Commit 3bfbf5f0 authored by Dudu Lu's avatar Dudu Lu Committed by Herbert Xu
Browse files

crypto: krb5enc - fix async decrypt skipping hash verification 



krb5enc_dispatch_decrypt() sets req->base.complete as the skcipher
callback, which is the caller's own completion handler. When the
skcipher completes asynchronously, this signals "done" to the caller
without executing krb5enc_dispatch_decrypt_hash(), completely bypassing
the integrity verification (hash check).

Compare with the encrypt path which correctly uses
krb5enc_encrypt_done as an intermediate callback to chain into the
hash computation on async completion.

Fix by adding krb5enc_decrypt_done as an intermediate callback that
chains into krb5enc_dispatch_decrypt_hash() upon async skcipher
completion, matching the encrypt path's callback pattern.

Also fix EBUSY/EINPROGRESS handling throughout: remove
krb5enc_request_complete() which incorrectly swallowed EINPROGRESS
notifications that must be passed up to callers waiting on backlogged
requests, and add missing EBUSY checks in krb5enc_encrypt_ahash_done
for the dispatch_encrypt return value.

Fixes: d1775a17 ("crypto: Add 'krb5enc' hash and cipher AEAD algorithm")
Signed-off-by: default avatarDudu Lu <phx0fer@gmail.com>

Unset MAY_BACKLOG on the async completion path so the user won't
see back-to-back EINPROGRESS notifications.

Signed-off-by: default avatarHerbert Xu <herbert@gondor.apana.org.au>
parent 5aa58c3a

crypto/krb5enc.c

+31 −21
Original line number Diff line number Diff line
@@ -39,12 +39,6 @@ struct krb5enc_request_ctx { 
	char tail[];

};



static void krb5enc_request_complete(struct aead_request *req, int err)

{

	if (err != -EINPROGRESS)

		aead_request_complete(req, err);

}



/**

 * crypto_krb5enc_extractkeys - Extract Ke and Ki keys from the key blob.

 * @keys: Where to put the key sizes and pointers
@@ -127,7 +121,7 @@ static void krb5enc_encrypt_done(void *data, int err) 
{

	struct aead_request *req = data;



	krb5enc_request_complete(req, err);

	aead_request_complete(req, err);

}



/*
@@ -188,13 +182,15 @@ static void krb5enc_encrypt_ahash_done(void *data, int err) 
	struct ahash_request *ahreq = (void *)(areq_ctx->tail + ictx->reqoff);



	if (err)

		return krb5enc_request_complete(req, err);

		goto out;



	krb5enc_insert_checksum(req, ahreq->result);



	err = krb5enc_dispatch_encrypt(req,

				       aead_request_flags(req) & ~CRYPTO_TFM_REQ_MAY_SLEEP);

	if (err != -EINPROGRESS)

	err = krb5enc_dispatch_encrypt(req, 0);

	if (err == -EINPROGRESS)

		return;



out:

	aead_request_complete(req, err);

}
@@ -265,17 +261,16 @@ static void krb5enc_decrypt_hash_done(void *data, int err) 
{

	struct aead_request *req = data;



	if (err)

		return krb5enc_request_complete(req, err);



	if (!err)

		err = krb5enc_verify_hash(req);

	krb5enc_request_complete(req, err);

	aead_request_complete(req, err);

}



/*

 * Dispatch the hashing of the plaintext after we've done the decryption.

 */

static int krb5enc_dispatch_decrypt_hash(struct aead_request *req)

static int krb5enc_dispatch_decrypt_hash(struct aead_request *req,

					 unsigned int flags)

{

	struct crypto_aead *krb5enc = crypto_aead_reqtfm(req);

	struct aead_instance *inst = aead_alg_instance(krb5enc);
@@ -291,7 +286,7 @@ static int krb5enc_dispatch_decrypt_hash(struct aead_request *req) 
	ahash_request_set_tfm(ahreq, auth);

	ahash_request_set_crypt(ahreq, req->dst, hash,

				req->assoclen + req->cryptlen - authsize);

	ahash_request_set_callback(ahreq, aead_request_flags(req),

	ahash_request_set_callback(ahreq, flags,

				   krb5enc_decrypt_hash_done, req);



	err = crypto_ahash_digest(ahreq);
@@ -301,6 +296,21 @@ static int krb5enc_dispatch_decrypt_hash(struct aead_request *req) 
	return krb5enc_verify_hash(req);

}



static void krb5enc_decrypt_done(void *data, int err)

{

	struct aead_request *req = data;



	if (err)

		goto out;



	err = krb5enc_dispatch_decrypt_hash(req, 0);

	if (err == -EINPROGRESS)

		return;



out:

	aead_request_complete(req, err);

}



/*

 * Dispatch the decryption of the ciphertext.

 */
@@ -324,7 +334,7 @@ static int krb5enc_dispatch_decrypt(struct aead_request *req) 


	skcipher_request_set_tfm(skreq, ctx->enc);

	skcipher_request_set_callback(skreq, aead_request_flags(req),

				      req->base.complete, req->base.data);

				      krb5enc_decrypt_done, req);

	skcipher_request_set_crypt(skreq, src, dst,

				   req->cryptlen - authsize, req->iv);
@@ -339,7 +349,7 @@ static int krb5enc_decrypt(struct aead_request *req) 
	if (err < 0)

		return err;



	return krb5enc_dispatch_decrypt_hash(req);

	return krb5enc_dispatch_decrypt_hash(req, aead_request_flags(req));

}



static int krb5enc_init_tfm(struct crypto_aead *tfm)