[CRYPTO] authenc: Fix hash verification

The previous code incorrectly included the hash in the verification which
also meant that we'd crash and burn when it comes to actually verifying
the hash since we'd go past the end of the SG list.

This patch fixes that by subtracting authsize from cryptlen at the start.

Signed-off-by: Herbert Xu <herbert@gondor.apana.org.au>

diff --git a/crypto/authenc.c b/crypto/authenc.c
index a61dea1c2fe680ff6d776f4a08c5bb470986b7ab..82e03ffa62455a3afd8a058e395e66da2ad37e6d 100644 (file)
--- a/crypto/authenc.c
+++ b/crypto/authenc.c
@@ -158,7 +158,8 @@ static int crypto_authenc_encrypt(struct aead_request *req)
        return crypto_authenc_hash(req);
 }
 
-static int crypto_authenc_verify(struct aead_request *req)
+static int crypto_authenc_verify(struct aead_request *req,
+                                unsigned int cryptlen)
 {
        struct crypto_aead *authenc = crypto_aead_reqtfm(req);
        struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
@@ -170,7 +171,6 @@ static int crypto_authenc_verify(struct aead_request *req)
        u8 *ohash = aead_request_ctx(req);
        u8 *ihash;
        struct scatterlist *src = req->src;
-       unsigned int cryptlen = req->cryptlen;
        unsigned int authsize;
        int err;
 
@@ -214,16 +214,22 @@ static int crypto_authenc_decrypt(struct aead_request *req)
        struct crypto_aead *authenc = crypto_aead_reqtfm(req);
        struct crypto_authenc_ctx *ctx = crypto_aead_ctx(authenc);
        struct ablkcipher_request *abreq = aead_request_ctx(req);
+       unsigned int cryptlen = req->cryptlen;
+       unsigned int authsize = crypto_aead_authsize(authenc);
        int err;
 
-       err = crypto_authenc_verify(req);
+       if (cryptlen < authsize)
+               return -EINVAL;
+       cryptlen -= authsize;
+
+       err = crypto_authenc_verify(req, cryptlen);
        if (err)
                return err;
 
        ablkcipher_request_set_tfm(abreq, ctx->enc);
        ablkcipher_request_set_callback(abreq, aead_request_flags(req),
                                        crypto_authenc_decrypt_done, req);
-       ablkcipher_request_set_crypt(abreq, req->src, req->dst, req->cryptlen,
+       ablkcipher_request_set_crypt(abreq, req->src, req->dst, cryptlen,
                                     req->iv);
 
        return crypto_ablkcipher_decrypt(abreq);