From f8d33fac84806eebd2ba31a3136066eeca19255f Mon Sep 17 00:00:00 2001 From: Eric Biggers Date: Wed, 3 Jan 2018 11:16:29 -0800 Subject: [PATCH] crypto: skcipher - prevent using skciphers without setting key Similar to what was done for the hash API, update the skcipher API to track whether each transform has been keyed, and reject encryption/decryption if a key is needed but one hasn't been set. This isn't as important as the equivalent fix for the hash API because symmetric ciphers almost always require a key (the "null cipher" is the only exception), so are unlikely to be used without one. Still, tracking the key will prevent accidental unkeyed use. algif_skcipher also had to track the key anyway, so the new flag replaces that and simplifies the algif_skcipher implementation. Signed-off-by: Eric Biggers Signed-off-by: Herbert Xu --- crypto/algif_skcipher.c | 59 +++++++++------------------------------ crypto/skcipher.c | 30 +++++++++++++++++--- include/crypto/skcipher.h | 11 ++++---- 3 files changed, 45 insertions(+), 55 deletions(-) diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c index c5c47b680152..c88e5e4cd6a6 100644 --- a/crypto/algif_skcipher.c +++ b/crypto/algif_skcipher.c @@ -38,11 +38,6 @@ #include #include -struct skcipher_tfm { - struct crypto_skcipher *skcipher; - bool has_key; -}; - static int skcipher_sendmsg(struct socket *sock, struct msghdr *msg, size_t size) { @@ -50,8 +45,7 @@ static int skcipher_sendmsg(struct socket *sock, struct msghdr *msg, struct alg_sock *ask = alg_sk(sk); struct sock *psk = ask->parent; struct alg_sock *pask = alg_sk(psk); - struct skcipher_tfm *skc = pask->private; - struct crypto_skcipher *tfm = skc->skcipher; + struct crypto_skcipher *tfm = pask->private; unsigned ivsize = crypto_skcipher_ivsize(tfm); return af_alg_sendmsg(sock, msg, size, ivsize); @@ -65,8 +59,7 @@ static int _skcipher_recvmsg(struct socket *sock, struct msghdr *msg, struct sock *psk = ask->parent; struct alg_sock *pask = alg_sk(psk); struct af_alg_ctx *ctx = ask->private; - struct skcipher_tfm *skc = pask->private; - struct crypto_skcipher *tfm = skc->skcipher; + struct crypto_skcipher *tfm = pask->private; unsigned int bs = crypto_skcipher_blocksize(tfm); struct af_alg_async_req *areq; int err = 0; @@ -221,7 +214,7 @@ static int skcipher_check_key(struct socket *sock) int err = 0; struct sock *psk; struct alg_sock *pask; - struct skcipher_tfm *tfm; + struct crypto_skcipher *tfm; struct sock *sk = sock->sk; struct alg_sock *ask = alg_sk(sk); @@ -235,7 +228,7 @@ static int skcipher_check_key(struct socket *sock) err = -ENOKEY; lock_sock_nested(psk, SINGLE_DEPTH_NESTING); - if (!tfm->has_key) + if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY) goto unlock; if (!pask->refcnt++) @@ -314,41 +307,17 @@ static struct proto_ops algif_skcipher_ops_nokey = { static void *skcipher_bind(const char *name, u32 type, u32 mask) { - struct skcipher_tfm *tfm; - struct crypto_skcipher *skcipher; - - tfm = kzalloc(sizeof(*tfm), GFP_KERNEL); - if (!tfm) - return ERR_PTR(-ENOMEM); - - skcipher = crypto_alloc_skcipher(name, type, mask); - if (IS_ERR(skcipher)) { - kfree(tfm); - return ERR_CAST(skcipher); - } - - tfm->skcipher = skcipher; - - return tfm; + return crypto_alloc_skcipher(name, type, mask); } static void skcipher_release(void *private) { - struct skcipher_tfm *tfm = private; - - crypto_free_skcipher(tfm->skcipher); - kfree(tfm); + crypto_free_skcipher(private); } static int skcipher_setkey(void *private, const u8 *key, unsigned int keylen) { - struct skcipher_tfm *tfm = private; - int err; - - err = crypto_skcipher_setkey(tfm->skcipher, key, keylen); - tfm->has_key = !err; - - return err; + return crypto_skcipher_setkey(private, key, keylen); } static void skcipher_sock_destruct(struct sock *sk) @@ -357,8 +326,7 @@ static void skcipher_sock_destruct(struct sock *sk) struct af_alg_ctx *ctx = ask->private; struct sock *psk = ask->parent; struct alg_sock *pask = alg_sk(psk); - struct skcipher_tfm *skc = pask->private; - struct crypto_skcipher *tfm = skc->skcipher; + struct crypto_skcipher *tfm = pask->private; af_alg_pull_tsgl(sk, ctx->used, NULL, 0); sock_kzfree_s(sk, ctx->iv, crypto_skcipher_ivsize(tfm)); @@ -370,22 +338,21 @@ static int skcipher_accept_parent_nokey(void *private, struct sock *sk) { struct af_alg_ctx *ctx; struct alg_sock *ask = alg_sk(sk); - struct skcipher_tfm *tfm = private; - struct crypto_skcipher *skcipher = tfm->skcipher; + struct crypto_skcipher *tfm = private; unsigned int len = sizeof(*ctx); ctx = sock_kmalloc(sk, len, GFP_KERNEL); if (!ctx) return -ENOMEM; - ctx->iv = sock_kmalloc(sk, crypto_skcipher_ivsize(skcipher), + ctx->iv = sock_kmalloc(sk, crypto_skcipher_ivsize(tfm), GFP_KERNEL); if (!ctx->iv) { sock_kfree_s(sk, ctx, len); return -ENOMEM; } - memset(ctx->iv, 0, crypto_skcipher_ivsize(skcipher)); + memset(ctx->iv, 0, crypto_skcipher_ivsize(tfm)); INIT_LIST_HEAD(&ctx->tsgl_list); ctx->len = len; @@ -405,9 +372,9 @@ static int skcipher_accept_parent_nokey(void *private, struct sock *sk) static int skcipher_accept_parent(void *private, struct sock *sk) { - struct skcipher_tfm *tfm = private; + struct crypto_skcipher *tfm = private; - if (!tfm->has_key && crypto_skcipher_has_setkey(tfm->skcipher)) + if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY) return -ENOKEY; return skcipher_accept_parent_nokey(private, sk); diff --git a/crypto/skcipher.c b/crypto/skcipher.c index 11af5fd6a443..0fe2a2923ad0 100644 --- a/crypto/skcipher.c +++ b/crypto/skcipher.c @@ -598,8 +598,11 @@ static int skcipher_setkey_blkcipher(struct crypto_skcipher *tfm, err = crypto_blkcipher_setkey(blkcipher, key, keylen); crypto_skcipher_set_flags(tfm, crypto_blkcipher_get_flags(blkcipher) & CRYPTO_TFM_RES_MASK); + if (err) + return err; - return err; + crypto_skcipher_clear_flags(tfm, CRYPTO_TFM_NEED_KEY); + return 0; } static int skcipher_crypt_blkcipher(struct skcipher_request *req, @@ -674,6 +677,9 @@ static int crypto_init_skcipher_ops_blkcipher(struct crypto_tfm *tfm) skcipher->ivsize = crypto_blkcipher_ivsize(blkcipher); skcipher->keysize = calg->cra_blkcipher.max_keysize; + if (skcipher->keysize) + crypto_skcipher_set_flags(skcipher, CRYPTO_TFM_NEED_KEY); + return 0; } @@ -692,8 +698,11 @@ static int skcipher_setkey_ablkcipher(struct crypto_skcipher *tfm, crypto_skcipher_set_flags(tfm, crypto_ablkcipher_get_flags(ablkcipher) & CRYPTO_TFM_RES_MASK); + if (err) + return err; - return err; + crypto_skcipher_clear_flags(tfm, CRYPTO_TFM_NEED_KEY); + return 0; } static int skcipher_crypt_ablkcipher(struct skcipher_request *req, @@ -767,6 +776,9 @@ static int crypto_init_skcipher_ops_ablkcipher(struct crypto_tfm *tfm) sizeof(struct ablkcipher_request); skcipher->keysize = calg->cra_ablkcipher.max_keysize; + if (skcipher->keysize) + crypto_skcipher_set_flags(skcipher, CRYPTO_TFM_NEED_KEY); + return 0; } @@ -796,6 +808,7 @@ static int skcipher_setkey(struct crypto_skcipher *tfm, const u8 *key, { struct skcipher_alg *cipher = crypto_skcipher_alg(tfm); unsigned long alignmask = crypto_skcipher_alignmask(tfm); + int err; if (keylen < cipher->min_keysize || keylen > cipher->max_keysize) { crypto_skcipher_set_flags(tfm, CRYPTO_TFM_RES_BAD_KEY_LEN); @@ -803,9 +816,15 @@ static int skcipher_setkey(struct crypto_skcipher *tfm, const u8 *key, } if ((unsigned long)key & alignmask) - return skcipher_setkey_unaligned(tfm, key, keylen); + err = skcipher_setkey_unaligned(tfm, key, keylen); + else + err = cipher->setkey(tfm, key, keylen); - return cipher->setkey(tfm, key, keylen); + if (err) + return err; + + crypto_skcipher_clear_flags(tfm, CRYPTO_TFM_NEED_KEY); + return 0; } static void crypto_skcipher_exit_tfm(struct crypto_tfm *tfm) @@ -834,6 +853,9 @@ static int crypto_skcipher_init_tfm(struct crypto_tfm *tfm) skcipher->ivsize = alg->ivsize; skcipher->keysize = alg->max_keysize; + if (skcipher->keysize) + crypto_skcipher_set_flags(skcipher, CRYPTO_TFM_NEED_KEY); + if (alg->exit) skcipher->base.exit = crypto_skcipher_exit_tfm; diff --git a/include/crypto/skcipher.h b/include/crypto/skcipher.h index 562001cb412b..2f327f090c3e 100644 --- a/include/crypto/skcipher.h +++ b/include/crypto/skcipher.h @@ -401,11 +401,6 @@ static inline int crypto_skcipher_setkey(struct crypto_skcipher *tfm, return tfm->setkey(tfm, key, keylen); } -static inline bool crypto_skcipher_has_setkey(struct crypto_skcipher *tfm) -{ - return tfm->keysize; -} - static inline unsigned int crypto_skcipher_default_keysize( struct crypto_skcipher *tfm) { @@ -442,6 +437,9 @@ static inline int crypto_skcipher_encrypt(struct skcipher_request *req) { struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); + if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY) + return -ENOKEY; + return tfm->encrypt(req); } @@ -460,6 +458,9 @@ static inline int crypto_skcipher_decrypt(struct skcipher_request *req) { struct crypto_skcipher *tfm = crypto_skcipher_reqtfm(req); + if (crypto_skcipher_get_flags(tfm) & CRYPTO_TFM_NEED_KEY) + return -ENOKEY; + return tfm->decrypt(req); }