crypto: ccree - zero all of request ctx before use

In certain error path req_ctx->iv was being freed despite
not being allocated because it was not initialized to NULL.
Rather than play whack a mole with the structure various
field, zero it before use.

This fixes a kernel panic that may occur if an invalid
buffer size was requested triggering the bug above.

Fixes: 63ee04c8b491 ("crypto: ccree - add skcipher support")
Reported-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Gilad Ben-Yossef <gilad@benyossef.com>
Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/drivers/crypto/ccree/cc_cipher.c b/drivers/crypto/ccree/cc_cipher.c
index 64740dd6f5f1fc8342a4d2bae34efb2fef0fb084..9da0ecce5411e237b22b0241aaffa7399303f4f0 100644 (file)
--- a/drivers/crypto/ccree/cc_cipher.c
+++ b/drivers/crypto/ccree/cc_cipher.c
@@ -767,7 +767,7 @@ static int cc_cipher_encrypt(struct skcipher_request *req)
 {
        struct cipher_req_ctx *req_ctx = skcipher_request_ctx(req);
 
-       req_ctx->backup_info = NULL;
+       memset(req_ctx, 0, sizeof(*req_ctx));
 
        return cc_cipher_process(req, DRV_CRYPTO_DIRECTION_ENCRYPT);
 }
@@ -782,6 +782,8 @@ static int cc_cipher_decrypt(struct skcipher_request *req)
        gfp_t flags = cc_gfp_flags(&req->base);
        unsigned int len;
 
+       memset(req_ctx, 0, sizeof(*req_ctx));
+
        if (ctx_p->cipher_mode == DRV_CIPHER_CBC) {
 
                /* Allocate and save the last IV sized bytes of the source,
@@ -794,8 +796,6 @@ static int cc_cipher_decrypt(struct skcipher_request *req)
                len = req->cryptlen - ivsize;
                scatterwalk_map_and_copy(req_ctx->backup_info, req->src, len,
                                         ivsize, 0);
-       } else {
-               req_ctx->backup_info = NULL;
        }
 
        return cc_cipher_process(req, DRV_CRYPTO_DIRECTION_DECRYPT);