc99
Patch-mainline: v5.4-rc1
References: git-fixes

Add a pre-computed text length to avoid uninitialized value in the check.

Fixes: e47270665b5f ("crypto: mediatek - Add empty messages check in GCM mode")
Signed-off-by: Ryder Lee <ryder.lee@mediatek.com>
Signed-off-by: Vic Wu <vic.wu@mediatek.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/crypto/mediatek/mtk-aes.c |   10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

--- a/drivers/crypto/mediatek/mtk-aes.c
+++ b/drivers/crypto/mediatek/mtk-aes.c
@@ -905,14 +905,11 @@ static int mtk_aes_gcm_start(struct mtk_
 		aes->resume = mtk_aes_transfer_complete;
 		/* Compute total process length. */
 		aes->total = len + gctx->authsize;
-		/* Compute text length. */
-		gctx->textlen = req->cryptlen;
 		/* Hardware will append authenticated tag to output buffer */
 		scatterwalk_map_and_copy(tag, req->dst, len, gctx->authsize, 1);
 	} else {
 		aes->resume = mtk_aes_gcm_tag_verify;
 		aes->total = len;
-		gctx->textlen = req->cryptlen - gctx->authsize;
 	}
 
 	return mtk_aes_gcm_dma(cryp, aes, req->src, req->dst, len);
@@ -923,6 +920,10 @@ static int mtk_aes_gcm_crypt(struct aead
 	struct mtk_aes_base_ctx *ctx = crypto_aead_ctx(crypto_aead_reqtfm(req));
 	struct mtk_aes_gcm_ctx *gctx = mtk_aes_gcm_ctx_cast(ctx);
 	struct mtk_aes_reqctx *rctx = aead_request_ctx(req);
+	bool enc = !!(mode & AES_FLAGS_ENCRYPT);
+
+	/* Compute text length. */
+	gctx->textlen = req->cryptlen - (enc ? 0 : gctx->authsize);
 
 	/* Empty messages are not supported yet */
 	if (!gctx->textlen && !req->assoclen)
@@ -930,8 +931,7 @@ static int mtk_aes_gcm_crypt(struct aead
 
 	rctx->mode = AES_FLAGS_GCM | mode;
 
-	return mtk_aes_handle_queue(ctx->cryp, !!(mode & AES_FLAGS_ENCRYPT),
-				    &req->base);
+	return mtk_aes_handle_queue(ctx->cryp, enc, &req->base);
 }
 
 /*